Advancing MEMS Technology Usage through the MUMPS (Multi-User MEMS Processes) Program

NASA Technical Reports Server (NTRS)

Koester, D. A.; Markus, K. W.; Dhuler, V.; Mahadevan, R.; Cowen, A.

1995-01-01

In order to help provide access to advanced micro-electro-mechanical systems (MEMS) technologies and lower the barriers for both industry and academia, the Microelectronic Center of North Carolina (MCNC) and ARPA have developed a program which provides users with access to both MEMS processes and advanced electronic integration techniques. The four distinct aspects of this program, the multi-user MEMS processes (MUMP's), the consolidated micro-mechanical element library, smart MEMS, and the MEMS technology network are described in this paper. MUMP's is an ARPA-supported program created to provide inexpensive access to MEMS technology in a multi-user environment. It is both a proof-of-concept and educational tool that aids in the development of MEMS in the domestic community. MUMP's technologies currently include a 3-layer poly-silicon surface micromachining process and LIGA (lithography, electroforming, and injection molding) processes that provide reasonable design flexibility within set guidelines. The consolidated micromechanical element library (CaMEL) is a library of active and passive MEMS structures that can be downloaded by the MEMS community via the internet. Smart MEMS is the development of advanced electronics integration techniques for MEMS through the application of flip chip technology. The MEMS technology network (TechNet) is a menu of standard substrates and MEMS fabrication processes that can be purchased and combined to create unique process flows. TechNet provides the MEMS community greater flexibility and enhanced technology accessibility.

The conical conformal MEMS quasi-end-fire array antenna

NASA Astrophysics Data System (ADS)

Cong, Lin; Xu, Lixin; Li, Jianhua; Wang, Ting; Han, Qi

2017-03-01

The microelectromechanical system (MEMS) quasi-end-fire array antenna based on a liquid crystal polymer (LCP) substrate is designed and fabricated in this paper. The maximum radiation direction of the antenna tends to the cone axis forming an angle less than 90∘, which satisfies the proximity detection system applied at the forward target detection. Furthermore, the proposed antenna is fed at the ended side in order to save internal space. Moreover, the proposed antenna takes small covering area of the proximity detection system. The proposed antenna is fabricated by using the flexible MEMS process, and the measurement results agree well with the simulation results. This is the first time that a conical conformal array antenna is fabricated by the flexible MEMS process to realize the quasi-end-fire radiation. A pair of conformal MEMS array antennas resonates at 14.2 GHz with its mainlobes tending to the cone axis forming a 30∘ angle and a 31∘ angle separately, and the gains achieved are 1.82 dB in two directions, respectively. The proposed antenna meets the performance requirements for the proximity detection system which has vast application prospects.

Microelectromechanical resonator and method for fabrication

DOEpatents

Wittwer, Jonathan W [Albuquerque, NM; Olsson, Roy H [Albuquerque, NM

2009-11-10

A method is disclosed for the robust fabrication of a microelectromechanical (MEM) resonator. In this method, a pattern of holes is formed in the resonator mass with the position, size and number of holes in the pattern being optimized to minimize an uncertainty .DELTA.f in the resonant frequency f.sub.0 of the MEM resonator due to manufacturing process variations (e.g. edge bias). A number of different types of MEM resonators are disclosed which can be formed using this method, including capacitively transduced Lame, wineglass and extensional resonators, and piezoelectric length-extensional resonators.

Microelectromechanical resonator and method for fabrication

DOEpatents

Wittwer, Jonathan W [Albuquerque, NM; Olsson, Roy H [Albuquerque, NM

2010-01-26

A method is disclosed for the robust fabrication of a microelectromechanical (MEM) resonator. In this method, a pattern of holes is formed in the resonator mass with the position, size and number of holes in the pattern being optimized to minimize an uncertainty .DELTA.f in the resonant frequency f.sub.0 of the MEM resonator due to manufacturing process variations (e.g. edge bias). A number of different types of MEM resonators are disclosed which can be formed using this method, including capacitively transduced Lame, wineglass and extensional resonators, and piezoelectric length-extensional resonators.

Initial performance results for high-aspect ratio gold MEMS deformable mirrors

NASA Astrophysics Data System (ADS)

Fernández, Bautista; Kubby, Joel

2009-02-01

The fabrication and initial performance results of high-aspect ratio 3-dimensional Micro-Electro-Mechanical System (MEMS) Deformable Mirrors (DM) for Adaptive Optics (AO) will be discussed. The DM systems were fabricated out of gold, and consist of actuators bonded to a continuous face sheet, with different boundary conditions. DM mirror displacements vs. voltage have been measured with a white light interferometer and the corresponding results compared to Finite Element Analysis (FEA) simulations. Interferometer scans of a DM have shown that ~9.4um of stroke can be achieved with low voltage, thus showing that this fabrication process holds promise in the manufacturing of future MEMS DM's for the next generation of extremely large telescopes.

The MEMS process of a micro friction sensor

NASA Astrophysics Data System (ADS)

Yuan, Ming-Quan; Lei, Qiang; Wang, Xiong

2018-02-01

The research and testing techniques of friction sensor is an important support for hypersonic aircraft. Compared with the conventional skin friction sensor, the MEMS skin friction sensor has the advantages of small size, high sensitivity, good stability and dynamic response. The MEMS skin friction sensor can be integrated with other flow field sensors whose process is compatible with MEMS skin friction sensor to achieve multi-physical measurement of the flow field; and the micro-friction balance sensor array enable to achieve large area and accurate measurement for the near-wall flow. A MEMS skin friction sensor structure is proposed, which sensing element not directly contacted with the flow field. The MEMS fabrication process of the sensing element is described in detail. The thermal silicon oxide is used as the mask to solve the selection ratio problem of silicon DRIE. The optimized process parameters of silicon DRIE: etching power 1600W/LF power 100 W; SF6 flux 360 sccm; C4F8 flux 300 sccm; O2 flux 300 sccm. With Cr/Au mask, etch depth of glass shallow groove can be controlled in 30°C low concentration HF solution; the spray etch and wafer rotate improve the corrosion surface quality of glass shallow groove. The MEMS skin friction sensor samples were fabricated by the above MEMS process, and results show that the error of the length and width of the elastic cantilever is within 2 μm, the depth error of the shallow groove is less than 0.03 μm, and the static capacitance error is within 0.2 pF, which satisfy the design requirements.

Investigation of improved designs for rotational micromirrors using multiuser MEMS processes

NASA Astrophysics Data System (ADS)

Lin, Julianna E.; Michael, Feras S. J.; Kirk, Andrew G.

2001-04-01

In recent years, the design of rotational micromirrors for use in optical cross connects has received much attention. Although several companies have already produced and marketed a number of torsional mirror devices, more work is still needed to determine how these mirrors can be integrated into optical systems to form compact optical switches. However, recently several commercial MEMS foundry services have become available. Thus, due to the low cost of these prototyping services, new devices can be fabricated in short amounts of time and the designs adapted to meet the needs of different applications. The purpose of this work is to investigate the fabrication of new micromirror designs using the Multi-User MEMS Processes (MUMPs) foundry service available from Cronos Integrated Microsystems, located in North Carolina, USA). Several sets of mirror designs were submitted for fabrication and the resulting structures characterized using a phase-shifting Mirau interferometer. The results of these devices are presented.

Design and fabrication of MEMS devices using the integration of MUMPs, trench-refilled molding, DRIE and bulk silicon etching processes

NASA Astrophysics Data System (ADS)

Wu, Mingching; Fang, Weileun

2005-03-01

This work integrates multi-depth DRIE etching, trench-refilled molding, two poly-Si layers MUMPs and bulk releasing to improve the variety and performance of MEMS devices. In summary, the present fabrication process, named MOSBE II, has three merits. First, this process can monolithically fabricate and integrate poly-Si thin-film structures with different thicknesses and stiffnesses, such as the flexible spring and the stiff mirror plate. Second, multi-depth structures, such as vertical comb electrodes, are available from the DRIE processes. Third, a cavity under the micromachined device is provided by the bulk silicon etching process, so that a large out-of-plane motion is allowed. In application, an optical scanner driven by the self-aligned vertical comb actuator was demonstrated. The poly-Si micromachined components fabricated by MOSBE II can further integrate with the MUMPs devices to establish a more powerful MOEMS platform.

A flexible, gigahertz, and free-standing thin film piezoelectric MEMS resonator with high figure of merit

NASA Astrophysics Data System (ADS)

Jiang, Yuan; Zhang, Menglun; Duan, Xuexin; Zhang, Hao; Pang, Wei

2017-07-01

In this paper, a 2.6 GHz air-gap type thin film piezoelectric MEMS resonator was fabricated on a flexible polyethylene terephthalate film. A fabrication process combining transfer printing and hot-embossing was adopted to form a free-standing structure. The flexible radio frequency MEMS resonator possesses a quality factor of 946 and an effective coupling coefficient of 5.10%, and retains its high performance at a substrate bending radius of 1 cm. The achieved performance is comparable to that of conventional resonators on rigid silicon wafers. Our demonstration provides a viable approach to realizing universal MEMS devices on flexible polymer substrates, which is of great significance for building future fully integrated and multi-functional wireless flexible electronic systems.

Key Processes of Silicon-On-Glass MEMS Fabrication Technology for Gyroscope Application.

PubMed

Ma, Zhibo; Wang, Yinan; Shen, Qiang; Zhang, Han; Guo, Xuetao

2018-04-17

MEMS fabrication that is based on the silicon-on-glass (SOG) process requires many steps, including patterning, anodic bonding, deep reactive ion etching (DRIE), and chemical mechanical polishing (CMP). The effects of the process parameters of CMP and DRIE are investigated in this study. The process parameters of CMP, such as abrasive size, load pressure, and pH value of SF1 solution are examined to optimize the total thickness variation in the structure and the surface quality. The ratio of etching and passivation cycle time and the process pressure are also adjusted to achieve satisfactory performance during DRIE. The process is optimized to avoid neither the notching nor lag effects on the fabricated silicon structures. For demonstrating the capability of the modified CMP and DRIE processes, a z-axis micro gyroscope is fabricated that is based on the SOG process. Initial test results show that the average surface roughness of silicon is below 1.13 nm and the thickness of the silicon is measured to be 50 μm. All of the structures are well defined without the footing effect by the use of the modified DRIE process. The initial performance test results of the resonant frequency for the drive and sense modes are 4.048 and 4.076 kHz, respectively. The demands for this kind of SOG MEMS device can be fulfilled using the optimized process.

Electrothermally-Actuated Micromirrors with Bimorph Actuators--Bending-Type and Torsion-Type.

PubMed

Tsai, Cheng-Hua; Tsai, Chun-Wei; Chang, Hsu-Tang; Liu, Shih-Hsiang; Tsai, Jui-Che

2015-06-22

Three different electrothermally-actuated MEMS micromirrors with Cr/Au-Si bimorph actuators are proposed. The devices are fabricated with the SOIMUMPs process developed by MEMSCAP, Inc. (Durham, NC, USA). A silicon-on-insulator MEMS process has been employed for the fabrication of these micromirrors. Electrothermal actuation has achieved a large angular movement in the micromirrors. Application of an external electric current 0.04 A to the bending-type, restricted-torsion-type, and free-torsion-type mirrors achieved rotation angles of 1.69°, 3.28°, and 3.64°, respectively.

Novel technique for fabrication of multi-layered microcoils in microelectromechanical systems (MEMS) applications

NASA Astrophysics Data System (ADS)

Chang, Hung-Pin; Qian, Jiangyuan; Bachman, Mark; Congdon, Philip; Li, Guann-pyng

2002-07-01

A novel planarization technique, compressive molding planarization (CMP) is developed for implementation of a multi-layered micro coil device. Applying CMP and other micromachining techniques, a multi-layered micro coil device has been designed and fabricated, and its use in the magnetic micro actuators for hard disk drive applications has been demonstrated, showing that it can produce milli-Newton of magnetic force suitable for driving a micro actuator. The novel CMP technique can be equally applicable in other MEMS devices fabrication to ease the process integration for the complicated structure.

Ultrananocrystalline diamond films with optimized dielectric properties for advanced RF MEMS capacitive switches

DOEpatents

Sumant, Anirudha V.; Auciello, Orlando H.; Mancini, Derrick C.

2013-01-15

An efficient deposition process is provided for fabricating reliable RF MEMS capacitive switches with multilayer ultrananocrystalline (UNCD) films for more rapid recovery, charging and discharging that is effective for more than a billion cycles of operation. Significantly, the deposition process is compatible for integration with CMOS electronics and thereby can provide monolithically integrated RF MEMS capacitive switches for use with CMOS electronic devices, such as for insertion into phase array antennas for radars and other RF communication systems.

The Development of a Portable Hard Disk Encryption/Decryption System with a MEMS Coded Lock.

PubMed

Zhang, Weiping; Chen, Wenyuan; Tang, Jian; Xu, Peng; Li, Yibin; Li, Shengyong

2009-01-01

In this paper, a novel portable hard-disk encryption/decryption system with a MEMS coded lock is presented, which can authenticate the user and provide the key for the AES encryption/decryption module. The portable hard-disk encryption/decryption system is composed of the authentication module, the USB portable hard-disk interface card, the ATA protocol command decoder module, the data encryption/decryption module, the cipher key management module, the MEMS coded lock controlling circuit module, the MEMS coded lock and the hard disk. The ATA protocol circuit, the MEMS control circuit and AES encryption/decryption circuit are designed and realized by FPGA(Field Programmable Gate Array). The MEMS coded lock with two couplers and two groups of counter-meshing-gears (CMGs) are fabricated by a LIGA-like process and precision engineering method. The whole prototype was fabricated and tested. The test results show that the user's password could be correctly discriminated by the MEMS coded lock, and the AES encryption module could get the key from the MEMS coded lock. Moreover, the data in the hard-disk could be encrypted or decrypted, and the read-write speed of the dataflow could reach 17 MB/s in Ultra DMA mode.

Scalable fabrication of carbon-based MEMS/NEMS and their applications: a review

NASA Astrophysics Data System (ADS)

Jiang, Shulan; Shi, Tielin; Zhan, Xiaobin; Xi, Shuang; Long, Hu; Gong, Bo; Li, Junjie; Cheng, Siyi; Huang, Yuanyuan; Tang, Zirong

2015-11-01

The carbon-based micro/nano electromechanical system (MEMS/NEMS) technique provides a powerful approach to large-scale manufacture of high-aspect-ratio carbon structures for wafer-level processing. The fabricated three-dimensional (3D) carbon structures have the advantages of excellent electrical and electrochemical properties, and superior biocompatibility. In order to improve their performance for applications in micro energy storage devices and microsensors, an increase in the footprint surface area is of great importance. Various approaches have been proposed for fabricating large surface area carbon-based structures, including the integration of nanostructures such as carbon nanotubes (CNTs), graphene, nanowires, nanofilms and nanowrinkles onto 3D structures, which has been proved to be effective and productive. Moreover, by etching the 3D photoresist microstructures through oxygen plasma or modifying the photoresist with specific materials which can be etched in the following pyrolysis process, micro/nano hierarchical carbon structures have been fabricated. These improved structures show excellent performance in various applications, especially in the fields of biological sensors, surface-enhanced Raman scattering, and energy storage devices such as micro-supercapacitors and fuel cells. With the rapid development of microelectronic devices, the carbon-based MEMS/NEMS technique could make more aggressive moves into microelectronics, sensors, miniaturized power systems, etc. In this review, the recent advances in the fabrication of micro/nano hierarchical carbon-based structures are introduced and the technical challenges and future outlook of the carbon-based MEMS/NEMS techniques are also analyzed.

A large-scan-angle piezoelectric MEMS optical scanner actuated by a Nb-doped PZT thin film

NASA Astrophysics Data System (ADS)

Naono, Takayuki; Fujii, Takamichi; Esashi, Masayoshi; Tanaka, Shuji

2014-01-01

Resonant 1D microelectromechanical systems (MEMS) optical scanners actuated by piezoelectric unimorph actuators with a Nb-doped lead zirconate titanate (PNZT) thin film were developed for endoscopic optical coherence tomography (OCT) application. The MEMS scanners were designed as the resonance frequency was less than 125 Hz to obtain enough pixels per frame in OCT images. The device size was within 3.4 mm × 2.5 mm, which is compact enough to be installed in a side-imaging probe with 4 mm inner diameter. The fabrication process started with a silicon-on-insulator wafer, followed by PNZT deposition by the Rf sputtering and Si bulk micromachining process. The fabricated MEMS scanners showed maximum optical scan angles of 146° at 90 Hz, 148° at 124 Hz, 162° at 180 Hz, and 152° at 394 Hz at resonance in atmospheric pressure. Such wide scan angles were obtained by a drive voltage below 1.3 Vpp, ensuring intrinsic safety in in vivo uses. The scanner with the unpoled PNZT film showed three times as large a scan angle as that with a poled PZT films. A swept-source OCT system was constructed using the fabricated MEMS scanner, and cross-sectional images of a fingertip with image widths of 4.6 and 2.3 mm were acquired. In addition, a PNZT-based angle sensor was studied for feedback operation.

Integrated MEMS-based variable optical attenuator and 10Gb/s receiver

NASA Astrophysics Data System (ADS)

Aberson, James; Cusin, Pierre; Fettig, H.; Hickey, Ryan; Wylde, James

2005-03-01

MEMS devices can be successfully commercialized in favour of competing technologies only if they offer an advantage to the customer in terms of lower cost or increased functionality. There are limited markets where MEMS can be manufactured cheaper than similar technologies due to large volumes: automotive, printing technology, wireless communications, etc. However, success in the marketplace can also be realized by adding significant value to a system at minimal cost or leverging MEMS technology when other solutions simply will not work. This paper describes a thermally actuated, MEMS based, variable optical attenuator that is co-packaged with existing opto-electronic devices to develop an integrated 10Gb/s SONET/SDH receiver. The configuration of the receiver opto-electronics and relatively low voltage availability (12V max) in optical systems bar the use of LCD, EO, and electro-chromic style attenuators. The device was designed and fabricated using a silicon-on-insulator (SOI) starting material. The design and performance of the device (displacement, power consumption, reliability, physical geometry) was defined by the receiver parameters geometry. This paper will describe how these design parameters (hence final device geometry) were determined in light of both the MEMS device fabrication process and the receiver performance. Reference will be made to the design tools used and the design flow which was a joint effort between the MEMS vendor and the end customer. The SOI technology offered a robust, manufacturable solution that gave the required performance in a cost-effective process. However, the singulation of the devices required the development of a new singulation technique that allowed large volumes of silicon to be removed during fabrication yet still offer high singulation yields.

MEMS-based liquid lens for capsule endoscope

NASA Astrophysics Data System (ADS)

Seo, S. W.; Han, S.; Seo, J. H.; Kim, Y. M.; Kang, M. S.; Min, N. G.; Choi, W. B.; Sung, M. Y.

2008-03-01

The capsule endoscope, a new application area of digital imaging, is growing rapidly but needs the versatile imaging capabilities such as auto-focusing and zoom-in to be an active diagnostic tool. The liquid lens based on MEMS technology can be a strong candidate because it is able to be small enough. In this paper, a cylinder-type liquid lens was designed based on Young-Lippmann model and then fabricated with MEMS technology combining the silicon thin-film process and the wafer bonding process. The focal length of the lens module including the fabricated liquid lens was changed reproducibly as a function of the applied voltage. With the change of 30V in the applied bias, the focal length of the constructed lens module could be tuned in the range of about 42cm. The fabricated liquid lens was also proven to be small enough to be adopted in the capsule endoscope, which means the liquid lens can be utilized for the imaging capability improvement of the capsule endoscope.

MEMS-based thermally-actuated image stabilizer for cellular phone camera

NASA Astrophysics Data System (ADS)

Lin, Chun-Ying; Chiou, Jin-Chern

2012-11-01

This work develops an image stabilizer (IS) that is fabricated using micro-electro-mechanical system (MEMS) technology and is designed to counteract the vibrations when human using cellular phone cameras. The proposed IS has dimensions of 8.8 × 8.8 × 0.3 mm3 and is strong enough to suspend an image sensor. The processes that is utilized to fabricate the IS includes inductive coupled plasma (ICP) processes, reactive ion etching (RIE) processes and the flip-chip bonding method. The IS is designed to enable the electrical signals from the suspended image sensor to be successfully emitted out using signal output beams, and the maximum actuating distance of the stage exceeds 24.835 µm when the driving current is 155 mA. Depending on integration of MEMS device and designed controller, the proposed IS can decrease the hand tremor by 72.5%.

CMOS compatible fabrication process of MEMS resonator for timing reference and sensing application

NASA Astrophysics Data System (ADS)

Huynh, Duc H.; Nguyen, Phuong D.; Nguyen, Thanh C.; Skafidas, Stan; Evans, Robin

2015-12-01

Frequency reference and timing control devices are ubiquitous in electronic applications. There is at least one resonator required for each of this device. Currently electromechanical resonators such as crystal resonator, ceramic resonator are the ultimate choices. This tendency will probably keep going for many more years. However, current market demands for small size, low power consumption, cheap and reliable products, has divulged many limitations of this type of resonators. They cannot be integrated into standard CMOS (Complement metaloxide- semiconductor) IC (Integrated Circuit) due to material and fabrication process incompatibility. Currently, these devices are off-chip and they require external circuitries to interface with the ICs. This configuration significantly increases the overall size and cost of the entire electronic system. In addition, extra external connection, especially at high frequency, will potentially create negative impacts on the performance of the entire system due to signal degradation and parasitic effects. Furthermore, due to off-chip packaging nature, these devices are quite expensive, particularly for high frequency and high quality factor devices. To address these issues, researchers have been intensively studying on an alternative for type of resonator by utilizing the new emerging MEMS (Micro-electro-mechanical systems) technology. Recent progress in this field has demonstrated a MEMS resonator with resonant frequency of 2.97 GHz and quality factor (measured in vacuum) of 42900. Despite this great achievement, this prototype is still far from being fully integrated into CMOS system due to incompatibility in fabrication process and its high series motional impedance. On the other hand, fully integrated MEMS resonator had been demonstrated but at lower frequency and quality factor. We propose a design and fabrication process for a low cost, high frequency and a high quality MEMS resonator, which can be integrated into a standard CMOS IC. This device is expected to operate in hundreds of Mhz frequency range; quality factor surpasses 10000 and series motional impedance low enough that could be matching into conventional system without enormous effort. This MEMS resonator can be used in the design of many blocks in wireless and RF (Radio Frequency) systems such as low phase noise oscillator, band pass filter, power amplifier and in many sensing application.

MEMS/ECD Method for Making Bi(2-x)Sb(x)Te3 Thermoelectric Devices

NASA Technical Reports Server (NTRS)

Lim, James; Huang, Chen-Kuo; Ryan, Margaret; Snyder, G. Jeffrey; Herman, Jennifer; Fleurial, Jean-Pierre

2008-01-01

A method of fabricating Bi(2-x)Sb(x)Te3-based thermoelectric microdevices involves a combination of (1) techniques used previously in the fabrication of integrated circuits and of microelectromechanical systems (MEMS) and (2) a relatively inexpensive MEMS-oriented electrochemical-deposition (ECD) technique. The present method overcomes the limitations of prior MEMS fabrication techniques and makes it possible to satisfy requirements.

Selected papers from the 12th International Workshop on Micro and Nanotechnology for Power Generation and Energy Conversion Applications (PowerMEMS 2012) (Atlanta, GA, USA, 2-5 December 2012)

NASA Astrophysics Data System (ADS)

Allen, Mark G.; Lang, Jeffrey

2013-11-01

Welcome to this special section of the Journal of Micromechanics and Microengineering (JMM). This section, co-edited by myself and by Professor Jeffrey Lang of the Massachusetts Institute of Technology, contains expanded versions of selected papers presented at the Power MEMS meeting held in Atlanta, GA, USA, in December of 2012. Professor Lang and I had the privilege of co-chairing Power MEMS 2012, the 12th International Workshop on Micro and Nanotechnology for Power Generation and Energy Conversion Applications. The scope of the PowerMEMS series of workshops ranges from basic principles, to materials and fabrication, to devices and systems, to applications. The many applications of power MEMS (microelectromehcanical systems) range from MEMS-enabled energy harvesting, storage, conversion and conditioning, to integrated systems that manage these processes. Why is the power MEMS field growing in importance? Smaller-scale power and power supplies (microwatts to tens of watts) are gaining in prominence due to many factors, including the ubiquity of low power portable electronic equipment and the proliferation of wireless sensor nodes that require extraction of energy from their embedding environment in order to function. MEMS manufacturing methods can be utilized to improve the performance of traditional power supply elements, such as allowing batteries to charge faster or shrinking the physical size of passive elements in small-scale power supplies. MEMS technologies can be used to fabricate energy harvesters that extract energy from an embedding environment to power wireless sensor nodes, in-body medical implants and other devices, in which the harvesters are on the small scales that are appropriately matched to the overall size of these microsystems. MEMS can enable the manufacturing of energy storage elements from nontraditional materials by bringing appropriate structure and surface morphology to these materials as well as fabricating the electrical interfaces required for their operation and interconnection. Clearly, the marriage of MEMS technologies and energy conversion is a vital application space; and we are pleased to bring you some of the latest results from that space in this special section. Approximately 130 papers were presented at the Power MEMS 2012 conference. From these, the 20 papers you have before you were selected based on paper quality and topical balance. As you can see, papers representing many of the important areas of power MEMS are included: energy harvesters using multiple transduction schemes; MEMS-based fabrication of compact passive elements (inductors, supercapacitors, transformers); MEMS-enabled power diagnostics; MEMS-based batteries; and low power circuitry adapted to interfacing MEMS-based harvesters to overall systems. All of the papers you will read in this special section comprise substantial expansion from the proceedings articles and were reviewed through JMM's normal reviewing process. Both Professor Lang and I hope that you will share our enthusiasm for the field of power MEMS and that you will find this special section of JMM exciting, interesting and useful.  Sincerely,  Mark G Allen

Electrothermally-Actuated Micromirrors with Bimorph Actuators—Bending-Type and Torsion-Type

PubMed Central

Tsai, Cheng-Hua; Tsai, Chun-Wei; Chang, Hsu-Tang; Liu, Shih-Hsiang; Tsai, Jui-Che

2015-01-01

Three different electrothermally-actuated MEMS micromirrors with Cr/Au-Si bimorph actuators are proposed. The devices are fabricated with the SOIMUMPs process developed by MEMSCAP, Inc. (Durham, NC, USA). A silicon-on-insulator MEMS process has been employed for the fabrication of these micromirrors. Electrothermal actuation has achieved a large angular movement in the micromirrors. Application of an external electric current 0.04 A to the bending-type, restricted-torsion-type, and free-torsion-type mirrors achieved rotation angles of 1.69°, 3.28°, and 3.64°, respectively. PMID:26110409

Optimization Of PVDF-TrFE Processing Conditions For The Fabrication Of Organic MEMS Resonators

PubMed Central

Ducrot, Pierre-Henri; Dufour, Isabelle; Ayela, Cédric

2016-01-01

This paper reports a systematic optimization of processing conditions of PVDF-TrFE piezoelectric thin films, used as integrated transducers in organic MEMS resonators. Indeed, despite data on electromechanical properties of PVDF found in the literature, optimized processing conditions that lead to these properties remain only partially described. In this work, a rigorous optimization of parameters enabling state-of-the-art piezoelectric properties of PVDF-TrFE thin films has been performed via the evaluation of the actuation performance of MEMS resonators. Conditions such as annealing duration, poling field and poling duration have been optimized and repeatability of the process has been demonstrated. PMID:26792224

Optimization Of PVDF-TrFE Processing Conditions For The Fabrication Of Organic MEMS Resonators.

PubMed

Ducrot, Pierre-Henri; Dufour, Isabelle; Ayela, Cédric

2016-01-21

This paper reports a systematic optimization of processing conditions of PVDF-TrFE piezoelectric thin films, used as integrated transducers in organic MEMS resonators. Indeed, despite data on electromechanical properties of PVDF found in the literature, optimized processing conditions that lead to these properties remain only partially described. In this work, a rigorous optimization of parameters enabling state-of-the-art piezoelectric properties of PVDF-TrFE thin films has been performed via the evaluation of the actuation performance of MEMS resonators. Conditions such as annealing duration, poling field and poling duration have been optimized and repeatability of the process has been demonstrated.

Sandia Advanced MEMS Design Tools, Version 2.2.5

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yarberry, Victor; Allen, James; Lantz, Jeffery

2010-01-19

The Sandia National Laboratories Advanced MEMS Design Tools, Version 2.2.5, is a collection of menus, prototype drawings, and executables that provide significant productivity enhancements when using AutoCAD to design MEMS components. This release is designed for AutoCAD 2000i, 2002, or 2004 and is supported under Windows NT 4.0, Windows 2000, or XP. SUMMiT V (Sandia Ultra planar Multi level MEMS Technology) is a 5 level surface micromachine fabrication technology, which customers internal and external to Sandia can access to fabricate prototype MEMS devices. This CD contains an integrated set of electronic files that: a) Describe the SUMMiT V fabrication processmore » b) Facilitate the process of designing MEMS with the SUMMiT process (prototype file, Design Rule Checker, Standard Parts Library) New features in this version: AutoCAD 2004 support has been added. SafeExplode ? a new feature that explodes blocks without affecting polylines (avoids exploding polylines into objects that are ignored by the DRC and Visualization tools). Layer control menu ? a pull-down menu for selecting layers to isolate, freeze, or thaw. Updated tools: A check has been added to catch invalid block names. DRC features: Added username/password validation, added a method to update the user?s password. SNL_DRC_WIDTH ? a value to control the width of the DRC error lines. SNL_BIAS_VALUE ? a value use to offset selected geometry SNL_PROCESS_NAME ? a value to specify the process name Documentation changes: The documentation has been updated to include the new features. While there exist some files on the CD that are used in conjunction with software package AutoCAD, these files are not intended for use independent of the CD. Note that the customer must purchase his/her own copy of AutoCAD to use with these files.« less

Poly-SiGe MEMS actuators for adaptive optics

NASA Astrophysics Data System (ADS)

Lin, Blake C.; King, Tsu-Jae; Muller, Richard S.

2006-01-01

Many adaptive optics (AO) applications require mirror arrays with hundreds to thousands of segments, necessitating a CMOS-compatible MEMS process to integrate the mirrors with their driving electronics. This paper proposes a MEMS actuator that is fabricated using low-temperature polycrystalline silicon-germanium (poly-SiGe) surface-micromaching technology (total thermal budget is 6 hours at or below 425°C). The MEMS actuator consists of three flexures and a hexagonal platform, on which a micromirror is to be assembled. The flexures are made of single-layer poly-SiGe with stress gradient across thickness of the film, making them bend out-of-plane after sacrificial-layer release to create a large nominal gap. The platform, on the other hand, has an additional stress-balancing SiGe layer deposited on top, making the dual-layer stack stay flat after release. Using this process, we have successfully fabricated the MEMS actuator which is lifted 14.6 μm out-of-plane by 290-μm-long flexures. The 2-μm-thick hexagonal mirror-platform exhibits a strain gradient of -5.5×10 -5 μm -1 (equivalent to 18 mm radius-of-curvature), which would be further reduced once the micromirror is assembled.

Infrastructure for the design and fabrication of MEMS for RF/microwave and millimeter wave applications

NASA Astrophysics Data System (ADS)

Nerguizian, Vahe; Rafaf, Mustapha

2004-08-01

This article describes and provides valuable information for companies and universities with strategies to start fabricating MEMS for RF/Microwave and millimeter wave applications. The present work shows the infrastructure developed for RF/Microwave and millimeter wave MEMS platforms, which helps the identification, evaluation and selection of design tools and fabrication foundries taking into account packaging and testing. The selected and implemented simple infrastructure models, based on surface and bulk micromachining, yield inexpensive and innovative approaches for distributed choices of MEMS operating tools. With different educational or industrial institution needs, these models may be modified for specific resource changes using a careful analyzed iteration process. The inputs of the project are evaluation selection criteria and information sources such as financial, technical, availability, accessibility, simplicity, versatility and practical considerations. The outputs of the project are the selection of different MEMS design tools or software (solid modeling, electrostatic/electromagnetic and others, compatible with existing standard RF/Microwave design tools) and different MEMS manufacturing foundries. Typical RF/Microwave and millimeter wave MEMS solutions are introduced on the platform during the evaluation and development phases of the project for the validation of realistic results and operational decision making choices. The encountered challenges during the investigation and the development steps are identified and the dynamic behavior of the infrastructure is emphasized. The inputs (resources) and the outputs (demonstrated solutions) are presented in tables and flow chart mode diagrams.

The Development of a Portable Hard Disk Encryption/Decryption System with a MEMS Coded Lock

PubMed Central

Zhang, Weiping; Chen, Wenyuan; Tang, Jian; Xu, Peng; Li, Yibin; Li, Shengyong

2009-01-01

In this paper, a novel portable hard-disk encryption/decryption system with a MEMS coded lock is presented, which can authenticate the user and provide the key for the AES encryption/decryption module. The portable hard-disk encryption/decryption system is composed of the authentication module, the USB portable hard-disk interface card, the ATA protocol command decoder module, the data encryption/decryption module, the cipher key management module, the MEMS coded lock controlling circuit module, the MEMS coded lock and the hard disk. The ATA protocol circuit, the MEMS control circuit and AES encryption/decryption circuit are designed and realized by FPGA(Field Programmable Gate Array). The MEMS coded lock with two couplers and two groups of counter-meshing-gears (CMGs) are fabricated by a LIGA-like process and precision engineering method. The whole prototype was fabricated and tested. The test results show that the user's password could be correctly discriminated by the MEMS coded lock, and the AES encryption module could get the key from the MEMS coded lock. Moreover, the data in the hard-disk could be encrypted or decrypted, and the read-write speed of the dataflow could reach 17 MB/s in Ultra DMA mode. PMID:22291566

High volume fabrication of laser targets using MEMS techniques

NASA Astrophysics Data System (ADS)

Spindloe, C.; Arthur, G.; Hall, F.; Tomlinson, S.; Potter, R.; Kar, S.; Green, J.; Higginbotham, A.; Booth, N.; Tolley, M. K.

2016-04-01

The latest techniques for the fabrication of high power laser targets, using processes developed for the manufacture of Micro-Electro-Mechanical System (MEMS) devices are discussed. These laser targets are designed to meet the needs of the increased shot numbers that are available in the latest design of laser facilities. Traditionally laser targets have been fabricated using conventional machining or coarse etching processes and have been produced in quantities of 10s to low 100s. Such targets can be used for high complexity experiments such as Inertial Fusion Energy (IFE) studies and can have many complex components that need assembling and characterisation with high precision. Using the techniques that are common to MEMS devices and integrating these with an existing target fabrication capability we are able to manufacture and deliver targets to these systems. It also enables us to manufacture novel targets that have not been possible using other techniques. In addition, developments in the positioning systems that are required to deliver these targets to the laser focus are also required and a system to deliver the target to a focus of an F2 beam at 0.1Hz is discussed.

Tribo-functionalizing Si and SU8 materials by surface modification for application in MEMS/NEMS actuator-based devices

NASA Astrophysics Data System (ADS)

Singh, R. A.; Satyanarayana, N.; Kustandi, T. S.; Sinha, S. K.

2011-01-01

Micro/nano-electro-mechanical-systems (MEMS/NEMS) are miniaturized devices built at micro/nanoscales. At these scales, the surface/interfacial forces are extremely strong and they adversely affect the smooth operation and the useful operating lifetimes of such devices. When these forces manifest in severe forms, they lead to material removal and thereby reduce the wear durability of the devices. In this paper, we present a simple, yet robust, two-step surface modification method to significantly enhance the tribological performance of MEMS/NEMS materials. The two-step method involves oxygen plasma treatment of polymeric films and the application of a nanolubricant, namely perfluoropolyether. We apply the two-step method to the two most important MEMS/NEMS structural materials, namely silicon and SU8 polymer. On applying surface modification to these materials, their initial coefficient of friction reduces by ~4-7 times and the steady-state coefficient of friction reduces by ~2.5-3.5 times. Simultaneously, the wear durability of both the materials increases by >1000 times. The two-step method is time effective as each of the steps takes the time duration of approximately 1 min. It is also cost effective as the oxygen plasma treatment is a part of the MEMS/NEMS fabrication process. The two-step method can be readily and easily integrated into MEMS/NEMS fabrication processes. It is anticipated that this method will work for any kind of structural material from which MEMS/NEMS are or can be made.

MEMS piezoresistive cantilever for the direct measurement of cardiomyocyte contractile force

NASA Astrophysics Data System (ADS)

Matsudaira, Kenei; Nguyen, Thanh-Vinh; Hirayama Shoji, Kayoko; Tsukagoshi, Takuya; Takahata, Tomoyuki; Shimoyama, Isao

2017-10-01

This paper reports on a method to directly measure the contractile forces of cardiomyocytes using MEMS (micro electro mechanical systems)-based force sensors. The fabricated sensor chip consists of piezoresistive cantilevers that can measure contractile forces with high frequency (several tens of kHz) and high sensing resolution (less than 0.1 nN). Moreover, the proposed method does not require a complex observation system or image processing, which are necessary in conventional optical-based methods. This paper describes the design, fabrication, and evaluation of the proposed device and demonstrates the direct measurements of contractile forces of cardiomyocytes using the fabricated device.

Flexible MEMS: A novel technology to fabricate flexible sensors and electronics

NASA Astrophysics Data System (ADS)

Tu, Hongen

This dissertation presents the design and fabrication techniques used to fabricate flexible MEMS (Micro Electro Mechanical Systems) devices. MEMS devices and CMOS(Complementary Metal-Oxide-Semiconductor) circuits are traditionally fabricated on rigid substrates with inorganic semiconductor materials such as Silicon. However, it is highly desirable that functional elements like sensors, actuators or micro fluidic components to be fabricated on flexible substrates for a wide variety of applications. Due to the fact that flexible substrate is temperature sensitive, typically only low temperature materials, such as polymers, metals, and organic semiconductor materials, can be directly fabricated on flexible substrates. A novel technology based on XeF2(xenon difluoride) isotropic silicon etching and parylene conformal coating, which is able to monolithically incorporate high temperature materials and fluidic channels, was developed at Wayne State University. The technology was first implemented in the development of out-of-plane parylene microneedle arrays that can be individually addressed by integrated flexible micro-channels. These devices enable the delivery of chemicals with controlled temporal and spatial patterns and allow us to study neurotransmitter-based retinal prosthesis. The technology was further explored by adopting the conventional SOI-CMOS processes. High performance and high density CMOS circuits can be first fabricated on SOI wafers, and then be integrated into flexible substrates. Flexible p-channel MOSFETs (Metal-Oxide-Semiconductor Field-Effect-Transistors) were successfully integrated and tested. Integration of pressure sensors and flow sensors based on single crystal silicon has also been demonstrated. A novel smart yarn technology that enables the invisible integration of sensors and electronics into fabrics has been developed. The most significant advantage of this technology is its post-MEMS and post-CMOS compatibility. Various high-performance MEMS devices and electronics can be integrated into flexible substrates. The potential of our technology is enormous. Many wearable and implantable devices can be developed based on this technology.

Amorphous Diamond for MEMS

NASA Astrophysics Data System (ADS)

Sullivan, J. P.

2002-03-01

Pure carbon films can exhibit surprising complexity in structure and properties. Amorphous diamond (tetrahedrally-coordinated amorphous carbon) is an amorphous quasi-two phase mixture of four-fold and three-fold coordinated carbon which is produced by pulsed excimer laser deposition, an energetic deposition process that leads to film growth by sub-surface carbon implantation and the creation of local metastability in carbon bonding. Modest annealing, < 900K, produces significant irreversible strain relaxation which is thermally activated with activation energies ranging from < 1 eV to > 2 eV. During annealing the material remains amorphous, but there is a detectable increase in medium-range order as measured by fluctuation microscopy. The strain relaxation permits the residual strain in the films to be reduced to < 0.00001, which is a critical requirement for the fabrication of microelectromechanical systems (MEMS). Amorphous diamond MEMS have been fabricated in order to evaluate the mechanical properties of this material under tension and flexure, and this has enabled the determination of elastic modulus (800 GPa), tensile strength (8 GPa), and fracture toughness (8 MPa m^1/2). In addition, amorphous diamond MEMS structures have been fabricated to measure internal dissipation and surface adhesion. The high hardness and strength and hydrophobic nature of the surface makes this material particularly suitable for the fabrication of high wear resistance and low stiction MEMS. Sandia is a multiprogram laboratory operated by Sandia Corp., a Lockheed Martin Co., for the U.S. Dept. of Energy under contract DE-AC04-94AL85000.

Process for fabricating a microelectromechanical structure

DOEpatents

Sniegowski, Jeffry J.; Krygowski, Thomas W.; Mani, Seethambal S.; Habermehl, Scott D.; Hetherington, Dale L.; Stevens, James E.; Resnick, Paul J.; Volk, Steven R.

2004-10-26

A process is disclosed for forming a microelectromechanical (MEM) structure on a substrate having from 5 to 6 or more layers of deposited and patterned polysilicon. The process is based on determining a radius of curvature of the substrate which is bowed due to accumulated stress in the layers of polysilicon and a sacrificial material used to buildup the MEM structure, and then providing one or more stress-compensation layers on a backside of the substrate to flatten the substrate and allow further processing.

Dynamic MEMS devices for multi-axial fatigue and elastic modulus measurement

NASA Astrophysics Data System (ADS)

White, Carolyn D.; Xu, Rui; Sun, Xiaotian; Komvopoulos, Kyriakos

2003-01-01

For reliable MEMS device fabrication and operation, there is a continued demand for precise characterization of materials at the micron scale. This paper presents a novel material characterization device for fatigue lifetime testing. The fatigue specimen is subjected to multi-axial loading, which is typical of most MEMS devices. Polycrystalline silicon (polysilicon) fatigue devices were fabricated using the MUMPS process with a three layer mask process ground plane, anchor, and structural layer of polysilicon. A fatigue device consists of two or three beams, attached to a rotating ring and anchored to the substrate on each end. In order to generate a sufficiently large stress, the fatigue devices were tested in resonance to produce a von Mises equivalent stress as high as 1 GPa, which is in the fracture strength range reported for polysilicon. A further increase of the stress in the beam specimens was obtained by introducing a notch with a focused ion beam. The notch resulted into a stress concentration factor of about 3.8, thereby producing maximum von Mises equivalent stress in the range of 1 through 4 GPa. This study provides insight into multi-axial fatigue testing under typical MEMS conditions and additional information about micron-scale polysilicon mechanical behavior, which is the current basic building material for MEMS devices.

MEMSlab: A Practical MEMS Course for the Fabrication, Packaging, and Testing of a Single-Axis Accelerometer

ERIC Educational Resources Information Center

Grundbacher, R.; Hoetzel, J. E.; Hierold, C.

2009-01-01

A microelectro-mechanical systems (MEMS) laboratory course (MEMSlab) in the Mechanical and Process Engineering Department at the Swiss Federal Institute of Technology (ETH Zurich), is presented. The course has been taught for four years and has been attended primarily by Master's students from mechanical and electrical engineering; since fall…

Manufacturing process and material selection in concurrent collaborative design of MEMS devices

NASA Astrophysics Data System (ADS)

Zha, Xuan F.; Du, H.

2003-09-01

In this paper we present knowledge of an intensive approach and system for selecting suitable manufacturing processes and materials for microelectromechanical systems (MEMS) devices in concurrent collaborative design environment. In the paper, fundamental issues on MEMS manufacturing process and material selection such as concurrent design framework, manufacturing process and material hierarchies, and selection strategy are first addressed. Then, a fuzzy decision support scheme for a multi-criteria decision-making problem is proposed for estimating, ranking and selecting possible manufacturing processes, materials and their combinations. A Web-based prototype advisory system for the MEMS manufacturing process and material selection, WebMEMS-MASS, is developed based on the client-knowledge server architecture and framework to help the designer find good processes and materials for MEMS devices. The system, as one of the important parts of an advanced simulation and modeling tool for MEMS design, is a concept level process and material selection tool, which can be used as a standalone application or a Java applet via the Web. The running sessions of the system are inter-linked with webpages of tutorials and reference pages to explain the facets, fabrication processes and material choices, and calculations and reasoning in selection are performed using process capability and material property data from a remote Web-based database and interactive knowledge base that can be maintained and updated via the Internet. The use of the developed system including operation scenario, use support, and integration with an MEMS collaborative design system is presented. Finally, an illustration example is provided.

Method for fabricating five-level microelectromechanical structures and microelectromechanical transmission formed

DOEpatents

Rodgers, M. Steven; Sniegowski, Jeffry J.; Miller, Samuel L.; McWhorter, Paul J.

2000-01-01

A process for forming complex microelectromechanical (MEM) devices having five layers or levels of polysilicon, including four structural polysilicon layers wherein mechanical elements can be formed, and an underlying polysilicon layer forming a voltage reference plane. A particular type of MEM device that can be formed with the five-level polysilicon process is a MEM transmission for controlling or interlocking mechanical power transfer between an electrostatic motor and a self-assembling structure (e.g. a hinged pop-up mirror for use with an incident laser beam). The MEM transmission is based on an incomplete gear train and a bridging set of gears that can be moved into place to complete the gear train to enable power transfer. The MEM transmission has particular applications as a safety component for surety, and for this purpose can incorporate a pin-in-maze discriminator responsive to a coded input signal.

A polymer-based Fabry-Perot filter integrated with 3-D MEMS structures

NASA Astrophysics Data System (ADS)

Zhang, Ping (Cerina); Le, Kevin; Malalur-Nagaraja-Rao, Smitha; Hsu, Lun-Chen; Chiao, J.-C.

2006-01-01

Polymers have been considered as one of the most versatile materials in making optical devices for communication and sensor applications. They provide good optical transparency to form filters, lenses and many optical components with ease of fabrication. They are scalable and compatible in dimensions with requirements in optics and can be fabricated on inorganic substrates, such as silicon and quartz. Recent polymer synthesis also made great progresses on conductive and nonlinear polymers, opening opportunities for new applications. In this paper, we discussed hybrid-material integration of polymers on silicon-based microelectromechanical system (MEMS) devices. The motivation is to combine the advantages of demonstrated silicon-based MEMS actuators and excellent optical performance of polymers. We demonstrated the idea with a polymer-based out-of-plane Fabry-Perot filter that can be self-assembled by scratch drive actuators. We utilized a fabrication foundry service, MUMPS (Multi-User MEMS Process), to demonstrate the feasibility and flexibility of integration. The polysilicon, used as the structural material for construction of 3-D framework and actuators, has high absorption in the visible and near infrared ranges. Therefore, previous efforts using a polysilicon layer as optical interfaces suffer from high losses. We applied the organic compound materials on the silicon-based framework within the optical signal propagation path to form the optical interfaces. In this paper, we have shown low losses in the optical signal processing and feasibility of building a thin-film Fabry-Perot filter. We discussed the optical filter designs, mechanical design, actuation mechanism, fabrication issues, optical measurements, and results.

Investigation of improving MEMS-type VOA reliability

NASA Astrophysics Data System (ADS)

Hong, Seok K.; Lee, Yeong G.; Park, Moo Y.

2003-12-01

MEMS technologies have been applied to a lot of areas, such as optical communications, Gyroscopes and Bio-medical components and so on. In terms of the applications in the optical communication field, MEMS technologies are essential, especially, in multi dimensional optical switches and Variable Optical Attenuators(VOAs). This paper describes the process for the development of MEMS type VOAs with good optical performance and improved reliability. Generally, MEMS VOAs have been fabricated by silicon micro-machining process, precise fibre alignment and sophisticated packaging process. Because, it is composed of many structures with various materials, it is difficult to make devices reliable. We have developed MEMS type VOSs with many failure mode considerations (FMEA: Failure Mode Effect Analysis) in the initial design step, predicted critical failure factors and revised the design, and confirmed the reliability by preliminary test. These predicted failure factors were moisture, bonding strength of the wire, which wired between the MEMS chip and TO-CAN and instability of supplied signals. Statistical quality control tools (ANOVA, T-test and so on) were used to control these potential failure factors and produce optimum manufacturing conditions. To sum up, we have successfully developed reliable MEMS type VOAs with good optical performances by controlling potential failure factors and using statistical quality control tools. As a result, developed VOAs passed international reliability standards (Telcodia GR-1221-CORE).

Investigation of improving MEMS-type VOA reliability

NASA Astrophysics Data System (ADS)

Hong, Seok K.; Lee, Yeong G.; Park, Moo Y.

2004-01-01

MEMS technologies have been applied to a lot of areas, such as optical communications, Gyroscopes and Bio-medical components and so on. In terms of the applications in the optical communication field, MEMS technologies are essential, especially, in multi dimensional optical switches and Variable Optical Attenuators(VOAs). This paper describes the process for the development of MEMS type VOAs with good optical performance and improved reliability. Generally, MEMS VOAs have been fabricated by silicon micro-machining process, precise fibre alignment and sophisticated packaging process. Because, it is composed of many structures with various materials, it is difficult to make devices reliable. We have developed MEMS type VOSs with many failure mode considerations (FMEA: Failure Mode Effect Analysis) in the initial design step, predicted critical failure factors and revised the design, and confirmed the reliability by preliminary test. These predicted failure factors were moisture, bonding strength of the wire, which wired between the MEMS chip and TO-CAN and instability of supplied signals. Statistical quality control tools (ANOVA, T-test and so on) were used to control these potential failure factors and produce optimum manufacturing conditions. To sum up, we have successfully developed reliable MEMS type VOAs with good optical performances by controlling potential failure factors and using statistical quality control tools. As a result, developed VOAs passed international reliability standards (Telcodia GR-1221-CORE).

Integrated otpical monitoring of MEMS for closed-loop control

NASA Astrophysics Data System (ADS)

Dawson, Jeremy M.; Wang, Limin; McCormick, W. B.; Rittenhouse, S. A.; Famouri, Parviz F.; Hornak, Lawrence A.

2003-01-01

Robust control and failure assessment of MEMS employed in physically demanding, mission critical applications will allow for higher degrees of quality assurance in MEMS operation. Device fault detection and closed-loop control require detailed knowledge of the operational states of MEMS over the lifetime of the device, obtained by a means decoupled from the system. Preliminary through-wafer optical monitoring research efforts have shown that through-wafer optical probing is suitable for characterizing and monitoring the behavior of MEMS, and can be implemented in an integrated optical monitoring package for continuous in-situ device monitoring. This presentation will discuss research undertaken to establish integrated optical device metrology for closed-loop control of a MUMPS fabricated lateral harmonic oscillator. Successful linear closed-loop control results using a through-wafer optical microprobe position feedback signal will be presented. A theoretical optical output field intensity study of grating structures, fabricated on the shuttle of the resonator, was performed to improve the position resolution of the optical microprobe position signal. Through-wafer microprobe signals providing a positional resolution of 2 μm using grating structures will be shown, along with initial binary Fresnel diffractive optical microelement design layout, process development, and testing results. Progress in the design, fabrication, and test of integrated optical elements for multiple microprobe signal delivery and recovery will be discussed, as well as simulation of device system model parameter changes for failure assessment.

Monolithic integration of a MOSFET with a MEMS device

DOEpatents

Bennett, Reid; Draper, Bruce

2003-01-01

An integrated microelectromechanical system comprises at least one MOSFET interconnected to at least one MEMS device on a common substrate. A method for integrating the MOSFET with the MEMS device comprises fabricating the MOSFET and MEMS device monolithically on the common substrate. Conveniently, the gate insulator, gate electrode, and electrical contacts for the gate, source, and drain can be formed simultaneously with the MEMS device structure, thereby eliminating many process steps and materials. In particular, the gate electrode and electrical contacts of the MOSFET and the structural layers of the MEMS device can be doped polysilicon. Dopant diffusion from the electrical contacts is used to form the source and drain regions of the MOSFET. The thermal diffusion step for forming the source and drain of the MOSFET can comprise one or more of the thermal anneal steps to relieve stress in the structural layers of the MEMS device.

A flexible Li-ion battery with design towards electrodes electrical insulation

NASA Astrophysics Data System (ADS)

Vieira, E. M. F.; Ribeiro, J. F.; Sousa, R.; Correia, J. H.; Goncalves, L. M.

2016-08-01

The application of micro electromechanical systems (MEMS) technology in several consumer electronics leads to the development of micro/nano power sources with high power and MEMS integration possibility. This work presents the fabrication of a flexible solid-state Li-ion battery (LIB) (~2.1 μm thick) with a design towards electrodes electrical insulation, using conventional, low cost and compatible MEMS fabrication processes. Kapton® substrate provides flexibility to the battery. E-beam deposited 300 nm thick Ge anode was coupled with LiCoO2/LiPON (cathode/solid-state electrolyte) in a battery system. LiCoO2 and LiPON films were deposited by RF-sputtering with a power source of 120 W and 100 W, respectively. LiCoO2 film was annealed at 400 °C after deposition. The new design includes Si3N4 and LiPO thin-films, providing electrode electrical insulation and a battery chemical stability safeguard, respectively. Microstructure and battery performance were investigated by scanning electron microscopy, electric resistivity and electrochemical measurements (open circuit potential, charge/discharge cycles and electrochemical impedance spectroscopy). A rechargeable thin-film and lightweight flexible LIB using MEMS processing compatible materials and techniques is reported.

Design, modeling and simulation of MEMS-based silicon Microneedles

NASA Astrophysics Data System (ADS)

Amin, F.; Ahmed, S.

2013-06-01

The advancement in semiconductor process engineering and nano-scale fabrication technology has made it convenient to transport specific biological fluid into or out of human skin with minimum discomfort. Fluid transdermal delivery systems such as Microneedle arrays are one such emerging and exciting Micro-Electro Mechanical System (MEMS) application which could lead to a total painless fluid delivery into skin with controllability and desirable yield. In this study, we aimed to revisit the problem with modeling, design and simulations carried out for MEMS based silicon hollow out of plane microneedle arrays for biomedical applications particularly for transdermal drug delivery. An approximate 200 μm length of microneedle with 40 μm diameter of lumen has been successfully shown formed by isotropic and anisotropic etching techniques using MEMS Pro design tool. These microneedles are arranged in size of 2 × 4 matrix array with center to center spacing of 750 μm. Furthermore, comparisons for fluid flow characteristics through these microneedle channels have been modeled with and without the contribution of the gravitational forces using mathematical models derived from Bernoulli Equation. Physical Process simulations have also been performed on TCAD SILVACO to optimize the design of these microneedles aligned with the standard Si-Fabrication lines.

Meissner-levitated micro-systems

NASA Astrophysics Data System (ADS)

Coombs, T. A.; Samad, I.; Hong, Z.; Eves, D.; Rastogi, A.

2006-06-01

Advanced silicon processing techniques developed for the Very Large Scale Integration (VLSI) industry have been exploited in recent years to enable the production of micro-fabricated moving mechanical systems known as Micro Electro Mechanical Systems (MEMS). These devices offer advantages in terms of cost, scalability and robustness over their preceding equivalents. Cambridge University have worked for many years on the investigation of high temperature superconductors (HTS) in flywheel energy storage applications. This experience is now being used to research into superconducting Micro-Bearings for MEMS, whereby circular permanent magnet arrays are levitated and spun above a superconductor to produce bearings suitable for motors and other micron scale devices. The novelty in the device lies in the fact that the rotor is levitated into position by Meissner flux exclusion, whilst stability is provided by flux pinned within the body of the superconductor. This work includes: the investigation of the properties of various magnetic materials, their fabrication processes and their suitability for MEMS; finite element analysis to analyse the interaction between the magnetic materials and YBCO to determine the stiffness and height of levitation. Finally a micro-motor with the above principles is currently being fabricated within the group.

MEMS 3-DoF gyroscope design, modeling and simulation through equivalent circuit lumped parameter model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mian, Muhammad Umer, E-mail: umermian@gmail.com; Khir, M. H. Md.; Tang, T. B.

Pre-fabrication, behavioural and performance analysis with computer aided design (CAD) tools is a common and fabrication cost effective practice. In light of this we present a simulation methodology for a dual-mass oscillator based 3 Degree of Freedom (3-DoF) MEMS gyroscope. 3-DoF Gyroscope is modeled through lumped parameter models using equivalent circuit elements. These equivalent circuits consist of elementary components which are counterpart of their respective mechanical components, used to design and fabricate 3-DoF MEMS gyroscope. Complete designing of equivalent circuit model, mathematical modeling and simulation are being presented in this paper. Behaviors of the equivalent lumped models derived for themore » proposed device design are simulated in MEMSPRO T-SPICE software. Simulations are carried out with the design specifications following design rules of the MetalMUMPS fabrication process. Drive mass resonant frequencies simulated by this technique are 1.59 kHz and 2.05 kHz respectively, which are close to the resonant frequencies found by the analytical formulation of the gyroscope. The lumped equivalent circuit modeling technique proved to be a time efficient modeling technique for the analysis of complex MEMS devices like 3-DoF gyroscopes. The technique proves to be an alternative approach to the complex and time consuming couple field analysis Finite Element Analysis (FEA) previously used.« less

A low-cost CMOS-MEMS piezoresistive accelerometer with large proof mass.

PubMed

Khir, Mohd Haris Md; Qu, Peng; Qu, Hongwei

2011-01-01

This paper reports a low-cost, high-sensitivity CMOS-MEMS piezoresistive accelerometer with large proof mass. In the device fabricated using ON Semiconductor 0.5 μm CMOS technology, an inherent CMOS polysilicon thin film is utilized as the piezoresistive sensing material. A full Wheatstone bridge was constructed through easy wiring allowed by the three metal layers in the 0.5 μm CMOS technology. The device fabrication process consisted of a standard CMOS process for sensor configuration, and a deep reactive ion etching (DRIE) based post-CMOS microfabrication for MEMS structure release. A bulk single-crystal silicon (SCS) substrate is included in the proof mass to increase sensor sensitivity. In device design and analysis, the self heating of the polysilicon piezoresistors and its effect to the sensor performance is also discussed. With a low operating power of 1.5 mW, the accelerometer demonstrates a sensitivity of 0.077 mV/g prior to any amplification. Dynamic tests have been conducted with a high-end commercial calibrating accelerometer as reference.

Mechanical characterization of poly-SiGe layers for CMOS-MEMS integrated application

NASA Astrophysics Data System (ADS)

Modlinski, Robert; Witvrouw, Ann; Verbist, Agnes; Puers, Robert; De Wolf, Ingrid

2010-01-01

Measuring mechanical properties at the microscale is essential to understand and to fabricate reliable MEMS. In this paper a tensile testing system and matching microscale test samples are presented. The test samples have a dog-bone-like structure. They are designed to mimic standard macro-tensile test samples. The micro-tensile tests are used to characterize 0.9 µm thick polycrystalline silicon germanium (poly-SiGe) films. The poly-SiGe film, that can be considered as a close equivalent to polycrystalline silicon (poly-Si), is studied as a very promising material for use in CMOS/MEMS integration in a single chip due to its low-temperature LPCVD deposition (T < 450 °C). The fabrication process of the poly-SiGe micro-tensile test structure is explained in detail: the design, the processing and post-processing, the testing and finally the results' discussion. The poly-SiGe micro-tensile results are also compared with nanoindentation data obtained on the same poly-SiGe films as well as with results obtained by other research groups.

Modeling methods of MEMS micro-speaker with electrostatic working principle

NASA Astrophysics Data System (ADS)

Tumpold, D.; Kaltenbacher, M.; Glacer, C.; Nawaz, M.; Dehé, A.

2013-05-01

The market for mobile devices like tablets, laptops or mobile phones is increasing rapidly. Device housings get thinner and energy efficiency is more and more important. Micro-Electro-Mechanical-System (MEMS) loudspeakers, fabricated in complementary metal oxide semiconductor (CMOS) compatible technology merge energy efficient driving technology with cost economical fabrication processes. In most cases, the fabrication of such devices within the design process is a lengthy and costly task. Therefore, the need for computer modeling tools capable of precisely simulating the multi-field interactions is increasing. The accurate modeling of such MEMS devices results in a system of coupled partial differential equations (PDEs) describing the interaction between the electric, mechanical and acoustic field. For the efficient and accurate solution we apply the Finite Element (FE) method. Thereby, we fully take the nonlinear effects into account: electrostatic force, charged moving body (loaded membrane) in an electric field, geometric nonlinearities and mechanical contact during the snap-in case between loaded membrane and stator. To efficiently handle the coupling between the mechanical and acoustic fields, we apply Mortar FE techniques, which allow different grid sizes along the coupling interface. Furthermore, we present a recently developed PML (Perfectly Matched Layer) technique, which allows limiting the acoustic computational domain even in the near field without getting spurious reflections. For computations towards the acoustic far field we us a Kirchhoff Helmholtz integral (e.g, to compute the directivity pattern). We will present simulations of a MEMS speaker system based on a single sided driving mechanism as well as an outlook on MEMS speakers using double stator systems (pull-pull-system), and discuss their efficiency (SPL) and quality (THD) towards the generated acoustic sound.

Formaldehyde gas sensor based on TiO2 thin membrane integrated with nano silicon structure

NASA Astrophysics Data System (ADS)

Zheng, Xuan; Ming, An-jie; Ye, Li; Chen, Feng-hua; Sun, Xi-long; Liu, Wei-bing; Li, Chao-bo; Ou, Wen; Wang, Wei-bing; Chen, Da-peng

2016-07-01

An innovative formaldehyde gas sensor based on thin membrane type metal oxide of TiO2 layer was designed and fabricated. This sensor under ultraviolet (UV) light emitting diode (LED) illumination exhibits a higher response to formaldehyde than that without UV illumination at low temperature. The sensitivities of the sensor under steady working condition were calculated for different gas concentrations. The sensitivity to formaldehyde of 7.14 mg/m3 is about 15.91 under UV illumination with response time of 580 s and recovery time of 500 s. The device was fabricated through micro-electro-mechanical system (MEMS) processing technology. First, plasma immersion ion implantation (PIII) was adopted to form black polysilicon, then a nanoscale TiO2 membrane with thickness of 53 nm was deposited by DC reactive magnetron sputtering to obtain the sensing layer. By such fabrication approaches, the nanoscale polysilicon presents continuous rough surface with thickness of 50 nm, which could improve the porosity of the sensing membrane. The fabrication process can be mass-produced for the MEMS process compatibility.

Microelectromechanical systems (MEMS) sensors based on lead zirconate titanate (PZT) films

NASA Astrophysics Data System (ADS)

Wang, Li-Peng

2001-12-01

In this thesis, modeling, fabrication and testing of microelectromechanical systems (MEMS) accelerometers based on piezoelectric lead zirconate titanate (PZT) films are investigated. Three different types of structures, cantilever beam, trampoline, and annular diaphragm, are studied. It demonstrates the high-performance, miniaturate, mass-production-compatible, and potentially circuitry-integratable piezoelectric-type PZT MEMS devices. Theoretical models of the cantilever-beam and trampoline accelerometers are derived via structural dynamics and the constitutive equations of piezoelectricity. The time-dependent transverse vibration equations, mode shapes, resonant frequencies, and sensitivities of the accelerometers are calculated through the models. Optimization of the silicon and PZT thickness is achieved with considering the effects of the structural dynamics, the material properties, and manufacturability for different accelerometer specifications. This work is the first demonstration of the fabrication of bulk-micromachined accelerometers combining a deep-trench reactive ion etching (DRIE) release strategy and thick piezoelectric PZT films deposited using a sol-gel method. Processing challenges which are overcome included materials compatibility, metallization, processing of thick layers, double-side processing, deep-trench silicon etching, post-etch cleaning and process integration. In addition, the processed PZT films are characterized by dielectric, ferroelectric (polarization electric-field hysteresis), and piezoelectric measurements and no adverse effects are found. Dynamic frequency response and impedance resonance measurements are performed to ascertain the performance of the MEMS accelerometers. The results show high sensitivities and broad frequency ranges of the piezoelectric-type PZT MEMS accelerometers; the sensitivities range from 0.1 to 7.6 pC/g for resonant frequencies ranging from 44.3 kHz to 3.7 kHz. The sensitivities were compared to theoretical values and a reasonable agreement (˜36% difference) is obtained.

Fabrication of Microhotplates Based on Laser Micromachining of Zirconium Oxide

NASA Astrophysics Data System (ADS)

Oblov, Konstantin; Ivanova, Anastasia; Soloviev, Sergey; Samotaev, Nikolay; Lipilin, Alexandr; Vasiliev, Alexey; Sokolov, Andrey

We present a novel approach to the fabrication of MEMS devices, which can be used for gas sensors operating in harsh environment in wireless and autonomous information systems. MEMS platforms based on ZrO2/Y2O3 (YSZ) are applied in these devices. The methods of ceramic MEMS devices fabrication with laser micromachining are considered. It is shown that the application of YSZ membranes permits a decrease in MEMS power consumption at 4500C down to ∼75 mW at continuous heating and down to ∼ 1 mW at pulse heating mode. The application of the platforms is not restricted by gas sensors: they can be used for fast thermometers, bolometric matrices, flowmeteres and other MEMS devices working under harsh environmental conditions.

DMD: a digital light processing application to projection displays

NASA Astrophysics Data System (ADS)

Feather, Gary A.

1989-01-01

Summary Revolutionary technologies achieve rapid product and subsequent business diffusion only when the in- ventors focus on technology application, maturation, and proliferation. A revolutionary technology is emerg- ing with micro-electromechanical systems (MEMS). MEMS are being developed by leveraging mature semi- conductor processing coupled with mechanical systems into complete, integrated, useful systems. The digital micromirror device (DMD), a Texas Instruments invented MEMS, has focused on its application to projec- tion displays. The DMD has demonstrated its application as a digital light processor, processing and produc- ing compelling computer and video projection displays. This tutorial discusses requirements in the projection display market and the potential solutions offered by this digital light processing system. The seminar in- cludes an evaluation of the market, system needs, design, fabrication, application, and performance results of a system using digital light processing solutions.

Through-wafer interrogation of microstructure motion for MEMS feedback control

NASA Astrophysics Data System (ADS)

Dawson, Jeremy M.; Chen, Jingdong; Brown, Kolin S.; Famouri, Parviz F.; Hornak, Lawrence A.

1999-09-01

Closed-loop MEMS control enables mechanical microsystems to adapt to the demands of the environment which they are actuating opening a new window of opportunity for future MEMS applications. Planar diffractive optical microsystems have the potential to enable the integrated optical interrogation of MEMS microstructure position fully decoupled from the means of mechanical actuation which is central to realization of feedback control. This paper presents the results of initial research evaluating through-wafer optical microsystems for MEMS integrated optical monitoring. Positional monitoring results obtained from a 1.3 micrometer wavelength through- wafer free-space optical probe of a lateral comb resonator fabricated using the Multi-User MEMS Process Service (MUMPS) are presented. Given the availability of positional information via probe signal feedback, a simulation of the application of nonlinear sliding control is presented illustrating position control of the lateral comb resonator structure.

Disc resonator gyroscope fabrication process requiring no bonding alignment

NASA Technical Reports Server (NTRS)

Shcheglov, Kirill V. (Inventor)

2010-01-01

A method of fabricating a resonant vibratory sensor, such as a disc resonator gyro. A silicon baseplate wafer for a disc resonator gyro is provided with one or more locating marks. The disc resonator gyro is fabricated by bonding a blank resonator wafer, such as an SOI wafer, to the fabricated baseplate, and fabricating the resonator structure according to a pattern based at least in part upon the location of the at least one locating mark of the fabricated baseplate. MEMS-based processing is used for the fabrication processing. In some embodiments, the locating mark is visualized using optical and/or infrared viewing methods. A disc resonator gyroscope manufactured according to these methods is described.

Large-aperture MOEMS Fabry-Perot interferometer for miniaturized spectral imagers

NASA Astrophysics Data System (ADS)

Rissanen, Anna; Langner, Andreas; Viherkanto, Kai; Mannila, Rami

2015-02-01

VTT's optical MEMS Fabry-Perot interferometers (FPIs) are tunable optical filters, which enable miniaturization of spectral imagers into small, mass producible hand-held sensors with versatile optical measurement capabilities. FPI technology has also created a basis for various hyperspectral imaging instruments, ranging from nanosatellites, environmental sensing and precision agriculture with UAVs to instruments for skin cancer detection. Until now, these application demonstrations have been mostly realized with piezo-actuated FPIs fabricated by non-monolithical assembly method, suitable for achieving very large optical apertures and with capacity to small-to-medium volumes; however large-volume production of MEMS manufacturing supports the potential for emerging spectral imaging applications also in large-volume applications, such as in consumer/mobile products. Previously reported optical apertures of MEMS FPIs in the visible range have been up to 2 mm in size; this paper presents the design, successful fabrication and characterization of MEMS FPIs for central wavelengths of λ = 500 nm and λ = 650 nm with optical apertures up to 4 mm in diameter. The mirror membranes of the FPI structures consist of ALD (atomic layer deposited) TiO2-Al2O3 λ/4- thin film Bragg reflectors, with the air gap formed by sacrificial polymer etching in O2 plasma. The entire fabrication process is conducted below 150 °C, which makes it possible to monolithically integrate the filter structures on other ICdevices such as detectors. The realized MEMS devices are aimed for nanosatellite space application as breadboard hyperspectral imager demonstrators.

Nanoionics-Based Switches for Radio-Frequency Applications

NASA Technical Reports Server (NTRS)

Nessel, James; Lee, Richard

2010-01-01

Nanoionics-based devices have shown promise as alternatives to microelectromechanical systems (MEMS) and semiconductor diode devices for switching radio-frequency (RF) signals in diverse systems. Examples of systems that utilize RF switches include phase shifters for electronically steerable phased-array antennas, multiplexers, cellular telephones and other radio transceivers, and other portable electronic devices. Semiconductor diode switches can operate at low potentials (about 1 to 3 V) and high speeds (switching times of the order of nanoseconds) but are characterized by significant insertion loss, high DC power consumption, low isolation, and generation of third-order harmonics and intermodulation distortion (IMD). MEMS-based switches feature low insertion loss (of the order of 0.2 dB), low DC power consumption (picowatts), high isolation (>30 dB), and low IMD, but contain moving parts, are not highly reliable, and must be operated at high actuation potentials (20 to 60 V) generated and applied by use of complex circuitry. In addition, fabrication of MEMS is complex, involving many processing steps. Nanoionics-based switches offer the superior RF performance and low power consumption of MEMS switches, without need for the high potentials and complex circuitry necessary for operation of MEMS switches. At the same time, nanoionics-based switches offer the high switching speed of semiconductor devices. Also, like semiconductor devices, nanoionics-based switches can be fabricated relatively inexpensively by use of conventional integrated-circuit fabrication techniques. More over, nanoionics-based switches have simple planar structures that can easily be integrated into RF power-distribution circuits.

Stress Analysis of SiC MEMS Using Raman Spectroscopy

NASA Astrophysics Data System (ADS)

Ness, Stanley J.; Marciniak, M. A.; Lott, J. A.; Starman, L. A.; Busbee, J. D.; Melzak, J. M.

2003-03-01

During the fabrication of Micro-Electro-Mechanical Systems (MEMS), residual stress is often induced in the thin films that are deposited to create these systems. These stresses can cause the device to fail due to buckling, curling, or fracture. Industry is looking for ways to characterize the stress during the deposition of thin films in order to reduce or eliminate device failure. Micro-Raman spectroscopy has been successfully used to characterize poly-Si MEMS devices made with the MUMPS® process. Raman spectroscopy was selected because it is nondestructive, fast and has the potential for in situ stress monitoring. This research attempts to use Raman spectroscopy to analyze the stress in SiC MEMS made with the MUSiC® process. Raman spectroscopy is performed on 1-2-micron-thick SiC thin films deposited on silicon, silicon nitride, and silicon oxide substrates. The most common poly-type of SiC found in thin film MEMS made with the MUSiC® process is 3C-SiC. Research also includes baseline spectra of 6H, 4H, and 15R poly-types of bulk SiC.

MEMS for Tunable Photonic Metamaterial Applications

NASA Astrophysics Data System (ADS)

Stark, Thomas

Photonic metamaterials are materials whose optical properties are derived from artificially-structured sub-wavelength unit cells, rather than from the bulk properties of the constituent materials. Examples of metamaterials include plasmonic materials, negative index materials, and electromagnetic cloaks. While advances in simulation tools and nanofabrication methods have allowed this field to grow over the past several decades, many challenges still exist. This thesis addresses two of these challenges: fabrication of photonic metamaterials with tunable responses and high-throughput nanofabrication methods for these materials. The design, fabrication, and optical characterization of a microelectromechanical systems (MEMS) tunable plasmonic spectrometer are presented. An array of holes in a gold film, with plasmon resonance in the mid-infrared, is suspended above a gold reflector, forming a Fabry-Perot interferometer of tunable length. The spectra exhibit the convolution of extraordinary optical transmission through the holes and Fabry-Perot resonances. Using MEMS, the interferometer length is modulated from 1.7 mum to 21.67 mum , thereby tuning the free spectral range from about 2900 wavenumbers to 230.7 wavenumbers and shifting the reflection minima and maxima across the infrared. Due to its broad spectral tunability in the fingerprint region of the mid-infrared, this device shows promise as a tunable biological sensing device. To address the issue of high-throughput, high-resolution fabrication of optical metamaterials, atomic calligraphy, a MEMS-based dynamic stencil lithography technique for resist-free fabrication of photonic metamaterials on unconventional substrates, has been developed. The MEMS consists of a moveable stencil, which can be actuated with nanometer precision using electrostatic comb drive actuators. A fabrication method and flip chip method have been developed, enabling evaporation of metals through the device handle for fabrication on an external substrate. While the MEMS can be used to fabricate over areas of approximately 100 square mum2, a piezoelectric step-and repeat system enables fabrication over cm length scales. Thus, this technique leverages the precision inherent to MEMS actuation, while enhancing nanofabrication thoughput. Fabricating metamaterials on new substrates will enable novel and tunable metamaterials. For example, by fabricating unit cells on a periodic auxetic mechanical scaffold, the optical properties can be tuned by straining the mechanical scaffold.

Microelectromechanical Systems for Aerodynamics Applications

NASA Technical Reports Server (NTRS)

Mehregany, Mehran; DeAnna, Russell G.; Reshotko, Eli

1996-01-01

Microelectromechanical systems (MEMS) embody the integration of sensors, actuators, and electronics on a single substrate using integrated circuit fabrication techniques and compatible micromachining processes. Silicon and its derivatives form the material base for the MEMS technology. MEMS devices, including micro-sensors and micro-actuators, are attractive because they can be made small (characteristic dimension about microns), be produced in large numbers with uniform performance, include electronics for high performance and sophisticated functionality, and be inexpensive. MEMS pressure sensors, wall-shear-stress sensors, and micromachined hot-wires are nearing application in aeronautics. MEMS actuators face a tougher challenge since they have to be scaled (up) to the physical phenomena that are being controlled. MEMS actuators are proposed, for example, for controlling the small structures in a turbulent boundary layer, for aircraft control, for cooling, and for mixing enhancement. Data acquisition or control logistics require integration of electronics along with the transducer elements with appropriate consideration of analog-to-digital conversion, multiplexing, and telemetry. Altogether, MEMS technology offers exciting opportunities for aerodynamics applications both in wind tunnels and in flight

Thermal Hysteresis of MEMS Packaged Capacitive Pressure Sensor (CPS) Based 3C-SiC

NASA Astrophysics Data System (ADS)

Marsi, N.; Majlis, B. Y.; Mohd-Yasin, F.; Hamzah, A. A.; Mohd Rus, A. Z.

2016-11-01

Presented herein are the effects of thermal hysteresis analyses of the MEMS packaged capacitive pressure sensor (CPS). The MEMS CPS was employed on Si-on-3C-SiC wafer that was performed using the hot wall low-pressure chemical vapour deposition (LPCVD) reactors at the Queensland Micro and Nanotechnology Center (QMNC), Griffith University and fabricated using the bulk-micromachining process. The MEMS CPS was operated at an extreme temperature up to 500°C and high external pressure at 5.0 MPa. The thermal hysteresis phenomenon that causes the deflection, strain and stress on the 3C-SiC diaphragm spontaneously influence the MEMS CPS performances. The differences of temperature, hysteresis, and repeatability test were presented to demonstrate the functionality of the MEMS packaged CPS. As expected, the output hysteresis has a low hysteresis (less than 0.05%) which has the hardness greater than the traditional silicon. By utilizing this low hysteresis, it was revealed that the MEMS packaged CPS has high repeatability and stability of the sensor.

Evolution from MEMS-based Linear Drives to Bio-based Nano Drives

NASA Astrophysics Data System (ADS)

Fujita, Hiroyuki

The successful extension of semiconductor technology to fabricate mechanical parts of the sizes from 10 to 100 micrometers opened wide ranges of possibilities for micromechanical devices and systems. The fabrication technique is called micromachining. Micromachining processes are based on silicon integrated circuits (IC) technology and used to build three-dimensional structures and movable parts by the combination of lithography, etching, film deposition, and wafer bonding. Microactuators are the key devices allowing MEMS to perform physical functions. Some of them are driven by electric, magnetic, and fluidic forces. Some others utilize actuator materials including piezoelectric (PZT, ZnO, quartz) and magnetostrictive materials (TbFe), shape memory alloy (TiNi) and bio molecular motors. This paper deals with the development of MEMS based microactuators, especially linear drives, following my own research experience. They include an electrostatic actuator, a superconductive levitated actuator, arrayed actuators, and a bio-motor-driven actuator.

Patterning of nanocrystalline diamond films for diamond microstructures useful in MEMS and other devices

DOEpatents

Gruen, Dieter M [Downers Grove, IL; Busmann, Hans-Gerd [Bremen, DE; Meyer, Eva-Maria [Bremen, DE; Auciello, Orlando [Bolingbrook, IL; Krauss, Alan R [late of Naperville, IL; Krauss, Julie R [Naperville, IL

2004-11-02

MEMS structure and a method of fabricating them from ultrananocrystalline diamond films having average grain sizes of less than about 10 nm and feature resolution of less than about one micron . The MEMS structures are made by contacting carbon dimer species with an oxide substrate forming a carbide layer on the surface onto which ultrananocrystalline diamond having average grain sizes of less than about 10 nm is deposited. Thereafter, microfabrication process are used to form a structure of predetermined shape having a feature resolution of less than about one micron.

Ultra-thin alumina and silicon nitride MEMS fabricated membranes for the electron multiplication

NASA Astrophysics Data System (ADS)

Prodanović, V.; Chan, H. W.; Graaf, H. V. D.; Sarro, P. M.

2018-04-01

In this paper we demonstrate the fabrication of large arrays of ultrathin freestanding membranes (tynodes) for application in a timed photon counter (TiPC), a novel photomultiplier for single electron detection. Low pressure chemical vapour deposited silicon nitride (Si x N y ) and atomic layer deposited alumina (Al2O3) with thicknesses down to only 5 nm are employed for the membrane fabrication. Detailed characterization of structural, mechanical and chemical properties of the utilized films is carried out for different process conditions and thicknesses. Furthermore, the performance of the tynodes is investigated in terms of secondary electron emission, a fundamental attribute that determines their applicability in TiPC. Studied features and presented fabrication methods may be of interest for other MEMS application of alumina and silicon nitride as well, in particular where strong ultra-thin membranes are required.

A microelectromechanical accelerometer fabricated using printed circuit processing techniques

NASA Astrophysics Data System (ADS)

Rogers, J. E.; Ramadoss, R.; Ozmun, P. M.; Dean, R. N.

2008-01-01

A microelectromechanical systems (MEMS) capacitive-type accelerometer fabricated using printed circuit processing techniques is presented. A Kapton polymide film is used as the structural layer for fabricating the MEMS accelerometer. The accelerometer proof mass along with four suspension beams is defined in the Kapton polyimide film. The proof mass is suspended above a Teflon substrate using a spacer. The deflection of the proof mass is detected using a pair of capacitive sensing electrodes. The top electrode of the accelerometer is defined on the top surface of the Kapton film. The bottom electrode is defined in the metallization on the Teflon substrate. The initial gap height is determined by the distance between the bottom electrode and the Kapton film. For an applied external acceleration (normal to the proof mass), the proof mass deflects toward or away from the fixed bottom electrode due to inertial force. This deflection causes either a decrease or increase in the air-gap height thereby either increasing or decreasing the capacitance between the top and the bottom electrodes. An example PCB MEMS accelerometer with a square proof mass of membrane area 6.4 mm × 6.4 mm is reported. The measured resonant frequency is 375 Hz and the Q-factor in air is 0.52.

Deep anisotropic ICP plasma etching designed for high-volume MEMS manufacturing

NASA Astrophysics Data System (ADS)

Yu, Keven; Feldbaum, Michael; Pandhumsoporn, Tam; Gadgil, Prashant

1999-08-01

ICP plasma etching is gaining widespread acceptance as an enabling micromachining technology for advanced MEMS fabrication. Whereas this technology has shown a capability of delivering multiple novel applications for R and D, its acceptance by industry for high volume production has been limited. This acceptance into production will only occur when the plasma etching equipment with this technology offers the device performance, throughput, reliability, and uptime criteria required by a production facility. The design of the plasma etcher using this technology and the process capability it consequently delivers, has significant implications in making this a reality. Alcatel has been supplying such a technology to this MEMS industry for over 5 years and in the interim has evolved its product and process to make this technology production worthy. Alcatel's next generation etcher, the Alcatel 601E, offers multiple advantages to MEMS manufacturers in realizing their production goals.

Microelectromechanical Systems and Nephrology: The Next Frontier in Renal Replacement Technology

PubMed Central

Kim, Steven; Roy, Shuvo

2013-01-01

Microelectromechanical systems (MEMS) is playing a prominent role in the development of many new and innovative biomedical devices, but remains a relatively underutilized technology in nephrology. The future landscape of clinical medicine and research will only see further expansion of MEMS based technologies in device designs and applications. The enthusiasm stems from the ability to create small-scale device features with high precision in a cost effective manner. MEMS also offers the possibility to integrate multiple components into a single device. The adoption of MEMS has the potential to revolutionize how nephrologists manage kidney disease by improving the delivery of renal replacement therapies and enhancing the monitoring of physiologic parameters. To introduce nephrologists to MEMS, this review will first define relevant terms and describe the basic processes used to fabricate MEMS devices. Next, a survey of MEMS devices being developed for various biomedical applications will be illustrated with current examples. Finally, MEMS technology specific to nephrology will be highlighted and future applications will be examined. The adoption of MEMS offers novel avenues to improve the care of kidney disease patients and assist nephrologists in clinical practice. This review will serve as an introduction for nephrologists to the exciting world of MEMS. PMID:24206604

Pick-and-place process for sensitivity improvement of the capacitive type CMOS MEMS 2-axis tilt sensor

NASA Astrophysics Data System (ADS)

Chang, Chun-I.; Tsai, Ming-Han; Liu, Yu-Chia; Sun, Chih-Ming; Fang, Weileun

2013-09-01

This study exploits the foundry available complimentary metal-oxide-semiconductor (CMOS) process and the packaging house available pick-and-place technology to implement a capacitive type micromachined 2-axis tilt sensor. The suspended micro mechanical structures such as the spring, stage and sensing electrodes are fabricated using the CMOS microelectromechanical systems (MEMS) processes. A bulk block is assembled onto the suspended stage by pick-and-place technology to increase the proof-mass of the tilt sensor. The low temperature UV-glue dispensing and curing processes are employed to bond the block onto the stage. Thus, the sensitivity of the CMOS MEMS capacitive type 2-axis tilt sensor is significantly improved. In application, this study successfully demonstrates the bonding of a bulk solder ball of 100 µm in diameter with a 2-axis tilt sensor fabricated using the standard TSMC 0.35 µm 2P4M CMOS process. Measurements show the sensitivities of the 2-axis tilt sensor are increased for 2.06-fold (x-axis) and 1.78-fold (y-axis) after adding the solder ball. Note that the sensitivity can be further improved by reducing the parasitic capacitance and the mismatch of sensing electrodes caused by the solder ball.

FOREWORD: Focus on Novel Nanoelectromechanical 3D Structures: Fabrication and Properties Focus on Novel Nanoelectromechanical 3D Structures: Fabrication and Properties

NASA Astrophysics Data System (ADS)

Yamada, Shooji; Yamaguchi, Hiroshi; Ishihara, Sunao

2009-06-01

Microelectromechanical systems (MEMS) are widely used small electromechanical systems made of micrometre-sized components. Presently, we are witnessing a transition from MEMS to nanoelectromechanical systems (NEMS), which comprise devices integrating electrical and mechanical functionality on the nanoscale and offer new exciting applications. Similarly to MEMS, NEMS typically include a central transistor-like nanoelectronic unit for data processing, as well as mechanical actuators, pumps, and motors; and they may combine with physical, biological and chemical sensors. In the transition from MEMS to NEMS, component sizes need to be reduced. Therefore, many fabrication methods previously developed for MEMS are unsuitable for the production of high-precision NEMS components. The key challenge in NEMS is therefore the development of new methods for routine and reproducible nanofabrication. Two complementary types of method for NEMS fabrication are available: 'top-down' and 'bottom-up'. The top-down approach uses traditional lithography technologies, whereas bottom-up techniques include molecular self-organization, self-assembly and nanodeposition. The NT2008 conference, held at Ishikawa High-Tech Conference Center, Ishikawa, Japan, between 23-25 October 2008, focused on novel NEMS fabricated from new materials and on process technologies. The topics included compound semiconductors, small mechanical structures, nanostructures for micro-fluid and bio-sensors, bio-hybrid micro-machines, as well as their design and simulation. This focus issue compiles seven articles selected from 13 submitted manuscripts. The articles by Prinz et al and Kehrbusch et al introduce the frontiers of the top-down production of various operational NEMS devices, and Kometani et al present an example of the bottom-up approach, namely ion-beam induced deposition of MEMS and NEMS. The remaining articles report novel technologies for biological sensors. Taira et al have used manganese nanoparticles to improve the chemical analysis of biological samples by laser desorption/ionization mass spectrometry. Matsumoto et al have prepared sugar microarrays via click chemistry and have applied this to the detection and characterization of proteins. Yoshimura et al have expanded the single-nucleotide polymorphism typing method to differentiate genes from various food crops, such as indica and japonica rice. Finally, Takashi et al have designed a nanoparticle-based strip sensor, which can be used for rapid evaluation of the psychological condition of animals and humans. We hope that this focus issue will help readers to understand, from a materials science viewpoint, different aspects of frontier research into NEMS.

Method for fabricating a microelectromechanical resonator

DOEpatents

Wojciechowski, Kenneth E; Olsson, III, Roy H

2013-02-05

A method is disclosed which calculates dimensions for a MEM resonator in terms of integer multiples of a grid width G for reticles used to fabricate the resonator, including an actual sub-width L.sub.a=NG and an effective electrode width W.sub.e=MG where N and M are integers which minimize a frequency error f.sub.e=f.sub.d-f.sub.a between a desired resonant frequency f.sub.d and an actual resonant frequency f.sub.a. The method can also be used to calculate an overall width W.sub.o for the MEM resonator, and an effective electrode length L.sub.e which provides a desired motional impedance for the MEM resonator. The MEM resonator can then be fabricated using these values for L.sub.a, W.sub.e, W.sub.o and L.sub.e. The method can also be applied to a number j of MEM resonators formed on a common substrate.

Emerging leadership of surface micromachined MEMS for wavelength switching in telecommunications systems

NASA Astrophysics Data System (ADS)

Staple, Bevan D.; Muller, Lilac; Miller, David C.

2003-01-01

We introduce the Network Photonics" CrossWave as the first commercially-available, MEMS-based wavelength selective switch. The CrossWave combines the functionality of signal de-multiplexing, switching and re-multiplexing in a single all-optical operation using a dispersive element and 1-D MEMS. 1-D MEMS, where micromirrors are configured in a single array with a single mirror per wavelength, are fabricated in a standard surface micromachining process. In this paper we present three generations of micromirror designs. With proper design optimization and process improvements we have demonstrated exceptional mirror flatness (<16.2m-1 curvature), surface error (

Micro-Electro-Mechanical Systems (MEMS) Fabrication Course Projects Review for FY15

DTIC Science & Technology

2015-09-01

TECHNICAL DOCUMENT 3298 September 2015 Micro-Electro-Mechanical Systems (MEMS) Fabrication Course Projects Review for FY15 Paul D. Swanson...Naval Warfare Systems Center Pacific (SSC Pacific), San Diego, CA. SSC Pacific’s Naval Innovative Science and Engineering (NISE) Program provided...for Miniaturized Flow Cytometer o Howard Dyckman: 71730 Infrared Waveguides o Teresa Emery: 55360 Bistable MEMS systems for Energy

A Low-Cost CMOS-MEMS Piezoresistive Accelerometer with Large Proof Mass

PubMed Central

Khir, Mohd Haris Md; Qu, Peng; Qu, Hongwei

2011-01-01

This paper reports a low-cost, high-sensitivity CMOS-MEMS piezoresistive accelerometer with large proof mass. In the device fabricated using ON Semiconductor 0.5 μm CMOS technology, an inherent CMOS polysilicon thin film is utilized as the piezoresistive sensing material. A full Wheatstone bridge was constructed through easy wiring allowed by the three metal layers in the 0.5 μm CMOS technology. The device fabrication process consisted of a standard CMOS process for sensor configuration, and a deep reactive ion etching (DRIE) based post-CMOS microfabrication for MEMS structure release. A bulk single-crystal silicon (SCS) substrate is included in the proof mass to increase sensor sensitivity. In device design and analysis, the self heating of the polysilicon piezoresistors and its effect to the sensor performance is also discussed. With a low operating power of 1.5 mW, the accelerometer demonstrates a sensitivity of 0.077 mV/g prior to any amplification. Dynamic tests have been conducted with a high-end commercial calibrating accelerometer as reference. PMID:22164052

Meso scale MEMS inertial switch fabricated using an electroplated metal-on-insulator process

NASA Astrophysics Data System (ADS)

Gerson, Y.; Schreiber, D.; Grau, H.; Krylov, S.

2014-02-01

In this work, we report on a novel simple yet robust two-mask metal-on-insulator (MOI) process and illustrate its implementation for the fabrication of a meso scale MEMS inertial switch. The devices were fabricated of a ˜40 µm thick layer of nickel electrodeposited on top of a 4 µm thick thermal field oxide (TOX) covering a single crystal silicon wafer. A 40 µm thick layer of KMPR® resist was used as a mold and allowed the formation of high-aspect-ratio (1:5) metal structures. The devices were released by the sacrificial etching of the TOX layer in hydrofluoric acid. The fabricated devices were mounted in a ceramic enclosure and were characterized using both an electromagnet shaker and a drop tester. The functionality of the switch, aimed to trigger an electrical circuit when subjected to an acceleration pulse with amplitude of 300 g and duration of 200 µs, was demonstrated experimentally and the performance targets were achieved. The experimental results were consistent with the model predictions obtained through finite element simulations.

Stylus type MEMS texture sensor covered with corrugated diaphragm

NASA Astrophysics Data System (ADS)

Tsukamoto, Takashiro; Asao, Hideaki; Tanaka, Shuji

2017-09-01

In this paper, a stylus type MEMS texture sensor covered with a corrugated palylene diaphragm, which prevent debris from jamming into the sensor without significant degradation of sensitivity and bandwidth, was reported. A new fabrication process using a lost-foil method to make the corrugated diaphragm on a 3-axis piezoresistive force sensor at wafer level has been developed. The texture sensor could detect the surface microstructure as small as about 10 \

Fabrication of MEMS components using ultrafine-grained aluminium alloys

NASA Astrophysics Data System (ADS)

Qiao, Xiao Guang; Gao, Nong; Moktadir, Zakaria; Kraft, Michael; Starink, Marco J.

2010-04-01

A novel process for the fabrication of a microelectromechanical systems (MEMS) metallic component with features smaller than 10 µm and high thermal conductivity was investigated. This may be applied to new or improved microscale components, such as (micro-) heat exchangers. In the first stage of processing, equal channel angular pressing (ECAP) was employed to refine the grain size of commercial purity aluminium (Al-1050) to the ultrafine-grained (UFG) material. Embossing was conducted using a micro silicon mould fabricated by deep reactive ion etching (DRIE). Both cold embossing and hot embossing were performed on the coarse-grained and UFG Al-1050. Cold embossing on UFG Al-1050 led to a partially transferred pattern from the micro silicon mould and high failure rate of the mould. Hot embossing on UFG Al-1050 provided a smooth embossed surface with a fully transferred pattern and a low failure rate of the mould, while hot embossing on the coarse-grained Al-1050 resulted in a rougher surface with shear bands.

Microelectromechanical systems(MEMS): Launching Research Concepts into the Marketplace

NASA Astrophysics Data System (ADS)

Arney, Susanne

1999-04-01

More than a decade following the demonstration of the first spinning micromotors and microgears, the field of microelectromechanical systems (MEMS) has burgeoned on a worldwide basis. Integrated circuit design, fabrication, and packaging techniques have provided the foundation for the growth of an increasingly mature MEMS infrastructure which spans numerous topics of research as well as industrial application. The remarkable proliferation of MEMS concepts into such contrasting arenas of application as automotive sensors, biology, optical and wireless telecommunications, displays, printing, and physics experiments will be described. Challenges to commercialization of research prototypes will be discussed with emphasis on the development of design, fabrication, packaging, reliability and standards which fundamentally enable the application of MEMS to a highly diversified marketplace.

Respiration detection chip with integrated temperature-insensitive MEMS sensors and CMOS signal processing circuits.

PubMed

Wei, Chia-Ling; Lin, Yu-Chen; Chen, Tse-An; Lin, Ren-Yi; Liu, Tin-Hao

2015-02-01

An airflow sensing chip, which integrates MEMS sensors with their CMOS signal processing circuits into a single chip, is proposed for respiration detection. Three micro-cantilever-based airflow sensors were designed and fabricated using a 0.35 μm CMOS/MEMS 2P4M mixed-signal polycide process. Two main differences were present among these three designs: they were either metal-covered or metal-free structures, and had either bridge-type or fixed-type reference resistors. The performances of these sensors were measured and compared, including temperature sensitivity and airflow sensitivity. Based on the measured results, the metal-free structure with fixed-type reference resistors is recommended for use, because it has the highest airflow sensitivity and also can effectively reduce the output voltage drift caused by temperature change.

Nanotwinned metal MEMS films with unprecedented strength and stability

PubMed Central

Sim, Gi-Dong; Krogstad, Jessica A.; Reddy, K. Madhav; Xie, Kelvin Y.; Valentino, Gianna M.; Weihs, Timothy P.; Hemker, Kevin J.

2017-01-01

Silicon-based microelectromechanical systems (MEMS) sensors have become ubiquitous in consumer-based products, but realization of an interconnected network of MEMS devices that allows components to be remotely monitored and controlled, a concept often described as the “Internet of Things,” will require a suite of MEMS materials and properties that are not currently available. We report on the synthesis of metallic nickel-molybdenum-tungsten films with direct current sputter deposition, which results in fully dense crystallographically textured films that are filled with nanotwins. These films exhibit linear elastic mechanical behavior and tensile strengths exceeding 3 GPa, which is unprecedented for materials that are compatible with wafer-level device fabrication processes. The ultrahigh strength is attributed to a combination of solid solution strengthening and the presence of dense nanotwins. These films also have excellent thermal and mechanical stability, high density, and electrical properties that are attractive for next-generation metal MEMS applications. PMID:28782015

A MEMS AlN transducer array with flexible interconnections for use as a cochlear implant

NASA Astrophysics Data System (ADS)

Knisely, Katherine; Zhao, Chuming; Grosh, Karl

2015-12-01

A completely implantable artificial organ of Corti (CIAO) was fabricated using batch MEMS processing techniques. A silicon backbone supports five piezoelectric cantilevers, each of which is designed to have an in vivo resonance corresponding to its tonotopic location in the guinea pig ST (20-40 kHz). An attachable polymer ribbon cable extends 4cm from the probe to an electrode bay, where electrical connections to each cantilever are accessed. The actuation responses of the fabricated devices were measured using laser vibrometry confirming the fluid-loaded resonance conforming to the straight section of the first turn of the guinea pig cochlea. First generation devices have been fabricated and the actuated resonances were measured to range from 80.3-134.2kHz in air and 24.3-41.0 kHz in water.

Laser-assisted advanced assembly for MEMS fabrication

NASA Astrophysics Data System (ADS)

Atanasov, Yuriy Andreev

Micro Electro-Mechanical Systems (MEMS) are currently fabricated using methods originally designed for manufacturing semiconductor devices, using minimum if any assembly at all. The inherited limitations of this approach narrow the materials that can be employed and reduce the design complexity, imposing limitations on MEMS functionality. The proposed Laser-Assisted Advanced Assembly (LA3) method solves these problems by first fabricating components followed by assembly of a MEMS device. Components are micro-machined using a laser or by photolithography followed by wet/dry etching out of any material available in a thin sheet form. A wide range of materials can be utilized, including biocompatible metals, ceramics, polymers, composites, semiconductors, and materials with special properties such as memory shape alloys, thermoelectric, ferromagnetic, piezoelectric, and more. The approach proposed allows enhancing the structural and mechanical properties of the starting materials through heat treatment, tribological coatings, surface modifications, bio-functionalization, and more, a limited, even unavailable possibility with existing methods. Components are transferred to the substrate for assembly using the thermo-mechanical Selective Laser Assisted Die Transfer (tmSLADT) mechanism for microchips assembly, already demonstrated by our team. Therefore, the mechanical and electronic part of the MEMS can be fabricated using the same equipment/method. The viability of the Laser-Assisted Advanced Assembly technique for MEMS is demonstrated by fabricating magnetic switches for embedding in a conductive carbon-fiber metamaterial for use in an Electromagnetic-Responsive Mobile Cyber-Physical System (E-RMCPS), which is expected to improve the wireless communication system efficiency within a battery-powered device.

ProTEK PSB as Biotechnology Photosensitive Protection Mask on 3C-SiC-on-Si in MEMS Sensor

NASA Astrophysics Data System (ADS)

Marsi, N.; Majlis, B. Y.; Mohd-Yasin, F.; Hamzah, A. A.; Mohd Rus, A. Z.

2016-11-01

This project presents the fabrication of MEMS employing a cubic silicon carbide (3C- SiC) on silicon wafer using newly developed ProTEK PSB as biotechnology photosensitive protection mask. This new biotechnology can reduce the number of processes and simplify the process flow with minimal impact on overall undercut performance. The 680 pm thick wafer is back-etched, leaving the 3C-SiC thin film with a thickness of 1.0 μm as the flexible diaphragm to detect pressure. The effect of the new coating of ProTEK PSB on different KOH solvents were investigated depending on various factors such as development time, final cure temperature and the thickness of the ProTEK PSB deposited layer. It is found that 6.174 μm thickness of ProTEK PSB offers some possibility of reducing the processing time compared to silicon nitride etch masks in KOH (55%wt, 80°C). The new ProTEK PSB biotechnology photosensitive protection mask indicates good stability and sustains its performance in different treatments under KOH and IPA for 8 hours. This work also revealed that the fabrication of MEMS sensors using the new biotechnology photosensitive protection mask provides a simple assembly approach and reduces manufacturing costs. The MEMS sensor can operate up to 500 °C as indicated under the sensitivity of 0.826 pF/MPa with nonlinearity and hysteresis of 0.61% and 3.13%, respectively.

The iMoD display: considerations and challenges in fabricating MOEMS on large area glass substrates

NASA Astrophysics Data System (ADS)

Chui, Clarence; Floyd, Philip D.; Heald, David; Arbuckle, Brian; Lewis, Alan; Kothari, Manish; Cummings, Bill; Palmateer, Lauren; Bos, Jan; Chang, Daniel; Chiang, Jedi; Wang, Li-Ming; Pao, Edmon; Su, Fritz; Huang, Vincent; Lin, Wen-Jian; Tang, Wen-Chung; Yeh, Jia-Jiun; Chan, Chen-Chun; Shu, Fang-Ann; Ju, Yuh-Diing

2007-01-01

QUALCOMM has developed and transferred to manufacturing iMoD displays, a MEMS-based reflective display technology. The iMoD array architecture allows for development at wafer scale, yet easily scales up to enable fabrication on flat-panel display (FPD) lines. In this paper, we will describe the device operation, process flow and fabrication, technology transfer issues, and display performance.

MEMS: A new approach to micro-optics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sniegowski, J.J.

1997-12-31

MicroElectroMechanical Systems (MEMS) and their fabrication technologies provide great opportunities for application to micro-optical systems (MOEMS). Implementing MOEMS technology ranges from simple, passive components to complicated, active systems. Here, an overview of polysilicon surface micromachining MEMS combined with optics is presented. Recent advancements to the technology, which may enhance its appeal for micro-optics applications are emphasized. Of all the MEMS fabrication technologies, polysilicon surface micromachining technology has the greatest basis in and leverages the most the infrastructure for silicon integrated circuit fabrication. In that respect, it provides the potential for very large volume, inexpensive production of MOEMS. This paper highlightsmore » polysilicon surface micromachining technology in regards to its capability to provide both passive and active mechanical elements with quality optical elements.« less

Surface micromachined MEMS deformable mirror based on hexagonal parallel-plate electrostatic actuator

NASA Astrophysics Data System (ADS)

Ma, Wenying; Ma, Changwei; Wang, Weimin

2018-03-01

Deformable mirrors (DM) based on microelectromechanical system (MEMS) technology are being applied in adaptive optics (AO) system for astronomical telescopes and human eyes more and more. In this paper a MEMS DM with hexagonal actuator is proposed and designed. The relationship between structural design and performance parameters, mainly actuator coupling, is analyzed carefully and calculated. The optimum value of actuator coupling is obtained. A 7-element DM prototype is fabricated using a commercial available standard three-layer polysilicon surface multi-user-MEMS-processes (PolyMUMPs). Some key performances, including surface figure and voltage-displacement curve, are measured through a 3D white light profiler. The measured performances are very consistent with the theoretical values. The proposed DM will benefit the miniaturization of AO systems and lower their cost.

Evolving MEMS Resonator Designs for Fabrication

NASA Technical Reports Server (NTRS)

Hornby, Gregory S.; Kraus, William F.; Lohn, Jason D.

2008-01-01

Because of their small size and high reliability, microelectromechanical (MEMS) devices have the potential to revolution many areas of engineering. As with conventionally-sized engineering design, there is likely to be a demand for the automated design of MEMS devices. This paper describes our current status as we progress toward our ultimate goal of using an evolutionary algorithm and a generative representation to produce designs of a MEMS device and successfully demonstrate its transfer to an actual chip. To produce designs that are likely to transfer to reality, we present two ways to modify evaluation of designs. The first is to add location noise, differences between the actual dimensions of the design and the design blueprint, which is a technique we have used for our work in evolving antennas and robots. The second method is to add prestress to model the warping that occurs during the extreme heat of fabrication. In future we expect to fabricate and test some MEMS resonators that are evolved in this way.

Additive manufacturing of three-dimensional (3D) microfluidic-based microelectromechanical systems (MEMS) for acoustofluidic applications.

PubMed

Cesewski, Ellen; Haring, Alexander P; Tong, Yuxin; Singh, Manjot; Thakur, Rajan; Laheri, Sahil; Read, Kaitlin A; Powell, Michael D; Oestreich, Kenneth J; Johnson, Blake N

2018-06-13

Three-dimensional (3D) printing now enables the fabrication of 3D structural electronics and microfluidics. Further, conventional subtractive manufacturing processes for microelectromechanical systems (MEMS) relatively limit device structure to two dimensions and require post-processing steps for interface with microfluidics. Thus, the objective of this work is to create an additive manufacturing approach for fabrication of 3D microfluidic-based MEMS devices that enables 3D configurations of electromechanical systems and simultaneous integration of microfluidics. Here, we demonstrate the ability to fabricate microfluidic-based acoustofluidic devices that contain orthogonal out-of-plane piezoelectric sensors and actuators using additive manufacturing. The devices were fabricated using a microextrusion 3D printing system that contained integrated pick-and-place functionality. Additively assembled materials and components included 3D printed epoxy, polydimethylsiloxane (PDMS), silver nanoparticles, and eutectic gallium-indium as well as robotically embedded piezoelectric chips (lead zirconate titanate (PZT)). Electrical impedance spectroscopy and finite element modeling studies showed the embedded PZT chips exhibited multiple resonant modes of varying mode shape over the 0-20 MHz frequency range. Flow visualization studies using neutrally buoyant particles (diameter = 0.8-70 μm) confirmed the 3D printed devices generated bulk acoustic waves (BAWs) capable of size-selective manipulation, trapping, and separation of suspended particles in droplets and microchannels. Flow visualization studies in a continuous flow format showed suspended particles could be moved toward or away from the walls of microfluidic channels based on selective actuation of in-plane or out-of-plane PZT chips. This work suggests additive manufacturing potentially provides new opportunities for the design and fabrication of acoustofluidic and microfluidic devices.

Development of amorphous SiC for MEMS-based microbridges

NASA Astrophysics Data System (ADS)

Summers, James B.; Scardelletti, Maximilian; Parro, Rocco; Zorman, Christian A.

2007-02-01

This paper reports our effort to develop amorphous hydrogenated silicon carbide (a-SiC:H) films specifically designed for MEMS-based microbridges using methane and silane as the precursor gases. In our work, the a-SiC:H films were deposited in a simple, commercial PECVD system at a fixed temperature of 300°C. Films with thicknesses from 100 nm to 1000 nm, a typical range for many MEMS applications, were deposited. Deposition parameters such as deposition pressure and methane-to-silane ratio were varied in order to obtain films with suitable residual stresses. Average residual stress in the as-deposited films selected for device fabrication was found by wafer curvature measurements to be -658 +/- 22 MPa, which could be converted to 177 +/- 40 MPa after thermal annealing at 450°C, making them suitable for micromachined bridges, membranes and other anchored structures. Bulk micromachined membranes were constructed to determine the Young's modulus of the annealed films, which was found to be 205 +/- 6 GPa. Chemical inertness was tested in aggressive solutions such as KOH and HF. Prototype microbridge actuators were fabricated using a simple surface micromachining process to assess the potential of the a-SiC:H films as structural layers for MEMS applications.

Fabrication of 3D Carbon Microelectromechanical Systems (C-MEMS).

PubMed

Pramanick, Bidhan; Martinez-Chapa, Sergio O; Madou, Marc; Hwang, Hyundoo

2017-06-17

A wide range of carbon sources are available in nature, with a variety of micro-/nanostructure configurations. Here, a novel technique to fabricate long and hollow glassy carbon microfibers derived from human hairs is introduced. The long and hollow carbon structures were made by the pyrolysis of human hair at 900 °C in a N2 atmosphere. The morphology and chemical composition of natural and pyrolyzed human hairs were investigated using scanning electron microscopy (SEM) and electron-dispersive X-ray spectroscopy (EDX), respectively, to estimate the physical and chemical changes due to pyrolysis. Raman spectroscopy was used to confirm the glassy nature of the carbon microstructures. Pyrolyzed hair carbon was introduced to modify screen-printed carbon electrodes ; the modified electrodes were then applied to the electrochemical sensing of dopamine and ascorbic acid. Sensing performance of the modified sensors was improved as compared to the unmodified sensors. To obtain the desired carbon structure design, carbon micro-/nanoelectromechanical system (C-MEMS/C-NEMS) technology was developed. The most common C-MEMS/C-NEMS fabrication process consists of two steps: (i) the patterning of a carbon-rich base material, such as a photosensitive polymer, using photolithography; and (ii) carbonization through the pyrolysis of the patterned polymer in an oxygen-free environment. The C-MEMS/NEMS process has been widely used to develop microelectronic devices for various applications, including in micro-batteries, supercapacitors, glucose sensors, gas sensors, fuel cells, and triboelectric nanogenerators. Here, recent developments of a high-aspect ratio solid and hollow carbon microstructures with SU8 photoresists are discussed. The structural shrinkage during pyrolysis was investigated using confocal microscopy and SEM. Raman spectroscopy was used to confirm the crystallinity of the structure, and the atomic percentage of the elements present in the material before and after pyrolysis was measured using EDX.

Development of High Precision Metal Micro-Electro-Mechanical-Systems Column for Portable Surface Acoustic Wave Gas Chromatograph

NASA Astrophysics Data System (ADS)

Iwaya, Takamitsu; Akao, Shingo; Sakamoto, Toshihiro; Tsuji, Toshihiro; Nakaso, Noritaka; Yamanaka, Kazushi

2012-07-01

In the field of environmental measurement and security, a portable gas chromatograph (GC) is required for the on-site analysis of multiple hazardous gases. Although the gas separation column has been downsized using micro-electro-mechanical-systems (MEMS) technology, an MEMS column made of silicon and glass still does not have sufficient robustness and a sufficiently low fabrication cost for a portable GC. In this study, we fabricated a robust and inexpensive high-precision metal MEMS column by combining diffusion-bonded etched stainless-steel plates with alignment evaluation using acoustic microscopy. The separation performance was evaluated using a desktop GC with a flame ionization detector and we achieved the high separation performance comparable to the best silicon MEMS column fabricated using a dynamic coating method. As an application, we fabricated a palm-size surface acoustic wave (SAW) GC combining this column with a ball SAW sensor and succeeded in separating and detecting a mixture of volatile organic compounds.

MEMS Applications in Aerodynamic Measurement Technology

NASA Technical Reports Server (NTRS)

Reshotko, E.; Mehregany, M.; Bang, C.

1998-01-01

Microelectromechanical systems (MEMS) embodies the integration of sensors, actuators, and electronics on a single substrate using integrated circuit fabrication techniques and compatible bulk and surface micromachining processes. Silicon and its derivatives form the material base for the MEMS technology. MEMS devices, including microsensors and microactuators, are attractive because they can be made small (characteristic dimension about 100 microns), be produced in large numbers with uniform performance, include electronics for high performance and sophisticated functionality, and be inexpensive. For aerodynamic measurements, it is preferred that sensors be small so as to approximate measurement at a point, and in fact, MEMS pressure sensors, wall shear-stress sensors, heat flux sensors and micromachined hot wires are nearing application. For the envisioned application to wind tunnel models, MEMS sensors can be placed on the surface or in very shallow grooves. MEMS devices have often been fabricated on stiff, flat silicon substrates, about 0.5 mm thick, and therefore were not easily mounted on curved surfaces. However, flexible substrates are now available and heat-flux sensor arrays have been wrapped around a curved turbine blade. Electrical leads can also be built into the flexible substrate. Thus MEMS instrumented wind tunnel models do not require deep spanwise grooves for tubes and leads that compromise the strength of conventionally instrumented models. With MEMS, even the electrical leads can potentially be eliminated if telemetry of the signals to an appropriate receiver can be implemented. While semiconductor silicon is well known for its electronic properties, it is also an excellent mechanical material for MEMS applications. However, silicon electronics are limited to operations below about 200 C, and silicon's mechanical properties start to diminish above 400 C. In recent years, silicon carbide (SiC) has emerged as the leading material candidate for applications in high temperature environments and can be used for high-temperature MEMS applications. With SiC, diodes and more complex electronics have been shown to operate to about 600 C, while the mechanical properties of SiC are maintained to much higher temperatures. Even when MEMS devices show benefits in the laboratory, there are many packaging challenges for any aeronautics application. Incorporating MEMS into these applications requires new approaches to packaging that goes beyond traditional integrated circuit (IC) packaging technologies. MEMS must interact mechanically, as well as electrically with their environment, making most traditional chip packaging and mounting techniques inadequate. Wind tunnels operate over wide temperature ranges in an environment that is far from being a 'clean-room.' In flight, aircraft are exposed to natural elements (e.g. rain, sun, ice, insects and dirt) and operational interferences(e.g. cleaning and deicing fluids, and maintenance crews). In propulsion systems applications, MEMS devices will have to operate in environments containing gases with very high temperatures, abrasive particles and combustion products. Hence deployment and packaging that maintains the integrity of the MEMS system is crucial. This paper presents an overview of MEMS fabrication and materials, descriptions of available sensors with more details on those being developed in our laboratories, and a discussion of sensor deployment options for wind tunnel and flight applications.

Integrated electronics and fluidic MEMS for bioengineering

NASA Astrophysics Data System (ADS)

Fok, Ho Him Raymond

Microelectromechanical systems (MEMS) and microelectronics have become enabling technologies for many research areas. This dissertation presents the use of fluidic MEMS and microelectronics for bioengineering applications. In particular, the versatility of MEMS and microelectronics is highlighted by the presentation of two different applications, one for in-vitro study of nano-scale dynamics during cell division and one for in-vivo monitoring of biological activities at the cellular level. The first application of an integrated system discussed in this dissertation is to utilize fluidic MEMS for studying dynamics in the mitotic spindle, which could lead to better chemotherapeutic treatments for cancer patients. Previous work has developed the use of electrokinetic phenomena on the surface of a glass-based platform to assemble microtubules, the building blocks of mitotic spindles. Nevertheless, there are two important limitations of this type of platform. First, an unconventional microfabrication process is necessary for the glass-based platform, which limits the utility of this platform. In order to overcome this limitation, in this dissertation a convenient microfluidic system is fabricated using a negative photoresist called SU-8. The fabrication process for the SU-8-based system is compatible with other fabrication techniques used in developing microelectronics, and this compatibility is essential for integrating electronics for studying dynamics in the mitotic spindle. The second limitation of the previously-developed glass-based platform is its lack of bio-compatibility. For example, microtubules strongly interact with the surface of the glass-based platform, thereby hindering the study of dynamics in the mitotic spindle. This dissertation presents a novel approach for assembling microtubules away from the surface of the platform, and a fabrication process is developed to assemble microtubules between two self-aligned thin film electrodes on thick SU-8 pedestals. This approach also allows the in-vitro model to mimic the three-dimensionality of the cellular mitotic spindle that is absent in previous work. The second application of an integrated bioengineering system discussed in this dissertation is to design and fabricate active electronics and sensors for an in-vivo application to monitor neural activity at the cellular level. Temperature sensors were chosen for a first demonstration. In order for temperature sensors to be able to be implanted into brain interfaces, it is necessary for these devices to be fabricated using processes that are compatible with bio-compatible substrates such as glass and plastic. This dissertation addresses this challenge by developing temperature sensors integrated with biasing circuitry using zinc oxide thin film transistors (TFTs) fabricated on polyimide substrates. The integrated sensors show good temperature sensitivity, which is critical for monitoring neural temperature at the cellular level. This dissertation also describes the unique requirements of encapsulating implantable electronics. For instance, encapsulation schemes must be designed in such a way that they both protect electronic devices from extracellular fluids and also do not interfere with the functionality of these devices. In this work, SU-8 is used as a convenient and effective encapsulation layer. Thermal engineering to prevent active electronics from overheating and to ensure accurate temperature measurement from temperature sensors is also discussed, and a synergistic encapsulation and thermal engineering combination is presented.

Recent Advances of MEMS Resonators for Lorentz Force Based Magnetic Field Sensors: Design, Applications and Challenges.

PubMed

Herrera-May, Agustín Leobardo; Soler-Balcazar, Juan Carlos; Vázquez-Leal, Héctor; Martínez-Castillo, Jaime; Vigueras-Zuñiga, Marco Osvaldo; Aguilera-Cortés, Luz Antonio

2016-08-24

Microelectromechanical systems (MEMS) resonators have allowed the development of magnetic field sensors with potential applications such as biomedicine, automotive industry, navigation systems, space satellites, telecommunications and non-destructive testing. We present a review of recent magnetic field sensors based on MEMS resonators, which operate with Lorentz force. These sensors have a compact structure, wide measurement range, low energy consumption, high sensitivity and suitable performance. The design methodology, simulation tools, damping sources, sensing techniques and future applications of magnetic field sensors are discussed. The design process is fundamental in achieving correct selection of the operation principle, sensing technique, materials, fabrication process and readout systems of the sensors. In addition, the description of the main sensing systems and challenges of the MEMS sensors are discussed. To develop the best devices, researches of their mechanical reliability, vacuum packaging, design optimization and temperature compensation circuits are needed. Future applications will require multifunctional sensors for monitoring several physical parameters (e.g., magnetic field, acceleration, angular ratio, humidity, temperature and gases).

Design, Simulation and Fabrication of Triaxial MEMS High Shock Accelerometer.

PubMed

Zhang, Zhenhai; Shi, Zhiguo; Yang, Zhan; Xie, Zhihong; Zhang, Donghong; Cai, De; Li, Kejie; Shen, Yajing

2015-04-01

On the basis of analyzing the disadvantage of other structural accelerometer, three-axis high g MEMS piezoresistive accelerometer was put forward in order to apply to the high-shock test field. The accelerometer's structure and working principle were discussed in details. The simulation results show that three-axis high shock MEMS accelerometer can bear high shock. After bearing high shock impact in high-shock shooting test, three-axis high shock MEMS accelerometer can obtain the intact metrical information of the penetration process and still guarantee the accurate precision of measurement in high shock load range, so we can not only analyze the law of stress wave spreading and the penetration rule of the penetration process of the body of the missile, but also furnish the testing technology of the burst point controlling. The accelerometer has far-ranging application in recording the typical data that projectile penetrating hard target and furnish both technology guarantees for penetration rule and defend engineering.

Recent Advances of MEMS Resonators for Lorentz Force Based Magnetic Field Sensors: Design, Applications and Challenges

PubMed Central

Herrera-May, Agustín Leobardo; Soler-Balcazar, Juan Carlos; Vázquez-Leal, Héctor; Martínez-Castillo, Jaime; Vigueras-Zuñiga, Marco Osvaldo; Aguilera-Cortés, Luz Antonio

2016-01-01

Microelectromechanical systems (MEMS) resonators have allowed the development of magnetic field sensors with potential applications such as biomedicine, automotive industry, navigation systems, space satellites, telecommunications and non-destructive testing. We present a review of recent magnetic field sensors based on MEMS resonators, which operate with Lorentz force. These sensors have a compact structure, wide measurement range, low energy consumption, high sensitivity and suitable performance. The design methodology, simulation tools, damping sources, sensing techniques and future applications of magnetic field sensors are discussed. The design process is fundamental in achieving correct selection of the operation principle, sensing technique, materials, fabrication process and readout systems of the sensors. In addition, the description of the main sensing systems and challenges of the MEMS sensors are discussed. To develop the best devices, researches of their mechanical reliability, vacuum packaging, design optimization and temperature compensation circuits are needed. Future applications will require multifunctional sensors for monitoring several physical parameters (e.g., magnetic field, acceleration, angular ratio, humidity, temperature and gases). PMID:27563912

Experiments in ultrasonic flaw detection using a MEMS transducer

NASA Astrophysics Data System (ADS)

Jain, Akash; Greve, David W.; Oppenheim, Irving J.

2003-08-01

In earlier work we developed a MEMS phased array transducer, fabricated in the MUMPs process, and we reported on initial experimental studies in which the device was affixed into contact with solids. We demonstrated the successful detection of signals from a conventional ultrasonic source, and the successful localization of the source in an off-axis geometry using phased array signal processing. We now describe the predicted transmission and coupling characteristics for such devices in contact with solids, demonstrating reasonable agreement with experimental behavior. We then describe the results of flaw detection experiments, as well as results for fluid-coupled detectors.

MEMS (Micro-Electro-Mechanical Systems) for Automotive and Consumer Electronics

NASA Astrophysics Data System (ADS)

Marek, Jiri; Gómez, Udo-Martin

MEMS sensors gained over the last two decades an impressive width of applications: (a) ESP: A car is skidding and stabilizes itself without driver intervention (b) Free-fall detection: A laptop falls to the floor and protects the hard drive by parking the read/write drive head automatically before impact. (c) Airbag: An airbag fires before the driver/occupant involved in an impending automotive crash impacts the steering wheel, thereby significantly reducing physical injury risk. MEMS sensors are sensing the environmental conditions and are giving input to electronic control systems. These crucial MEMS sensors are making system reactions to human needs more intelligent, precise, and at much faster reaction rates than humanly possible. Important prerequisites for the success of sensors are their size, functionality, power consumption, and costs. This technical progress in sensor development is realized by micro-machining. The development of these processes was the breakthrough to industrial mass-production for micro-electro-mechanical systems (MEMS). Besides leading-edge micromechanical processes, innovative and robust ASIC designs, thorough simulations of the electrical and mechanical behaviour, a deep understanding of the interactions (mainly over temperature and lifetime) of the package and the mechanical structures are needed. This was achieved over the last 20 years by intense and successful development activities combined with the experience of volume production of billions of sensors. This chapter gives an overview of current MEMS technology, its applications and the market share. The MEMS processes are described, and the challenges of MEMS, compared to standard IC fabrication, are discussed. The evolution of MEMS requirements is presented, and a short survey of MEMS applications is shown. Concepts of newest inertial sensors for ESP-systems are given with an emphasis on the design concepts of the sensing element and the evaluation circuit for achieving excellent noise performance. The chapter concludes with an outlook on arising new MEMS applications such as energy harvester and micro fuel cells.

Fabrication and electrical characterization of partially metallized vias fabricated by inkjet

NASA Astrophysics Data System (ADS)

Khorramdel, B.; Mäntysalo, M.

2016-04-01

Through silicon vias (TSVs), acting as vertical interconnections, play an important role in micro-electro-mechanical systems (MEMS) 3D wafer level packaging. Today, taking advantage of nanoparticle inks, inkjet technologies as local filling methods could be used to plate the inside the vias with a conductive material, rather than using a current method, such as chemical vapor deposition or electrolytic growth. This could decrease the processing time, cost and waste material produced. In this work, we have fabricated and demonstrated electrical characterization of TSVs with a top diameter of 85 μm, and partially metallized on their inside walls using silver nanoparticle ink and drop-on-demand inkjet printing. Electrical measurement showed that the resistance of a single via with a void free coverage from top to bottom could be less than 4 Ω, which is still acceptable for MEMS applications.

Micro-patterning of resin-bonded NdFeB magnet for a fully integrated electromagnetic actuator

NASA Astrophysics Data System (ADS)

Tao, Kai; Wu, Jin; Kottapalli, Ajay Giri Prakash; Chen, Di; Yang, Zhuoqing; Ding, Guifu; Lye, Sun Woh; Miao, Jianmin

2017-12-01

This paper reports a fully-integrated, batch-fabricated electromagnetic actuator which features micro-patterned NdFeB magnets. The entire actuator is fabricated through MEMS-compatible laminated surface micromachining technology, eliminating the requirement for further component assembly processes. The fabrication strategy allowed the entire volume of the actuator to be reduced to a small size of 2.5 × 2.5 × 2 mm3, which is one of the smallest NdFeB-based electromagnetic actuators demonstrated to date. The magnetic properties of NdFeB thin films are further investigated and optimized using different types of lithographically-defined micromolds. By altering the direction of the input current, actuating displacements of approximately ±10 μm are achieved during both the attraction and the repulsion operations. This work demonstrates the viability and compatibility of using polymer-bonded magnets for magnetic MEMS applications.

Low Power Consumption Design and Fabrication of Thin Film Core for Micro Fluxgate.

PubMed

Lv, Hui; Liu, Shibin

2016-03-01

The soft magnetic characteristic of core is a critical factor to performance of the micro fluxgate. Porous thin film core can be effectively used to decrease the value of saturation magnetic field strength (H(s)) and improve soft magnetic behavior. It is conducive to impelling the micro fluxgate toward the direction of low power consumption. In this work, negative photoresist is used to fabricate a porous core by MEMS technology. Through the processes of ultraviolet-lithography, the porous pattern transfer from the mask to the microstructure on silicon substrate. The experiment result complies with the anticipation and indicates that this MEMS technique can be applied to improve the characteristic of thin film core and decrease power consumption of fluxgate sensor.

Uncooled infrared imaging using bimaterial microcantilever arrays

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grbovic, Dragoslav; Lavrik, Nickolay V; Rajic, Slobodan

2006-01-01

We report on the fabrication and characterization of microcantilever based uncooled focal plane array (FPA) for infrared imaging. By combining a streamlined design of microcantilever thermal transducers with a highly efficient optical readout, we minimized the fabrication complexity while achieving a competitive level of imaging performance. The microcantilever FPAs were fabricated using a straightforward fabrication process that involved only three photolithographic steps (i.e. three masks). A designed and constructed prototype of an IR imager employed a simple optical readout based on a noncoherent low-power light source. The main figures of merit of the IR imager were found to be comparablemore » to those of uncooled MEMS infrared detectors with substantially higher degree of fabrication complexity. In particular, the NETD and the response time of the implemented MEMS IR detector were measured to be as low as 0.5K and 6 ms, respectively. The potential of the implemented designs can also be concluded from the fact that the constructed prototype enabled IR imaging of close to room temperature objects without the use of any advanced data processing. The most unique and practically valuable feature of the implemented FPAs, however, is their scalability to high resolution formats, such as 2000x2000, without progressively growing device complexity and cost.« less

Design and fabrication of a MEMS chevron-type thermal actuator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baracu, Angela, E-mail: angela.baracu@imt.ro; Voicu, Rodica; Müller, Raluca

This paper presents the design and fabrication of a MEMS chevron-type thermal actuator. The device was designed for fabrication in the standard MEMS technology, where the topography of the upper layers depends on the patterns of structural and sacrificial layers underneath. The proposed actuator presents some advantages over usual thermal vertical chevron actuators by means of low operating voltages, high output force and linear movement without deformation of the shaft. The device simulations were done using COVENTOR software. The movement obtained by simulation was 12 μm, for a voltage of 0.2 V and the current intensity of 257 mA. Themore » design optimizes the in-plane displacement by fixed anchors and beam inclination angle. Heating is provided by Joule dissipation. The material used for manufacture of chevron-based actuator was aluminum due to its thermal and mechanical properties. The release of the movable part was performed using isotropic dry etching by Reactive Ion Etching (RIE). A first inspection was achieved using Scanning Electron Microscope (SEM). In order to obtain the in-plane displacement we carried out electrical measurements. The thermal actuator can be used for a variety of optical and microassembling applications. This kind of thermal actuator could be integrated easily with other micro devices since its fabrication is compatible with the general semiconductor processes.« less

Fabrication of a high aspect ratio thick silicon wafer mold and electroplating using flipchip bonding for MEMS applications

NASA Astrophysics Data System (ADS)

Kim, Bong-Hwan; Kim, Jong-Bok

2009-06-01

We have developed a microfabrication process for high aspect ratio thick silicon wafer molds and electroplating using flipchip bonding with THB 151N negative photoresist (JSR micro). This fabrication technique includes large area and high thickness silicon wafer mold electroplating. The process consists of silicon deep reactive ion etching (RIE) of the silicon wafer mold, photoresist bonding between the silicon mold and the substrate, nickel electroplating and a silicon removal process. High thickness silicon wafer molds were made by deep RIE and flipchip bonding. In addition, nickel electroplating was developed. Dry film resist (ORDYL MP112, TOK) and thick negative-tone photoresist (THB 151N, JSR micro) were used as bonding materials. In order to measure the bonding strength, the surface energy was calculated using a blade test. The surface energy of the bonding wafers was found to be 0.36-25.49 J m-2 at 60-180 °C for the dry film resist and 0.4-1.9 J m-2 for THB 151N in the same temperature range. Even though ORDYL MP112 has a better value of surface energy than THB 151N, it has a critical disadvantage when it comes to removing residue after electroplating. The proposed process can be applied to high aspect ratio MEMS structures, such as air gap inductors or vertical MEMS probe tips.

Development of an alternating magnetic-field-assisted finishing process for microelectromechanical systems micropore x-ray optics.

PubMed

Riveros, Raul E; Yamaguchi, Hitomi; Mitsuishi, Ikuyuki; Takagi, Utako; Ezoe, Yuichiro; Kato, Fumiki; Sugiyama, Susumu; Yamasaki, Noriko; Mitsuda, Kazuhisa

2010-06-20

X-ray astronomy research is often limited by the size, weight, complexity, and cost of functioning x-ray optics. Micropore optics promises an economical alternative to traditional (e.g., glass or foil) x-ray optics; however, many manufacturing difficulties prevent micropore optics from being a viable solution. Ezoe et al. introduced microelectromechanical systems (MEMS) micropore optics having curvilinear micropores in 2008. Made by either deep reactive ion etching or x-ray lithography, electroforming, and molding (LIGA), MEMS micropore optics suffer from high micropore sidewall roughness (10-30nmrms) which, by current standards, cannot be improved. In this research, a new alternating magnetic-field-assisted finishing process was developed using a mixture of ferrofluid and microscale abrasive slurry. A machine was built, and a set of working process parameters including alternating frequency, abrasive size, and polishing time was selected. A polishing experiment on a LIGA-fabricated MEMS micropore optic was performed, and a change in micropore sidewall roughness of 9.3+/-2.5nmrms to 5.7+/-0.7nmrms was measured. An improvement in x-ray reflectance was also seen. This research shows the feasibility and confirms the effects of this new polishing process on MEMS micropore optics.

Design, fabrication and actuation of a MEMS-based image stabilizer for photographic cell phone applications

NASA Astrophysics Data System (ADS)

Chiou, Jin-Chern; Hung, Chen-Chun; Lin, Chun-Ying

2010-07-01

This work presents a MEMS-based image stabilizer applied for anti-shaking function in photographic cell phones. The proposed stabilizer is designed as a two-axis decoupling XY stage 1.4 × 1.4 × 0.1 mm3 in size, and adequately strong to suspend an image sensor for anti-shaking photographic function. This stabilizer is fabricated by complex fabrication processes, including inductively coupled plasma (ICP) processes and flip-chip bonding technique. Based on the special designs of a hollow handle layer and a corresponding wire-bonding assisted holder, electrical signals of the suspended image sensor can be successfully sent out with 32 signal springs without incurring damage during wire-bonding packaging. The longest calculated traveling distance of the stabilizer is 25 µm which is sufficient to resolve the anti-shaking problem in a three-megapixel image sensor. Accordingly, the applied voltage for the 25 µm moving distance is 38 V. Moreover, the resonant frequency of the actuating device with the image sensor is 1.123 kHz.

Fabrication of high aspect ratio structure and its releasing for silicon on insulator MEMS/MOEMS device application

NASA Astrophysics Data System (ADS)

Fan, Ji; Zhang, Wen Ting; Liu, Jin Quan; Wu, Wen Jie; Zhu, Tao; Tu, Liang Cheng

2015-04-01

We systematically investigate the fabrication and dry-release technology for a high aspect ratio (HAR) structure with vertical and smooth silicon etching sidewalls. One-hundred-micrometer silicon on insulator (SOI) wafers are used in this work. By optimizing the process parameters of inductively coupled plasma deep reactive-ion etching, a HAR (˜25∶1) structure with a microtrench width of 4 μm has been demonstrated. A perfect etching profile has been obtained in which the structures present an almost perfect verticality of 0.10 μm and no sidewall scallops. The root-mean square roughness of silicon sidewalls is 20 to 29 nm. An in situ dry-release method using notching effect is employed after etching. By analysis, we found that the final notch length is typically an aspect-ratio-dependent process. The structure designed in this work has been successfully released by this in situ dry-release method, and the released bottom roughness effectively prohibits the stiction mechanism. The results demonstrate potential applications for design and fabrication of HAR SOI MEMS/MOEMS.

Fabrication of Scalable Indoor Light Energy Harvester and Study for Agricultural IoT Applications

NASA Astrophysics Data System (ADS)

Watanabe, M.; Nakamura, A.; Kunii, A.; Kusano, K.; Futagawa, M.

2015-12-01

A scalable indoor light energy harvester was fabricated by microelectromechanical system (MEMS) and printing hybrid technology and evaluated for agricultural IoT applications under different environmental input power density conditions, such as outdoor farming under the sun, greenhouse farming under scattered lighting, and a plant factory under LEDs. We fabricated and evaluated a dye- sensitized-type solar cell (DSC) as a low cost and “scalable” optical harvester device. We developed a transparent conductive oxide (TCO)-less process with a honeycomb metal mesh substrate fabricated by MEMS technology. In terms of the electrical and optical properties, we achieved scalable harvester output power by cell area sizing. Second, we evaluated the dependence of the input power scalable characteristics on the input light intensity, spectrum distribution, and light inlet direction angle, because harvested environmental input power is unstable. The TiO2 fabrication relied on nanoimprint technology, which was designed for optical optimization and fabrication, and we confirmed that the harvesters are robust to a variety of environments. Finally, we studied optical energy harvesting applications for agricultural IoT systems. These scalable indoor light harvesters could be used in many applications and situations in smart agriculture.

Development of a MEMS acoustic emission sensor system

NASA Astrophysics Data System (ADS)

Greve, David W.; Oppenheim, Irving J.; Wu, Wei; Wright, Amelia P.

2007-04-01

An improved multi-channel MEMS chip for acoustic emission sensing has been designed and fabricated in 2006 to create a device that is smaller in size, superior in sensitivity, and more practical to manufacture than earlier designs. The device, fabricated in the MUMPS process, contains four resonant-type capacitive transducers in the frequency range between 100 kHz and 500 kHz on a chip with an area smaller than 2.5 sq. mm. The completed device, with its circuit board, electronics, housing, and connectors, possesses a square footprint measuring 25 mm x 25 mm. The small footprint is an important attribute for an acoustic emission sensor, because multiple sensors must typically be arrayed around a crack location. Superior sensitivity was achieved by a combination of four factors: the reduction of squeeze film damping, a resonant frequency approximating a rigid body mode rather than a bending mode, a ceramic package providing direct acoustic coupling to the structural medium, and high-gain amplifiers implemented on a small circuit board. Manufacture of the system is more practical because of higher yield (lower unit costs) in the MUMPS fabrication task and because of a printed circuit board matching the pin array of the MEMS chip ceramic package for easy assembly and compactness. The transducers on the MEMS chip incorporate two major mechanical improvements, one involving squeeze film damping and one involving the separation of resonance modes. For equal proportions of hole area to plate area, a triangular layout of etch holes reduces squeeze film damping as compared to the conventional square layout. The effect is modeled analytically, and is verified experimentally by characterization experiments on the new transducers. Structurally, the transducers are plates with spring supports; a rigid plate would be the most sensitive transducer, and bending decreases the sensitivity. In this chip, the structure was designed for an order-of-magnitude separation between the first and the second mode frequency, strongly approximating the desirable rigid plate limit. The effect is modeled analytically and is verified experimentally by measurement of the resonance frequencies in the new transducers. Another improvement arises from the use of a pin grid array ceramic package, in which the MEMS chip is acoustically coupled to the structure with only two interfaces, through a ceramic medium that is negligible in thickness when compared to wavelengths of interest. Like other acoustic emission sensors, those on the 2006 MEMS chip are sensitive only to displacements normal to the surface on which the device is mounted. To overcome that long-standing limitation, a new MEMS sensor sensitive to in-plane motion has been designed, featuring a different spring-mass mechanism and creating the signal by the change in capacitance between stationary and moving fingers. Predicted damping is much lower for the case of the in-plane sensor, and squeeze-film damping is used selectively to isolate the desired in-plane mechanical response from any unwanted out-of-plane response. The new spring-mass mechanism satisfies the design rules for the PolyMUMPS fabrication (foundry) process. A 3-D MEMS sensor system is presently being fabricated, collocating two in-plane sensors and one out-of-plane sensor at the mm scale, which is very short compared to the acoustic wavelength of interest for stress waves created by acoustic emission events.

Design of a multi-axis implantable MEMS sensor for intraosseous bone stress monitoring

NASA Astrophysics Data System (ADS)

Alfaro, Fernando; Weiss, Lee; Campbell, Phil; Miller, Mark; Fedder, Gary K.

2009-08-01

The capability to assess the biomechanical properties of living bone is important for basic research as well as the clinical management of skeletal trauma and disease. Even though radiodensitometric imaging is commonly used to infer bone quality, bone strength does not necessarily correlate well with these non-invasive measurements. This paper reports on the design, fabrication and initial testing of an implantable ultra-miniature multi-axis sensor for directly measuring bone stresses at a micro-scale. The device, which is fabricated with CMOS-MEMS processes, is intended to be permanently implanted within open fractures, or embedded in bone grafts, or placed on implants at the interfaces between bone and prosthetics. The stress sensor comprises an array of piezoresistive pixels to detect a stress tensor at the interfacial area between the MEMS chip and bone, with a resolution to 100 Pa, in 1 s averaging. The sensor system design and manufacture is also compatible with the integration of wireless RF telemetry, for power and data retrieval, all within a 3 mm × 3 mm × 0.3 mm footprint. The piezoresistive elements are integrated within a textured surface to enhance sensor integration with bone. Finite element analysis led to a sensor design for normal and shear stress detection. A wired sensor was fabricated in the Jazz 0.35 µm BiCMOS process and then embedded in mock bone material to characterize its response to tensile and bending loads up to 250 kPa.

MEMS Incandescent Light Source

NASA Technical Reports Server (NTRS)

Tuma, Margaret; King, Kevin; Kim, Lynn; Hansler, Richard; Jones, Eric; George, Thomas

2001-01-01

A MEMS-based, low-power, incandescent light source is being developed. This light source is fabricated using three bonded chips. The bottom chip consists of a reflector on Silicon, the middle chip contains a Tungsten filament bonded to silicon and the top layer is a transparent window. A 25-micrometer-thick spiral filament is fabricated in Tungsten using lithography and wet-etching. A proof-of-concept device has been fabricated and tested in a vacuum chamber. Results indicate that the filament is electrically heated to approximately 2650 K. The power required to drive the proof-of-concept spiral filament to incandescence is 1.25 W. The emitted optical power is expected to be approximately 1.0 W with the spectral peak at 1.1 microns. The micromachining techniques used to fabricate this light source can be applied to other MEMS devices.

System-in Package of Integrated Humidity Sensor Using CMOS-MEMS Technology.

PubMed

Lee, Sung Pil

2015-10-01

Temperature/humidity microchips with micropump were fabricated using a CMOS-MEMS process and combined with ZigBee modules to implement a sensor system in package (SIP) for a ubiquitous sensor network (USN) and/or a wireless communication system. The current of a diode temperature sensor to temperature and a normalized current of FET humidity sensor to relative humidity showed linear characteristics, respectively, and the use of the micropump has enabled a faster response. A wireless reception module using the same protocol as that in transmission systems processed the received data within 10 m and showed temperature and humidity values in the display.

Evaluation of a Programmable Voltage-Controlled MEMS Oscillator, Type SiT3701, Over a Wide Temperature Range

NASA Technical Reports Server (NTRS)

Patterson, Richard; Hammoud, Ahmad

2009-01-01

Semiconductor chips based on MEMS (Micro-Electro-Mechanical Systems) technology, such as sensors, transducers, and actuators, are becoming widely used in today s electronics due to their high performance, low power consumption, tolerance to shock and vibration, and immunity to electro-static discharge. In addition, the MEMS fabrication process allows for the miniaturization of individual chips as well as the integration of various electronic circuits into one module, such as system-on-a-chip. These measures would simplify overall system design, reduce parts count and interface, improve reliability, and reduce cost; and they would meet requirements of systems destined for use in space exploration missions. In this work, the performance of a recently-developed MEMS voltage-controlled oscillator was evaluated under a wide temperature range. Operation of this new commercial-off-the-shelf (COTS) device was also assessed under thermal cycling to address some operational conditions of the space environment

RF-MEMS tunable interdigitated capacitor and fixed spiral inductor for band pass filter applications

NASA Astrophysics Data System (ADS)

Bade, Ladon Ahmed; Dennis, John Ojur; Khir, M. Haris Md; Wen, Wong Peng

2016-11-01

This research presents the tunable Radio Frequency Micro Electromechanical Systems (RF-MEMS) coupled band-pass filter (BPF), which possess a wide tuning range and constructed by using the Chebyshev fourth degree equivalent circuit consisting of fixed inductors and interdigitated tunable capacitors. The suggested method was authenticated by designing a new tunable BPF with a 100% tuning range from 3.1 GHz to 4.9 GHz. The Metal Multi-User MEMS Process (Metal MUMPs) was involved in the process of design of this band-pass filter. It aimed to achieve the reconfiguration of frequencies and show high efficiency of RF in the applications that using Ultra Wide Band (UWB) such as wireless sensor networks. The RF performance of this filter was found to be very satisfactory due to its simple fabrication. Moreover, it showed less insertion loss of around 4 dB and high return loss of around 20 dB.

Manufacture of Micromirror Arrays Using a CMOS-MEMS Technique

PubMed Central

Kao, Pin-Hsu; Dai, Ching-Liang; Hsu, Cheng-Chih; Wu, Chyan-Chyi

2009-01-01

In this study we used the commercial 0.35 μm CMOS (complementary metal oxide semiconductor) process and simple maskless post-processing to fabricate an array of micromirrors exhibiting high natural frequency. The micromirrors were manufactured from aluminum; the sacrificial layer was silicon dioxide. Because we fabricated the micromirror arrays using the standard CMOS process, they have the potential to be integrated with circuitry on a chip. For post-processing we used an etchant to remove the sacrificial layer and thereby suspend the micromirrors. The micromirror array contained a circular membrane and four fixed beams set symmetrically around and below the circular mirror; these four fan-shaped electrodes controlled the tilting of the micromirror. A MEMS (microelectromechanical system) motion analysis system and a confocal 3D-surface topography were used to characterize the properties and configuration of the micromirror array. Each micromirror could be rotated in four independent directions. Experimentally, we found that the micromirror had a tilting angle of about 2.55° when applying a driving voltage of 40 V. The natural frequency of the micromirrors was 59.1 kHz. PMID:22454581

Manufacture of Micromirror Arrays Using a CMOS-MEMS Technique.

PubMed

Kao, Pin-Hsu; Dai, Ching-Liang; Hsu, Cheng-Chih; Wu, Chyan-Chyi

2009-01-01

In this study we used the commercial 0.35 μm CMOS (complementary metal oxide semiconductor) process and simple maskless post-processing to fabricate an array of micromirrors exhibiting high natural frequency. The micromirrors were manufactured from aluminum; the sacrificial layer was silicon dioxide. Because we fabricated the micromirror arrays using the standard CMOS process, they have the potential to be integrated with circuitry on a chip. For post-processing we used an etchant to remove the sacrificial layer and thereby suspend the micromirrors. The micromirror array contained a circular membrane and four fixed beams set symmetrically around and below the circular mirror; these four fan-shaped electrodes controlled the tilting of the micromirror. A MEMS (microelectromechanical system) motion analysis system and a confocal 3D-surface topography were used to characterize the properties and configuration of the micromirror array. Each micromirror could be rotated in four independent directions. Experimentally, we found that the micromirror had a tilting angle of about 2.55° when applying a driving voltage of 40 V. The natural frequency of the micromirrors was 59.1 kHz.

In vivo cellular imaging with microscopes enabled by MEMS scanners

NASA Astrophysics Data System (ADS)

Ra, Hyejun

High-resolution optical imaging plays an important role in medical diagnosis and biomedical research. Confocal microscopy is a widely used imaging method for obtaining cellular and sub-cellular images of biological tissue in reflectance and fluorescence modes. Its characteristic optical sectioning capability also enables three-dimensional (3-D) image reconstruction. However, its use has mostly been limited to excised tissues due to the requirement of high numerical aperture (NA) lenses for cellular resolution. Microscope miniaturization can enable in vivo imaging to make possible early cancer diagnosis and biological studies in the innate environment. In this dissertation, microscope miniaturization for in vivo cellular imaging is presented. The dual-axes confocal (DAC) architecture overcomes limitations of the conventional single-axis confocal (SAC) architecture to allow for miniaturization with high resolution. A microelectromechanical systems (MEMS) scanner is the central imaging component that is key in miniaturization of the DAC architecture. The design, fabrication, and characterization of the two-dimensional (2-D) MEMS scanner are presented. The gimbaled MEMS scanner is fabricated on a double silicon-on-insulator (SOI) wafer and is actuated by self-aligned vertical electrostatic combdrives. The imaging performance of the MEMS scanner in a DAC configuration is shown in a breadboard microscope setup, where reflectance and fluorescence imaging is demonstrated. Then, the MEMS scanner is integrated into a miniature DAC microscope. The whole imaging system is integrated into a portable unit for research in small animal models of human biology and disease. In vivo 3-D imaging is demonstrated on mouse skin models showing gene transfer and siRNA silencing. The siRNA silencing process is sequentially imaged in one mouse over time.

Design, fabrication and characterization of MEMS deformable mirrors for ocular adaptive optics

NASA Astrophysics Data System (ADS)

Park, Hyunkyu

This dissertation describes the design and modeling of MEMS-based bimorph deformable mirrors for adaptive optics as well as the characterization of fabricated devices. The objective of this research is to create a compact and low-cost deformable mirror that can be used as a phase corrector particularly for vision science applications. A fundamental theory of adaptive optics is reviewed, paying attention to the phase corrector which is a key component of the adaptive optics system. Several types of phase corrector are presented and the minimization of their size and cost using micro electromechanical systems (MEMS) technology is also discussed. Since this research is targeted towards the ophthalmic applications of adaptive optics, aberrations of the human eye are illustrated and the benefits of corrections by adaptive optics are explained. A couple of actuator types of the phase corrector that can be used in vision science are introduced and discussed their suitability for the purpose. The requirements to be an ideal deformable mirror for ocular adaptive optics are presented. The characteristics of bimorph deformable mirrors originally developed for laser communications are investigated in an effort to understand their suitability for ophthalmological adaptive optics applications. A Phase shifting interferometer setup is developed for optical characterization and fundamental theory of interferogram analysis is described along with wavefront reconstruction. The theoretical analysis of the bimorph deformable mirror begins with developing an analytical model of the laminated structure. The finite element models are also developed using COMSOL Multiphysics. Using the FEM results, the performance of deformable mirrors under various structure dimensions and operating conditions is analyzed for optimization. A basic theory of piezoelectricity is explained, followed by introduction of applications to MEMS devices. The material properties of single crystal PMN-PT adopted in this research are described and characterized. The fabrication process of the optimized deformable mirror is presented and advanced techniques used in the process are described in detail. The fabricated deformable mirrors are characterized and the comparison with FEM is described. Finally, the dissertation ends up with suggestions for further developments and tests for the mirror.

MEMS testing and applications in automotive and aerospace industries

NASA Astrophysics Data System (ADS)

Ma, Zhichun; Chen, Xuyuan

2009-05-01

MEMS technology combines micromachining and integrated circuit fabrication technologies to produce highly reliable MEMS transducers. This paper presents an overview of MEMS transducers applications, particularly in automotive and aerospace industries, which includes inertia sensors for safety, navigation, and guidance control, thermal anemometer for temperature and heat-flux sensors in engine applications, MEMS atomizers for fuel injection, and micromachined actuators for flow control applications. Design examples for the devices in above mentioned applications are also presented and test results are given.

Characterization of shape and deformation of MEMS by quantitative optoelectronic metrology techniques

NASA Astrophysics Data System (ADS)

Furlong, Cosme; Pryputniewicz, Ryszard J.

2002-06-01

Recent technological trends based on miniaturization of mechanical, electro-mechanical, and photonic devices to the microscopic scale, have led to the development of microelectromechanical systems (MEMS). Effective development of MEMS components requires the synergism of advanced design, analysis, and fabrication methodologies, and also of quantitative metrology techniques for characterizing their performance, reliability, and integrity during the electronic packaging cycle. In this paper, we describe opto-electronic techniques for measuring, with sub-micrometer accuracy, shape and changes in states of deformation of MEMS strictures. With the described opto-electronic techniques, it is possible to characterize MEMS components using the display and data modes. In the display mode, interferometric information related to shape and deformation is displayed at video frame rates, providing the capability for adjusting and setting experimental conditions. In the data mode, interferometric information related to shape and deformation is recorded as high-spatial and high-digital resolution images, which are further processed to provide quantitative 3D information. Furthermore, the quantitative 3D data are exported to computer-aided design (CAD) environments and utilized for analysis and optimization of MEMS devices. Capabilities of opto- electronic techniques are illustrated with representative applications demonstrating their applicability to provide indispensable quantitative information for the effective development and optimization of MEMS devices.

Integrating nanosphere lithography in device fabrication

NASA Astrophysics Data System (ADS)

Laurvick, Tod V.; Coutu, Ronald A.; Lake, Robert A.

2016-03-01

This paper discusses the integration of nanosphere lithography (NSL) with other fabrication techniques, allowing for nano-scaled features to be realized within larger microelectromechanical system (MEMS) based devices. Nanosphere self-patterning methods have been researched for over three decades, but typically not for use as a lithography process. Only recently has progress been made towards integrating many of the best practices from these publications and determining a process that yields large areas of coverage, with repeatability and enabled a process for precise placement of nanospheres relative to other features. Discussed are two of the more common self-patterning methods used in NSL (i.e. spin-coating and dip coating) as well as a more recently conceived variation of dip coating. Recent work has suggested the repeatability of any method depends on a number of variables, so to better understand how these variables affect the process a series of test vessels were developed and fabricated. Commercially available 3-D printing technology was used to incrementally alter the test vessels allowing for each variable to be investigated individually. With these deposition vessels, NSL can now be used in conjunction with other fabrication steps to integrate features otherwise unattainable through current methods, within the overall fabrication process of larger MEMS devices. Patterned regions in 1800 series photoresist with a thickness of ~700nm are used to capture regions of self-assembled nanospheres. These regions are roughly 2-5 microns in width, and are able to control the placement of 500nm polystyrene spheres by controlling where monolayer self-assembly occurs. The resulting combination of photoresist and nanospheres can then be used with traditional deposition or etch methods to utilize these fine scale features in the overall design.

Fabrication and analysis of radiofrequency MEMS series capacitive single-pole double-throw switch

NASA Astrophysics Data System (ADS)

Bansal, Deepak; Bajpai, Anuroop; Kumar, Prem; Kaur, Maninder; Rangra, Kamaljit

2016-10-01

A compact radiofrequency (RF) MEMS single-pole double-throw (SPDT) switch based on series capacitive configuration is proposed. The critical process parameters are analyzed to improve the fabrication process. A technique of cold-hot thermal shock for lift-off method is explored. The residual stress in the structure is quantified by lancet test structures that come out to be 51 MPa. Effect of residual stress on actuation voltage is explored, which changes its value from 24 to 22 V. Resonance frequency and switching speed of the switch are 11 kHz and 44 μs, respectively, measured using laser Doppler vibrometer. Measured bandwidth of the SPDT switch is 20 GHz (5 to 25 GHz), which is verified with finite element method simulations in high frequency structure simulator©; and an equivalent LCR circuit in advanced design system©;. Insertion loss of the switch lies in -0.1 to -0.5 dB with isolation better than -20 dB for the above-mentioned bandwidth.

Piezoelectric microgenerators--current status and challenges.

PubMed

Kim, Hyun-Uk; Lee, Woo-Ho; Dias, H V Rasika; Priya, Shashank

2009-08-01

This manuscript reviews the developments made in design and fabrication of piezoelectric microgenerators and presents a method for making a comparative study within various vibration energy harvesting mechanisms. Current generation vibration energy harvesters have power density in the range of 0.8 microW/mm3. The manuscript also reports our results on synthesis of barium titanate (BT) thin films for MEMS (micro-electromechanical systems) based energy harvester. BT sol-gel was synthesized by aqueous process using barium acetate and titanium bis (ammonium lacto) dihydroxide with PVP (Polyvinylpyrrolidone). After optimizing the annealing temperature and time, textured BT films with 600 nm thickness were obtained on (111) Pt/Ti/SiO2 wafer. A MEMS fabrication process flow was designed to produce microcantilever chips from BT films constituting 6 cantilevers connected in series with an interdigital electrode pattern. We also present some concepts for further improvement of the power density of vibration energy harvesters by incorporating 3-D structure, magnetoelectric material, and a multimodal scheme.

Implantable Wireless MEMS Sensors for Medical Uses

NASA Technical Reports Server (NTRS)

Chimbayo, Alexander

2006-01-01

Sensors designed and fabricated according to the principles of microelectromechanical systems (MEMS) are being developed for several medical applications in outer space and on Earth. The designs of these sensors are based on a core design family of pressure sensors, small enough to fit into the eye of a needle, that are fabricated by a "dissolved wafer" process. The sensors are expected to be implantable, batteryless, and wireless. They would be both powered and interrogated by hand-held radio transceivers from distances up to about 6 in. (about 15 cm). One type of sensor would be used to measure blood pressure, particularly for congestive heart failure. Another type would be used to monitor fluids in patients who have hydrocephalus (high brain pressure). Still other types would be used to detect errors in delivery of drugs and to help patients having congestive heart failure.

Electrowetting Lens Employing Hemispherical Cavity Formed by Hydrofluoric Acid, Nitric Acid, and Acetic Acid Etching of Silicon

NASA Astrophysics Data System (ADS)

Lee, June Kyoo; Choi, Ju Chan; Jang, Won Ick; Kim, Hak-Rin; Kong, Seong Ho

2012-06-01

We demonstrate the design of an electrowetting lens employing a high-aspect-ratio hemispherical lens cavity and its micro-electro-mechanical-system (MEMS) fabrication process in this study. Our preliminary simulation results showed that the physical and electrical durability of the lens can be improved by the mitigation of stresses on the insulator at the hemispherical cavity. High-aspect-ratio hemispherical cavities with various diameters and very smooth sidewall surfaces were uniformly fabricated on a silicon wafer by a sophisticated isotropic wet etching technique. Moreover, we experimentally investigated the optical properties of the MEMS-based electrowetting lens with the proposed cavity. Two immiscible liquids in the proposed lens cavity were electrostatically controlled with negligible optical distortion and low focal-length hysteresis due to the fully axis-symmetrical geometry and smooth sidewall of the cavity.

Integrated Inductors for RF Transmitters in CMOS/MEMS Smart Microsensor Systems

PubMed Central

Kim, Jong-Wan; Takao, Hidekuni; Sawada, Kazuaki; Ishida, Makoto

2007-01-01

This paper presents the integration of an inductor by complementary metal-oxide-semiconductor (CMOS) compatible processes for integrated smart microsensor systems that have been developed to monitor the motion and vital signs of humans in various environments. Integration of radio frequency transmitter (RF) technology with complementary metal-oxide-semiconductor/micro electro mechanical systems (CMOS/MEMS) microsensors is required to realize the wireless smart microsensors system. The essential RF components such as a voltage controlled RF-CMOS oscillator (VCO), spiral inductors for an LC resonator and an integrated antenna have been fabricated and evaluated experimentally. The fabricated RF transmitter and integrated antenna were packaged with subminiature series A (SMA) connectors, respectively. For the impedance (50 Ω) matching, a bonding wire type inductor was developed. In this paper, the design and fabrication of the bonding wire inductor for impedance matching is described. Integrated techniques for the RF transmitter by CMOS compatible processes have been successfully developed. After matching by inserting the bonding wire inductor between the on-chip integrated antenna and the VCO output, the measured emission power at distance of 5 m from RF transmitter was -37 dBm (0.2 μW).

Wavelength tunable MEMS VCSELs for OCT imaging

NASA Astrophysics Data System (ADS)

Sahoo, Hitesh Kumar; Ansbæk, Thor; Ottaviano, Luisa; Semenova, Elizaveta; Hansen, Ole; Yvind, Kresten

2018-02-01

MEMS VCSELs are one of the most promising swept source (SS) lasers for optical coherence tomography (OCT) and one of the best candidates for future integration with endoscopes, surgical probes and achieving an integrated OCT system. However, the current MEMS-based SS are processed on the III-V wafers, which are small, expensive and challenging to work with. Furthermore, the actuating part, i.e., the MEMS, is on the top of the structure which causes a strong dependence on packaging to decrease its sensitivity to the operating environment. This work addresses these design drawbacks and proposes a novel design framework. The proposed device uses a high contrast grating mirror on a Si MEMS stage as the bottom mirror, all of which is defined in an SOI wafer. The SOI wafer is then bonded to an InP III-V wafer with the desired active layers, thereby sealing the MEMS. Finally, the top mirror, a dielectric DBR (7 pairs of TiO2 - SiO2), is deposited on top. The new device is based on a silicon substrate with MEMS defined on a silicon membrane in an enclosed cavity. Thus the device is much more robust than the existing MEMS VCSELs. This design also enables either a two-way actuation on the MEMS or a smaller optical cavity (pull-away design), i.e., wider FSR (Free Spectral Range) to increase the wavelength sweep. Fabrication of the proposed device is outlined and the results of device characterization are reported.

Linear-Quadratic Control of a MEMS Micromirror using Kalman Filtering

DTIC Science & Technology

2011-12-01

LINEAR-QUADRATIC CONTROL OF A MEMS MICROMIRROR USING KALMAN FILTERING THESIS Jamie P...A MEMS MICROMIRROR USING KALMAN FILTERING THESIS Presented to the Faculty Department of Electrical Engineering Graduate School of...actuated micromirrors fabricated by PolyMUMPs. Successful application of these techniques enables demonstration of smooth, stable deflections of 50% and

MEMS Device Being Developed for Active Cooling and Temperature Control

NASA Technical Reports Server (NTRS)

Moran, Matthew E.

2001-01-01

High-capacity cooling options remain limited for many small-scale applications such as microelectronic components, miniature sensors, and microsystems. A microelectromechanical system (MEMS) is currently under development at the NASA Glenn Research Center to meet this need. It uses a thermodynamic cycle to provide cooling or heating directly to a thermally loaded surface. The device can be used strictly in the cooling mode, or it can be switched between cooling and heating modes in milliseconds for precise temperature control. Fabrication and assembly are accomplished by wet etching and wafer bonding techniques routinely used in the semiconductor processing industry. Benefits of the MEMS cooler include scalability to fractions of a millimeter, modularity for increased capacity and staging to low temperatures, simple interfaces and limited failure modes, and minimal induced vibration.

MEMS capacitive accelerometer-based middle ear microphone.

PubMed

Young, Darrin J; Zurcher, Mark A; Semaan, Maroun; Megerian, Cliff A; Ko, Wen H

2012-12-01

The design, implementation, and characterization of a microelectromechanical systems (MEMS) capacitive accelerometer-based middle ear microphone are presented in this paper. The microphone is intended for middle ear hearing aids as well as future fully implantable cochlear prosthesis. Human temporal bones acoustic response characterization results are used to derive the accelerometer design requirements. The prototype accelerometer is fabricated in a commercial silicon-on-insulator (SOI) MEMS process. The sensor occupies a sensing area of 1 mm × 1 mm with a chip area of 2 mm × 2.4 mm and is interfaced with a custom-designed low-noise electronic IC chip over a flexible substrate. The packaged sensor unit occupies an area of 2.5 mm × 6.2 mm with a weight of 25 mg. The sensor unit attached to umbo can detect a sound pressure level (SPL) of 60 dB at 500 Hz, 35 dB at 2 kHz, and 57 dB at 8 kHz. An improved sound detection limit of 34-dB SPL at 150 Hz and 24-dB SPL at 500 Hz can be expected by employing start-of-the-art MEMS fabrication technology, which results in an articulation index of approximately 0.76. Further micro/nanofabrication technology advancement is needed to enhance the microphone sensitivity for improved understanding of normal conversational speech.

A MEMS square Chladni plate resonator

NASA Astrophysics Data System (ADS)

Pala, Sedat; Azgın, Kıvanç

2016-10-01

This paper presents the design, fabrication and tests of a micro-fabricated MEMS ‘Chladni’ plate resonator. The proposed MEMS resonator has a square plate geometry having a side length of 1400 µm and a height of 35 µm. Its geometry and electrode layout are designed to analyze and test as many modes as possible. The MEMS plate is fabricated using a silicon-on-insulator process with a 35 µm thick < \\text{1} \\text{1} \\text{1}> silicon layer on a glass substrate. Transverse vibration of the plate is investigated to obtain closed form natural frequencies and mode shapes, which are derived using the Rayleigh-Ritz energy method, with an electrostatic softening effect included. Closed form equations for the calculation of effective stiffness’, masses and natural frequencies of the two modes (mode (1,1) and mode (2,0)-(0,2)) are presented, with and without electrostatic softening. The analytical model is verified for those modes by finite-element simulations, frequency response tests in vacuum and laser Doppler vibrometer (LDV) experiments. The derived model deviates from the finite-element analysis by 3.35% for mode (1,1) and 6.15% for mode (2,0)-(0,2). For verification, the frequency responses of the plates are measured with both electrostatic excitation-detection at around 20 mTorr vacuum ambient and LDV at around 0.364 mTorr vacuum ambient. The resonance frequency and Q-factor of mode (1,1) are measured to be 104.2 kHz and 14 300, respectively. For mode (2,0)-(0,2), the measured resonance frequency and Q-factor are 156.68 kHz and 10 700, respectively. The presented LDV results also support both natural frequencies of interest and corresponding mode shapes of the plate structure.

Beyond CMOS: heterogeneous integration of III–V devices, RF MEMS and other dissimilar materials/devices with Si CMOS to create intelligent microsystems

PubMed Central

Kazior, Thomas E.

2014-01-01

Advances in silicon technology continue to revolutionize micro-/nano-electronics. However, Si cannot do everything, and devices/components based on other materials systems are required. What is the best way to integrate these dissimilar materials and to enhance the capabilities of Si, thereby continuing the micro-/nano-electronics revolution? In this paper, I review different approaches to heterogeneously integrate dissimilar materials with Si complementary metal oxide semiconductor (CMOS) technology. In particular, I summarize results on the successful integration of III–V electronic devices (InP heterojunction bipolar transistors (HBTs) and GaN high-electron-mobility transistors (HEMTs)) with Si CMOS on a common silicon-based wafer using an integration/fabrication process similar to a SiGe BiCMOS process (BiCMOS integrates bipolar junction and CMOS transistors). Our III–V BiCMOS process has been scaled to 200 mm diameter wafers for integration with scaled CMOS and used to fabricate radio-frequency (RF) and mixed signals circuits with on-chip digital control/calibration. I also show that RF microelectromechanical systems (MEMS) can be integrated onto this platform to create tunable or reconfigurable circuits. Thus, heterogeneous integration of III–V devices, MEMS and other dissimilar materials with Si CMOS enables a new class of high-performance integrated circuits that enhance the capabilities of existing systems, enable new circuit architectures and facilitate the continued proliferation of low-cost micro-/nano-electronics for a wide range of applications. PMID:24567473

Beyond CMOS: heterogeneous integration of III-V devices, RF MEMS and other dissimilar materials/devices with Si CMOS to create intelligent microsystems.

PubMed

Kazior, Thomas E

2014-03-28

Advances in silicon technology continue to revolutionize micro-/nano-electronics. However, Si cannot do everything, and devices/components based on other materials systems are required. What is the best way to integrate these dissimilar materials and to enhance the capabilities of Si, thereby continuing the micro-/nano-electronics revolution? In this paper, I review different approaches to heterogeneously integrate dissimilar materials with Si complementary metal oxide semiconductor (CMOS) technology. In particular, I summarize results on the successful integration of III-V electronic devices (InP heterojunction bipolar transistors (HBTs) and GaN high-electron-mobility transistors (HEMTs)) with Si CMOS on a common silicon-based wafer using an integration/fabrication process similar to a SiGe BiCMOS process (BiCMOS integrates bipolar junction and CMOS transistors). Our III-V BiCMOS process has been scaled to 200 mm diameter wafers for integration with scaled CMOS and used to fabricate radio-frequency (RF) and mixed signals circuits with on-chip digital control/calibration. I also show that RF microelectromechanical systems (MEMS) can be integrated onto this platform to create tunable or reconfigurable circuits. Thus, heterogeneous integration of III-V devices, MEMS and other dissimilar materials with Si CMOS enables a new class of high-performance integrated circuits that enhance the capabilities of existing systems, enable new circuit architectures and facilitate the continued proliferation of low-cost micro-/nano-electronics for a wide range of applications.

Fabrication of 3D surface structures using grayscale lithography

NASA Astrophysics Data System (ADS)

Stilson, Christopher; Pal, Rajan; Coutu, Ronald A.

2014-03-01

The ability to design and develop 3D microstructures is important for microelectromechanical systems (MEMS) fabrication. Previous techniques used to create 3D devices included tedious steps in direct writing and aligning patterns onto a substrate followed by multiple photolithography steps using expensive, customized equipment. Additionally, these techniques restricted batch processing and placed limits on achievable shapes. Gray-scale lithography enables the fabrication of a variety of shapes using a single photolithography step followed by reactive ion etching (RIE). Micromachining 3D silicon structures for MEMS can be accomplished using gray-scale lithography along with dry anisotropic etching. In this study, we investigated: using MATLAB for mask designs; feasibility of using 1 μm Heidelberg mask maker to direct write patterns onto photoresist; using RIE processing to etch patterns into a silicon substrate; and the ability to tailor etch selectivity for precise fabrication. To determine etch rates and to obtain desired etch selectivity, parameters such as gas mixture, gas flow, and electrode power were studied. This process successfully demonstrates the ability to use gray-scale lithography and RIE for use in the study of micro-contacts. These results were used to produce a known engineered non-planer surface for testing micro-contacts. Surface structures are between 5 μm and 20 μm wide with varying depths and slopes based on mask design and etch rate selectivity. The engineered surfaces will provide more insight into contact geometries and failure modes of fixed-fixed micro-contacts.

In situ MEMS testing: correlation of high-resolution X-ray diffraction with mechanical experiments and finite element analysis

NASA Astrophysics Data System (ADS)

Schifferle, Andreas; Dommann, Alex; Neels, Antonia

2017-12-01

New methods are needed in microsystems technology for evaluating microelectromechanical systems (MEMS) because of their reduced size. The assessment and characterization of mechanical and structural relations of MEMS are essential to assure the long-term functioning of devices, and have a significant impact on design and fabrication.

The NASA GSFC MEMS Colloidal Thruster

NASA Technical Reports Server (NTRS)

Cardiff, Eric H.; Jamieson, Brian G.; Norgaard, Peter C.; Chepko, Ariane B.

2004-01-01

A number of upcoming missions require different thrust levels on the same spacecraft. A highly scaleable and efficient propulsion system would allow substantial mass savings. One type of thruster that can throttle from high to low thrust while maintaining a high specific impulse is a Micro-Electro-Mechanical System (MEMS) colloidal thruster. The NASA GSFC MEMS colloidal thruster has solved the problem of electrical breakdown to permit the integration of the electrode on top of the emitter by a novel MEMS fabrication technique. Devices have been successfully fabricated and the insulation properties have been tested to show they can support the required electric field. A computational finite element model was created and used to verify the voltage required to successfully operate the thruster. An experimental setup has been prepared to test the devices with both optical and Time-Of-Flight diagnostics.

Design, fabrication, and evaluation of on-chip micro-supercapacitors

NASA Astrophysics Data System (ADS)

Beidaghi, Majid; Chen, Wei; Wang, Chunlei

2011-06-01

Development of miniaturized electronic systems has stimulated the demand for miniaturized power sources that can be integrated into such systems. Among the different micro power sources micro electrochemical energy storage and conversion devices are particularly attractive because of their high efficiency and relatively high energy density. Electrochemical micro-capacitors or micro-supercapacitors offer higher power density compared to micro-batteries and micro-fuel cells. In this paper, development of on-chip micro-supercapacitors based on interdigitated C-MEMS electrode microarrays is introduced. C-MEMS electrodes are employed both as electrode material for electric double layer capacitor (EDLC) or as three dimensional (3D) current collectors of EDLC or pseudo-capacitive materials. Recent advancements in fabrication methods of C-MEMS based micro-supercapacitors are discussed and electrochemical properties of C-MEMS electrodes and it composites are reviewed.

Process Development for the Fabrication of Spheroidal Microdevice Packages Utilizing MEMS Technologies

DTIC Science & Technology

2014-03-27

in a thin conductive layer, the wafer surface can be made into the cathode while using a stainless steel plate as an anode. Bath temperature, voltage...beakers with polytetrafluoroethylene (PTFE) tools while under a fume hood, as HF is known to attack glass and polystyrene [62]. Additionally

Staging of RF-accelerating Units in a MEMS-based Ion Accelerator

NASA Astrophysics Data System (ADS)

Persaud, A.; Seidl, P. A.; Ji, Q.; Feinberg, E.; Waldron, W. L.; Schenkel, T.; Ardanuc, S.; Vinayakumar, K. B.; Lal, A.

Multiple Electrostatic Quadrupole Array Linear Accelerators (MEQALACs) provide an opportunity to realize compact radio- frequency (RF) accelerator structures that can deliver very high beam currents. MEQALACs have been previously realized with acceleration gap distances and beam aperture sizes of the order of centimeters. Through advances in Micro-Electro-Mechanical Systems (MEMS) fabrication, MEQALACs can now be scaled down to the sub-millimeter regime and batch processed on wafer substrates. In this paper we show first results from using three RF stages in a compact MEMS-based ion accelerator. The results presented show proof-of-concept with accelerator structures formed from printed circuit boards using a 3 × 3 beamlet arrangement and noble gas ions at 10 keV. We present a simple model to describe the measured results. We also discuss some of the scaling behaviour of a compact MEQALAC. The MEMS-based approach enables a low-cost, highly versatile accelerator covering a wide range of currents (10 μA to 100 mA) and beam energies (100 keV to several MeV). Applications include ion-beam analysis, mass spectrometry, materials processing, and at very high beam powers, plasma heating.

Staging of RF-accelerating Units in a MEMS-based Ion Accelerator

DOE PAGES

Persaud, A.; Seidl, P. A.; Ji, Q.; ...

2017-10-26

Multiple Electrostatic Quadrupole Array Linear Accelerators (MEQALACs) provide an opportunity to realize compact radio- frequency (RF) accelerator structures that can deliver very high beam currents. MEQALACs have been previously realized with acceleration gap distances and beam aperture sizes of the order of centimeters. Through advances in Micro-Electro-Mechanical Systems (MEMS) fabrication, MEQALACs can now be scaled down to the sub-millimeter regime and batch processed on wafer substrates. In this paper we show first results from using three RF stages in a compact MEMS-based ion accelerator. The results presented show proof-of-concept with accelerator structures formed from printed circuit boards using a 3more » × 3 beamlet arrangement and noble gas ions at 10 keV. We present a simple model to describe the measured results. We also discuss some of the scaling behaviour of a compact MEQALAC. The MEMS-based approach enables a low-cost, highly versatile accelerator covering a wide range of currents (10 μA to 100 mA) and beam energies (100 keV to several MeV). Applications include ion-beam analysis, mass spectrometry, materials processing, and at very high beam powers, plasma heating.« less

Staging of RF-accelerating Units in a MEMS-based Ion Accelerator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Persaud, A.; Seidl, P. A.; Ji, Q.

Multiple Electrostatic Quadrupole Array Linear Accelerators (MEQALACs) provide an opportunity to realize compact radio- frequency (RF) accelerator structures that can deliver very high beam currents. MEQALACs have been previously realized with acceleration gap distances and beam aperture sizes of the order of centimeters. Through advances in Micro-Electro-Mechanical Systems (MEMS) fabrication, MEQALACs can now be scaled down to the sub-millimeter regime and batch processed on wafer substrates. In this paper we show first results from using three RF stages in a compact MEMS-based ion accelerator. The results presented show proof-of-concept with accelerator structures formed from printed circuit boards using a 3more » × 3 beamlet arrangement and noble gas ions at 10 keV. We present a simple model to describe the measured results. We also discuss some of the scaling behaviour of a compact MEQALAC. The MEMS-based approach enables a low-cost, highly versatile accelerator covering a wide range of currents (10 μA to 100 mA) and beam energies (100 keV to several MeV). Applications include ion-beam analysis, mass spectrometry, materials processing, and at very high beam powers, plasma heating.« less

Micromachined integrated self-adaptive nonlinear stops for mechanical shock protection of MEMS

NASA Astrophysics Data System (ADS)

Xu, Kaisi; Jiang, Fushuai; Zhang, Wei; Hao, Yilong

2018-06-01

This paper presents a novel concept of self-adaptive nonlinear stops (SANS) for the generic in-plane shock protection of microelectromechanical systems (MEMS) suspensions. This new shock protection strategy decouples the reliability design from the device design and is compatible with wafer-level MEMS batch fabrication without the requirement of additional processes or materials. SANS increase shock reliability by limiting the travel of the suspension in a compliant manner with efficient energy dissipation. Using numerical simulation, we analyzed the energy dissipation and the impact force between suspensions and shock stops under a half-sine shock impulse (3000 g (1 g  ≈  9.8 m s‑2), 0.15 ms). The simulation results indicate that SANS can reduce approximately 89.4% of the impact force compared with hard stops, and additionally, dissipate more than 22.7% of the total mechanical energy in a round trip of the proof mass. To prove the improvement in shock protection, we designed and fabricated model test specimens of both SANS and conventional hard stops. The experimental results demonstrate that test specimens of SANS achieved twice the robustness compared with those of hard stops.

Development of a high hertz-stress contact for conventional batch production using a unique scribing technology

NASA Astrophysics Data System (ADS)

Bhuiyan, M. M. I.; Alamgir, T.; Bhuiyan, M.; Kajihara, M.

2013-12-01

Gradually the electronic devices are getting more compact dimension with respect to the width and thickness. As a result, the contacts are becoming thinner and which leads the contact to be loose and unstable contact. In comercial stamping methode, connector tip diameter should be more than 300μm due to its size limitation. Consequently, the connector contact resistance is becoming higher due to weak contact force. To overcome this problem there were few more basic research using MEMS and Electro Fine Forming (EFF) technology to make high Hertz-Stress Contact (5μm) due to the limitation in the commercial stamping process and the result was in satisfactory level. However, since the MEMS and EFF fabrication is costly therefore, a new method is introduced in this paper using the commercial Phosphor Bronze stamping method to reduce the production cost. Moreover, scribing method is used to make tip on the contact. Accordingly, more compact fine pitch contact is successfully fabricated and tested with 5μm High Hertz Stress without using the MEMS and EFF technology. Hence the manufactured contact resistance becomes less than 20mΩ ±5mΩ.

Study of scratch drive actuator force characteristics

NASA Astrophysics Data System (ADS)

Li, Lijie; Brown, J. Gordon; Uttamchandani, Deepak

2002-11-01

Microactuators are one of the key components in MEMS technology, and various designs have been realized through different fabrication processes. One type of microactuator commonly used is the scratch drive actuator (SDA) that is frequently fabricated by surface micromachining processes. An experimental investigation has been conducted on the force characteristics of SDAs fabricated using the JDSU Microsystems MUMPs process. One-, two-, three- and four-plate SDAs connected to box-springs have been designed and fabricated for these experiments using MUMPs run 44. The spring constant for the box-springs has been calculated by FEM using ANSYS software. The product of the spring constant and spring extension is used to measure the forces produced by these SDAs. It is estimated that the forces produced exceed 250 μN from a one-plate SDA and 850 μN from a four-plate SDA.

Development of a compact optical MEMS scanner with integrated VCSEL light source and diffractive optics

NASA Astrophysics Data System (ADS)

Krygowski, Thomas W.; Reyes, David; Rodgers, M. Steven; Smith, James H.; Warren, Mial E.; Sweatt, William C.; Blum-Spahn, Olga; Wendt, Joel R.; Asbill, Randolph E.

1999-09-01

In this work the design and initial fabrication results are reported for the components of a compact optical-MEMS laser scanning system. This system integrates a silicon MEMS laser scanner, a Vertical Cavity Surface Emitting Laser (VCSEL) and passive optical components. The MEMS scanner and VCSEL are mounted onto a fused silica substrate which serves as an optical interconnect between the devices. Two Diffractive Optical Elements (DOE's) are etched into the fused silica substrate to focus the VCSEL beam and increase the scan range. The silicon MEMS scanner consists of an actuator that continuously scans the position of a large polysilicon gold- coated shuttle containing a third DOE. Interferometric measurements show that the residual stress in the 50 micrometer X 1000 micrometer shuttle is extremely low, with a maximum deflection of only 0.18 micrometer over an 800 micrometer span for an unmetallized case and a deflection of 0.56 micrometer for the metallized case. A conservative estimate for the scan range is approximately plus or minus 4 degrees, with a spot size of about 0.5 mm, producing 50 resolvable spots. The basic system architecture, optical and MEMS design is reported in this paper, with an emphasis on the design and fabrication of the silicon MEMS scanner portion of the system.

Design and Fabrication of High Gain Multi-element Multi-segment Quarter-sector Cylindrical Dielectric Resonator Antenna

NASA Astrophysics Data System (ADS)

Ranjan, Pinku; Gangwar, Ravi Kumar

2017-12-01

A novel design and analysis of quarter cylindrical dielectric resonator antenna (q-CDRA) with multi-element and multi-segment (MEMS) approach has been presented. The MEMS q-CDRA has been designed by splitting four identical quarters from a solid cylinder and then multi-segmentation approach has been utilized to design q-CDRA. The proposed antenna has been designed for enhancement in bandwidth as well as for high gain. For bandwidth enhancement, multi-segmentation method has been explained for the selection of dielectric constant of materials. The performance of the proposed MEMS q-CDRA has been demonstrated with design guideline of MEMS approach. To validate the antenna performance, three segments q-CDRA has been fabricated and analyzed practically. The simulated results have been in good agreement with measured one. The MEMS q-CDRA has wide impedance bandwidth (|S11|≤-10 dB) of 133.8 % with monopole-like radiation pattern. The proposed MEMS q-CDRA has been operating at TM01δ mode with the measured gain of 6.65 dBi and minimum gain of 4.5 dBi in entire operating frequency band (5.1-13.7 GHz). The proposed MEMS q-CDRA may find appropriate applications in WiMAX and WLAN band.

Design and Simulation of an Electrothermal Actuator Based Rotational Drive

NASA Astrophysics Data System (ADS)

Beeson, Sterling; Dallas, Tim

2008-10-01

As a participant in the Micro and Nano Device Engineering (MANDE) Research Experience for Undergraduates program at Texas Tech University, I learned how MEMS devices operate and the limits of their operation. Using specialized AutoCAD-based design software and the ANSYS simulation program, I learned the MEMS fabrication process used at Sandia National Labs, the design limitations of this process, the abilities and drawbacks of micro devices, and finally, I redesigned a MEMS device called the Chevron Torsional Ratcheting Actuator (CTRA). Motion is achieved through electrothermal actuation. The chevron (bent-beam) actuators cause a ratcheting motion on top of a hub-less gear so that as voltage is applied the CTRA spins. The voltage applied needs to be pulsed and the frequency of the pulses determine the angular frequency of the device. The main objective was to design electromechanical structures capable of transforming the electrical signals into mechanical motion without overheating. The design was optimized using finite element analysis in ANSYS allowing multi-physics simulations of our model system.

Reliable bonding using indium-based solders

NASA Astrophysics Data System (ADS)

Cheong, Jongpil; Goyal, Abhijat; Tadigadapa, Srinivas; Rahn, Christopher

2004-01-01

Low temperature bonding techniques with high bond strengths and reliability are required for the fabrication and packaging of MEMS devices. Indium and indium-tin based bonding processes are explored for the fabrication of a flextensional MEMS actuator, which requires the integration of lead zirconate titanate (PZT) substrate with a silicon micromachined structure at low temperatures. The developed technique can be used either for wafer or chip level bonding. The lithographic steps used for the patterning and delineation of the seed layer limit the resolution of this technique. Using this technique, reliable bonds were achieved at a temperature of 200°C. The bonds yielded an average tensile strength of 5.41 MPa and 7.38 MPa for samples using indium and indium-tin alloy solders as the intermediate bonding layers respectively. The bonds (with line width of 100 microns) showed hermetic sealing capability of better than 10-11 mbar-l/s when tested using a commercial helium leak tester.

Reliable bonding using indium-based solders

NASA Astrophysics Data System (ADS)

Cheong, Jongpil; Goyal, Abhijat; Tadigadapa, Srinivas; Rahn, Christopher

2003-12-01

Low temperature bonding techniques with high bond strengths and reliability are required for the fabrication and packaging of MEMS devices. Indium and indium-tin based bonding processes are explored for the fabrication of a flextensional MEMS actuator, which requires the integration of lead zirconate titanate (PZT) substrate with a silicon micromachined structure at low temperatures. The developed technique can be used either for wafer or chip level bonding. The lithographic steps used for the patterning and delineation of the seed layer limit the resolution of this technique. Using this technique, reliable bonds were achieved at a temperature of 200°C. The bonds yielded an average tensile strength of 5.41 MPa and 7.38 MPa for samples using indium and indium-tin alloy solders as the intermediate bonding layers respectively. The bonds (with line width of 100 microns) showed hermetic sealing capability of better than 10-11 mbar-l/s when tested using a commercial helium leak tester.

Hemispherical array of sensors with contractively wrapped polymer petals for flow sensing

NASA Astrophysics Data System (ADS)

Kanhere, Elgar; Wang, Nan; Kottapalli, Ajay Giri Prakash; Miao, Jianmin; Triantafyllou, Michael

2017-11-01

Hemispherical arrays have inherent advantages that allow simultaneous detection of flow speed and direction due to their shape. Though MEMS technology has progressed leaps and bounds, fabrication of array of sensors on a hemispherical surface is still a challenge. In this work, a novel approach of constructing hemispherical array is presented which employs a technique of contractively wrapping a hemispherical surface with flexible liquid crystal polymer petals. This approach also leverages the offerings from rapid prototyping technology and established standard MEMS fabrication processes. Hemispherical arrays of piezoresistive sensors are constructed with two types of petal wrappings, 4-petals and 8-petals, on a dome. The flow sensing and direction detection abilities of the dome are evaluated through experiments in wind tunnel. Experimental results demonstrate that a dome equipped with a dense array of sensors can provide information pertaining to the stimulus, through visualization of output profile over the entire surface.

Micro Electromechanical Systems (MEMS) Based Microfluidic Devices for Biomedical Applications

PubMed Central

Ashraf, Muhammad Waseem; Tayyaba, Shahzadi; Afzulpurkar, Nitin

2011-01-01

Micro Electromechanical Systems (MEMS) based microfluidic devices have gained popularity in biomedicine field over the last few years. In this paper, a comprehensive overview of microfluidic devices such as micropumps and microneedles has been presented for biomedical applications. The aim of this paper is to present the major features and issues related to micropumps and microneedles, e.g., working principles, actuation methods, fabrication techniques, construction, performance parameters, failure analysis, testing, safety issues, applications, commercialization issues and future prospects. Based on the actuation mechanisms, the micropumps are classified into two main types, i.e., mechanical and non-mechanical micropumps. Microneedles can be categorized according to their structure, fabrication process, material, overall shape, tip shape, size, array density and application. The presented literature review on micropumps and microneedles will provide comprehensive information for researchers working on design and development of microfluidic devices for biomedical applications. PMID:21747700

Micromachining of a bimorph Pb(Zr,Ti)O3 (PZT) cantilever using a micro-electromechanical systems (MEMS) process for energy harvesting application.

PubMed

Kim, Moonkeun; Hwang, Beomseok; Jeong, Jaehwa; Min, Nam Ki; Kwon, Kwang-Ho

2012-07-01

We designed and fabricated a bimorph Pb(Zr,Ti)O3 (PZT) cantilever with an integrated Si proof mass to obtain a low resonant frequency for an energy harvesting application. The cantilevers were fabricated on the micro-electromechanical systems (MEMS) scale. A mode of piezoelectric conversions were d31 and d33 mode in cantilever vibration Therefore, we designed and fabricated a single cantilever with d31 unimorph, d31 bimorph, d33 unimorph, and d33 bimorph modes. Finally, we fabricated a device with beam dimensions of about 5,400 microm x 480 microm x 14 microm (< +/- 5%), and an integrated Si proof mass with dimensions of about 1,481 microm x 988 microm x 450 microm (< +/- 5%). In order to measure the d31 and d33 modes, we fabricated top and bottom electrodes. The distance between the top electrodes was 50 microm and the resonant frequency was 89.4 Hz. The average powers of the d31 unimorph, d31 bimorph, d33 unimorph, and d33 bimorph modes were 3.90, 9.60, 21.42, and 22.47 nW at 0.8 g (g = 9.8 m/s2) and optimal resistance, respectively.

Fabrication of Quench Condensed Thin Films Using an Integrated MEMS Fab on a Chip

NASA Astrophysics Data System (ADS)

Lally, Richard; Reeves, Jeremy; Stark, Thomas; Barrett, Lawrence; Bishop, David

Atomic calligraphy is a microelectromechanical systems (MEMS)-based dynamic stencil nanolithography technique. Integrating MEMS devices into a bonded stacked array of three die provides a unique platform for conducting quench condensed thin film mesoscopic experiments. The atomic calligraphy Fab on a Chip process incorporates metal film sources, electrostatic comb driven stencil plate, mass sensor, temperature sensor, and target surface into one multi-die assembly. Three separate die are created using the PolyMUMPs process and are flip-chip bonded together. A die containing joule heated sources must be prepared with metal for evaporation prior to assembly. A backside etch of the middle/central die exposes the moveable stencil plate allowing the flux to pass through the stencil from the source die to the target die. The chip assembly is mounted in a cryogenic system at ultra-high vacuum for depositing extremely thin films down to single layers of atoms across targeted electrodes. Experiments such as the effect of thin film alloys or added impurities on their superconductivity can be measured in situ with this process.

Advances in photonic MOEMS-MEMS device thinning and polishing

NASA Astrophysics Data System (ADS)

McAneny, James J.; Kennedy, Mark; McGroggan, Tom

2010-02-01

As devices continue to increase in density and complexity, ever more stringent specifications are placed on the wafer scale equipment manufacturers to produce higher quality and higher output. This results in greater investment and more resource being diverted into producing tools and processes which can meet the latest demanding criteria. Substrate materials employed in the fabrication process range from Silicon through InP and include GaAs, InSb and other optical networking or waveguide materials. With this diversity of substrate materials presented, controlling the geometries and surfaces grows progressively more challenging. This article highlights the key parameters which require close monitoring and control in order to produce highly precise wafers as part of the fabrication process. Several as cut and commercially available standard polished wafer materials were used in empirical trials to test tooling options in generating high levels of geometric control over the dimensions while producing high quality surface finishes. Specific attention was given to the measurement and control of: flatness; parallelism/TTV; surface roughness and final target thickness as common specifications required by the industry. By combining the process variables of: plate speed, download pressure, slurry flow rate and concentration, pad type and wafer travel path across the polish pad, the effect of altering these variables was recorded and analysed to realize the optimum process conditions for the materials under test. The results being then used to design improved methods and tooling for the thinning and polishing of photonic materials applied to MOEMS-MEMS device fabrication.

BioMEMS for biosensors and closed-loop drug delivery.

PubMed

Coffel, Joel; Nuxoll, Eric

2018-06-15

The efficacy of pharmaceutical treatments can be greatly enhanced by physiological feedback from the patient using biosensors, though this is often invasive or infeasible. By adapting microelectromechanical systems (MEMS) technology to miniaturize such biosensors, previously inaccessible signals can be obtained, often from inside the patient. This is enabled by the device's extremely small footprint which minimizes both power consumption and implantation trauma, as well as the transport time for chemical analytes, in turn decreasing the sensor's response time. MEMS fabrication also allows mass production which can be easily scaled without sacrificing its high reproducibility and reliability, and allows seamless integration with control circuitry and telemetry which is already produced using the same materials and fabrication steps. By integrating these systems with drug delivery devices, many of which are also MEMS-based, closed loop drug delivery can be achieved. This paper surveys the types of signal transduction devices available for biosensing-primarily electrochemical, optical, and mechanical-looking at their implementation via MEMS technology. The impact of MEMS technology on the challenges of biosensor development, particularly safety, power consumption, degradation, fouling, and foreign body response, are also discussed. Copyright © 2018 Elsevier B.V. All rights reserved.

Realize multiple hermetic chamber pressures for system-on-chip process by using the capping wafer with diverse cavity depths

NASA Astrophysics Data System (ADS)

Cheng, Shyh-Wei; Weng, Jui-Chun; Liang, Kai-Chih; Sun, Yi-Chiang; Fang, Weileun

2018-04-01

Many mechanical and thermal characteristics, for example the air damping, of suspended micromachined structures are sensitive to the ambient pressure. Thus, micromachined devices such as the gyroscope and accelerometer have different ambient pressure requirements. Commercially available process platforms could be used to fabricate and integrate devices of various functions to reduce the chip size. However, it remains a challenge to offer different ambient pressures for micromachined devices after sealing them by wafer level capping (WLC). This study exploits the outgassing characteristics of the CMOS chip to fabricate chambers of various pressures after the WLC of the Si-above-CMOS (TSMC 0.18 µm 1P5M CMOS process) MEMS process platform. The pressure of the sealed chamber can be modulated by the chamber volume after the outgassing. In other words, the pressure of hermetic sealed chambers can be easily and properly defined by the etching depth of the cavity on an Si capping wafer. In applications, devices sealed with different cavity depths are implemented using the Si-above-CMOS (TSMC 0.18 µm 1P5M CMOS process) MEMS process platform to demonstrate the present approach. Measurements show the feasibility of this simple chamber pressure modulation approach on eight-inch wafers.

Microelectromechanical System (MEMS) Device Being Developed for Active Cooling and Temperature Control

NASA Technical Reports Server (NTRS)

Beach, Duane E.

2003-01-01

High-capacity cooling options remain limited for many small-scale applications such as microelectronic components, miniature sensors, and microsystems. A microelectromechanical system (MEMS) using a Stirling thermodynamic cycle to provide cooling or heating directly to a thermally loaded surface is being developed at the NASA Glenn Research Center to meet this need. The device can be used strictly in the cooling mode or can be switched between cooling and heating modes in milliseconds for precise temperature control. Fabrication and assembly employ techniques routinely used in the semiconductor processing industry. Benefits of the MEMS cooler include scalability to fractions of a millimeter, modularity for increased capacity and staging to low temperatures, simple interfaces, limited failure modes, and minimal induced vibration. The MEMS cooler has potential applications across a broad range of industries such as the biomedical, computer, automotive, and aerospace industries. The basic capabilities it provides can be categorized into four key areas: 1) Extended environmental temperature range in harsh environments; 2) Lower operating temperatures for electronics and other components; 3) Precision spatial and temporal thermal control for temperature-sensitive devices; and 4) The enabling of microsystem devices that require active cooling and/or temperature control. The rapidly expanding capabilities of semiconductor processing in general, and microsystems packaging in particular, present a new opportunity to extend Stirling-cycle cooling to the MEMS domain. The comparatively high capacity and efficiency possible with a MEMS Stirling cooler provides a level of active cooling that is impossible at the microscale with current state-of-the-art techniques. The MEMS cooler technology builds on decades of research at Glenn on Stirling-cycle machines, and capitalizes on Glenn s emerging microsystems capabilities.

Deep Reactive Ion Etching (DRIE) of High Aspect Ratio SiC Microstructures using a Time-Multiplexed Etch-Passivate Process

NASA Technical Reports Server (NTRS)

Evans, Laura J.; Beheim, Glenn M.

2006-01-01

High aspect ratio silicon carbide (SiC) microstructures are needed for microengines and other harsh environment micro-electro-mechanical systems (MEMS). Previously, deep reactive ion etching (DRIE) of low aspect ratio (AR less than or = 1) deep (greater than 100 micron) trenches in SiC has been reported. However, existing DRIE processes for SiC are not well-suited for definition of high aspect ratio features because such simple etch-only processes provide insufficient control over sidewall roughness and slope. Therefore, we have investigated the use of a time-multiplexed etch-passivate (TMEP) process, which alternates etching with polymer passivation of the etch sidewalls. An optimized TMEP process was used to etch high aspect ratio (AR greater than 5) deep (less than 100 micron) trenches in 6H-SiC. Power MEMS structures (micro turbine blades) in 6H-SiC were also fabricated.

Cost-effective MEMS piezoresistive cantilever-based sensor fabrication for gait movement analysis

NASA Astrophysics Data System (ADS)

Saadon, Salem; Anuar, A. F. M.; Wahab, Yufridin

2017-03-01

The conventional photolithography of crystalline silicon technique is limited to two-dimensional and structure scaling. It's also requiring a lot of time and chemical involves for the whole process. These problems can be overcome by using laser micromachining technique, that capable to produce three-dimensional structure and simultaneously avoiding the photo mask needs. In this paper, we reported on the RapidX-250 Excimer laser micromachining with 248 nm KrF to create in-time mask design and assisting in the fabrication process of piezo-resistive micro cantilever structures. Firstly, laser micromachining parameters have been investigated in order to fabricate the acceleration sensor to analyzing human gait movement. Preliminary result shows that the fabricated sensor able to define the movement difference of human motion regarding the electrical characteristic of piezo-resistor.

Heat transfer implications in the first MEMS fabricated thermal transiration-driven vacuum pump for gases

NASA Technical Reports Server (NTRS)

Vargo, S. E.; Green, A. A.; Muntz, E. P.

2000-01-01

The success of NASA's future space missions and the development of portable, commercial instrument packages will depend greatly on miniaturized components enabled by the use of microelectromechanical systems (MEMS).

Design and analysis of a high Q MEMS passive RF filter

NASA Astrophysics Data System (ADS)

Rathee, Vishal; Pande, Rajesh

2016-04-01

Over the past few years, significant growth has been observed in using MEMS based passive components in the RF microelectronics domain, especially in transceiver system. This is due to some excellent properties of the MEMS devices like low loss, low cost and excellent isolation. This paper presents a design of high performance MEMS passive band pass filter, consisting of L and C with improved quality factor and insertion loss less than the reported filters. In this paper we have presented a design of 2nd order band pass filter with 2.4GHz centre frequency and 83MHz bandwidth for Bluetooth application. The simulation results showed improved Q-factor of 34 and Insertion loss of 1.7dB to 1.9dB. The simulation results needs to be validated by fabricating the device, fabrication flow of which is also presented in the paper.

Recent Progress in Silicon-Based MEMS Field Emission Thrusters

NASA Astrophysics Data System (ADS)

Lenard, Roger X.; Kravitz, Stanley H.; Tajmar, Martin

2005-02-01

The Indium Field Emission Thruster (In-FET) is a highly characterized and space-proven device based on space-qualified liquid metal ion sources. There is also extensive experience with liquid metal ion sources for high-brightness semiconductor fabrications and inspection Like gridded ion engines, In-FETs efficiently accelerate ions through a series of high voltage electrodes. Instead of a plasma discharge to generate ions, which generates a mixture of singly and doubly charged ions as well as neutrals, indium metal is melted (157°C) and fed to the tip of a capillary tube where very high local electric fields perform more-efficient field emission ionization, providing nearly 100% singly charged species. In-FETs do not have the associated losses or lifetime concerns of a magnetically confined discharge and hollow cathode in ion thrusters. For In-FETs, propellant efficiencies ˜100% stipulate single-emitter currents ⩽10μA, perhaps as low as 5μA of current. This low emitter current results in ⩽0.5 W/emitter. Consequently, if the In-FET is to be used for future Human and Robotic missions under President Bush's Exploration plan, a mechanism to generate very high power levels is necessary. Efficient high-power operation requires many emitter/extractor pairs. Conventional fabrication techniques allow 1-10 emitters in a single module, with pain-staking precision required. Properly designed and fabricated In-FETs possess electric-to-jet efficiency >90% and a specific mass <0.25 kg/kWe. MEMS techniques allow reliable batch processing with ˜160,000 emitters in a 10×10-cm array. Developing a 1.5kW 10×10-cm module is a necessary stepping-stone for >500 kWe systems where groups of 9 or 16 modules, with a single PPU/feed system, form the building blocks for even higher-power exploration systems. In 2003, SNL and ARCS produced a MEMS-based In-FET 5×5 emitter module with individually addressable emitter/extractor pairs on a 15×15mm wafer. The first MEMS thruster prototype has already been tested to demonstrate the proof-of-concept in laboratory-scale testing. In this paper we discuss progress that has been achieved in the past year on fabricating silicon-based MEMS In-FETs.

Route to one-step microstructure mold fabrication for PDMS microfluidic chip

NASA Astrophysics Data System (ADS)

Lv, Xiaoqing; Geng, Zhaoxin; Fan, Zhiyuan; Wang, Shicai; Su, Yue; Fang, Weihao; Pei, Weihua; Chen, Hongda

2018-04-01

The microstructure mold fabrication for PDMS microfluidic chip remains complex and time-consuming process requiring special equipment and protocols: photolithography and etching. Thus, a rapid and cost-effective method is highly needed. Comparing with the traditional microfluidic chip fabricating process based on the micro-electromechanical system (MEMS), this method is simple and easy to implement, and the whole fabrication process only requires 1-2 h. Different size of microstructure from 100 to 1000 μm was fabricated, and used to culture four kinds of breast cancer cell lines. Cell viability and morphology was assessed when they were cultured in the micro straight channels, micro square holes and the bonding PDMS-glass microfluidic chip. The experimental results indicate that the microfluidic chip is good and meet the experimental requirements. This method can greatly reduce the process time and cost of the microfluidic chip, and provide a simple and effective way for the structure design and in the field of biological microfabrications and microfluidic chips.

A front-end wafer-level microsystem packaging technique with micro-cap array

NASA Astrophysics Data System (ADS)

Chiang, Yuh-Min

2002-09-01

The back-end packaging process is the remaining challenge for the micromachining industry to commercialize microsystem technology (MST) devices at low cost. This dissertation presents a novel wafer level protection technique as a final step of the front-end fabrication process for MSTs. It facilitates improved manufacturing throughput and automation in package assembly, wafer level testing of devices, and enhanced device performance. The method involves the use of a wafer-sized micro-cap array, which consists of an assortment of small caps micro-molded onto a material with adjustable shapes and sizes to serve as protective structures against the hostile environments during packaging. The micro-cap array is first constructed by a micromachining process with micro-molding technique, then sealed to the device wafer at wafer level. Epoxy-based wafer-level micro cap array has been successfully fabricated and showed good compatibility with conventional back-end packaging processes. An adhesive transfer technique was demonstrated to seal the micro cap array with a MEMS device wafer. No damage or gross leak was observed while wafer dicing or later during a gross leak test. Applications of the micro cap array are demonstrated on MEMS, microactuators fabricated using CRONOS MUMPS process. Depending on the application needs, the micro-molded cap can be designed and modified to facilitate additional component functions, such as optical, electrical, mechanical, and chemical functions, which are not easily achieved in the device by traditional means. Successful fabrication of a micro cap array comprised with microlenses can provide active functions as well as passive protection. An optical tweezer array could be one possibility for applications of a micro cap with microlenses. The micro cap itself could serve as micro well for DNA or bacteria amplification as well.

Through-wafer optical probe characterization for microelectromechanical systems positional state monitoring and feedback control

NASA Astrophysics Data System (ADS)

Dawson, Jeremy M.; Chen, Jingdong; Brown, Kolin S.; Famouri, Parviz F.; Hornak, Lawrence A.

2000-12-01

Implementation of closed-loop microelectromechanical system (MEMS) control enables mechanical microsystems to adapt to the demands of the environment that they are actuating, opening a broad range of new opportunities for future MEMS applications. Integrated optical microsystems have the potential to enable continuous in situ optical interrogation of MEMS microstructure position fully decoupled from the means of mechanical actuation that is necessary for realization of feedback control. We present the results of initial research evaluating through-wafer optical microprobes for surface micromachined MEMS integrated optical position monitoring. Results from the through-wafer free-space optical probe of a lateral comb resonator fabricated using the multiuser MEMS process service (MUMPS) indicate significant positional information content with an achievable return probe signal dynamic range of up to 80% arising from film transmission contrast. Static and dynamic deflection analysis and experimental results indicate a through-wafer probe positional signal sensitivity of 40 mV/micrometers for the present setup or 10% signal change per micrometer. A simulation of the application of nonlinear sliding control is presented illustrating position control of the lateral comb resonator structure given the availability of positional state information.

MEMS scanner with 2D tilt, piston, and focus motion

NASA Astrophysics Data System (ADS)

Lani, S.; Bayat, D.; Petremand, Y.; Regamey, Y.-J.; Onillon, E.; Pierer, J.; Grossmann, S.

2017-02-01

A MEMS scanner with a high level of motion freedom has been developed. It includes a 2D mechanical tilting capability of +/- 15°, a piston motion of 50μm and a focus/defocus control system of a 2mm diameter mirror. The tilt and piston motion is achieved with an electromagnetic actuation (moving magnet) and the focus control with a deformation of the reflective surface with pneumatic actuation. This required the fabrication of at least one channel on the compliant membrane and a closed cavity below the mirror surface and connected to an external pressure regulator (vacuum to several bars). The fabrication relies on 3 SOI wafers, 2 for forming the compliant membranes and the integrated channel, and 1 to form the cavity mirror. All wafers were then assembled by fusion bonding. Pneumatic actuation for focus control can be achieved from front or back side; function of packaging concept. A reflective coating can be added at the mirror surface depending of the application. The tilt and piston actuation is achieved by electromagnetic actuation for which a magnet is fixed on the moving part of the MEMS device. Finally the MEMS device is mounted on a ceramic PCB, containing the actuation micro-coils. Concept, fabrication, and testing of the devices will be presented. A case study for application in an endoscope with an integrated high power laser and a MEMS steering mechanism will be presented.

Power Mems Development

DTIC Science & Technology

2010-12-31

laboratories. Task 1.2 Contributors: Sunny Kedia, Shinzo Onishi , Scott Samson, Drew Hanser Task 1.2 Deliverable: Functional MEMS-based DC-DC...Shinzo Onishi , Drew Hanser, Weidong Wang, Sunny Kedia, John Bumgarner Deliverable: Prototype device fabricated on a thin-film diamond heat spreader

MEMS, Ka-Band Single-Pole Double-Throw (SPDT) Switch for Switched Line Phase Shifters

NASA Technical Reports Server (NTRS)

Scardelletti, Maximilian C.; Ponchak, George E.; Varaljay, Nicholas C.

2002-01-01

Ka-band MEMS doubly anchored cantilever beam capacitive shunt devices are used to demonstrate a MEMS SPDT switch fabricated on high resistivity silicon (HRS) utilizing finite ground coplanar waveguide (FGC) transmission lines. The SPDT switch has an insertion loss (IL), return loss (RL), and isolation of 0.3dB, 40dB, and 30 dB, respectively at Ka-band.

Conception, fabrication and characterization of a silicon based MEMS inertial switch with a threshold value of 5 g

NASA Astrophysics Data System (ADS)

Zhang, Fengtian; Wang, Chao; Yuan, Mingquan; Tang, Bin; Xiong, Zhuang

2017-12-01

Most of the MEMS inertial switches developed in recent years are intended for shock and impact sensing with a threshold value above 50 g. In order to follow the requirement of detecting linear acceleration signal at low-g level, a silicon based MEMS inertial switch with a threshold value of 5 g was designed, fabricated and characterized. The switch consisted of a large proof mass, supported by circular spiral springs. An analytical model of the structure stiffness of the proposed switch was derived and verified by finite-element simulation. The structure fabrication was based on a customized double-buried layer silicon-on-insulator wafer and encapsulated by glass wafers. The centrifugal experiment and nanoindentation experiment were performed to measure the threshold value as well as the structure stiffness. The actual threshold values were measured to be 0.1-0.3 g lower than the pre-designed value of 5 g due to the dimension loss during non-contact lithography processing. Concerning the reliability assessment, a series of environmental experiments were conducted and the switches remained operational without excessive errors. However, both the random vibration and the shock tests indicate that the metal particles generated during collision of contact parts might affect the contact reliability and long-time stability. According to the conclusion reached in this report, an attentive study on switch contact behavior should be included in future research.

Laser ablation for membrane processing of AlGaN/GaN- and micro structured ferroelectric thin film MEMS and SiC pressure sensors for extreme conditions

NASA Astrophysics Data System (ADS)

Zehetner, J.; Vanko, G.; Dzuba, J.; Ryger, I.; Lalinsky, T.; Benkler, Manuel; Lucki, Michal

2015-05-01

AlGaN/GaN based high electron mobility transistors (HEMTs), Schottky diodes and/or resistors have been presented as sensing devices for mechanical or chemical sensors operating in extreme conditions. In addition we investigate ferroelectric thin films for integration into micro-electro-mechanical-systems (MEMS). Creation of appropriate diaphragms and/or cantilevers out of SiC is necessary for further improvement of sensing properties of such MEMS sensors. For example sensitivity of the AlGaN/GaN based MEMS pressure sensor can be modified by membrane thickness. We demonstrated that a 4H-SiC 80μm thick diaphragms can be fabricated much faster with laser ablation than by electrochemical, photochemical or reactive ion etching (RIE). We were able to verify the feasibility of this process by fabrication of micromechanical membrane structures also in bulk 3C-SiC, borosilicate glass, sapphire and Al2O3 ceramic substrates by femtosecond laser (520nm) ablation. On a 350μm thick 4H-SiC substrate we produced an array of 275μm deep and 1000μm to 3000μm of diameter blind holes without damaging the 2μm AlN layer at the back side. In addition we investigated ferroelectric thin films as they can be deposited and micro-patterned by a direct UV-lithography method after the ablation process for a specific membrane design. The risk to harm or damage the function of thin films was eliminated by that means. Some defects in the ablated membranes are also affected by the polarisation of the laser light. Ripple structures oriented perpendicular to the laser polarisation promote creation of pin holes which would perforate a thin membrane. We developed an ablation technique strongly inhibiting formation of ripples and pin poles.

New optoelectronic methodology for nondestructive evaluation of MEMS at the wafer level

NASA Astrophysics Data System (ADS)

Furlong, Cosme; Ferguson, Curtis F.; Melson, Michael J.

2004-02-01

One of the approaches to fabrication of MEMS involves surface micromachining to define dies on single crystal silicon wafers, dicing of the wafers to separate the dies, and electronic packaging of the individual dies. Dicing and packaging of MEMS accounts for a large fraction of the fabrication costs, therefore, nondestructive evaluation at the wafer level, before dicing, can have significant implications on improving production yield and costs. In this paper, advances in development of optoelectronic holography (OEH) techniques for nondestructive, noninvasive, full-field of view evaluation of MEMS at the wafer level are described. With OEH techniques, quantitative measurements of shape and deformation of MEMS, as related to their performance and integrity, are obtained with sub-micrometer spatial resolution and nanometer measuring accuracy. To inspect an entire wafer with OEH methodologies, measurements of overlapping regions of interest (ROI) on a wafer are recorded and adjacent ROIs are stitched together through efficient 3D correlation analysis algorithms. Capabilities of the OEH techniques are illustrated with representative applications, including determination of optimal inspection conditions to minimize inspection time while achieving sufficient levels of accuracy and resolution.

Platinum nanowire microelectrode arrays for neurostimulation applications: Fabrication, characterization, and in-vitro retinal cell stimulation

NASA Astrophysics Data System (ADS)

Whalen, John J., III

Implantable electrical neurostimulating devices are being developed for a number of applications, including artificial vision through retinal stimulation. The epiretinal prosthesis will use a two-dimensional array microelectrodes to address individual cells of the retina. MEMS fabrication processes can produce arrays of microelectrodes with these dimensions, but there are two critical issues that they cannot satisfy. One, the stimulating electrodes are the only part of the implanted electrical device that penetrate through the water impermeable package, and must do so without sacrificing hermeticity. Two, As electrode size decreases, the current density (A cm-2 ) increases, due to increased electrochemical impedance. This reduces the amount of charge that can be safely injected into the tissue. To date, MEMS processing method, cannot produce electrode arrays with good, prolonged hermetic properties. Similarly, MEMS approaches do not account for the increased impedance caused by decreased surface area. For these reasons there is a strong motivation for the development of a water-impermeable, substrate-penetrating electrode array with low electrochemical impedance. This thesis presents a stimulating electrode array fabricated from platinum nanowires using a modified electrochemical template synthesis approach. Nanowires are electrochemically deposited from ammonium hexachloroplatinate solution into lithographically patterned nanoporous anodic alumina templates to produce microarrays of platinum nanowires. The platinum nanowires penetrating through the ceramic aluminum oxide template serve as parallel electrical conduits through the water impermeable, electrically insulating substrate. Electrode impedance can be adjusted by either controlling the nanowire hydrous platinum oxide content or by partially etching the alumina template to expose additional surface area. A stepwise approach to this project was taken. First, the electrochemistry of ammonium hexachloroplatinate solution was characterized, and physical properties of electrodeposited thin films were correlated to deposition conditions used. Second, platinum nanowires were fabricated and their properties characterized, using similar deposition conditions. Third, the feasibility of fabricating platinum nanowire stimulating electrode arrays with a variety of surface structures was demonstrated. Fourth, the enhanced charge transfer characteristics of these structures were demonstrated using electrochemical techniques. Finally, retinal cell stimulation was demonstrated using electrodes from platinum nanowire arrays.

Characterization techniques to predict mechanical behaviour of green ceramic bodies fabricated by ceramic microstereolithography

NASA Astrophysics Data System (ADS)

Adake, Chandrashekhar V.; Bhargava, Parag; Gandhi, Prasanna

2018-02-01

Ceramic microstereolithography (CMSL) has emerged as solid free form (SFF) fabrication technology in which complex ceramic parts are fabricated from ceramic suspensions which are formulated by dispersing ceramic particles in UV curable resins. Ceramic parts are fabricated by exposing ceramic suspension to computer controlled UV light which polymerizes resin to polymer and this polymer forms rigid network around ceramic particles. A 3-dimensional part is created by piling cured layers one over the other. These ceramic parts are used to build microelectromechanical (MEMS) devices after thermal treatment. In many cases green ceramic parts can be directly utilized to build MEMS devices. Hence characterization of these parts is essential in terms of their mechanical behaviour prior to their use in MEMS devices. Mechanical behaviour of these green ceramic parts depends on cross link density which in turn depends on chemical structure of monomer, concentrations of photoinitiator and UV energy dose. Mechanical behaviour can be determined with the aid of nanoindentation. And extent of crosslinking can be verified with the aid of DSC. FTIR characterization is used to analyse (-C=C-) double bond conversion. This paper explains characterization tools to predict the mechanical behaviour of green ceramic bodies fabricated in CMSL

Carbon material based microelectromechanical system (MEMS): Fabrication and devices

NASA Astrophysics Data System (ADS)

Xu, Wenjun

This PhD dissertation presents the exploration and development of two carbon materials, carbon nanotubes (CNTs) and carbon fiber (CF), as either key functional components or unconventional substrates for a variety of MEMS applications. Their performance in three different types of MEMS devices, namely, strain/stress sensors, vibration-powered generators and fiber solar cells, were evaluated and the working mechanisms of these two non-traditional materials in these systems were discussed. The work may potentially enable the development of new types of carbon-MEMS devices. Carbon nanotubes were selected from the carbon family due to several advantageous characteristics that this nanomaterial offers. They carry extremely high mechanical strength (Ey=1TPa), superior electrical properties (current density of 4x109 A/cm2), exceptional piezoresistivity (G=2900), and unique spatial format (high aspect ratio hollow nanocylinder), among other properties. If properly utilized, all these merits can give rise to a variety of new types of carbon nanotube based micro- and nanoelectronics that can greatly fulfill the need for the next generation of faster, smaller and better devices. However, before these functions can be fully realized, one substantial issue to cope with is how to implement CNTs into these systems in an effective and controllable fashion. Challenges associated with CNTs integration include very poor dispersibility in solvents, lack of melting/sublimation point, and unfavorable rheology with regard to mixing and processing highly viscous, CNT-loaded polymer solutions. These issues hinder the practical progress of CNTs both in a lab scale and in the industrial level. To this end, a MEMS-assisted electrophoretic deposition technique was developed, aiming to achieve controlled integration of CNT into both conventional and flexible microsystems at room temperature with a relatively high throughput. MEMS technology has demonstrated strong capability in developing silicon and metal based microsystems. In this thesis, this mature technique was exploited to generate a variety of microelectrode structures to facilitate the micropatterning and manipulation of the CNTs. Selective deposition of electrically charged CNTs onto desired locations was realized in an EPD process through patterning of electric field lines created by the microelectrodes fabricated through MEMS techniques. A variety of 2-D and 3-D micropatterns of CNTs with waferscale areas have been successfully achieved in both rigid and elastic systems. The thickness and morphology of the generated CNT patterns was found to be readily controllable through the parameters of the fabrication process. Studies also showed that for this technique, high surface hydrophobicity of the non-conductive regions in microstructures was critical to accomplish well-defined selective micropatterning of CNTs. Upon clearing the hurdles of the CNT manipulation, a patterned PDMS/CNT nanocomposite was fabricated through the aforementioned approach and was incorporated, investigated and validated in elastic force/strain microsensors. The gauge factor of the sensor exhibited a strong dependence on both the initial resistance of the device and the applied strain. Detailed analysis of the data suggests that the piezoresistive effect of this specially constructed bi-layer composite could be due to three mechanisms, and the sensing mechanism may vary when physical properties of the CNT network embedded in the polymer matrix alter. The feasibility of the PDSM/CNT composite being utilized as an elastic electret was further explored. The nanocomposite composed of these two non-traditional electret materials exhibited electret characteristics with reasonable charge storage stability when charged using a corona discharge. The power generation capacity of the corona-charged composite has been characterized and successfully demonstrated in both a ball drop experiment and cyclic mechanical load experiments. Lastly, in an effort to develop carbon-material-based substrates for MEMS applications, a carbon fiber-based poly-Si solar cell was designed, fabricated and investigated. This fiber-type photovoltaics (PV) takes advantage of the excellent thermal stability, electrical conductivity and spatial format of the CF, which allows CF to serve as both the building block and the electrode in the PV configuration. The photovoltaic effects of the fiber PV were demonstrated with an open-circuit voltage of 0.14 V, a short-circuit current density of 1.7 mA/cm2, and output power density of 0.059mW/cm2 . The issues of this system were discussed as well.

Non-destructive residual pressure self-measurement method for the sensing chip of optical Fabry-Perot pressure sensor.

PubMed

Wang, Xue; Wang, Shuang; Jiang, Junfeng; Liu, Kun; Zhang, Xuezhi; Xiao, Mengnan; Xiao, Hai; Liu, Tiegen

2017-12-11

We introduce a simple residual pressure self-measurement method for the Fabry-Perot (F-P) cavity of optical MEMS pressure sensor. No extra installation is required and the structure of the sensor is unchanged. In the method, the relationship between residual pressure and external pressure under the same diaphragm deflection condition at different temperatures is analyzed by using the deflection formula of the circular plate with clamped edges and the ideal gas law. Based on this, the residual pressure under the flat condition can be obtained by pressure scanning process and calculation process. We carried out the experiment to compare the residual pressures of two batches MEMS sensors fabricated by two kinds of bonding process. The measurement result indicates that our approach is reliable enough for the measurement.

Development of a Compact Optical-MEMS Scanner with Integrated VCSEL Light Source and Diffractive Optics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krygowski, Thomas W.; Reyes, David; Rodgers, M. Steven

1999-06-30

In this work the design and initial fabrication results are reported for the components of a compact optical-MEMS laser scanning system. This system integrates a silicon MEMS laser scanner, a Vertical Cavity Surface Emitting Laser (VCSEL) and passive optical components. The MEMS scanner and VCSEL are mounted onto a fused silica substrate which serves as an optical interconnect between the devices. Two Diffractive Optical Elements (DOEs) are etched into the fused silica substrate to focus the VCSEL beam and increase the scan range. The silicon MEMS scanner consists of an actuator that continuously scans the position of a large polysiliconmore » gold-coated shuttle containing a third DOE. Interferometric measurements show that the residual stress in the 500 {micro}m x 1000 {micro}m shuttle is extremely low, with a maximum deflection of only 0.18{micro}m over an 800 {micro}m span for an unmetallized case and a deflection of 0.56{micro}m for the metallized case. A conservative estimate for the scan range is {approximately}{+-}4{degree}, with a spot size of about 0.5 mm, producing 50 resolvable spots. The basic system architecture, optical and MEMS design is reported in this paper, with an emphasis on the design and fabrication of the silicon MEMS scanner portion of the system.« less

Deformation analysis of MEMS structures by modified digital moiré methods

NASA Astrophysics Data System (ADS)

Liu, Zhanwei; Lou, Xinhao; Gao, Jianxin

2010-11-01

Quantitative deformation analysis of micro-fabricated electromechanical systems is of importance for the design and functional control of microsystems. In this paper, two modified digital moiré processing methods, Gaussian blurring algorithm combined with digital phase shifting and geometrical phase analysis (GPA) technique based on digital moiré method, are developed to quantitatively analyse the deformation behaviour of micro-electro-mechanical system (MEMS) structures. Measuring principles and experimental procedures of the two methods are described in detail. A digital moiré fringe pattern is generated by superimposing a specimen grating etched directly on a microstructure surface with a digital reference grating (DRG). Most of the grating noise is removed from the digital moiré fringes, which enables the phase distribution of the moiré fringes to be obtained directly. Strain measurement result of a MEMS structure demonstrates the feasibility of the two methods.

A review: aluminum nitride MEMS contour-mode resonator

NASA Astrophysics Data System (ADS)

Yunhong, Hou; Meng, Zhang; Guowei, Han; Chaowei, Si; Yongmei, Zhao; Jin, Ning

2016-10-01

Over the past several decades, the technology of micro-electromechanical system (MEMS) has advanced. A clear need of miniaturization and integration of electronics components has had new solutions for the next generation of wireless communications. The aluminum nitride (AlN) MEMS contour-mode resonator (CMR) has emerged and become promising and competitive due to the advantages of the small size, high quality factor and frequency, low resistance, compatibility with integrated circuit (IC) technology, and the ability of integrating multi-frequency devices on a single chip. In this article, a comprehensive review of AlN MEMS CMR technology will be presented, including its basic working principle, main structures, fabrication processes, and methods of performance optimization. Among these, the deposition and etching process of the AlN film will be specially emphasized and recent advances in various performance optimization methods of the CMR will be given through specific examples which are mainly focused on temperature compensation and reducing anchor losses. This review will conclude with an assessment of the challenges and future trends of the CMR. Project supported by National Natural Science Foundation (Nos. 61274001, 61234007, 61504130), the Nurturing and Development Special Projects of Beijing Science and Technology Innovation Base's Financial Support (No. Z131103002813070), and the National Defense Science and Technology Innovation Fund of CAS (No. CXJJ-14-M32).

Micromachine friction test apparatus

DOEpatents

deBoer, Maarten P.; Redmond, James M.; Michalske, Terry A.

2002-01-01

A microelectromechanical (MEM) friction test apparatus is disclosed for determining static or dynamic friction in MEM devices. The friction test apparatus, formed by surface micromachining, is based on a friction pad supported at one end of a cantilevered beam, with the friction pad overlying a contact pad formed on the substrate. A first electrostatic actuator can be used to bring a lower surface of the friction pad into contact with an upper surface of the contact pad with a controlled and adjustable force of contact. A second electrostatic actuator can then be used to bend the cantilevered beam, thereby shortening its length and generating a relative motion between the two contacting surfaces. The displacement of the cantilevered beam can be measured optically and used to determine the static or dynamic friction, including frictional losses and the coefficient of friction between the surfaces. The test apparatus can also be used to assess the reliability of rubbing surfaces in MEM devices by producing and measuring wear of those surfaces. Finally, the friction test apparatus, which is small in size, can be used as an in situ process quality tool for improving the fabrication of MEM devices.

Resonant Magnetic Field Sensors Based On MEMS Technology.

PubMed

Herrera-May, Agustín L; Aguilera-Cortés, Luz A; García-Ramírez, Pedro J; Manjarrez, Elías

2009-01-01

Microelectromechanical systems (MEMS) technology allows the integration of magnetic field sensors with electronic components, which presents important advantages such as small size, light weight, minimum power consumption, low cost, better sensitivity and high resolution. We present a discussion and review of resonant magnetic field sensors based on MEMS technology. In practice, these sensors exploit the Lorentz force in order to detect external magnetic fields through the displacement of resonant structures, which are measured with optical, capacitive, and piezoresistive sensing techniques. From these, the optical sensing presents immunity to electromagnetic interference (EMI) and reduces the read-out electronic complexity. Moreover, piezoresistive sensing requires an easy fabrication process as well as a standard packaging. A description of the operation mechanisms, advantages and drawbacks of each sensor is considered. MEMS magnetic field sensors are a potential alternative for numerous applications, including the automotive industry, military, medical, telecommunications, oceanographic, spatial, and environment science. In addition, future markets will need the development of several sensors on a single chip for measuring different parameters such as the magnetic field, pressure, temperature and acceleration.

Resonant Magnetic Field Sensors Based On MEMS Technology

PubMed Central

Herrera-May, Agustín L.; Aguilera-Cortés, Luz A.; García-Ramírez, Pedro J.; Manjarrez, Elías

2009-01-01

Microelectromechanical systems (MEMS) technology allows the integration of magnetic field sensors with electronic components, which presents important advantages such as small size, light weight, minimum power consumption, low cost, better sensitivity and high resolution. We present a discussion and review of resonant magnetic field sensors based on MEMS technology. In practice, these sensors exploit the Lorentz force in order to detect external magnetic fields through the displacement of resonant structures, which are measured with optical, capacitive, and piezoresistive sensing techniques. From these, the optical sensing presents immunity to electromagnetic interference (EMI) and reduces the read-out electronic complexity. Moreover, piezoresistive sensing requires an easy fabrication process as well as a standard packaging. A description of the operation mechanisms, advantages and drawbacks of each sensor is considered. MEMS magnetic field sensors are a potential alternative for numerous applications, including the automotive industry, military, medical, telecommunications, oceanographic, spatial, and environment science. In addition, future markets will need the development of several sensors on a single chip for measuring different parameters such as the magnetic field, pressure, temperature and acceleration. PMID:22408480

Heavily Boron-Doped Silicon Layer for the Fabrication of Nanoscale Thermoelectric Devices

PubMed Central

Liu, Yang; Deng, Lingxiao; Zhang, Mingliang; Zhang, Shuyuan; Ma, Jing; Song, Peishuai; Liu, Qing; Ji, An; Yang, Fuhua; Wang, Xiaodong

2018-01-01

Heavily boron-doped silicon layers and boron etch-stop techniques have been widely used in the fabrication of microelectromechanical systems (MEMS). This paper provides an introduction to the fabrication process of nanoscale silicon thermoelectric devices. Low-dimensional structures such as silicon nanowire (SiNW) have been considered as a promising alternative for thermoelectric applications in order to achieve a higher thermoelectric figure of merit (ZT) than bulk silicon. Here, heavily boron-doped silicon layers and boron etch-stop processes for the fabrication of suspended SiNWs will be discussed in detail, including boron diffusion, electron beam lithography, inductively coupled plasma (ICP) etching and tetramethylammonium hydroxide (TMAH) etch-stop processes. A 7 μm long nanowire structure with a height of 280 nm and a width of 55 nm was achieved, indicating that the proposed technique is useful for nanoscale fabrication. Furthermore, a SiNW thermoelectric device has also been demonstrated, and its performance shows an obvious reduction in thermal conductivity. PMID:29385759

n+ GaAs/AuGeNi-Au Thermocouple-Type RF MEMS Power Sensors Based on Dual Thermal Flow Paths in GaAs MMIC

PubMed Central

Zhang, Zhiqiang; Liao, Xiaoping

2017-01-01

To achieve radio frequency (RF) power detection, gain control, and circuit protection, this paper presents n+ GaAs/AuGeNi-Au thermocouple-type RF microelectromechanical system (MEMS) power sensors based on dual thermal flow paths. The sensors utilize a conversion principle of RF power-heat-voltage, where a thermovoltage is obtained as the RF power changes. To improve the heat transfer efficiency and the sensitivity, structures of two heat conduction paths are designed: one in which a thermal slug of Au is placed between two load resistors and hot junctions of the thermocouples, and one in which a back cavity is fabricated by the MEMS technology to form a substrate membrane underneath the resistors and the hot junctions. The improved sensors were fabricated by a GaAs monolithic microwave integrated circuit (MMIC) process. Experiments show that these sensors have reflection losses of less than −17 dB up to 12 GHz. At 1, 5, and 10 GHz, measured sensitivities are about 63.45, 53.97, and 44.14 µV/mW for the sensor with the thermal slug, and about 111.03, 94.79, and 79.04 µV/mW for the sensor with the thermal slug and the back cavity, respectively. PMID:28629144

n⁺ GaAs/AuGeNi-Au Thermocouple-Type RF MEMS Power Sensors Based on Dual Thermal Flow Paths in GaAs MMIC.

PubMed

Zhang, Zhiqiang; Liao, Xiaoping

2017-06-17

To achieve radio frequency (RF) power detection, gain control, and circuit protection, this paper presents n⁺ GaAs/AuGeNi-Au thermocouple-type RF microelectromechanical system (MEMS) power sensors based on dual thermal flow paths. The sensors utilize a conversion principle of RF power-heat-voltage, where a thermovoltage is obtained as the RF power changes. To improve the heat transfer efficiency and the sensitivity, structures of two heat conduction paths are designed: one in which a thermal slug of Au is placed between two load resistors and hot junctions of the thermocouples, and one in which a back cavity is fabricated by the MEMS technology to form a substrate membrane underneath the resistors and the hot junctions. The improved sensors were fabricated by a GaAs monolithic microwave integrated circuit (MMIC) process. Experiments show that these sensors have reflection losses of less than -17 dB up to 12 GHz. At 1, 5, and 10 GHz, measured sensitivities are about 63.45, 53.97, and 44.14 µ V/mW for the sensor with the thermal slug, and about 111.03, 94.79, and 79.04 µ V/mW for the sensor with the thermal slug and the back cavity, respectively.

Fast tunable blazed MEMS grating for external cavity lasers

NASA Astrophysics Data System (ADS)

Tormen, Maurizio; Niedermann, Philippe; Hoogerwerf, Arno; Shea, Herbert; Stanley, Ross

2017-11-01

Diffractive MEMS are interesting for a wide range of applications, including displays, scanners or switching elements. Their advantages are compactness, potentially high actuation speed and in the ability to deflect light at large angles. We have designed and fabricated deformable diffractive MEMS grating to be used as tuning elements for external cavity lasers. The resulting device is compact, has wide tunability and a high operating speed. The initial design is a planar grating where the beams are free-standing and attached to each other using leaf springs. Actuation is achieved through two electrostatic comb drives at either end of the grating. To prevent deformation of the free-standing grating, the device is 10 μm thick made from a Silicon on Insulator (SOI) wafer in a single mask process. At 100V a periodicity tuning of 3% has been measured. The first resonant mode of the grating is measured at 13.8 kHz, allowing high speed actuation. This combination of wide tunability and high operating speed represents state of the art in the domain of tunable MEMS filters. In order to improve diffraction efficiency and to expand the usable wavelength range, a blazed version of the deformable MEMS grating has been designed. A key issue is maintaining the mechanical properties of the original device while providing optically smooth blazed beams. Using a process based on anisotropic KOH etching, blazed gratings have been obtained and preliminary characterization is promising.

Design and fabrication of vibration based energy harvester using microelectromechanical system piezoelectric cantilever for low power applications.

PubMed

Kim, Moonkeun; Lee, Sang-Kyun; Yang, Yil Suk; Jeong, Jaehwa; Min, Nam Ki; Kwon, Kwang-Ho

2013-12-01

We fabricated dual-beam cantilevers on the microelectromechanical system (MEMS) scale with an integrated Si proof mass. A Pb(Zr,Ti)O3 (PZT) cantilever was designed as a mechanical vibration energy-harvesting system for low power applications. The resonant frequency of the multilayer composition cantilevers were simulated using the finite element method (FEM) with parametric analysis carried out in the design process. According to simulations, the resonant frequency, voltage, and average power of a dual-beam cantilever was 69.1 Hz, 113.9 mV, and 0.303 microW, respectively, at optimal resistance and 0.5 g (gravitational acceleration, m/s2). Based on these data, we subsequently fabricated cantilever devices using dual-beam cantilevers. The harvested power density of the dual-beam cantilever compared favorably with the simulation. Experiments revealed the resonant frequency, voltage, and average power density to be 78.7 Hz, 118.5 mV, and 0.34 microW, respectively. The error between the measured and simulated results was about 10%. The maximum average power and power density of the fabricated dual-beam cantilever at 1 g were 0.803 microW and 1322.80 microW cm(-3), respectively. Furthermore, the possibility of a MEMS-scale power source for energy conversion experiments was also tested.

Design, Fabrication, and Characterization of a Microelectromechanical Directional Microphone

DTIC Science & Technology

2011-06-01

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES...Figure 5.2 SOIC packaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 Figure 5.3 Laboratory setup...Mean Squared SOC System-On-Chip SOIC Small Outline Integrated Circuit SOIMUMPS Silicon-On-Insulator Multi-User MEMS Process SPL Sound Pressure Level

Laser processing for strengthening of the self-restoring metal-elastomer interface on a silicone sheet

NASA Astrophysics Data System (ADS)

Yasuda, Kiyokazu

2012-08-01

A self-restoring microsystem is a unique concept which realizes the sensing functionality and robust interface which mechanically and electrically connects a deformable object such as a human body with printed electronic devices. For this purpose, the formation of conductive wiring on an elastomer substrate was attempted using the nickel ink printing process. Before the wiring process, surface patterning of a silicone sheet by a galvano-scanned infrared laser was conducted for the enhancement of interface adhesion of the metal deposit and polymer. Characterization of the fabricated pattern was conducted by optical microscopy. The novel method was successfully demonstrated as a fabrication of selective patterns of metal particles on self-restoring MEMS.

Design and fabrication of non silicon substrate based MEMS energy harvester for arbitrary surface applications

NASA Astrophysics Data System (ADS)

Balpande, Suresh S.; Pande, Rajesh S.

2016-04-01

Internet of Things (IoT) uses MEMS sensor nodes and actuators to sense and control objects through Internet. IOT deploys millions of chemical battery driven sensors at different locations which are not reliable many times because of frequent requirement of charging & battery replacement in case of underground laying, placement at harsh environmental conditions, huge count and difference between demand (24 % per year) and availability (energy density growing rate 8% per year). Energy harvester fabricated on silicon wafers have been widely used in manufacturing MEMS structures. These devices require complex fabrication processes, costly chemicals & clean room. In addition to this silicon wafer based devices are not suitable for curved surfaces like pipes, human bodies, organisms, or other arbitrary surface like clothes, structure surfaces which does not have flat and smooth surface always. Therefore, devices based on rigid silicon wafers are not suitable for these applications. Flexible structures are the key solution for this problems. Energy transduction mechanism generates power from free surrounding vibrations or impact. Sensor nodes application has been purposefully selected due to discrete power requirement at low duty cycle. Such nodes require an average power budget in the range of about 0.1 microwatt to 1 mW over a period of 3-5 seconds. Energy harvester is the best alternate source in contrast with battery for sensor node application. Novel design of Energy Harvester based on cheapest flexible non silicon substrate i.e. cellulose acetate substrate have been modeled, simulated and analyzed on COMSOL multiphysics and fabricated using sol-gel spin coating setup. Single cantilever based harvester generates 60-75 mV peak electric potential at 22Hz frequency and approximately 22 µW power at 1K-Ohm load. Cantilever array can be employed for generating higher voltage by replicating this structure. This work covers design, optimization, fabrication of harvester and schottky diodes based voltage multiplier.

Design and fabrication of non silicon substrate based MEMS energy harvester for arbitrary surface applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Balpande, Suresh S., E-mail: balpandes@rknec.edu; Pande, Rajesh S.

Internet of Things (IoT) uses MEMS sensor nodes and actuators to sense and control objects through Internet. IOT deploys millions of chemical battery driven sensors at different locations which are not reliable many times because of frequent requirement of charging & battery replacement in case of underground laying, placement at harsh environmental conditions, huge count and difference between demand (24 % per year) and availability (energy density growing rate 8% per year). Energy harvester fabricated on silicon wafers have been widely used in manufacturing MEMS structures. These devices require complex fabrication processes, costly chemicals & clean room. In addition tomore » this silicon wafer based devices are not suitable for curved surfaces like pipes, human bodies, organisms, or other arbitrary surface like clothes, structure surfaces which does not have flat and smooth surface always. Therefore, devices based on rigid silicon wafers are not suitable for these applications. Flexible structures are the key solution for this problems. Energy transduction mechanism generates power from free surrounding vibrations or impact. Sensor nodes application has been purposefully selected due to discrete power requirement at low duty cycle. Such nodes require an average power budget in the range of about 0.1 microwatt to 1 mW over a period of 3-5 seconds. Energy harvester is the best alternate source in contrast with battery for sensor node application. Novel design of Energy Harvester based on cheapest flexible non silicon substrate i.e. cellulose acetate substrate have been modeled, simulated and analyzed on COMSOL multiphysics and fabricated using sol-gel spin coating setup. Single cantilever based harvester generates 60-75 mV peak electric potential at 22Hz frequency and approximately 22 µW power at 1K-Ohm load. Cantilever array can be employed for generating higher voltage by replicating this structure. This work covers design, optimization, fabrication of harvester and schottky diodes based voltage multiplier.« less

Grayscale photomask fabricated by laser direct writing in metallic nano-films.

PubMed

Guo, Chuan Fei; Cao, Sihai; Jiang, Peng; Fang, Ying; Zhang, Jianming; Fan, Yongtao; Wang, Yongsheng; Xu, Wendong; Zhao, Zhensheng; Liu, Qian

2009-10-26

The grayscale photomask plays a key role in grayscale lithography for creating 3D microstructures like micro-optical elements and MEMS structures, but how to fabricate grayscale masks in a cost-effective way is still a big challenge. Here we present novel low cost grayscale masks created in a two-step method by laser direct writing on Sn nano-films, which demonstrate continuous-tone gray levels depended on writing powers. The mechanism of the gray levels is due to the coexistence of the metal and the oxides formed in a laser-induced thermal process. The photomasks reveal good technical properties in fabricating 3D microstructures for practical applications.

MEMS-based fuel cells with integrated catalytic fuel processor and method thereof

DOEpatents

Jankowski, Alan F [Livermore, CA; Morse, Jeffrey D [Martinez, CA; Upadhye, Ravindra S [Pleasanton, CA; Havstad, Mark A [Davis, CA

2011-08-09

Described herein is a means to incorporate catalytic materials into the fuel flow field structures of MEMS-based fuel cells, which enable catalytic reforming of a hydrocarbon based fuel, such as methane, methanol, or butane. Methods of fabrication are also disclosed.

A hybrid life cycle inventory of nano-scale semiconductor manufacturing.

PubMed

Krishnan, Nikhil; Boyd, Sarah; Somani, Ajay; Raoux, Sebastien; Clark, Daniel; Dornfeld, David

2008-04-15

The manufacturing of modern semiconductor devices involves a complex set of nanoscale fabrication processes that are energy and resource intensive, and generate significant waste. It is important to understand and reduce the environmental impacts of semiconductor manufacturing because these devices are ubiquitous components in electronics. Furthermore, the fabrication processes used in the semiconductor industry are finding increasing application in other products, such as microelectromechanical systems (MEMS), flat panel displays, and photovoltaics. In this work we develop a library of typical gate-to-gate materials and energy requirements, as well as emissions associated with a complete set of fabrication process models used in manufacturing a modern microprocessor. In addition, we evaluate upstream energy requirements associated with chemicals and materials using both existing process life cycle assessment (LCA) databases and an economic input-output (EIO) model. The result is a comprehensive data set and methodology that may be used to estimate and improve the environmental performance of a broad range of electronics and other emerging applications that involve nano and micro fabrication.

Research on ion implantation in MEMS device fabrication by theory, simulation and experiments

NASA Astrophysics Data System (ADS)

Bai, Minyu; Zhao, Yulong; Jiao, Binbin; Zhu, Lingjian; Zhang, Guodong; Wang, Lei

2018-06-01

Ion implantation is widely utilized in microelectromechanical systems (MEMS), applied for embedded lead, resistors, conductivity modifications and so forth. In order to achieve an expected device, the principle of ion implantation must be carefully examined. The elementary theory of ion implantation including implantation mechanism, projectile range and implantation-caused damage in the target were studied, which can be regarded as the guidance of ion implantation in MEMS device design and fabrication. Critical factors including implantations dose, energy and annealing conditions are examined by simulations and experiments. The implantation dose mainly determines the dopant concentration in the target substrate. The implantation energy is the key factor of the depth of the dopant elements. The annealing time mainly affects the repair degree of lattice damage and thus the activated elements’ ratio. These factors all together contribute to ions’ behavior in the substrates and characters of the devices. The results can be referred to in the MEMS design, especially piezoresistive devices.

Wafer-to-wafer bonding of nonplanarized MEMS surfaces using solder

NASA Astrophysics Data System (ADS)

Sparks, D.; Queen, G.; Weston, R.; Woodward, G.; Putty, M.; Jordan, L.; Zarabadi, S.; Jayakar, K.

2001-11-01

The fabrication and reliability of a solder wafer-to-wafer bonding process is discussed. Using a solder reflow process allows vacuum packaging to be accomplished with unplanarized complementary metal-oxide semiconductor (CMOS) surface topography. This capability enables standard CMOS processes, and integrated microelectromechanical systems devices to be packaged at the chip-level. Alloy variations give this process the ability to bond at lower temperatures than most alternatives. Factors affecting hermeticity, shorts, Q values, shifting cavity pressure, wafer saw cleanliness and corrosion resistance will be covered.

Electrothermal actuators fabricated in four-level planarized surface-miromachined polycrystalline silicon

DOE Office of Scientific and Technical Information (OSTI.GOV)

Comtois, J.H.; Michalicek, A.; Barron, C.C.

1997-11-01

This paper presents the results of tests performed on a variety of electrochemical microactuators and arrays of these actuators fabricated in the SUMMiT process at the U.S. Department of Energy`s Sandia National Laboratories. These results are intended to aid designers of thermally actuated mechanisms, and they apply to similar actuators made in other polysilicon MEMS processes such as the MUMPS process. Measurements include force and deflection versus input power, maximum operating frequency, effects of long term operation, and ideal actuator and array geometries for different applications` force requirements. Also, different methods of arraying these actuators together are compared. It ismore » found that a method using rotary joints, enabled by the advanced features of the SUMMiT fabrication process, is the most efficient array design. The design and operation of a thermally actuated stepper motor is explained to illustrate a useful application of these arrays.« less

Microstructure factor and mechanical and electronic properties of hydrogenated amorphous and nanocrystalline silicon thin-films for microelectromechanical systems applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mouro, J.; Gualdino, A.; Chu, V.

2013-11-14

Thin-film silicon allows the fabrication of MEMS devices at low processing temperatures, compatible with monolithic integration in advanced electronic circuits, on large-area, low-cost, and flexible substrates. The most relevant thin-film properties for applications as MEMS structural layers are the deposition rate, electrical conductivity, and mechanical stress. In this work, n{sup +}-type doped hydrogenated amorphous and nanocrystalline silicon thin-films were deposited by RF-PECVD, and the influence of the hydrogen dilution in the reactive mixture, the RF-power coupled to the plasma, the substrate temperature, and the deposition pressure on the structural, electrical, and mechanical properties of the films was studied. Three differentmore » types of silicon films were identified, corresponding to three internal structures: (i) porous amorphous silicon, deposited at high rates and presenting tensile mechanical stress and low electrical conductivity, (ii) dense amorphous silicon, deposited at intermediate rates and presenting compressive mechanical stress and higher values of electrical conductivity, and (iii) nanocrystalline silicon, deposited at very low rates and presenting the highest compressive mechanical stress and electrical conductivity. These results show the combinations of electromechanical material properties available in silicon thin-films and thus allow the optimized selection of a thin silicon film for a given MEMS application. Four representative silicon thin-films were chosen to be used as structural material of electrostatically actuated MEMS microresonators fabricated by surface micromachining. The effect of the mechanical stress of the structural layer was observed to have a great impact on the device resonance frequency, quality factor, and actuation force.« less

Integrated Optoelectronic Position Sensor for Scanning Micromirrors.

PubMed

Cheng, Xiang; Sun, Xinglin; Liu, Yan; Zhu, Lijun; Zhang, Xiaoyang; Zhou, Liang; Xie, Huikai

2018-03-26

Scanning micromirrors have been used in a wide range of areas, but many of them do not have position sensing built in, which significantly limits their application space. This paper reports an integrated optoelectronic position sensor (iOE-PS) that can measure the linear displacement and tilting angle of electrothermal MEMS (Micro-electromechanical Systems) scanning mirrors. The iOE-PS integrates a laser diode and its driving circuits, a quadrant photo-detector (QPD) and its readout circuits, and a band-gap reference all on a single chip, and it has been fabricated in a standard 0.5 μm CMOS (Complementary Metal Oxide Semiconductor) process. The footprint of the iOE-PS chip is 5 mm × 5 mm. Each quadrant of the QPD has a photosensitive area of 500 µm × 500 µm and the spacing between adjacent quadrants is 500 μm. The iOE-PS chip is simply packaged underneath of an electrothermally-actuated MEMS mirror. Experimental results show that the iOE-PS has a linear response when the MEMS mirror plate moves vertically between 2.0 mm and 3.0 mm over the iOE-PS chip or scans from -5 to +5°. Such MEMS scanning mirrors integrated with the iOE-PS can greatly reduce the complexity and cost of the MEMS mirrors-enabled modules and systems.

A MEMS Condenser Microphone-Based Intracochlear Acoustic Receiver.

PubMed

Pfiffner, Flurin; Prochazka, Lukas; Peus, Dominik; Dobrev, Ivo; Dalbert, Adrian; Sim, Jae Hoon; Kesterke, Rahel; Walraevens, Joris; Harris, Francesca; Roosli, Christof; Obrist, Dominik; Huber, Alexander

2017-10-01

Intracochlear sound pressure (ICSP) measurements are limited by the small dimensions of the human inner ear and the requirements imposed by the liquid medium. A robust intracochlear acoustic receiver (ICAR) for repeated use with a simple data acquisition system that provides the required high sensitivity and small dimensions does not yet exist. The work described in this report aims to fill this gap and presents a new microelectromechanical systems (MEMS) condenser microphone (CMIC)-based ICAR concept suitable for ICSP measurements in human temporal bones. The ICAR head consisted of a passive protective diaphragm (PD) sealing the MEMS CMIC against the liquid medium, enabling insertion into the inner ear. The components of the MEMS CMIC-based ICAR were expressed by a lumped element model (LEM) and compared to the performance of successfully fabricated ICARs. Good agreement was achieved between the LEM and the measurements with different sizes of the PD. The ICSP measurements in a human cadaver temporal bone yielded data in agreement with the literature. Our results confirm that the presented MEMS CMIC-based ICAR is a promising technology for measuring ICSP in human temporal bones in the audible frequency range. A sensor for evaluation of the biomechanical hearing process by quantification of ICSP is presented. The concept has potential as an acoustic receiver in totally implantable cochlear implants.

A novel safety device with metal counter meshing gears discriminator directly driven by axial flux permanent magnet micromotors based on MEMS technology

NASA Astrophysics Data System (ADS)

Zhang, Weiping; Chen, Wenyuan; Zhao, Xiaolin; Li, Shengyong; Jiang, Yong

2005-08-01

In a novel safety device based on MEMS technology for high consequence systems, the discriminator consists of two groups of metal counter meshing gears and two pawl/ratchet wheel mechanisms. Each group of counter meshing gears is onepiece and driven directly by an axial flux permanent magnet micromotor respectively. The energy-coupling element is an optical shutter with two collimators and a coupler wheel. The safety device's probability is less than 1/106. It is fabricated by combination of an LiGA-like process and precision mechanical engineering. The device has simple structure, few dynamic problems, high strength and strong reliability.

A wide-range variable-frequency resonant tunneling diode oscillator using a variable resonator suitable for simple MEMS process

NASA Astrophysics Data System (ADS)

Yamashita, Takashi; Nakano, Daisuke; Mori, Masayuki; Maezawa, Koichi

2018-04-01

A resonant tunneling diode oscillator having a wide frequency variation range based on a novel MEMS resonator was proposed, which exploits the change in the signal propagation velocity on a coplanar waveguide according to a movable ground plane. First, we discussed the velocity modulation mechanism, and clarified the importance of the dielectric constant of the substrate. Then, a prototype device oscillating in a 10 to 20 GHz frequency range was fabricated to demonstrate the basic operation. A large and continuous increase in the oscillation frequency of about two times was achieved with this device. This is promising for various applications including THz spectroscopy.

Batch fabrication of precision miniature permanent magnets

DOEpatents

Christenson, Todd R.; Garino, Terry J.; Venturini, Eugene L.

2002-01-01

A new class of processes for fabrication of precision miniature rare earth permanent magnets is disclosed. Such magnets typically have sizes in the range 0.1 to 10 millimeters, and dimensional tolerances as small as one micron. Very large magnetic fields can be produced by such magnets, lending to their potential application in MEMS and related electromechanical applications, and in miniature millimeter-wave vacuum tubes. This abstract contains simplifications, and is supplied only for purposes of searching, not to limit or alter the scope or meaning of any claims herein.

Delamination study of chip-to-chip bonding for a LIGA-based safety and arming system

NASA Astrophysics Data System (ADS)

Subramanian, Gowrishankar; Deeds, Michael; Cochran, Kevin R.; Raghavan, Raghu; Sandborn, Peter A.

1999-08-01

The development of a miniature underwater weapon safety and arming system requires reliable chip-to-chip bonding of die that contain microelectromechanical actuators and sensors fabricated using a LIGA MEMS fabrication process. Chip-to- chip bonding is associated for several different bond materials (indium solder, thermoplastic paste, thermoplastic film and epoxy film), and bonding configurations (with an alloy 42 spacer, silicon to ceramic, and silicon to silicon). Metrology using acoustic micro imaging has been developed to determine the fraction of delamination of samples.

Research and Education in Development of Multifunctional Sensors and MEMS Devices

DTIC Science & Technology

2015-07-15

UNDERREPRESENTED MINORITY GROUPS IN MEMS AND SENSOR DEVELOPMENT AND FABRICATION 3.1 EDUCATION AND CURRICULAR DEVELOPMENT Dr. Williams (Co- PI ...dye-sensitized solar cell (DSSC) works.  Prepare a DSSC using crushed blackberries and raspberries , to serve as the source of sensitizer molecules

Multi-Probe SPM using Interference Patterns for a Parallel Nano Imaging

NASA Astrophysics Data System (ADS)

Koyama, Hirotaka; Oohira, Fumikazu; Hosogi, Maho; Hashiguchi, Gen

This paper proposes a new composition of the multi-probe using optical interference patterns for a parallel nano imaging in a large area scanning. We achieved large-scale integration with 50,000 probes fabricated with MEMS technology, and measured the optical interference patterns with CCD, which was difficult in a conventional single scanning probe. In this research, the multi-probes are made of Si3N4 by MEMS process, and, the multi-probes are joined with a Pyrex glass by an anodic bonding. We designed, fabricated, and evaluated the characteristics of the probe. In addition, we changed the probe shape to decrease the warpage of the Si3N4 probe. We used the supercritical drying to avoid stiction of the Si3N4 probe with the glass surface and fabricated 4 types of the probe shapes without stiction. We took some interference patterns by CCD and measured the position of them. We calculate the probe height using the interference displacement and compared the result with the theoretical deflection curve. As a result, these interference patterns matched the theoretical deflection curve. We found that this multi-probe chip using interference patterns is effective in measurement for a parallel nano imaging.

Design, fabrication, and testing of a low frequency MEMS piezoelectromagnetic energy harvester

NASA Astrophysics Data System (ADS)

Fernandes, Egon; Martin, Blake; Rua, Isabel; Zarabi, Sid; Debéda, Hélène; Nairn, David; Wei, Lan; Salehian, Armaghan

2018-03-01

This paper details a power solution for smart grid applications to replace batteries by harvesting the electromagnetic energy from a current-carrying wire. A MEMS piezoelectromagnetic energy harvester has been fabricated using PZT screen-printing technology with a centrally-supported meandering geometry. The energy harvesting device employs a symmetric geometry to increase its power output by reducing the effects of the torsional modes and the resultant overall strain nodes in the system subsequently reduce the complexities for the electrode fabrication. The unit is modelled using COMSOL to determine mode shapes and frequency response functions. A 12.7 mm by 14.7 mm unit is fabricated by screen-printing 75 μm-thick PZT on a stainless steel substrate and then experimentally tested to validate the FEA results. Experimentally, the harvester is shown to produce 9 μW from a wire carrying 7 A while operating at a distance of 6.5 mm from the wire. The design of the current work results in a greater normalized power density than other MEMS based piezoelectromagnetic devices and shows great potential relative to larger devices that use bulk or thin film piezoelectrics.

MEMS/MOEMS foundry services at INO

NASA Astrophysics Data System (ADS)

García-Blanco, Sonia; Ilias, Samir; Williamson, Fraser; Généreux, Francis; Le Noc, Loïc; Poirier, Michel; Proulx, Christian; Tremblay, Bruno; Provençal, Francis; Desroches, Yan; Caron, Jean-Sol; Larouche, Carl; Beaupré, Patrick; Fortin, Benoit; Topart, Patrice; Picard, Francis; Alain, Christine; Pope, Timothy; Jerominek, Hubert

2010-06-01

In the MEMS manufacturing world, the "fabless" model is getting increasing importance in recent years as a way for MEMS manufactures and startups to minimize equipment costs and initial capital investment. In order for this model to be successful, the fabless company needs to work closely with a MEMS foundry service provider. Due to the lack of standardization in MEMS processes, as opposed to CMOS microfabrication, the experience in MEMS development processes and the flexibility of the MEMS foundry are of vital importance. A multidisciplinary team together with a complete microfabrication toolset allows INO to offer unique MEMS foundry services to fabless companies looking for low to mid-volume production. Companies that benefit from their own microfabrication facilities can also be interested in INO's assistance in conducting their research and development work during periods where production runs keep their whole staff busy. Services include design, prototyping, fabrication, packaging, and testing of various MEMS and MOEMS devices on wafers fully compatible with CMOS integration. Wafer diameters ranging typically from 1 inch to 6 inches can be accepted while 8-inch wafers can be processed in some instances. Standard microfabrication techniques such as metal, dielectric, and semiconductor film deposition and etching as well as photolithographic pattern transfer are available. A stepper permits reduction of the critical dimension to around 0.4 μm. Metals deposited by vacuum deposition methods include Au, Ag, Al, Al alloys, Ti, Cr, Cu, Mo, MoCr, Ni, Pt, and V with thickness varying from 5 nm to 2 μm. Electroplating of several materials including Ni, Au and In is also available. In addition, INO has developed and built a gold black deposition facility to answer customer's needs for broadband microbolometric detectors. The gold black deposited presents specular reflectance of less than 10% in the wavelength range from 0.2 μm to 100 μm with thickness ranging from 20 to 35 μm and a density of 0.3% the bulk density of gold. Two Balzers thin-film deposition instruments (BAP-800 and BAK-760) permit INO to offer optical thin film manufacturing. Recent work in this field includes the design and development of a custom filter for the James Webb Space Telescope (JWST) as collaboration with the Canadian company ComDEV. An overview of the different microfabrication foundry services offered by INO will be presented together with the most recent achievements in the field of MEMS/MOEMS.

Miniaturized imaging spectrometer based on Fabry-Perot MOEMS filters and HgCdTe infrared focal plane arrays

NASA Astrophysics Data System (ADS)

Velicu, S.; Buurma, C.; Bergeson, J. D.; Kim, Tae Sung; Kubby, J.; Gupta, N.

2014-05-01

Imaging spectrometry can be utilized in the midwave infrared (MWIR) and long wave infrared (LWIR) bands to detect, identify and map complex chemical agents based on their rotational and vibrational emission spectra. Hyperspectral datasets are typically obtained using grating or Fourier transform spectrometers to separate the incoming light into spectral bands. At present, these spectrometers are large, cumbersome, slow and expensive, and their resolution is limited by bulky mechanical components such as mirrors and gratings. As such, low-cost, miniaturized imaging spectrometers are of great interest. Microfabrication of micro-electro-mechanicalsystems (MEMS)-based components opens the door for producing low-cost, reliable optical systems. We present here our work on developing a miniaturized IR imaging spectrometer by coupling a mercury cadmium telluride (HgCdTe)-based infrared focal plane array (FPA) with a MEMS-based Fabry-Perot filter (FPF). The two membranes are fabricated from silicon-oninsulator (SOI) wafers using bulk micromachining technology. The fixed membrane is a standard silicon membrane, fabricated using back etching processes. The movable membrane is implemented as an X-beam structure to improve mechanical stability. The geometries of the distributed Bragg reflector (DBR)-based tunable FPFs are modeled to achieve the desired spectral resolution and wavelength range. Additionally, acceptable fabrication tolerances are determined by modeling the spectral performance of the FPFs as a function of DBR surface roughness and membrane curvature. These fabrication non-idealities are then mitigated by developing an optimized DBR process flow yielding high-performance FPF cavities. Zinc Sulfide (ZnS) and Germanium (Ge) are chosen as the low and the high index materials, respectively, and are deposited using an electron beam process. Simulations are presented showing the impact of these changes and non-idealities in both a device and systems level.

The fabrication of diversiform nanostructure forests based on residue nanomasks synthesized by oxygen plasma removal of photoresist

NASA Astrophysics Data System (ADS)

Mao, Haiyang; Wu, Di; Wu, Wengang; Xu, Jun; Hao, Yilong

2009-11-01

A simple lithography-free approach for fabricating diversiform nanostructure forests is presented. The key technique of the approach is that randomly distributed nanoscale residues can be synthesized on substrates simply by removing photoresist with oxygen plasma bombardment. These nanoresidues can function as masks in the subsequent etching process for nanopillars. By further spacer and then deep etching processes, a variety of forests composed of regular, tulip-like or hollow-head nanopillars as well as nanoneedles are successfully achieved in different etching conditions. The pillars have diameters of 30-200 nm and heights of 400 nm-3 µm. The needles reach several microns in height, with their tips less than 10 nm in diameter. Moreover, microstructures containing these nanostructure forests, such as surface microchannels, have also been fabricated. This approach is compatible with conventional micro/nano-electromechanical system (MEMS/NEMS) fabrication.

Comparison of mechanical characteristics of focused ion beam fabricated silicon nanowires

NASA Astrophysics Data System (ADS)

Ina, Ginnosuke; Fujii, Tatsuya; Kozeki, Takahiro; Miura, Eri; Inoue, Shozo; Namazu, Takahiro

2017-06-01

In this study, we investigate the effects of focused ion beam (FIB)-induced damage and specimen size on the mechanical properties of Si nanowires (NWs) by a microelectromechanical system (MEMS)-based tensile testing technique. By an FIB fabrication technique, three types of Si NWs, which are as-FIB-fabricated, annealed, and FIB-implanted NWs, are prepared. A sacrificial-oxidized NW is also prepared to compare the mechanical properties of these FIB-based NWs. The quasi-static uniaxial tensile tests of all the NWs are conducted by scanning electron microscopy (SEM). The fabrication process and specimen size dependences on Young’s modulus and fracture strength are observed. Annealing is effective for improving the Young’s modulus of the FIB-damaged Si. Transmission electron microscopy (TEM) suggests that the mechanism behind the process dependence on the mechanical characteristics is related to the crystallinity of the FIB-damaged portion.

Graphitization in Carbon MEMS and Carbon NEMS

NASA Astrophysics Data System (ADS)

Sharma, Swati

Carbon MEMS (CMEMS) and Carbon NEMS (CNEMS) are an emerging class of miniaturized devices. Due to the numerous advantages such as scalable manufacturing processes, inexpensive and readily available precursor polymer materials, tunable surface properties and biocompatibility, carbon has become a preferred material for a wide variety of future sensing applications. Single suspended carbon nanowires (CNWs) integrated on CMEMS structures fabricated by electrospinning of SU8 photoresist on photolithographially patterned SU8 followed by pyrolysis are utilized for understanding the graphitization process in micro and nano carbon materials. These monolithic CNW-CMEMS structures enable the fabrication of very high aspect ratio CNWs of predefined length. The CNWs thus fabricated display core---shell structures having a graphitic shell with a glassy carbon core. The electrical conductivity of these CNWs is increased by about 100% compared to glassy carbon as a result of enhanced graphitization. We explore various tunable fabrication and pyrolysis parameters to improve graphitization in the resulting CNWs. We also suggest gas-sensing application of the thus fabricated single suspended CNW-CMEMS devices by using the CNW as a nano-hotplate for local chemical vapor deposition. In this thesis we also report on results from an optimization study of SU8 photoresist derived carbon electrodes. These electrodes were applied to the simultaneous detection of traces of Cd(II) and Pb(II) through anodic stripping voltammetry and detection limits as low as 0.7 and 0.8 microgL-1 were achieved. To further improve upon the electrochemical behavior of the carbon electrodes we elucidate a modified pyrolysis technique featuring an ultra-fast temperature ramp for obtaining bubbled porous carbon from lithographically patterned SU8. We conclude this dissertation by suggesting the possible future works on enhancing graphitization as well as on electrochemical applications

Ka-Band, RF MEMS Switches on CMOS Grade Silicon with a Polyimide Interface Layer

NASA Technical Reports Server (NTRS)

Ponchak, George E.; Varaljay, Nicholas C.; Papapolymerou, John

2003-01-01

For the first time, RF MEMS switcbes on CMOS grade Si witb a polyimide interface layer are fabricated and characterized. At Ka-Band (36.6 GHz), an insertion loss of 0.52 dB and an isolation of 20 dB is obtained.

Fabrication and characterization of resonant SOI micromechanical silicon sensors based on DRIE micromachining, freestanding release process and silicon direct bonding

NASA Astrophysics Data System (ADS)

Gigan, Olivier; Chen, Hua; Robert, Olivier; Renard, Stephane; Marty, Frederic

2002-11-01

This paper is dedicated to the fabrication and technological aspect of a silicon microresonator sensor. The entire project includes the fabrication processes, the system modelling/simulation, and the electronic interface. The mechanical model of such resonator is presented including description of frequency stability and Hysterises behaviour of the electrostatically driven resonator. Numeric model and FEM simulations are used to simulate the system dynamic behaviour. The complete fabrication process is based on standard microelectronics technology with specific MEMS technological steps. The key steps are described: micromachining on SOI by Deep Reactive Ion Etching (DRIE), specific release processes to prevent sticking (resist and HF-vapour release process) and collective vacuum encapsulation by Silicon Direct Bonding (SDB). The complete process has been validated and prototypes have been fabricated. The ASIC was designed to interface the sensor and to control the vibration amplitude. This electronic was simulated and designed to work up to 200°C and implemented in a standard 0.6μ CMOS technology. Characterizations of sensor prototypes are done both mechanically and electrostatically. These measurements showed good agreements with theory and FEM simulations.

TOPICAL REVIEW: Self-assembly from milli- to nanoscales: methods and applications

NASA Astrophysics Data System (ADS)

Mastrangeli, M.; Abbasi, S.; Varel, C.; Van Hoof, C.; Celis, J.-P.; Böhringer, K. F.

2009-08-01

The design and fabrication techniques for microelectromechanical systems (MEMS) and nanodevices are progressing rapidly. However, due to material and process flow incompatibilities in the fabrication of sensors, actuators and electronic circuitry, a final packaging step is often necessary to integrate all components of a heterogeneous microsystem on a common substrate. Robotic pick-and-place, although accurate and reliable at larger scales, is a serial process that downscales unfavorably due to stiction problems, fragility and sheer number of components. Self-assembly, on the other hand, is parallel and can be used for device sizes ranging from millimeters to nanometers. In this review, the state-of-the-art in methods and applications for self-assembly is reviewed. Methods for assembling three-dimensional (3D) MEMS structures out of two-dimensional (2D) ones are described. The use of capillary forces for folding 2D plates into 3D structures, as well as assembling parts onto a common substrate or aggregating parts to each other into 2D or 3D structures, is discussed. Shape matching and guided assembly by magnetic forces and electric fields are also reviewed. Finally, colloidal self-assembly and DNA-based self-assembly, mainly used at the nanoscale, are surveyed, and aspects of theoretical modeling of stochastic assembly processes are discussed.

1.05-GHz CMOS oscillator based on lateral- field-excited piezoelectric AlN contour- mode MEMS resonators.

PubMed

Zuo, Chengjie; Van der Spiegel, Jan; Piazza, Gianluca

2010-01-01

This paper reports on the first demonstration of a 1.05-GHz microelectromechanical (MEMS) oscillator based on lateral-field-excited (LFE) piezoelectric AlN contourmode resonators. The oscillator shows a phase noise level of -81 dBc/Hz at 1-kHz offset frequency and a phase noise floor of -146 dBc/Hz, which satisfies the global system for mobile communications (GSM) requirements for ultra-high frequency (UHF) local oscillators (LO). The circuit was fabricated in the AMI semiconductor (AMIS) 0.5-microm complementary metaloxide- semiconductor (CMOS) process, with the oscillator core consuming only 3.5 mW DC power. The device overall performance has the best figure-of-merit (FoM) when compared with other gigahertz oscillators that are based on film bulk acoustic resonator (FBAR), surface acoustic wave (SAW), and CMOS on-chip inductor and capacitor (CMOS LC) technologies. A simple 2-mask process was used to fabricate the LFE AlN resonators operating between 843 MHz and 1.64 GHz with simultaneously high Q (up to 2,200) and kt 2 (up to 1.2%). This process further relaxes manufacturing tolerances and improves yield. All these advantages make these devices suitable for post-CMOS integrated on-chip direct gigahertz frequency synthesis in reconfigurable multiband wireless communications.

Self-assembly from milli- to nanoscales: methods and applications

PubMed Central

Mastrangeli, M; Abbasi, S; Varel, C; Van Hoof, C; Celis, J-P; Böhringer, K F

2009-01-01

The design and fabrication techniques for microelectromechanical systems (MEMS) and nanodevices are progressing rapidly. However, due to material and process flow incompatibilities in the fabrication of sensors, actuators and electronic circuitry, a final packaging step is often necessary to integrate all components of a heterogeneous microsystem on a common substrate. Robotic pick-and-place, although accurate and reliable at larger scales, is a serial process that downscales unfavorably due to stiction problems, fragility and sheer number of components. Self-assembly, on the other hand, is parallel and can be used for device sizes ranging from millimeters to nanometers. In this review, the state-of-the-art in methods and applications for self-assembly is reviewed. Methods for assembling three-dimensional (3D) MEMS structures out of two-dimensional (2D) ones are described. The use of capillary forces for folding 2D plates into 3D structures, as well as assembling parts onto a common substrate or aggregating parts to each other into 2D or 3D structures, is discussed. Shape matching and guided assembly by magnetic forces and electric fields are also reviewed. Finally, colloidal self-assembly and DNA-based self-assembly, mainly used at the nanoscale, are surveyed, and aspects of theoretical modeling of stochastic assembly processes are discussed. PMID:20209016

Grayscale lithography-automated mask generation for complex three-dimensional topography

NASA Astrophysics Data System (ADS)

Loomis, James; Ratnayake, Dilan; McKenna, Curtis; Walsh, Kevin M.

2016-01-01

Grayscale lithography is a relatively underutilized technique that enables fabrication of three-dimensional (3-D) microstructures in photosensitive polymers (photoresists). By spatially modulating ultraviolet (UV) dosage during the writing process, one can vary the depth at which photoresist is developed. This means complex structures and bioinspired designs can readily be produced that would otherwise be cost prohibitive or too time intensive to fabricate. The main barrier to widespread grayscale implementation, however, stems from the laborious generation of mask files required to create complex surface topography. We present a process and associated software utility for automatically generating grayscale mask files from 3-D models created within industry-standard computer-aided design (CAD) suites. By shifting the microelectromechanical systems (MEMS) design onus to commonly used CAD programs ideal for complex surfacing, engineering professionals already familiar with traditional 3-D CAD software can readily utilize their pre-existing skills to make valuable contributions to the MEMS community. Our conversion process is demonstrated by prototyping several samples on a laser pattern generator-capital equipment already in use in many foundries. Finally, an empirical calibration technique is shown that compensates for nonlinear relationships between UV exposure intensity and photoresist development depth as well as a thermal reflow technique to help smooth microstructure surfaces.

Aligning Optical Fibers by Means of Actuated MEMS Wedges

NASA Technical Reports Server (NTRS)

Morgan, Brian; Ghodssi, Reza

2007-01-01

Microelectromechanical systems (MEMS) of a proposed type would be designed and fabricated to effect lateral and vertical alignment of optical fibers with respect to optical, electro-optical, optoelectronic, and/or photonic devices on integrated circuit chips and similar monolithic device structures. A MEMS device of this type would consist of a pair of oppositely sloped alignment wedges attached to linear actuators that would translate the wedges in the plane of a substrate, causing an optical fiber in contact with the sloping wedge surfaces to undergo various displacements parallel and perpendicular to the plane. In making it possible to accurately align optical fibers individually during the packaging stages of fabrication of the affected devices, this MEMS device would also make it possible to relax tolerances in other stages of fabrication, thereby potentially reducing costs and increasing yields. In a typical system according to the proposal (see Figure 1), one or more pair(s) of alignment wedges would be positioned to create a V groove in which an optical fiber would rest. The fiber would be clamped at a suitable distance from the wedges to create a cantilever with a slight bend to push the free end of the fiber gently to the bottom of the V groove. The wedges would be translated in the substrate plane by amounts Dx1 and Dx2, respectively, which would be chosen to move the fiber parallel to the plane by a desired amount Dx and perpendicular to the plane by a desired amount Dy. The actuators used to translate the wedges could be variants of electrostatic or thermal actuators that are common in MEMS.

A quality quantitative method of silicon direct bonding based on wavelet image analysis

NASA Astrophysics Data System (ADS)

Tan, Xiao; Tao, Zhi; Li, Haiwang; Xu, Tiantong; Yu, Mingxing

2018-04-01

The rapid development of MEMS (micro-electro-mechanical systems) has received significant attention from researchers in various fields and subjects. In particular, the MEMS fabrication process is elaborate and, as such, has been the focus of extensive research inquiries. However, in MEMS fabrication, component bonding is difficult to achieve and requires a complex approach. Thus, improvements in bonding quality are relatively important objectives. A higher quality bond can only be achieved with improved measurement and testing capabilities. In particular, the traditional testing methods mainly include infrared testing, tensile testing, and strength testing, despite the fact that using these methods to measure bond quality often results in low efficiency or destructive analysis. Therefore, this paper focuses on the development of a precise, nondestructive visual testing method based on wavelet image analysis that is shown to be highly effective in practice. The process of wavelet image analysis includes wavelet image denoising, wavelet image enhancement, and contrast enhancement, and as an end result, can display an image with low background noise. In addition, because the wavelet analysis software was developed with MATLAB, it can reveal the bonding boundaries and bonding rates to precisely indicate the bond quality at all locations on the wafer. This work also presents a set of orthogonal experiments that consist of three prebonding factors, the prebonding temperature, the positive pressure value and the prebonding time, which are used to analyze the prebonding quality. This method was used to quantify the quality of silicon-to-silicon wafer bonding, yielding standard treatment quantities that could be practical for large-scale use.

Sensing magnetic flux density of artificial neurons with a MEMS device.

PubMed

Tapia, Jesus A; Herrera-May, Agustin L; García-Ramírez, Pedro J; Martinez-Castillo, Jaime; Figueras, Eduard; Flores, Amira; Manjarrez, Elías

2011-04-01

We describe a simple procedure to characterize a magnetic field sensor based on microelectromechanical systems (MEMS) technology, which exploits the Lorentz force principle. This sensor is designed to detect, in future applications, the spiking activity of neurons or muscle cells. This procedure is based on the well-known capability that a magnetic MEMS device can be used to sense a small magnetic flux density. In this work, an electronic neuron (FitzHugh-Nagumo) is used to generate controlled spike-like magnetic fields. We show that the magnetic flux density generated by the hardware of this neuron can be detected with a new MEMS magnetic field sensor. This microdevice has a compact resonant structure (700 × 600 × 5 μm) integrated by an array of silicon beams and p-type piezoresistive sensing elements, which need an easy fabrication process. The proposed microsensor has a resolution of 80 nT, a sensitivity of 1.2 V.T(-1), a resonant frequency of 13.87 kHz, low power consumption (2.05 mW), quality factor of 93 at atmospheric pressure, and requires a simple signal processing circuit. The importance of our study is twofold. First, because the artificial neuron can generate well-controlled magnetic flux density, we suggest it could be used to analyze the resolution and performance of different magnetic field sensors intended for neurobiological applications. Second, the introduced MEMS magnetic field sensor may be used as a prototype to develop new high-resolution biomedical microdevices to sense magnetic fields from cardiac tissue, nerves, spinal cord, or the brain.

Reliability Modeling of Microelectromechanical Systems Using Neural Networks

NASA Technical Reports Server (NTRS)

Perera. J. Sebastian

2000-01-01

Microelectromechanical systems (MEMS) are a broad and rapidly expanding field that is currently receiving a great deal of attention because of the potential to significantly improve the ability to sense, analyze, and control a variety of processes, such as heating and ventilation systems, automobiles, medicine, aeronautical flight, military surveillance, weather forecasting, and space exploration. MEMS are very small and are a blend of electrical and mechanical components, with electrical and mechanical systems on one chip. This research establishes reliability estimation and prediction for MEMS devices at the conceptual design phase using neural networks. At the conceptual design phase, before devices are built and tested, traditional methods of quantifying reliability are inadequate because the device is not in existence and cannot be tested to establish the reliability distributions. A novel approach using neural networks is created to predict the overall reliability of a MEMS device based on its components and each component's attributes. The methodology begins with collecting attribute data (fabrication process, physical specifications, operating environment, property characteristics, packaging, etc.) and reliability data for many types of microengines. The data are partitioned into training data (the majority) and validation data (the remainder). A neural network is applied to the training data (both attribute and reliability); the attributes become the system inputs and reliability data (cycles to failure), the system output. After the neural network is trained with sufficient data. the validation data are used to verify the neural networks provided accurate reliability estimates. Now, the reliability of a new proposed MEMS device can be estimated by using the appropriate trained neural networks developed in this work.

Review of the potential of a wireless MEMS and TFT microsystems for the measurement of pressure in the GI tract.

PubMed

Arshak, A; Arshak, K; Waldron, D; Morris, D; Korostynska, O; Jafer, E; Lyons, G

2005-06-01

Telemetry capsules have existed since the 1950s and were used to measure temperature, pH or pressure inside the gastrointestinal (GI) tract. It was hoped that these capsules would replace invasive techniques in the diagnosis of function disorders in the GI tract. However, problems such as signal loss and uncertainty of the pills position limited their use in a clinical setting. In this paper, a review of the capabilities of MicroElectroMechanical Systems (MEMS) and thick film technology (TFT) for the fabrication of a wireless pressure sensing microsystem is presented. The circuit requirements and methods of data transfer are examined. The available fabrication methods for MEMS sensors are also discussed and examples of wireless sensors are given. Finally the limitations of each technology are examined.

Modeling and simulation of blazed grating based on MEMS scanning micro-mirror for NIR micro-spectrometer

NASA Astrophysics Data System (ADS)

Zhou, Ying; Wen, Zhiyu; Yang, Tingyan; Lei, Hongjie

2015-11-01

Near infrared micro-spectrometer (NIRMS) as a vital detection equipment for various elements has been investigated over the last few years. Traditional MEMS NIRMS employs CCD array detectors for NIR spectrum collection and this leads to higher fabrication cost. In this paper, to ensure the higher diffraction efficiency as well as lower fabrication cost, a novel blazed grating based on MEMS scanning micro-mirror (SMM) is proposed. By our design method, the NIRMS needs only one single InGaAs detector photo diode to collect NIR spectrum and ensure the high diffraction efficiency. Our results show that the diffraction efficiency of the blazed grating is almost 50% and the peak value reaches to 90% in the range of 900-2,100 nm while the optical scanning angle is 14.2°.

A novel fabrication method for suspended high-aspect-ratio microstructures

NASA Astrophysics Data System (ADS)

Yang, Yao-Joe; Kuo, Wen-Cheng

2005-11-01

Suspended high-aspect-ratio structures (suspended HARS) are widely used for MEMS devices such as micro-gyroscopes, micro-accelerometers, optical switches and so on. Various fabrication methods, such as SOI, SCREAM, AIM, SBM and BELST processes, were proposed to fabricate HARS. However, these methods focus on the fabrication of suspended microstructures with relatively small widths of trench opening (e.g. less than 10 µm). In this paper, we propose a novel process for fabricating very high-aspect-ratio suspended structures with large widths of trench opening using photoresist as an etching mask. By enhancing the microtrenching effect, we can easily release the suspended structure without thoroughly removing the floor polymer inside the trenches for the cases with a relatively small trench aspect ratio. All the process steps can be integrated into a single-run single-mask ICP-RIE process, which effectively reduces the process complexity and fabrication cost. We also discuss the phenomenon of corner erosion, which results in the undesired etching of silicon structures during the structure-releasing step. By using the proposed process, 100 µm thick suspended structures with the trench aspect ratio of about 20 are demonstrated. Also, the proposed process can be used to fabricate devices for applications which require large in-plane displacement. This paper was orally presented in the Transducers'05, Seoul, Korea (paper ID: 3B1.3).

Modeling of stress-induced curvature in surface-micromachined devices

NASA Astrophysics Data System (ADS)

Cowan, William D.; Bright, Victor M.; Elvin, Alex A.; Koester, David A.

1997-09-01

This paper compares measured to modeled stress-induced curvature of simple piston micromirrors. Two similar flexure-beam micromirror designs were fabricate using the 11th DARPA-supported multi-user MEMS processes (MUMPs) run. The test devices vary only in the MUMPs layers used for fabrication. In one case the mirror plate is the 1.5 micrometers thick Poly2 layer. The other mirror design employs stacked Poly1 and Poly2 layers for a total thickness of 3.5 micrometers . Both mirror structures are covered with the standard MUMPs metallization of approximately 200 angstrom of chromium and 0.5 micrometers of gold. Curvature of these devices was measured to within +/- 5 nm with a computer controlled microscope laser interferometer system. As intended, the increased thickness of the stacked polysilicon layers reduces the mirror curvature by a factor of 4. The two micromirror designs were modeled using IntelliCAD, a commercial CAD system for MEMS. The basis of analysis was the finite element method. Simulated results using MUMPs 11 film parameters showed qualitative agreement with measured data, but obvious quantitative differences. Subsequent remeasurement of the metal stress and use of the new value significantly improved model agreement with the measured data. The paper explores the effect of several film parameters on the modeled structures. Implications for MEMS film metrology, and test structures are considered.

Pre-stressed piezoelectric bimorph micro-actuators based on machined 40 µm PZT thick films: batch scale fabrication and integration with MEMS

NASA Astrophysics Data System (ADS)

Wilson, S. A.; Jourdain, R. P.; Owens, S.

2010-09-01

The projected force-displacement capability of piezoelectric ceramic films in the 20-50 µm thickness range suggests that they are well suited to many micro-fluidic and micro-pneumatic applications. Furthermore when they are configured as bending actuators and operated at ~ 1 V µm - 1 they do not necessarily conform to the high-voltage, very low-displacement piezoelectric stereotype. Even so they are rarely found today in commercial micro-electromechanical devices, such as micro-pumps and micro-valves, and the main barriers to making them much more widely available would appear to be processing incompatibilities rather than commercial desirability. In particular, the issues associated with integration of these devices into MEMS at the production level are highly significant and they have perhaps received less attention in the mainstream than they deserve. This paper describes a fabrication route based on ultra-precision ceramic machining and full-wafer bonding for cost-effective batch scale production of thick film PZT bimorph micro-actuators and their integration with MEMS. The resulting actuators are pre-stressed (ceramic in compression) which gives them added performance, they are true bimorphs with bi-directional capability and they exhibit full bulk piezoelectric ceramic properties. The devices are designed to integrate with ancillary systems components using transfer-bonding techniques. The work forms part of the European Framework 6 Project 'Q2M—Quality to Micro'.

Release of MEMS devices with hard-baked polyimide sacrificial layer

NASA Astrophysics Data System (ADS)

Boroumand Azad, Javaneh; Rezadad, Imen; Nath, Janardan; Smith, Evan; Peale, Robert E.

2013-03-01

Removal of polyimides used as sacrificial layer in fabricating MEMS devices can be challenging after hardbaking, which may easily result by the end of multiple-step processing. We consider the specific commercial co-developable polyimide ProLift 100 (Brewer Science). Excessive heat hardens this material, so that during wet release in TMAH based solvents, intact sheets break free from the substrate, move around in the solution, and break delicate structures. On the other hand, dry reactive-ion etching of hard-baked ProLift is so slow, that MEMS structures are damaged from undesirably-prolonged physical bombardment by plasma ions. We found that blanket exposure to ultraviolet light allows rapid dry etch of the ProLift surrounding the desired structures without damaging them. Subsequent removal of ProLift from under the devices can then be safely performed using wet or dry etch. We demonstrate the approach on PECVD-grown silicon-oxide cantilevers of 100 micron × 100 micron area supported 2 microns above the substrate by ~100-micron-long 8-micron-wide oxide arms.

Fabrication of microelectromechanical systems (MEMS) cantilevers for photoacoustic (PA) detection of terahertz (THz) radiation

NASA Astrophysics Data System (ADS)

Newberry, R.; Glauvitz, N.; Coutu, R. A.; Medvedev, I. R.; Petkie, D.

2014-03-01

Historically, spectroscopy has been a cumbersome endeavor due to the relatively large sizes (3ft - 100ft in length) of modern spectroscopy systems. Taking advantage of the photoacoustic effect would allow for much smaller absorption chambers since the photoacoustic (PA) effect is independent of the absorption path length. In order to detect the photoacoustic waves being generated, a photoacoustic microphone would be required. This paper reports on the fabrication efforts taken in order to create microelectromechanical systems (MEMS) cantilevers for the purpose of sensing photoacoustic waves generated via terahertz (THz) radiation passing through a gaseous sample. The cantilevers are first modeled through the use of the finite element modeling software, CoventorWare®. The cantilevers fabricated with bulk micromachining processes and are 7x2x0.010mm on a silicon-on-insulator (SOI) wafer which acts as the physical structure of the cantilever. The devices are released by etching through the wafer's backside and etching through the buried oxide with hydrofluoric acid. The cantilevers are placed in a test chamber and their vibration and deflection are measured via a Michelson type interferometer that reflects a laser off a gold tip evaporated onto the tip of the cantilever. The test chamber is machined from stainless steel and housed in a THz testing environment at Wright State University. Fabricated devices have decreased residual stress and larger radii of curvatures by approximately 10X.

Detailed study of scratch drive actuator characteristics using high-speed imaging

NASA Astrophysics Data System (ADS)

Li, Lijie; Brown, James G.; Uttamchandani, Deepak G.

2001-10-01

Microactuators are one of the key components in MEMS and Microsystems technology, and various designs have been realized through different fabrication processes. One type of microactuator commonly used is the scratch drive actuator (SDA) that is frequently fabricated by surface micromachining processes. An experimental investigation has been conducted on the characteristics of SDAs fabricated using the Cronos Microsystems MUMPs process. The motivation is to compare the response of SDAs located on the same die, and SDAs located on the different dies from the same fabrication batch. A high-speed imaging camera has been used to precisely determine important SDA characteristics such as step size, velocity, maximum velocity, and acceleration over long travel distance. These measurements are important from a repeatability point of view, and in order to fully exploit the potential of the SDA as a precise positioning mechanism. 2- and 3-stage SDAs have been designed and fabricated for these experiments. Typical step sizes varying from 7 nm at a driving voltage of 60 V to 23 nm at 290 V have been obtained.

MEMS switches having non-metallic crossbeams

NASA Technical Reports Server (NTRS)

Scardelletti, Maximillian C (Inventor)

2009-01-01

A RF MEMS switch comprising a crossbeam of SiC, supported by at least one leg above a substrate and above a plurality of transmission lines forming a CPW. Bias is provided by at least one layer of metal disposed on a top surface of the SiC crossbeam, such as a layer of chromium followed by a layer of gold, and extending beyond the switch to a biasing pad on the substrate. The switch utilizes stress and conductivity-controlled non-metallic thin cantilevers or bridges, thereby improving the RF characteristics and operational reliability of the switch. The switch can be fabricated with conventional silicon integrated circuit (IC) processing techniques. The design of the switch is very versatile and can be implemented in many transmission line mediums.

1.65 mm diameter forward-viewing confocal endomicroscopic catheter using a flip-chip bonded electrothermal MEMS fiber scanner.

PubMed

Seo, Yeong-Hyeon; Hwang, Kyungmin; Jeong, Ki-Hun

2018-02-19

We report a 1.65 mm diameter forward-viewing confocal endomicroscopic catheter using a flip-chip bonded electrothermal MEMS fiber scanner. Lissajous scanning was implemented by the electrothermal MEMS fiber scanner. The Lissajous scanned MEMS fiber scanner was precisely fabricated to facilitate flip-chip connection, and bonded with a printed circuit board. The scanner was successfully combined with a fiber-based confocal imaging system. A two-dimensional reflectance image of the metal pattern 'OPTICS' was successfully obtained with the scanner. The flip-chip bonded scanner minimizes electrical packaging dimensions. The inner diameter of the flip-chip bonded MEMS fiber scanner is 1.3 mm. The flip-chip bonded MEMS fiber scanner is fully packaged with a 1.65 mm diameter housing tube, 1 mm diameter GRIN lens, and a single mode optical fiber. The packaged confocal endomicroscopic catheter can provide a new breakthrough for diverse in-vivo endomicroscopic applications.

Low voltage driven RF MEMS capacitive switch using reinforcement for reduced buckling

NASA Astrophysics Data System (ADS)

Bansal, Deepak; Bajpai, Anuroop; Kumar, Prem; Kaur, Maninder; Kumar, Amit; Chandran, Achu; Rangra, Kamaljit

2017-02-01

Variation in actuation voltage for RF MEMS switches is observed as a result of stress-generated buckling of MEMS structures. Large voltage driven RF-MEMS switches are a major concern in space bound communication applications. In this paper, we propose a low voltage driven RF MEMS capacitive switch with the introduction of perforations and reinforcement. The performance of the fabricated switch is compared with conventional capacitive RF MEMS switches. The pull-in voltage of the switch is reduced from 70 V to 16.2 V and the magnitude of deformation is reduced from 8 µm to 1 µm. The design of the reinforcement frame enhances the structural stiffness by 46 % without affecting the high frequency response of the switch. The measured isolation and insertion loss of the reinforced switch is more than 20 dB and 0.4 dB over the X band range.

Sources of stress gradients in electrodeposited Ni MEMS.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hearne, Sean Joseph; Floro, Jerrold Anthony; Dyck, Christopher William

2004-06-01

The ability of future integrated metal-semiconductor micro-systems such as RF MEMS to perform highly complex functions will depend on developing freestanding metal structures that offer improved conductivity and reflectivity over polysilicon structures. For example, metal-based RF MEMS technology could replace the bulky RF system presently used in communications, navigation, and avionics systems. However, stress gradients that induce warpage of active components have prevented the implementation of this technology. Figure 1, is an interference micrograph image of a series of cantilever beams fabricated from electrodeposited Ni. The curvature in the beams was the result of stress gradients intrinsic to the electrodepositionmore » process. To study the sources of the stress in electrodeposition of Ni we have incorporated a wafer curvature based stress sensor, the multibeam optical stress sensor, into an electrodeposition cell. We have determined that there are two regions of stress induced by electrodepositing Ni from a sulfamate-based bath (Fig 2). The stress evolution during the first region, 0-1000{angstrom}, was determined to be dependent only on the substrate material (Au vs. Cu), whereas the stress evolution during the second region, >1000{angstrom}, was highly dependent on the deposition conditions. In this region, the stress varied from +0.5 GPa to -0.5GPa, depending solely on the deposition rate. We examined four likely sources for the compressive intrinsic stress, i.e. reduction in tensile stress, and determined that only the adatom diffusion into grain boundaries model of Sheldon, et al. could account for the observed compressive stress. In the presentation, we shall discuss the compressive stress generation mechanisms considered and the ramifications of these results on fabrication of electrodeposited Ni for MEMS applications.« less

MEMS based hair flow-sensors as model systems for acoustic perception studies

NASA Astrophysics Data System (ADS)

Krijnen, Gijs J. M.; Dijkstra, Marcel; van Baar, John J.; Shankar, Siripurapu S.; Kuipers, Winfred J.; de Boer, Rik J. H.; Altpeter, Dominique; Lammerink, Theo S. J.; Wiegerink, Remco

2006-02-01

Arrays of MEMS fabricated flow sensors inspired by the acoustic flow-sensitive hairs found on the cerci of crickets have been designed, fabricated and characterized. The hairs consist of up to 1 mm long SU-8 structures mounted on suspended membranes with normal translational and rotational degrees of freedom. Electrodes on the membrane and on the substrate form variable capacitors, allowing for capacitive read-out. Capacitance versus voltage, frequency dependence and directional sensitivity measurements have been successfully carried out on fabricated sensor arrays, showing the viability of the concept. The sensors form a model system allowing for investigations on sensory acoustics by their arrayed nature, their adaptivity via electrostatic interaction (frequency tuning and parametric amplification) and their susceptibility to noise (stochastic resonance).

Fabrication and characterisation of nanocrystalline graphite MEMS resonators using a geometric design to control buckling

NASA Astrophysics Data System (ADS)

Fishlock, S. J.; O'Shea, S. J.; McBride, J. W.; Chong, H. M. H.; Pu, S. H.

2017-09-01

The simulation, fabrication and characterisation of nanographite MEMS resonators is reported in this paper. The deposition of nanographite is achieved using plasma-enhanced chemical vapour deposition directly onto numerous substrates such as commercial silicon wafers. As a result, many of the reliability issues of devices based on transferred graphene are avoided. The fabrication of the resonators is presented along with a simple undercutting method to overcome buckling, by changing the effective stress of the structure from ~436 MPa compressive, to ~13 MPa tensile. The characterisation of the resonators using electrostatic actuation and laser Doppler vibrometry is reported, demonstrating resonator frequencies from 5-640 kHz and quality factor above 1819 in vacuum obtained.

Integrated Optoelectronic Position Sensor for Scanning Micromirrors

PubMed Central

Cheng, Xiang; Sun, Xinglin; Liu, Yan; Zhu, Lijun; Zhang, Xiaoyang; Zhou, Liang

2018-01-01

Scanning micromirrors have been used in a wide range of areas, but many of them do not have position sensing built in, which significantly limits their application space. This paper reports an integrated optoelectronic position sensor (iOE-PS) that can measure the linear displacement and tilting angle of electrothermal MEMS (Micro-electromechanical Systems) scanning mirrors. The iOE-PS integrates a laser diode and its driving circuits, a quadrant photo-detector (QPD) and its readout circuits, and a band-gap reference all on a single chip, and it has been fabricated in a standard 0.5 μm CMOS (Complementary Metal Oxide Semiconductor) process. The footprint of the iOE-PS chip is 5 mm × 5 mm. Each quadrant of the QPD has a photosensitive area of 500 µm × 500 µm and the spacing between adjacent quadrants is 500 μm. The iOE-PS chip is simply packaged underneath of an electrothermally-actuated MEMS mirror. Experimental results show that the iOE-PS has a linear response when the MEMS mirror plate moves vertically between 2.0 mm and 3.0 mm over the iOE-PS chip or scans from −5 to +5°. Such MEMS scanning mirrors integrated with the iOE-PS can greatly reduce the complexity and cost of the MEMS mirrors-enabled modules and systems. PMID:29587451

Eddy-current-damped microelectromechanical switch

DOEpatents

Christenson, Todd R.; Polosky, Marc A.

2007-10-30

A microelectromechanical (MEM) device is disclosed that includes a shuttle suspended for movement above a substrate. A plurality of permanent magnets in the shuttle of the MEM device interact with a metal plate which forms the substrate or a metal portion thereof to provide an eddy-current damping of the shuttle, thereby making the shuttle responsive to changes in acceleration or velocity of the MEM device. Alternately, the permanent magnets can be located in the substrate, and the metal portion can form the shuttle. An electrical switch closure in the MEM device can occur in response to a predetermined acceleration-time event. The MEM device, which can be fabricated either by micromachining or LIGA, can be used for sensing an acceleration or deceleration event (e.g. in automotive applications such as airbag deployment or seat belt retraction).

Eddy-current-damped microelectromechanical switch

DOEpatents

Christenson, Todd R [Albuquerque, NM; Polosky, Marc A [Tijeras, NM

2009-12-15

A microelectromechanical (MEM) device is disclosed that includes a shuttle suspended for movement above a substrate. A plurality of permanent magnets in the shuttle of the MEM device interact with a metal plate which forms the substrate or a metal portion thereof to provide an eddy-current damping of the shuttle, thereby making the shuttle responsive to changes in acceleration or velocity of the MEM device. Alternately, the permanent magnets can be located in the substrate, and the metal portion can form the shuttle. An electrical switch closure in the MEM device can occur in response to a predetermined acceleration-time event. The MEM device, which can be fabricated either by micromachining or LIGA, can be used for sensing an acceleration or deceleration event (e.g. in automotive applications such as airbag deployment or seat belt retraction).

Application of Inkjet-Printing Technology to Micro-Electro-Mechanical Systems

DTIC Science & Technology

2014-05-01

dimensional MEMS using inkjet-printing metal nanoparticles and demonstrated resonant inductive coils, electrostatic-drive motors, and electrothermal actuators...telecommunications base stataions, satellites and defense systems [48]. 1.4 Printed Microshell Encapsulation In this thesis, a fabrication process was...that the solvent of the ink needs to be heat-compatible, which may limit the range of solvent that can be used. For example, most bio -compatible

The MEMS Knudsen Compressor as a Vacuum Pump for Space Exploration Applications

NASA Technical Reports Server (NTRS)

Vargo, S. E.; Muntz, E. P.; Tang, W. C.

2000-01-01

Several lander, probe and rover missions currently under study at the Jet Propulsion Laboratory (JPL) and especially in the Microdevices Laboratory (MDL) Center for Space Microelectronics Technology, focus on utilizing microelectromechanical systems (MEMS) based instruments for science data gathering. These small instruments and NASA's commitment to "faster, better, cheaper" type missions has brought about the need for novel approaches to satisfying mission requirements. Existing in-situ instrument systems clearly lack novel and integrated methods for satisfying their vacuum needs. One attractive candidate for a MEMS vacuum pump is the Knudsen Compressor, which operates based on thermal transpiration. Thermal transpiration describes gas flows induced by temperature differences maintained across orifices, porous membranes or capillary tubes under rarefied conditions. This device has two overwhelmingly attractive features as a MEMS vacuum pump - no moving parts and no fluids. An initial estimate of a Knudsen Compressor's pumping power requirements for a surface atmospheric sampling task on Mars is less than 80 mW, significantly below than alternative pumps. Due to the relatively low energy use for this task and the applicability of the Knudsen Compressor to other applications, the development of a Knudsen Compressor utilizing MEMS fabrication techniques has been initiated. This paper discusses the initial fabrication of a single-stage MEMS Knudsen Compressor vacuum pump, provides performance criteria such as pumping speed, size, energy use and ultimate pressure and details vacuum pump applications in several MDL related in-situ instruments.

MEMS ultrasonic transducer for monitoring of steel structures

NASA Astrophysics Data System (ADS)

Jain, Akash; Greve, David W.; Oppenheim, Irving J.

2002-06-01

Ultrasonic methods can be used to monitor crack propagation, weld failure, or section loss at critical locations in steel structures. However, ultrasonic inspection requires a skilled technician, and most commonly the signal obtained at any inspection is not preserved for later use. A preferred technology would use a MEMS device permanently installed at a critical location, polled remotely, and capable of on-chip signal processing using a signal history. We review questions related to wave geometry, signal levels, flaw localization, and electromechanical design issues for microscale transducers, and then describe the design, characterization, and initial testing of a MEMS transducer to function as a detector array. The device is approximately 1-cm square and was fabricated by the MUMPS process. The chip has 23 sensor elements to function in a phased array geometry, each element containing 180 hexagonal polysilicon diaphragms with a typical leg length of 49 microns and an unloaded natural frequency near 3.5 MHz. We first report characterization studies including capacitance-voltage measurements and admittance measurements, and then report initial experiments using a conventional piezoelectric transducer for excitation, with successful detection of signals in an on-axis transmission experiment and successful source localization from phased array performance in an off-axis transmission experiment.

A High-Q Resonant Pressure Microsensor with Through-Glass Electrical Interconnections Based on Wafer-Level MEMS Vacuum Packaging

PubMed Central

Luo, Zhenyu; Chen, Deyong; Wang, Junbo; Li, Yinan; Chen, Jian

2014-01-01

This paper presents a high-Q resonant pressure microsensor with through-glass electrical interconnections based on wafer-level MEMS vacuum packaging. An approach to maintaining high-vacuum conditions by integrating the MEMS fabrication process with getter material preparation is presented in this paper. In this device, the pressure under measurement causes a deflection of a pressure-sensitive silicon square diaphragm, which is further translated to stress build up in “H” type doubly-clamped micro resonant beams, leading to a resonance frequency shift. The device geometries were optimized using FEM simulation and a 4-inch SOI wafer was used for device fabrication, which required only three photolithographic steps. In the device fabrication, a non-evaporable metal thin film as the getter material was sputtered on a Pyrex 7740 glass wafer, which was then anodically bonded to the patterned SOI wafer for vacuum packaging. Through-glass via holes predefined in the glass wafer functioned as the electrical interconnections between the patterned SOI wafer and the surrounding electrical components. Experimental results recorded that the Q-factor of the resonant beam was beyond 22,000, with a differential sensitivity of 89.86 Hz/kPa, a device resolution of 10 Pa and a nonlinearity of 0.02% F.S with the pressure varying from 50 kPa to 100 kPa. In addition, the temperature drift coefficient was less than −0.01% F.S/°C in the range of −40 °C to 70 °C, the long-term stability error was quantified as 0.01% F.S over a 5-month period and the accuracy of the microsensor was better than 0.01% F.S. PMID:25521385

A high-Q resonant pressure microsensor with through-glass electrical interconnections based on wafer-level MEMS vacuum packaging.

PubMed

Luo, Zhenyu; Chen, Deyong; Wang, Junbo; Li, Yinan; Chen, Jian

2014-12-16

This paper presents a high-Q resonant pressure microsensor with through-glass electrical interconnections based on wafer-level MEMS vacuum packaging. An approach to maintaining high-vacuum conditions by integrating the MEMS fabrication process with getter material preparation is presented in this paper. In this device, the pressure under measurement causes a deflection of a pressure-sensitive silicon square diaphragm, which is further translated to stress build up in "H" type doubly-clamped micro resonant beams, leading to a resonance frequency shift. The device geometries were optimized using FEM simulation and a 4-inch SOI wafer was used for device fabrication, which required only three photolithographic steps. In the device fabrication, a non-evaporable metal thin film as the getter material was sputtered on a Pyrex 7740 glass wafer, which was then anodically bonded to the patterned SOI wafer for vacuum packaging. Through-glass via holes predefined in the glass wafer functioned as the electrical interconnections between the patterned SOI wafer and the surrounding electrical components. Experimental results recorded that the Q-factor of the resonant beam was beyond 22,000, with a differential sensitivity of 89.86 Hz/kPa, a device resolution of 10 Pa and a nonlinearity of 0.02% F.S with the pressure varying from 50 kPa to 100 kPa. In addition, the temperature drift coefficient was less than -0.01% F.S/°C in the range of -40 °C to 70 °C, the long-term stability error was quantified as 0.01% F.S over a 5-month period and the accuracy of the microsensor was better than 0.01% F.S.

Design and simulation of multi-color infrared CMOS metamaterial absorbers

NASA Astrophysics Data System (ADS)

Cheng, Zhengxi; Chen, Yongping; Ma, Bin

2016-05-01

Metamaterial electromagnetic wave absorbers, which usually can be fabricated in a low weight thin film structure, have a near unity absorptivity in a special waveband, and therefore have been widely applied from microwave to optical waveband. To increase absorptance of CMOS MEMS devices in 2-5 μmm waveband, multi-color infrared metamaterial absorbers are designed with CSMC 0.5 μmm 2P3M and 0.18 μmm 1P6M CMOS technology in this work. Metal-insulator-metal (MIM) three-layer MMAs and Insulator-metal-insulator-metal (MIMI) four-layer MMAs are formed by CMOS metal interconnect layers and inter metal dielectrics layer. To broaden absorption waveband in 2-5μmm range, MMAs with a combination of different sizes cross bars are designed. The top metal layer is a periodic aluminum square array or cross bar array with width ranging from submicron to several microns. The absorption peak position and intensity of MMAs can be tuned by adjusting the top aluminum micro structure array. Post-CMOS process is adopted to fabricate MMAs. The infrared absorption spectra of MMAs are verified with finite element method simulation, and the effects of top metal structure sizes, patterns, and films thickness are also simulated and intensively discussed. The simulation results show that CMOS MEMS MMAs enhance infrared absorption in 2-20 μmm. The MIM broad MMA has an average absorptance of 0.22 in 2-5 μmm waveband, and 0.76 in 8-14 μm waveband. The CMOS metamaterial absorbers can be inherently integrated in many kinds of MEMS devices fabricated with CMOS technology, such as uncooled bolometers, infrared thermal emitters.

Modular reservoir concept for MEMS-based transdermal drug delivery systems

NASA Astrophysics Data System (ADS)

Cantwell, Cara T.; Wei, Pinghung; Ziaie, Babak; Rao, Masaru P.

2014-11-01

While MEMS-based transdermal drug delivery device development efforts have typically focused on tightly-integrated solutions, we propose an alternate conception based upon a novel, modular drug reservoir approach. By decoupling the drug storage functionality from the rest of the delivery system, this approach seeks to minimize cold chain storage volume, enhance compatibility with conventional pharmaceutical practices, and allow independent optimization of reservoir device design, materials, and fabrication. Herein, we report the design, fabrication, and preliminary characterization of modular reservoirs that demonstrate the virtue of this approach within the application context of transdermal insulin administration for diabetes management.

Design and Fabrication of a Miniaturized GMI Magnetic Sensor Based on Amorphous Wire by MEMS Technology

PubMed Central

Chen, Jiawen; Li, Jianhua; Li, Yiyuan; Chen, Yulong

2018-01-01

A miniaturized Co-based amorphous wire GMI (Giant magneto-impedance) magnetic sensor was designed and fabricated in this paper. The Co-based amorphous wire was used as the sense element due to its high sensitivity to the magnetic field. A three-dimensional micro coil surrounding the Co-based amorphous wire was fabricated by MEMS (Micro-Electro-Mechanical System) technology, which was used to extract the electrical signal. The three-dimensional micro pick-up coil was designed and simulated with HFSS (High Frequency Structure Simulator) software to determine the key parameters. Surface micro machining MEMS (Micro-Electro-Mechanical System) technology was employed to fabricate the three-dimensional coil. The size of the developed amorphous wire magnetic sensor is 5.6 × 1.5 × 1.1 mm3. Helmholtz coil was used to characterize the performance of the device. The test results of the sensor sample show that the voltage change is 130 mV/Oe and the linearity error is 4.83% in the range of 0~45,000 nT. The results indicate that the developed miniaturized magnetic sensor has high sensitivity. By testing the electrical resistance of the samples, the results also showed high uniformity of each device. PMID:29494477

Tensile-stressed microelectromechanical apparatus and tiltable micromirrors formed therefrom

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fleming, James G.

A microelectromechanical (MEM) apparatus is disclosed which includes a pair of tensile-stressed actuators suspending a platform above a substrate to tilt the platform relative to the substrate. A tensile stress built into the actuators initially tilts the platform when a sacrificial material used in fabrication of the MEM apparatus is removed. Further tilting of the platform can occur with a change in the ambient temperature about the MEM apparatus, or by applying a voltage to one or both of the tensile-stressed actuators. The MEM apparatus can be used to form a tiltable micromirror or an array of such devices, andmore » also has applications for thermal management within satellites.« less

Development of advanced second-generation micromirror devices fabricated in a four-level planarized surface-micromachined polycrystalline silicon process

NASA Astrophysics Data System (ADS)

Michalicek, M. Adrian; Comtois, John H.; Schriner, Heather K.

1998-04-01

This paper describes the design and characterization of several types of micromirror devices to include process capabilities, device modeling, and test data resulting in deflection versus applied potential curves and surface contour measurements. These devices are the first to be fabricated in the state-of-the-art four-level planarized polysilicon process available at Sandia National Laboratories known as the Sandia Ultra-planar Multi-level MEMS Technology. This enabling process permits the development of micromirror devices with near-ideal characteristics which have previously been unrealizable in standard three-layer polysilicon processes. This paper describes such characteristics which have previously been unrealizable in standard three-layer polysilicon processes. This paper describes such characteristics as elevated address electrodes, various address wiring techniques, planarized mirror surfaces suing Chemical Mechanical Polishing, unique post-process metallization, and the best active surface area to date.

A MEMS Micro-Translation Stage with Long Linear Translation

NASA Technical Reports Server (NTRS)

Ferguson, Cynthia K.; English, J. M.; Nordin, G. P.; Ashley, P. R.; Abushagur, M. A. G.

2004-01-01

A MEMS Micro-Translation Stage (MTS) actuator concept has been developed that is capable of traveling long distances, while maintaining low power, low voltage, and accuracy as required by many applications, including optical coupling. The Micro-Translation Stage (MTS) uses capacitive electrostatic forces in a linear motor application, with stationary stators arranged linearly on both sides of a channel, and matching rotors on a moveable shuttle. This creates a force that allows the shuttle to be pulled along the channel. It is designed to carry 100 micron-sized elements on the top surface, and can travel back and forth in the channel, either in a stepping fashion allowing many interim stops, or it can maintain constant adjustable speeds for a controlled scanning motion. The MTS travel range is limited only by the size of the fabrication wafer. Analytical modeling and simulations were performed based on the fabrication process, to assure the stresses, friction and electrostatic forces were acceptable to allow successful operation of this device. The translation forces were analyzed to be near 0.5 micron N, with a 300 micron N stop-to-stop time of 11.8 ms.

HAREM: high aspect ratio etching and metallization for microsystems fabrication

NASA Astrophysics Data System (ADS)

Sarajlic, Edin; Yamahata, Christophe; Cordero, Mauricio; Collard, Dominique; Fujita, Hiroyuki

2008-07-01

We report a simple bulk micromachining method for the fabrication of high aspect ratio monocrystalline silicon MEMS (microelectromechanical systems) in a standard silicon wafer. We call this two-mask microfabrication process high aspect ratio etching and metallization or HAREM: it combines double-side etching and metallization to create suspended micromechanical structures with electrically 'insulating walls' on their backside. The insulating walls ensure a proper electrical insulation between the different actuation and sensing elements situated on either fixed or movable parts of the device. To demonstrate the high potential of this simple microfabrication method, we have designed and characterized electrostatically actuated microtweezers that integrate a differential capacitive sensor. The prototype showed an electrical insulation better than 1 GΩ between the different elements of the device. Furthermore, using a lock-in amplifier circuit, we could measure the position of the moving probe with few nanometers resolution for a displacement range of about 3 µm. This work was presented in part at the 21st IEEE MEMS Conference (Tucson, AZ, USA, 13-17 January, 2008) (doi:10.1109/MEMSYS.2008.4443656).

A novel polyimide based micro heater with high temperature uniformity

DOE PAGES

Yu, Shifeng; Wang, Shuyu; Lu, Ming; ...

2017-02-06

MEMS based micro heaters are a key component in micro bio-calorimetry, nondispersive infrared gas sensors, semiconductor gas sensors and microfluidic actuators. A micro heater with a uniform temperature distribution in the heating area and short response time is desirable in ultrasensitive temperature-dependent measurements. In this study, we propose a novel micro heater design to reach a uniform temperature in a large heating area by optimizing the heating power density distribution in the heating area. A polyimide membrane is utilized as the substrate to reduce the thermal mass and heat loss which allows for fast thermal response as well as amore » simplified fabrication process. A gold and titanium heating element is fabricated on the flexible polyimide substrate using the standard MEMS technique. The temperature distribution in the heating area for a certain power input is measured by an IR camera, and is consistent with FEA simulation results. Finally, this design can achieve fast response and uniform temperature distribution, which is quite suitable for the programmable heating such as impulse and step driving.« less

A novel polyimide based micro heater with high temperature uniformity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu, Shifeng; Wang, Shuyu; Lu, Ming

MEMS based micro heaters are a key component in micro bio-calorimetry, nondispersive infrared gas sensors, semiconductor gas sensors and microfluidic actuators. A micro heater with a uniform temperature distribution in the heating area and short response time is desirable in ultrasensitive temperature-dependent measurements. In this study, we propose a novel micro heater design to reach a uniform temperature in a large heating area by optimizing the heating power density distribution in the heating area. A polyimide membrane is utilized as the substrate to reduce the thermal mass and heat loss which allows for fast thermal response as well as amore » simplified fabrication process. A gold and titanium heating element is fabricated on the flexible polyimide substrate using the standard MEMS technique. The temperature distribution in the heating area for a certain power input is measured by an IR camera, and is consistent with FEA simulation results. Finally, this design can achieve fast response and uniform temperature distribution, which is quite suitable for the programmable heating such as impulse and step driving.« less

Syngas generation from n-butane with an integrated MEMS assembly for gas processing in micro-solid oxide fuel cell systems.

PubMed

Bieberle-Hütter, A; Santis-Alvarez, A J; Jiang, B; Heeb, P; Maeder, T; Nabavi, M; Poulikakos, D; Niedermann, P; Dommann, A; Muralt, P; Bernard, A; Gauckler, L J

2012-11-21

An integrated system of a microreformer and a carrier allowing for syngas generation from liquefied petroleum gas (LPG) for micro-SOFC application is discussed. The microreformer with an overall size of 12.7 mm × 12.7 mm × 1.9 mm is fabricated with micro-electro-mechanical system (MEMS) technologies. As a catalyst, a special foam-like material made from ceria-zirconia nanoparticles doped with rhodium is used to fill the reformer cavity of 58.5 mm(3). The microreformer is fixed onto a microfabricated structure with built-in fluidic channels and integrated heaters, the so-called functional carrier. It allows for thermal decoupling of the cold inlet gas and the hot fuel processing zone. Two methods for heating the microreformer are compared in this study: a) heating in an external furnace and b) heating with the two built-in heaters on the functional carrier. With both methods, high butane conversion rates of 74%-85% are obtained at around 550 °C. In addition, high hydrogen and carbon monoxide yields and selectivities are achieved. The results confirm those from classical lab reformers built without MEMS technology (N. Hotz et al., Chem. Eng. Sci., 2008, 63, 5193; N. Hotz et al., Appl. Catal., B, 2007, 73, 336). The material combinations and processing techniques enable syngas production with the present MEMS based microreformer with high performance for temperatures up to 700 °C. The functional carrier is the basis for a new platform, which can integrate the micro-SOFC membranes and the gas processing unit as subsystem of an entire micro-SOFC system.

Electroplating moulds using dry film thick negative photoresist

NASA Astrophysics Data System (ADS)

Kukharenka, E.; Farooqui, M. M.; Grigore, L.; Kraft, M.; Hollinshead, N.

2003-07-01

This paper reports on progress on the feasibility of fabricating moulds for electroplating using Ordyl P-50100 (negative) acrylate polymer based dry film photoresist, commercially available from Elga Europe (http://www.elgaeurope.it). We used this photoresist as an alternative to SU8 negative epoxy based photoresist, which is very difficult to process and remove after electroplating (Lorenz et al 1998 Microelectron. Eng. 41/42 371-4, Eyre et al 1998 Proc. MEMS'98 (Heidelberg) (Piscataway, NJ: IEEE) pp 218-22). Ordyl P-50100 is easy to work with and can be easily removed after processing. A single layer of Ordyl P-50100 was deposited by lamination up to 20 µm thickness. Thicker layers (200 µm and more) can be achieved with multilayer lamination using a manual laminator. For our applications we found that Ordyl P-50100 dry film photoresist is a very good alternative to SU8 for the realization of 100 µm high moulds. The results presented will open up new possibilities for low-cost LIGA-type processes for MEMS applications.

Investigation of polymer derived ceramics cantilevers for application of high speed atomic force microscopy

NASA Astrophysics Data System (ADS)

Wu, Chia-Yun

High speed Atomic Force Microscopy (AFM) has a wide variety of applications ranging from nanomanufacturing to biophysics. In order to have higher scanning speed of certain AFM modes, high resonant frequency cantilevers are needed; therefore, the goal of this research is to investigate using polymer derived ceramics for possible applications in making high resonant frequency AFM cantilevers using complex cross sections. The polymer derived ceramic that will be studied, is silicon carbide. Polymer derived ceramics offer a potentially more economic fabrication approach for MEMS due to their relatively low processing temperatures and ease of complex shape design. Photolithography was used to make the desired cantilever shapes with micron scale size followed by a wet etching process to release the cantilevers from the substrates. The whole manufacturing process we use borrow well-developed techniques from the semiconducting industry, and as such this project also could offer the opportunity to reduce the fabrication cost of AFM cantilevers and MEMS in general. The characteristics of silicon carbide made from the precursor polymer, SMP-10 (Starfire Systems), were studied. In order to produce high qualities of silicon carbide cantilevers, where the major concern is defects, proper process parameters needed to be determined. Films of polymer derived ceramics often have defects due to shrinkage during the conversion process. Thus control of defects was a central issue in this study. A second, related concern was preventing oxidation; the polymer derived ceramics we chose is easily oxidized during processing. Establishing an environment without oxygen in the whole process was a significant challenge in the project. The optimization of the parameters for using photolithography and wet etching process was the final and central goal of the project; well established techniques used in microfabrication were modified for use in making the cantilever in the project. The techniques developed here open a path to the fabrication of cantilevers with unconventional cross sections.

CMOS compatible thin-film ALD tungsten nanoelectromechanical devices

NASA Astrophysics Data System (ADS)

Davidson, Bradley Darren

This research focuses on the development of a novel, low-temperature, CMOS compatible, atomic-layer-deposition (ALD) enabled NEMS fabrication process for the development of ALD Tungsten (WALD) NEMS devices. The devices are intended for use in CMOS/NEMS hybrid systems, and NEMS based micro-processors/controllers capable of reliable operation in harsh environments not accessible to standard CMOS technologies. The majority of NEMS switches/devices to date have been based on carbon-nano-tube (CNT) designs. The devices consume little power during actuation, and as expected, have demonstrated actuation voltages much smaller than MEMS switches. Unfortunately, NEMS CNT switches are not typically CMOS integrable due to the high temperatures required for their growth, and their fabrication typically results in extremely low and unpredictable yields. Thin-film NEMS devices offer great advantages over reported CNT devices for several reasons, including: higher fabrication yields, low-temperature (CMOS compatible) deposition techniques like ALD, and increased control over design parameters/device performance metrics, i.e., device geometry. Furthermore, top-down, thin-film, nano-fabrication techniques are better capable of producing complicated device geometries than CNT based processes, enabling the design and development of multi-terminal switches well-suited for low-power hybrid NEMS/CMOS systems as well as electromechanical transistors and logic devices for use in temperature/radiation hard computing architectures. In this work several novel, low-temperature, CMOS compatible fabrication technologies, employing WALD as a structural layer for MEMS or NEMS devices, were developed. The technologies developed are top-down nano-scale fabrication processes based on traditional micro-machining techniques commonly used in the fabrication of MEMS devices. Using these processes a variety of novel WALD NEMS devices have been successfully fabricated and characterized. Using two different WALD fabrication technologies two generations of 2-terminal WALD NEMS switches have been developed. These devices have functional gap heights of 30-50 nm, and actuation voltages typically ranging from 3--5 Volts. Via the extension of a two terminal WALD technology novel 3-terminal WALD NEMS devices were developed. These devices have actuation voltages ranging from 1.5--3 Volts, reliabilities in excess of 2 million cycles, and have been designed to be the fundamental building blocks for WALD NEMS complementary inverters. Through the development of these devices several advancements in the modeling and design of thin-film NEMS devices were achieved. A new model was developed to better characterize pre-actuation currents commonly measured for NEMS switches with nano-scale gate-to-source gap heights. The developed model is an extension of the standard field-emission model and considers the electromechanical response, and electric field effects specific to thin-film NEMS switches. Finally, a multi-physics FEM/FD based model was developed to simulate the dynamic behavior of 2 or 3-terminal electrostatically actuated devices whose electrostatic domains have an aspect ratio on the order of 10-3. The model uses a faux-Lagrangian finite difference method to solve Laplaces equation in a quasi-statatically deforming domain. This model allows for the numerical characterization and design of thin-film NEMS devices not feasible using typical non-specialized BEM/FEM based software. Using this model several novel and feasible designs for fixed-fixed 3-terminal WALD NEMS switches capable for the construction of complementary inverters were discovered.

Fabrication of SOI structures with buried cavities using Si wafer direct bonding and electrochemical etch-stop

NASA Astrophysics Data System (ADS)

Chung, Gwiy-Sang

2003-10-01

This paper describes the fabrication of SOI structures with buried cavities using SDB and electrochemical etch-stop. These methods are suitable for thick membrane fabrication with accurate thickness, uniformity, and flatness. After a feed-through hole for supplied voltage and buried cavities was formed on a handle Si wafer with p-type, the handle wafer was bonded to an active Si wafer consisting of a p-type substrate with an n-type epitaxial layer corresponding to membrane thickness. The bonded pair was then thinned until electrochemical etch-stop occurred at the pn junction during electrochemical etchback. By using the SDB SOI structure with buried cavities, active membranes, which have a free standing structure with a dimension of 900×900 μm2, were fabricated. It is confirmed that the fabrication process of the SDB SOI structure with buried cavities is a powerful and versatile technology for new MEMS applications.

Design of a micromachined terahertz electromagnetic crystals (EMXT) channel-drop filter on silicon-substrate

NASA Astrophysics Data System (ADS)

Zhou, Kai; Liu, Yong; Si, Liming; Lv, Xin

2013-08-01

An integrated 0.5 THz electromagnetic crystals(EMXT) channel-drop filter based on PBG structure is presented in this paper. A channel-drop filter is a device in which a narrow bandwidth is redirected to another "drop" waveguide while other frequencies are unaffected. It's capable of extracting a certain frequency from a continuous spectrum in the bus channel and passing it to the test channel. It has potential applications in photonic integrated circuits, radio astronomy, THz spectroscopy, THz communication and remote sensing radar receiver. PBG structures(or photonic crystals) are periodic structures which possess band gaps, where the electromagnetic wave of certain ranges of frequencies cannot pass through and is reflected. The proposed channel-drop filter consists of input waveguide,output waveguide and PBG structure. The proposed filter is simulated using the finite element method and can be fabricated by micro-electromechanical systems (MEMS) technology,due to its low cost, high performance and high processing precision.The filter operation principle and fabrication process are discussed.The simulation results show its ability to filter the frequency of 496GHz with a linewidth of approximately 4GHz and transmission of 27.2 dB above background.The loss at resonant frequency is less than 1dB considering the thickness and roughness of gold layer required by the MEMS process.The channel drop efficiency is 84%.

Polydimethylsiloxane films doped with NdFeB powder: magnetic characterization and potential applications in biomedical engineering and microrobotics.

PubMed

Iacovacci, V; Lucarini, G; Innocenti, C; Comisso, N; Dario, P; Ricotti, L; Menciassi, A

2015-12-01

This work reports the fabrication, magnetic characterization and controlled navigation of film-shaped microrobots consisting of a polydimethylsiloxane-NdFeB powder composite material. The fabrication process relies on spin-coating deposition, powder orientation and permanent magnetization. Films with different powder concentrations (10 %, 30 %, 50 % and 70 % w/w) were fabricated and characterized in terms of magnetic properties and magnetic navigation performances (by exploiting an electromagnet-based platform). Standardized data are provided, thus enabling the exploitation of these composite materials in a wide range of applications, from MEMS/microrobot development to biomedical systems. Finally, the possibility to microfabricate free-standing polymeric structures and the biocompatibility of the proposed composite materials is demonstrated.

Optical MEMS platform for low-cost on-chip integration of planar light circuits and optical switching

NASA Astrophysics Data System (ADS)

German, Kristine A.; Kubby, Joel; Chen, Jingkuang; Diehl, James; Feinberg, Kathleen; Gulvin, Peter; Herko, Larry; Jia, Nancy; Lin, Pinyen; Liu, Xueyuan; Ma, Jun; Meyers, John; Nystrom, Peter; Wang, Yao Rong

2004-07-01

Xerox Corporation has developed a technology platform for on-chip integration of latching MEMS optical waveguide switches and Planar Light Circuit (PLC) components using a Silicon On Insulator (SOI) based process. To illustrate the current state of this new technology platform, working prototypes of a Reconfigurable Optical Add/Drop Multiplexer (ROADM) and a l-router will be presented along with details of the integrated latching MEMS optical switches. On-chip integration of optical switches and PLCs can greatly reduce the size, manufacturing cost and operating cost of multi-component optical equipment. It is anticipated that low-cost, low-overhead optical network products will accelerate the migration of functions and services from high-cost long-haul markets to price sensitive markets, including networks for metropolitan areas and fiber to the home. Compared to the more common silica-on-silicon PLC technology, the high index of refraction of silicon waveguides created in the SOI device layer enables miniaturization of optical components, thereby increasing yield and decreasing cost projections. The latching SOI MEMS switches feature moving waveguides, and are advantaged across multiple attributes relative to alternative switching technologies, such as thermal optical switches and polymer switches. The SOI process employed was jointly developed under the auspice of the NIST APT program in partnership with Coventor, Corning IntelliSense Corp., and MicroScan Systems to enable fabrication of a broad range of free space and guided wave MicroOptoElectroMechanical Systems (MOEMS).

Structural tests using a MEMS acoustic emission sensor

NASA Astrophysics Data System (ADS)

Oppenheim, Irving J.; Greve, David W.; Ozevin, Didem; Hay, D. Robert; Hay, Thomas R.; Pessiki, Stephen P.; Tyson, Nathan L.

2006-03-01

In a collaborative project at Lehigh and Carnegie Mellon, a MEMS acoustic emission sensor was designed and fabricated as a suite of six resonant-type capacitive transducers in the frequency range between 100 and 500 kHz. Characterization studies showed good comparisons between predicted and experimental electro-mechanical behavior. Acoustic emission events, simulated experimentally in steel ball impact and in pencil lead break tests, were detected and source localization was demonstrated. In this paper we describe the application of the MEMS device in structural testing, both in laboratory and in field applications. We discuss our findings regarding housing and mounting (acoustic coupling) of the MEMS device with its supporting electronics, and we then report the results of structural testing. In all tests, the MEMS transducers were used in parallel with commercial acoustic emission sensors, which thereby serve as a benchmark and permit a direct observation of MEMS device functionality. All tests involved steel structures, with particular interest in propagation of existing cracks or flaws. A series of four laboratory tests were performed on beam specimens fabricated from two segments (Grade 50 steel) with a full penetration weld (E70T-4 electrode material) at midspan. That weld region was notched, an initial fatigue crack was induced, and the specimens were then instrumented with one commercial transducer and with one MEMS device; data was recorded from five individual transducers on the MEMS device. Under a four-point bending test, the beam displayed both inelastic behavior and crack propagation, including load drops associated with crack instability. The MEMS transducers detected all instability events as well as many or most of the acoustic emissions occurring during plasticity and stable crack growth. The MEMS transducers were less sensitive than the commercial transducer, and did not detect as many events, but the normalized cumulative burst count obtained from the MEMS transducers paralleled the count obtained from the commercial transducer. Waveform analysis of signals from the MEMS transducers provided additional information concerning arrivals of P-waves and S-waves. Similarly, the analysis provided additional confirmation that the acoustic emissions emanated from the damage zone near the crack tip, and were not spurious signals or artifacts. Subsequent tests were conducted in a field application where the MEMS transducers were redundant to a group of commercial transducers. The application example is a connection plate in truss bridge construction under passage of heavy traffic loads. The MEMS transducers were found to be functional, but were less sensitive in their present form than existing commercial transducers. We conclude that the transducers are usable in their current configuration and we outline applications for which they are presently suited, and then we discuss alternate MEMS structures that would provide greater sensitivity.

Characterization of the MEMS Directional Sound Sensor Fabricated Using the SOIMUMPS Process

DTIC Science & Technology

2008-06-01

ABBREVIATIONS AND ACRONYMS ASW Anti- Submarine Warfare AUV Autonomous Underwater Vehicle DRIE Deep Reactive Ion Etching FAS Federation of American...as the frequency diverges from the resonant frequency (2980 Hz ) of the sensor. This analysis points out some disadvantages of the current set up of...sound sensor has important military applications, in particular to anti- submarine warfare (ASW). The sensor considered in this thesis is modeled on

Development of a low-cost x-ray mask for high-aspect-ratio MEM smart structures

NASA Astrophysics Data System (ADS)

Ajmera, Pratul K.; Stadler, Stefan; Abdollahi, Neda

1998-07-01

A cost-effective process with short fabrication time for making x-ray masks for research and development purposes is described here for fabricating high-aspect ratio microelectromechanical structures using synchrotron based x- ray lithography. Microscope cover glass slides as membrane material is described. Slides with an initial thickness of 175 micrometers are etched to a thickness in the range of 10 - 25 micrometers using a diluted HF and buffered hydrofluoric acid solutions. The thinned slides are glued on supportive mask frames and sputtered with a chromium/silver sandwich layer which acts as a plating base layer for the deposition of the gold absorber. The judicial choice of glue and mask frame material are significant parameters in a successful fabrication process. Gold absorber structures are electroplated on the membrane. Calculations are done for contrast and dose ratio obtained in the photoresist after synchrotron radiation as a function of the mask design parameters. Exposure experiments are performed to prove the applicability of the fabricated x-ray mask.

Solid-Liquid Interdiffusion Bonding of Silicon Carbide to Steel for High Temperature MEMS Sensor Packaging and Bonding

NASA Astrophysics Data System (ADS)

Chan, Matthew Wei-Jen

Complex engineering systems ranging from automobile engines to geothermal wells require specialized sensors to monitor conditions such as pressure, acceleration and temperature in order to improve efficiency and monitor component lifetime in what may be high temperature, corrosive, harsh environments. Microelectromechanical systems (MEMS) have demonstrated their ability to precisely and accurately take measurements under such conditions. The systems being monitored are typically made from metals, such as steel, while the MEMS sensors used for monitoring are commonly fabricated from silicon, silicon carbide and aluminum nitride, and so there is a sizable thermal expansion mismatch between the two. For these engineering applications the direct bonding of MEMS sensors to the components being monitored is often required. This introduces several challenges, namely the development of a bond that is capable of surviving high temperature harsh environments while mitigating the thermally induced strains produced during bonding. This project investigates the development of a robust packaging and bonding process, using the gold-tin metal system and the solid-liquid interdiffusion (SLID) bonding process, to join silicon carbide substrates directly to type-316 stainless steel. The SLID process enables bonding at lower temperatures while producing a bond capable of surviving higher temperatures. Finite element analysis was performed to model the thermally induced strains generated in the bond and to understand the optimal way to design the bond. The cross-sectional composition of the bonds has been analyzed and the bond strength has been investigated using die shear testing. The effects of high temperature aging on the bond's strength and the metallurgy of the bond were studied. Additionally, loading of the bond was performed at temperatures over 415 °C, more than 100 °C, above the temperature used for bonding, with full survival of the bond, thus demonstrating the benefit of SLID bonding for high temperature applications. Lastly, this dissertation provides recommendations for improving the strength and durability of the bond at temperatures of 400 °C and provides the framework for future work in the area of high temperature harsh environment MEMS packaging that would take directly bonded MEMS to temperatures of 600 °C and beyond.

MEMS Stirling Cooler Development Update

NASA Technical Reports Server (NTRS)

Moran, Matthew E.; Wesolek, Danielle

2003-01-01

This presentation provides an update on the effort to build and test a prototype unit of the patented MEMS Stirling cooler concept. A micro-scale regenerator has been fabricated by Polar Thermal Technologies and is currently being integrated into a Stirling cycle simulator at Johns Hopkins University Applied Physics Laboratory. A discussion of the analysis, design, assembly, and test plans for the prototype will be presented.

Thermally-induced voltage alteration for analysis of microelectromechanical devices

DOEpatents

Walraven, Jeremy A.; Cole, Jr., Edward I.

2002-01-01

A thermally-induced voltage alteration (TIVA) apparatus and method are disclosed for analyzing a microelectromechanical (MEM) device with or without on-board integrated circuitry. One embodiment of the TIVA apparatus uses constant-current biasing of the MEM device while scanning a focused laser beam over electrically-active members therein to produce localized heating which alters the power demand of the MEM device and thereby changes the voltage of the constant-current source. This changing voltage of the constant-current source can be measured and used in combination with the position of the focused and scanned laser beam to generate an image of any short-circuit defects in the MEM device (e.g. due to stiction or fabrication defects). In another embodiment of the TIVA apparatus, an image can be generated directly from a thermoelectric potential produced by localized laser heating at the location of any short-circuit defects in the MEM device, without any need for supplying power to the MEM device. The TIVA apparatus can be formed, in part, from a scanning optical microscope, and has applications for qualification testing or failure analysis of MEM devices.

Human Pulse Wave Measurement by MEMS Electret Condenser Microphone

NASA Astrophysics Data System (ADS)

Nomura, Shusaku; Hanasaka, Yasushi; Ishiguro, Tadashi; Ogawa, Hiroshi

A micro Electret Condenser Microphone (ECM) fabricated by Micro Electro Mechanical System (MEMS) technology was employed as a novel apparatus for human pulse wave measurement. Since ECM frequency response characteristic, i.e. sensitivity, logically maintains a constant level at lower than the resonance frequency (stiffness control), the slightest pressure difference at around 1.0Hz generated by human pulse wave is expected to detect by MEMS-ECM. As a result of the verification of frequency response of MEMS-ECM, it was found that -20dB/dec of reduction in the sensitivity around 1.0Hz was engendered by a high input-impedance amplifier, i.e. the field effect transistor (FET), mounted near MEMS chip for amplifying tiny ECM signal. Therefore, MEMS-ECM is assumed to be equivalent with a differentiation circuit at around human pulse frequency. Introducing compensation circuit, human pulse wave was successfully obtained. In addition, the radial and ulnar artery tracing, and pulse wave velocity measurement at forearm were demonstrated; as illustrating a possible application of this micro device.

Simulation of MEMS for the Next Generation Space Telescope

NASA Technical Reports Server (NTRS)

Mott, Brent; Kuhn, Jonathan; Broduer, Steve (Technical Monitor)

2001-01-01

The NASA Goddard Space Flight Center (GSFC) is developing optical micro-electromechanical system (MEMS) components for potential application in Next Generation Space Telescope (NGST) science instruments. In this work, we present an overview of the electro-mechanical simulation of three MEMS components for NGST, which include a reflective micro-mirror array and transmissive microshutter array for aperture control for a near infrared (NIR) multi-object spectrometer and a large aperture MEMS Fabry-Perot tunable filter for a NIR wide field camera. In all cases the device must operate at cryogenic temperatures with low power consumption and low, complementary metal oxide semiconductor (CMOS) compatible, voltages. The goal of our simulation efforts is to adequately predict both the performance and the reliability of the devices during ground handling, launch, and operation to prevent failures late in the development process and during flight. This goal requires detailed modeling and validation of complex electro-thermal-mechanical interactions and very large non-linear deformations, often involving surface contact. Various parameters such as spatial dimensions and device response are often difficult to measure reliably at these small scales. In addition, these devices are fabricated from a wide variety of materials including surface micro-machined aluminum, reactive ion etched (RIE) silicon nitride, and deep reactive ion etched (DRIE) bulk single crystal silicon. The above broad set of conditions combine to be a formidable challenge for space flight qualification analysis. These simulations represent NASA/GSFC's first attempts at implementing a comprehensive strategy to address complex MEMS structures.

Microelectromechanical-System-Based Variable-Focus Liquid Lens for Capsule Endoscopes

NASA Astrophysics Data System (ADS)

Seo, Sang Won; Han, Seungoh; Seo, Jun Ho; Kim, Young Mok; Kang, Moon Sik; Min, Nam Ki; Choi, Woo Beom; Sung, Man Young

2009-05-01

A liquid lens based on the electrowetting phenomenon was designed to be cylindrical to minimize dead area. The lens was fabricated with microelectromechanical-system (MEMS) technology using silicon thin film and wafer bonding processes. A multiple dielectric layer comprising Teflon, silicon nitride, and thermal oxide was formed on the cylinder wall. With a change of 11 Vrms in the applied bias, the lens module, including the fabricated liquid lens, showed a focal length change of approximately 166 mm. A capsule endoscope was assembled, including the lens module, and was successfully used to take images of a pig colon at various focal lengths.

AlN based piezoelectric micromirror.

PubMed

Shao, Jian; Li, Qi; Feng, Chuhuan; Li, Wei; Yu, Hongbin

2018-03-01

Aiming to pursue a micromirror possessing many desired characteristics, such as linear control, low power consumption, fast response, and easy fabrication, a new piezoelectric actuation strategy is presented. Different from conventional piezoelectric actuation cases, we first propose using AlN film as the active layer for actuating the micromirror. Owing to its good CMOS compatible deposition and patterning techniques, the AlN based piezoelectric micromirror has been successfully fabricated with a modified silicon-on-insulator-based microelectromechanical system (MEMS) process. At the same time, various mirror movement modes operating at high frequencies and excellent linear relationship between the movement and the control signal both have been experimentally demonstrated.

Wafer-Level Membrane-Transfer Process for Fabricating MEMS

NASA Technical Reports Server (NTRS)

Yang, Eui-Hyeok; Wiberg, Dean

2003-01-01

A process for transferring an entire wafer-level micromachined silicon structure for mating with and bonding to another such structure has been devised. This process is intended especially for use in wafer-level integration of microelectromechanical systems (MEMS) that have been fabricated on dissimilar substrates. Unlike in some older membrane-transfer processes, there is no use of wax or epoxy during transfer. In this process, the substrate of a wafer-level structure to be transferred serves as a carrier, and is etched away once the transfer has been completed. Another important feature of this process is that two electrodes constitutes an electrostatic actuator array. An SOI wafer and a silicon wafer (see Figure 1) are used as the carrier and electrode wafers, respectively. After oxidation, both wafers are patterned and etched to define a corrugation profile and electrode array, respectively. The polysilicon layer is deposited on the SOI wafer. The carrier wafer is bonded to the electrode wafer by using evaporated indium bumps. The piston pressure of 4 kPa is applied at 156 C in a vacuum chamber to provide hermetic sealing. The substrate of the SOI wafer is etched in a 25 weight percent TMAH bath at 80 C. The exposed buried oxide is then removed by using 49 percent HF droplets after an oxygen plasma ashing. The SOI top silicon layer is etched away by using an SF6 plasma to define the corrugation profile, followed by the HF droplet etching of the remaining oxide. The SF6 plasma with a shadow mask selectively etches the polysilicon membrane, if the transferred membrane structure needs to be patterned. Electrostatic actuators with various electrode gaps have been fabricated by this transfer technique. The gap between the transferred membrane and electrode substrate is very uniform ( 0.1 m across a wafer diameter of 100 mm, provided by optimizing the bonding control). Figure 2 depicts the finished product.

A fatigue test method for Pb(Zr,Ti)O3 thin films by using MEMS-based self-sensitive piezoelectric microcantilevers

NASA Astrophysics Data System (ADS)

Kobayashi, T.; Maeda, R.; Itoh, T.

2008-11-01

In the present study, we propose a new method for the fatigue test of lead zirconate titanate (PZT) thin films for MEMS devices by using self-sensitive piezoelectric microcantilevers developed in our previous study. We have deposited PZT thin films on SOI wafers and fabricated the microcantilevers through the MEMS microfabrication process. In the self-sensitive piezoelectric microcantilevers, the PZT thin films are separated in order to act as an actuator and a sensor. The fatigue characteristic of the PZT thin films can be evaluated by measuring the output voltage of the sensor as a function of time. When a sine wave of 20 Vpp and a dc bias of 10 V were applied to the PZT thin films for an actuator, the output voltage of the sensor fell down after 107 fatigue cycles. We have also investigated the influence of amplitude of the actuation sine wave and dc bias on the fatigue of the PZT thin films by using the proposed fatigue test method.

Microelectromechanical power generator and vibration sensor

DOEpatents

Roesler, Alexander W [Tijeras, NM; Christenson, Todd R [Albuquerque, NM

2006-11-28

A microelectromechanical (MEM) apparatus is disclosed which can be used to generate electrical power in response to an external source of vibrations, or to sense the vibrations and generate an electrical output voltage in response thereto. The MEM apparatus utilizes a meandering electrical pickup located near a shuttle which holds a plurality of permanent magnets. Upon movement of the shuttle in response to vibrations coupled thereto, the permanent magnets move in a direction substantially parallel to the meandering electrical pickup, and this generates a voltage across the meandering electrical pickup. The MEM apparatus can be fabricated by LIGA or micromachining.

Uncooled Micro-Cantilever Infrared Imager Optimization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Panagiotis, Datskos G.

2008-02-05

We report on the development, fabrication and characterization of microcantilever based uncooled focal plane array (FPA) for infrared imaging. By combining a streamlined design of microcantilever thermal transducers with a highly efficient optical readout, we minimized the fabrication complexity while achieving a competitive level of imaging performance. The microcantilever FPAs were fabricated using a straightforward fabrication process that involved only three photolithographic steps (i.e. three masks). A designed and constructed prototype of an IR imager employed a simple optical readout based on a noncoherent low-power light source. The main figures of merit of the IR imager were found to bemore » comparable to those of uncooled MEMS infrared detectors with substantially higher degree of fabrication complexity. In particular, the NETD and the response time of the implemented MEMS IR detector were measured to be as low as 0.5K and 6 ms, respectively. The potential of the implemented designs can also be concluded from the fact that the constructed prototype enabled IR imaging of close to room temperature objects without the use of any advanced data processing. The most unique and practically valuable feature of the implemented FPAs, however, is their scalability to high resolution formats, such as 2000 x 2000, without progressively growing device complexity and cost. The overall technical objective of the proposed work was to develop uncooled infrared arrays based on micromechanical sensors. Currently used miniature sensors use a number of different readout techniques to accomplish the sensing. The use of optical readout techniques sensing require the deposition of thin coatings on the surface of micromechanical thermal detectors. Oak Ridge National Laboratory (ORNL) is uniquely qualified to perform the required research and development (R&D) services that will assist our ongoing activities. Over the past decade ORNL has developed a number of unique methods and techniques that led to improved sensors using a number of different approaches.« less

Cantilever-type Thermal Microactuators Fabricated by SOI-MUMPs with U-type and I-type Configurations

NASA Astrophysics Data System (ADS)

Osada, Takahiro; Ochiai, Kuniyuki; Osada, Kazuki; Muro, Hideo

Recently, the micro fluid systems have been extensively studied, where microactuators such as micro valves fabricated by MEMS technology are essential for realizing these systems. In this paper thermal microactuators with U-type and I-type shapes fabricated by SOI-MUMPs technology have been investigated for optimizing their configurations.

Design and development of second order MEMS sound pressure gradient sensor

NASA Astrophysics Data System (ADS)

Albahri, Shehab

The design and development of a second order MEMS sound pressure gradient sensor is presented in this dissertation. Inspired by the directional hearing ability of the parasitoid fly, Ormia ochracea, a novel first order directional microphone that mimics the mechanical structure of the fly's ears and detects the sound pressure gradient has been developed. While the first order directional microphones can be very beneficial in a large number of applications, there is great potential for remarkable improvements in performance through the use of second order systems. The second order directional microphone is able to provide a theoretical improvement in Sound to Noise ratio (SNR) of 9.5dB, compared to the first-order system that has its maximum SNR of 6dB. Although second order microphone is more sensitive to sound angle of incidence, the nature of the design and fabrication process imposes different factors that could lead to deterioration in its performance. The first Ormia ochracea second order directional microphone was designed in 2004 and fabricated in 2006 at Binghamton University. The results of the tested parts indicate that the Ormia ochracea second order directional microphone performs mostly as an Omni directional microphone. In this work, the previous design is reexamined and analyzed to explain the unexpected results. A more sophisticated tool implementing a finite element package ANSYS is used to examine the previous design response. This new tool is used to study different factors that used to be ignored in the previous design, mainly; response mismatch and fabrication uncertainty. A continuous model using Hamilton's principle is introduced to verify the results using the new method. Both models agree well, and propose a new way for optimizing the second order directional microphone using geometrical manipulation. In this work we also introduce a new fabrication process flow to increase the fabrication yield. The newly suggested method uses the shell layered analysis method in ANSYS. The developed models simulate the fabricated chips at different stages; with the stress at each layer is introduced using thermal loading. The results indicate a new fabrication process flow to increase the rigidity of the composite layers, and countering the deformation caused by the high stress in the thermal oxide layer.

Stretchable electronics for wearable and high-current applications

NASA Astrophysics Data System (ADS)

Hilbich, Daniel; Shannon, Lesley; Gray, Bonnie L.

2016-04-01

Advances in the development of novel materials and fabrication processes are resulting in an increased number of flexible and stretchable electronics applications. This evolving technology enables new devices that are not readily fabricated using traditional silicon processes, and has the potential to transform many industries, including personalized healthcare, consumer electronics, and communication. Fabrication of stretchable devices is typically achieved through the use of stretchable polymer-based conductors, or more rigid conductors, such as metals, with patterned geometries that can accommodate stretching. Although the application space for stretchable electronics is extensive, the practicality of these devices can be severely limited by power consumption and cost. Moreover, strict process flows can impede innovation that would otherwise enable new applications. In an effort to overcome these impediments, we present two modified approaches and applications based on a newly developed process for stretchable and flexible electronics fabrication. This includes the development of a metallization pattern stamping process allowing for 1) stretchable interconnects to be directly integrated with stretchable/wearable fabrics, and 2) a process variation enabling aligned multi-layer devices with integrated ferromagnetic nanocomposite polymer components enabling a fully-flexible electromagnetic microactuator for large-magnitude magnetic field generation. The wearable interconnects are measured, showing high conductivity, and can accommodate over 20% strain before experiencing conductive failure. The electromagnetic actuators have been fabricated and initial measurements show well-aligned, highly conductive, isolated metal layers. These two applications demonstrate the versatility of the newly developed process and suggest potential for its furthered use in stretchable electronics and MEMS applications.

Accounting for Uncertainties in Strengths of SiC MEMS Parts

NASA Technical Reports Server (NTRS)

Nemeth, Noel; Evans, Laura; Beheim, Glen; Trapp, Mark; Jadaan, Osama; Sharpe, William N., Jr.

2007-01-01

A methodology has been devised for accounting for uncertainties in the strengths of silicon carbide structural components of microelectromechanical systems (MEMS). The methodology enables prediction of the probabilistic strengths of complexly shaped MEMS parts using data from tests of simple specimens. This methodology is intended to serve as a part of a rational basis for designing SiC MEMS, supplementing methodologies that have been borrowed from the art of designing macroscopic brittle material structures. The need for this or a similar methodology arises as a consequence of the fundamental nature of MEMS and the brittle silicon-based materials of which they are typically fabricated. When tested to fracture, MEMS and structural components thereof show wide part-to-part scatter in strength. The methodology involves the use of the Ceramics Analysis and Reliability Evaluation of Structures Life (CARES/Life) software in conjunction with the ANSYS Probabilistic Design System (PDS) software to simulate or predict the strength responses of brittle material components while simultaneously accounting for the effects of variability of geometrical features on the strength responses. As such, the methodology involves the use of an extended version of the ANSYS/CARES/PDS software system described in Probabilistic Prediction of Lifetimes of Ceramic Parts (LEW-17682-1/4-1), Software Tech Briefs supplement to NASA Tech Briefs, Vol. 30, No. 9 (September 2006), page 10. The ANSYS PDS software enables the ANSYS finite-element-analysis program to account for uncertainty in the design-and analysis process. The ANSYS PDS software accounts for uncertainty in material properties, dimensions, and loading by assigning probabilistic distributions to user-specified model parameters and performing simulations using various sampling techniques.

Fabrication of large diffractive optical elements in thick film on a concave lens surface.

PubMed

Xie, Yongjun; Lu, Zhenwu; Li, Fengyou

2003-05-05

We demonstrate experimentally the technique of fabricating large diffractive optical elements (DOEs) in thick film on a concave lens surface (mirrors) with precise alignment by using the strategy of double exposure. We adopt the method of double exposure to overcome the difficulty of processing thick photoresist on a large curved substrate. A uniform thick film with arbitrary thickness on a concave lens can be obtained with this technique. We fabricate a large concentric circular grating with a 10-ìm period on a concave lens surface in film with a thickness of 2.0 ìm after development. It is believed that this technique can also be used to fabricate larger DOEs in thicker film on the concave or convex lens surface with precise alignment. There are other potential applications of this technique, such as fabrication of micro-optoelectromechanical systems (MOEMS) or microelectromechanical systems (MEMS) and fabrication of microlens arrays on a large concave lens surface or convex lens surface with precise alignment.

High sensitivity capacitive MEMS microphone with spring supported diaphragm

NASA Astrophysics Data System (ADS)

Mohamad, Norizan; Iovenitti, Pio; Vinay, Thurai

2007-12-01

Capacitive microphones (condenser microphones) work on a principle of variable capacitance and voltage by the movement of its electrically charged diaphragm and back plate in response to sound pressure. There has been considerable research carried out to increase the sensing performance of microphones while reducing their size to cater for various modern applications such as mobile communication and hearing aid devices. This paper reviews the development and current performance of several condenser MEMS microphone designs, and introduces a microphone with spring supported diaphragm to further improve condenser microphone performance. The numerical analysis using Coventor FEM software shows that this new microphone design has a higher mechanical sensitivity compared to the existing edge clamped flat diaphragm condenser MEMS microphone. The spring supported diaphragm is shown to have a flat frequency response up to 7 kHz and more stable under the variations of the diaphragm residual stress. The microphone is designed to be easily fabricated using the existing silicon fabrication technology and the stability against the residual stress increases its reproducibility.

An optical biosensor using MEMS-based V-grooves

NASA Astrophysics Data System (ADS)

Tian, Ye; Ma, Xiaodong; Zou, Xiaotian; Wu, Nan; Wang, Xingwei

2011-05-01

An optical fiber biosensor featuring miniaturization, electromagnetic interference (EMI)-immunity, and flexibility is presented. The sensor was fabricated by aligning two gold-deposited optical single-mode fiber facets inside V-grooves on a silicon chip to form a Fabry-Perot (FP) cavity. The mirrors on the fiber facets were made of deposited gold (Au) films, which provided a high finesse to produce a highly sensitivity. Microelectromechanical systems (MEMS) fabrication techniques were used to precisely control the profile and angle of the V-grooves on the silicon. The biotin-terminated thiol molecule was firstly immobilized on the gold surface. Subsequently, the molecules of Neutravidin were specifically bound to the biotin-terminated self-assembled monolayers (SAMs). The induced changes of cavity length and refractive index (RI) upon the gold surface lead to an optical path difference (OPD) of the FP cavity, which was detected by demodulating the transmission spectrum phase shift. By taking advantage of MEMS techniques, multiple biosensors can be integrated into one small silicon chip for detecting various biomolecule targets simultaneously.

Fabrication of 3D electro-thermal micro actuators in silica glass by femtosecond laser wet etch and microsolidics

NASA Astrophysics Data System (ADS)

Li, Qichao; Shan, Chao; Yang, Qing; Chen, Feng; Bian, Hao; Hou, Xun

2017-02-01

This paper demonstrates a novel electro-thermal micro actuator's design, fabrication and device tests which combine microfluidic technology and microsolidics process. A three-dimensional solenoid microchannel with high aspect ratio is fabricated inside the silica glass by an improved femtosecond laser wet etch (FLWE) technology, and the diameter of the spiral coil is only 200 μm. Molten alloy (Bi/In/Sn/Pb) with high melting point is injected into the three-dimensional solenoid microchannel inside the silica glass , then it solidifys and forms an electro-thermal micro actuator. The device is capable of achieving precise temperature control and quick response, and can also be easily integrated into MEMS, sensors and `lab on a chip' (LOC) platform inside the fused silica substrate.

Fully Integrated, Miniature, High-Frequency Flow Probe Utilizing MEMS Leadless SOI Technology

NASA Technical Reports Server (NTRS)

Ned, Alex; Kurtz, Anthony; Shang, Tonghuo; Goodman, Scott; Giemette. Gera (d)

2013-01-01

This work focused on developing, fabricating, and fully calibrating a flowangle probe for aeronautics research by utilizing the latest microelectromechanical systems (MEMS), leadless silicon on insulator (SOI) sensor technology. While the concept of angle probes is not new, traditional devices had been relatively large due to fabrication constraints; often too large to resolve flow structures necessary for modern aeropropulsion measurements such as inlet flow distortions and vortices, secondary flows, etc. Mea surements of this kind demanded a new approach to probe design to achieve sizes on the order of 0.1 in. (.3 mm) diameter or smaller, and capable of meeting demanding requirements for accuracy and ruggedness. This approach invoked the use of stateof- the-art processing techniques to install SOI sensor chips directly onto the probe body, thus eliminating redundancy in sensor packaging and probe installation that have historically forced larger probe size. This also facilitated a better thermal match between the chip and its mount, improving stability and accuracy. Further, the leadless sensor technology with which the SOI sensing element is fabricated allows direct mounting and electrical interconnecting of the sensor to the probe body. This leadless technology allowed a rugged wire-out approach that is performed at the sensor length scale, thus achieving substantial sensor size reductions. The technology is inherently capable of high-frequency and high-accuracy performance in high temperatures and harsh environments.

Reliability enhancement of Ohmic RF MEMS switches

NASA Astrophysics Data System (ADS)

Kurth, Steffen; Leidich, Stefan; Bertz, Andreas; Nowack, Markus; Frömel, Jörg; Kaufmann, Christian; Faust, Wolfgang; Gessner, Thomas; Akiba, Akira; Ikeda, Koichi

2011-02-01

This contribution deals with capacitively actuated Ohmic switches in series single pole single throw (SPST) configuration for DC up to 4 GHz signal frequency (<0.5 dB insertion loss, 35 dB isolation) and in shunt switch SPST configuration for a frequency range from DC up to 80 GHz (<1.2 dB insertion loss, 18 dB isolation at 60 GHz). A novel high aspect ratio MEMS fabrication sequence in combination with wafer level packaging is applied for fabrication of the samples and allows for a relatively large actuation electrode area, and for high actuation force resulting in fast onresponse time of 10 μs and off-response time of 6 μs at less than 5 V actuation voltage. Large actuation electrode area and a particular design feature for electrode over travel and dynamic contact separation lead to high contact force in the closed state and to high force for contact separation to overcome sticking. The switch contacts, which are consisting of noble metal, are made in one of the latest process steps. This minimizes contamination of the contact surfaces by fabrication sequence residuals. A life time of 1 Billion switch cycles has been achieved. This paper covers design for reliability issues and reliability test methods using accelerated life time test. Different test methods are combined to examine electric and mechanical motion parameters as well as RF performance.

A MEMS-based Air Flow Sensor with a Free-standing Micro-cantilever Structure.

PubMed

Wang, Yu-Hsiang; Lee, Chia-Yen; Chiang, Che-Ming

2007-10-17

This paper presents a micro-scale air flow sensor based on a free-standingcantilever structure. In the fabrication process, MEMS techniques are used to deposit asilicon nitride layer on a silicon wafer. A platinum layer is deposited on the silicon nitridelayer to form a piezoresistor, and the resulting structure is then etched to create afreestanding micro-cantilever. When an air flow passes over the surface of the cantileverbeam, the beam deflects in the downward direction, resulting in a small variation in theresistance of the piezoelectric layer. The air flow velocity is determined by measuring thechange in resistance using an external LCR meter. The experimental results indicate that theflow sensor has a high sensitivity (0.0284 ω/ms -1 ), a high velocity measurement limit (45ms -1 ) and a rapid response time (0.53 s).

Producing fluid flow using 3D carbon electrodes

NASA Astrophysics Data System (ADS)

Rouabah, H. A.; Park, B. Y.; Zaouk, R. B.; Madou, M. J.; Green, Nicolas G.

2008-12-01

Moving and manipulating bio-particles and fluids on the microscale is central to many lab-on-a-chip applications. Techniques for pumping fluids which use electric fields have shown promise using both DC and AC voltages. AC techniques, however, require the use of integrated metal electrodes which have a low resistance but can suffer from unwanted chemical reactions even at low potentials. In this paper we introduce the use of carbon MEMS technology (C-MEMS), a fabrication method which produces 3D conductive polymeric structures. Results are presented of the fabrication of an innovative design of 3D AC-electroosmotic micropump and preliminary experimental measurements which demonstrate the potential of both the technology and the design.

Recent Advances in High-Resolution MEMS DM Fabrication and Integration

NASA Astrophysics Data System (ADS)

Bifano, T.; Cornelissen, S.; Bierden, P.

2010-09-01

Deformable mirrors fabricated using microelectromechanical systems technology (MEMS-DMs) have been studied at Boston University (BU) and developed/commercialized by Boston Micromachines Corporation (BMC) over the past decade. Recent advances that might have an impact on surveillance telescopes include demonstration of 4092 actuator DMs with continuous mirror face-sheets, and segmented DMs capable of frame rates of greater than 20kHz for devices with up to 1020 independent segments. The 4092 actuator DM, developed by BMC for the Gemini Planet Imaging GPI instrument, was recently delivered to the GPI instrument development team. Its packaging and platform development are described, and the performance results for the latest prototype devices are presented.

Bio-Inspired Stretchable Absolute Pressure Sensor Network

PubMed Central

Guo, Yue; Li, Yu-Hung; Guo, Zhiqiang; Kim, Kyunglok; Chang, Fu-Kuo; Wang, Shan X.

2016-01-01

A bio-inspired absolute pressure sensor network has been developed. Absolute pressure sensors, distributed on multiple silicon islands, are connected as a network by stretchable polyimide wires. This sensor network, made on a 4’’ wafer, has 77 nodes and can be mounted on various curved surfaces to cover an area up to 0.64 m × 0.64 m, which is 100 times larger than its original size. Due to Micro Electro-Mechanical system (MEMS) surface micromachining technology, ultrathin sensing nodes can be realized with thicknesses of less than 100 µm. Additionally, good linearity and high sensitivity (~14 mV/V/bar) have been achieved. Since the MEMS sensor process has also been well integrated with a flexible polymer substrate process, the entire sensor network can be fabricated in a time-efficient and cost-effective manner. Moreover, an accurate pressure contour can be obtained from the sensor network. Therefore, this absolute pressure sensor network holds significant promise for smart vehicle applications, especially for unmanned aerial vehicles. PMID:26729134

An Integrated Thermal Compensation System for MEMS Inertial Sensors

PubMed Central

Chiu, Sheng-Ren; Teng, Li-Tao; Chao, Jen-Wei; Sue, Chung-Yang; Lin, Chih-Hsiou; Chen, Hong-Ren; Su, Yan-Kuin

2014-01-01

An active thermal compensation system for a low temperature-bias-drift (TBD) MEMS-based gyroscope is proposed in this study. First, a micro-gyroscope is fabricated by a high-aspect-ratio silicon-on-glass (SOG) process and vacuum packaged by glass frit bonding. Moreover, a drive/readout ASIC, implemented by the 0.25 μm 1P5M standard CMOS process, is designed and integrated with the gyroscope by directly wire bonding. Then, since the temperature effect is one of the critical issues in the high performance gyroscope applications, the temperature-dependent characteristics of the micro-gyroscope are discussed. Furthermore, to compensate the TBD of the micro-gyroscope, a thermal compensation system is proposed and integrated in the aforementioned ASIC to actively tune the parameters in the digital trimming mechanism, which is designed in the readout ASIC. Finally, some experimental results demonstrate that the TBD of the micro-gyroscope can be compensated effectively by the proposed compensation system. PMID:24599191

Micro-masonry for 3D additive micromanufacturing.

PubMed

Keum, Hohyun; Kim, Seok

2014-08-01

Transfer printing is a method to transfer solid micro/nanoscale materials (herein called 'inks') from a substrate where they are generated to a different substrate by utilizing elastomeric stamps. Transfer printing enables the integration of heterogeneous materials to fabricate unexampled structures or functional systems that are found in recent advanced devices such as flexible and stretchable solar cells and LED arrays. While transfer printing exhibits unique features in material assembly capability, the use of adhesive layers or the surface modification such as deposition of self-assembled monolayer (SAM) on substrates for enhancing printing processes hinders its wide adaptation in microassembly of microelectromechanical system (MEMS) structures and devices. To overcome this shortcoming, we developed an advanced mode of transfer printing which deterministically assembles individual microscale objects solely through controlling surface contact area without any surface alteration. The absence of an adhesive layer or other modification and the subsequent material bonding processes ensure not only mechanical bonding, but also thermal and electrical connection between assembled materials, which further opens various applications in adaptation in building unusual MEMS devices.

Macro, mini, micro and nano (M(sup 3)N) technologies for the future

NASA Technical Reports Server (NTRS)

Friedrich, Craig R.; Warrington, Robert O.; Gao, Robert X.; Lin, Gang

1993-01-01

Microelectromechanical systems (MEMS), micro systems technologies (MST), and micromanufacturing are relatively recent phrases or acronyms that have become synonymous with the design, development, and manufacture of 'micro' devices and systems. Micromanufacturing encompasses MEMS or MST and, in addition, includes all of the processes involved in the production of micro things. Integration of mechanical and electrical components, including built-in computers, can be formed into systems which must be connected to the macroworld. Macro, mini, micro, and nano technologies are all a part of MEMS or micromanufacturing. At this point in the development of the technology, it is becoming apparent that mini systems, with micro components, could very well be the economic drivers of the technology for the foreseeable future. Initial research in the fabrication of microdevices using IC processing technology took place over thirty years ago. Anisotropic etching of silicon was used to produce piezoresistive diaphragms. Since the early 60's, there has been gradual progress in MEMS until the early 1980's when worldwide interest in the technology really started to develop. During this time high aspect ratio micromachining using x rays was started in Germany. In 1987 the concept of a 'silicon micromechanics foundry' was proposed. Since then the interest in the U.S., Germany, and Japan has increased to the point where hundreds of millions of dollars of research monies are being funneled into the technology (at least in Germany and Japan) and the technology has been classified as critical or as a technology or national importance by the U.S. government.

Micromechanical Devices to Reduce 1/f Noise in Magnetic Field and Electric Charge Sensors

NASA Astrophysics Data System (ADS)

Jaramillo, Gerardo

1/f noise is present in every aspect of nature. Sensors and read-out electronics have the ultimate detection limit set by the noise floor of the white noise. In order to increase signal-to-noise ratio (SNR) of low frequency signals buried by high 1/f noise, the signal can be up-converted to a high frequency signal that lies in the lower white noise regime of the sensing device. Mechanical modulation can be employed to move low frequency electronic signals to higher frequency region through the use of microresonators. This thesis has two goals: (1) develop and fabricate a hybrid micromechanical-magnetoresistive magnetic field sensor; and (2) design an electrometer to measure currents collected from air streams containing ionized nano-particles. First, we designed magnetoresistive-microelectromechanical systems (MR-MEMS) hybrid devices based on the monolithic integration of magnetic thin films and silicon-on-insulator (SOI) MEMS fabrication techniques. We used MgO-based magnetic tunnel junctions (MTJ) placed on a bulk micromachined silicon MEMS device to form a hybrid sensing device. The MEMS device was used to mechanically modulate the magnetic field signal detected by the MTJ, thereby reducing the effects of 1/f noise on the MTJ's output. Two actuator designs were investigated: cantilever and electrostatic comb-drive. The second component of the thesis presents a MEMS-based electrometer for the detection of small currents from ionized particles in a particle detection system for air-quality monitoring. One method of particle detection ionizes particles and then feeds a stream of charged particles into a Faraday cup electrometer. We replaced the Faraday cup with a filtering porous mesh sensing-electrode coupled to a MEMS electrometer with a noise floor below 1 fA rms. Experiments were conducted with fA level currents produced by 10 nm diameter particles within an airflow of 1.0 L/min. The MEMS electrometer was compared and calibrated using commercial electrometers and particle counters.

EDITORIAL: International MEMS Conference 2006

NASA Astrophysics Data System (ADS)

Tay, Francis E. H.; Jianmin, Miao; Iliescu, Ciprian

2006-04-01

The International MEMS conference (iMEMS2006) organized by the Institute of Bioengineering and Nanotechnology and Nanyang Technological University aims to provide a platform for academicians, professionals and industrialists in various related fields from all over the world to share and learn from each other. Of great interest is the incorporation of the theme of life sciences application using MEMS. It is the desire of this conference to initiate collaboration and form network of cooperation. This has continued to be the objective of iMEMS since its inception in 1997. The technological advance of MEMS over the past few decades has been truly exciting in terms of development and applications. In order to participate in this rapid development, a conference involving delegates from within the MEMS community and outside the community is very meaningful and timely. With the receipt of over 200 articles, delegates related to MEMS field from all over the world will share their perspectives on topics such as MEMS/MST Design, MEMS Teaching and Education, MEMS/MST Packaging, MEMS/MST Fabrication, Microsystems Applications, System Integration, Wearable Devices, MEMSWear and BioMEMS. Invited speakers and delegates from outside the field have also been involved to provide challenges, especially in the life sciences field, for the MEMS community to potentially address. The proceedings of the conference will be published as an issue in the online Journal of Physics: Conference Series and this can reach a wider audience and will facilitate the reference and citation of the work presented in the conference. We wish to express our deep gratitude to the International Scientific Committee members and the organizing committee members for contributing to the success of this conference. We would like to thank all the delegates, speakers and sponsors from all over the world for presenting and sharing their perspectives on topics related to MEMS and the challenges that MEMS can potentially address.

Study of the Use of Time-Mean Vortices to Generate Lift for MAV Applications

DTIC Science & Technology

2011-05-31

microplate to in-plane resonance. Computational effort centers around optimization of a range of parameters (geometry, frequency, amplitude of oscillation, etc...issue involved. Towards this end, a suspended microplate was fabricated via MEMS technology and driven to in-plane resonance via Lorentz force...force to drive the suspended MEMS-based microplate to in-plane resonance. Computational effort centers around optimization of a range of parameters

MEMS earthworm: a thermally actuated peristaltic linear micromotor

NASA Astrophysics Data System (ADS)

Arthur, Craig; Ellerington, Neil; Hubbard, Ted; Kujath, Marek

2011-03-01

This paper examines the design, fabrication and testing of a bio-mimetic MEMS (micro-electro mechanical systems) earthworm motor with external actuators. The motor consists of a passive mobile shuttle with two flexible diamond-shaped segments; each segment is independently squeezed by a pair of stationary chevron-shaped thermal actuators. Applying a specific sequence of squeezes to the earthworm segments, the shuttle can be driven backward or forward. Unlike existing inchworm drives that use clamping and thrusting actuators, the earthworm actuators apply only clamping forces to the shuttle, and lateral thrust is produced by the shuttle's compliant geometry. The earthworm assembly is fabricated using the PolyMUMPs process with planar dimensions of 400 µm width by 800 µm length. The stationary actuators operate within the range of 4-9 V and provide a maximum shuttle range of motion of 350 µm (approximately half its size), a maximum shuttle speed of 17 mm s-1 at 10 kHz, and a maximum dc shuttle force of 80 µN. The shuttle speed was found to vary linearly with both input voltage and input frequency. The shuttle force was found to vary linearly with the actuator voltage.

5 V Compatible Two-Axis PZT Driven MEMS Scanning Mirror with Mechanical Leverage Structure for Miniature LiDAR Application.

PubMed

Ye, Liangchen; Zhang, Gaofei; You, Zheng

2017-03-05

The MEMS (Micro-Electronical Mechanical System) scanning mirror is an optical MEMS device that can scan laser beams across one or two dimensions. MEMS scanning mirrors can be applied in a variety of applications, such as laser display, bio-medical imaging and Light Detection and Ranging (LiDAR). These commercial applications have recently created a great demand for low-driving-voltage and low-power MEMS mirrors. However, no reported two-axis MEMS scanning mirror is available for usage in a universal supplying voltage such as 5 V. In this paper, we present an ultra-low voltage driven two-axis MEMS scanning mirror which is 5 V compatible. In order to realize low voltage and low power, a two-axis MEMS scanning mirror with mechanical leverage driven by PZT (Lead zirconate titanate) ceramic is designed, modeled, fabricated and characterized. To further decrease the power of the MEMS scanning mirror, a new method of impedance matching for PZT ceramic driven by a two-frequency mixed signal is established. As experimental results show, this MEMS scanning mirror reaches a two-axis scanning angle of 41.9° × 40.3° at a total driving voltage of 4.2 Vpp and total power of 16 mW. The effective diameter of reflection of the mirror is 2 mm and the operating frequencies of two-axis scanning are 947.51 Hz and 1464.66 Hz, respectively.

5 V Compatible Two-Axis PZT Driven MEMS Scanning Mirror with Mechanical Leverage Structure for Miniature LiDAR Application

PubMed Central

Ye, Liangchen; Zhang, Gaofei; You, Zheng

2017-01-01

The MEMS (Micro-Electronical Mechanical System) scanning mirror is an optical MEMS device that can scan laser beams across one or two dimensions. MEMS scanning mirrors can be applied in a variety of applications, such as laser display, bio-medical imaging and Light Detection and Ranging (LiDAR). These commercial applications have recently created a great demand for low-driving-voltage and low-power MEMS mirrors. However, no reported two-axis MEMS scanning mirror is available for usage in a universal supplying voltage such as 5 V. In this paper, we present an ultra-low voltage driven two-axis MEMS scanning mirror which is 5 V compatible. In order to realize low voltage and low power, a two-axis MEMS scanning mirror with mechanical leverage driven by PZT (Lead zirconate titanate) ceramic is designed, modeled, fabricated and characterized. To further decrease the power of the MEMS scanning mirror, a new method of impedance matching for PZT ceramic driven by a two-frequency mixed signal is established. As experimental results show, this MEMS scanning mirror reaches a two-axis scanning angle of 41.9° × 40.3° at a total driving voltage of 4.2 Vpp and total power of 16 mW. The effective diameter of reflection of the mirror is 2 mm and the operating frequencies of two-axis scanning are 947.51 Hz and 1464.66 Hz, respectively. PMID:28273880

A Novel MUMPs-compatible single-layer out-of-plane electrothermal actuator

NASA Astrophysics Data System (ADS)

Tang, Weider; Wu, Mingching; Ho, Yi-Ping; Yeh, Mau-Shium; Fang, Weileun

2002-11-01

Microactuator is one of the key components for the microelectromechanical systems (MEMS), and it can be categorized as out-of-plane and in-plane according to the motion types. Most of the existing out-of-plane thermal actuators are multi-layer structures. In this paper, a novel electrothermal single-layer out-of-plane actuator is provided and it characteristics and advantages of this device are stated as follows: (1) This actuator is consisted of only a single thin film material, therefore, it can prevent from delaminating after a long-term operation. Besides, owing to its symmetric geometric design, the inner-beams of this structure don"t have any current passed through them and the inner-beams also provide a geometric constraint to allow the two free ends of the structure to bend upwards symmetrically. (2) This device can be operated at a relative low voltage (<5 volt), and deflected upwards about 4 μm in the experiment test. Besides, the fabrication process is very simple and it is MUMPs(Multi-User MEMS Processes)-compatible. Presently, a prototype structure has been successfully fabricated and tested. This structure offers the potential applications in the adaptive optics systems, and Fabry-Perot filters, etc. Besides, it also provides an interface to cooperate with integrated circuits (IC) and various optical elements to construct an embedded-control optical system.

Nanocrystalline mesoporous SMO thin films prepared by sol gel process for MEMS-based hydrogen sensor

NASA Astrophysics Data System (ADS)

Gong, Jianwei; Fei, Weifeng; Seal, Sudipta; Chen, Quanfang

2004-01-01

MEMS based SnO2 gas sensor with sol gel synthesized mesoporous nanocrystalline (<10 nm) semiconductor thin (100~150 nm) film has been recently developed. The SnO2 nano film is fabricated with the combination of polymeric sol gel chemistry with block copolymers used for structure directing agents. The novel hydrogen sensor has a fast response time (1s) and quick recovery time (3s), as well as good sensitivity (about 90%), comparing to other hydrogen sensors developed. The improved capabilities are credited to the large surface to volume ratio of gas sensing thin film with nano sized porous surface topology, which can greatly increase the sensitivity even at relatively low working temperature. The gas sensing film is deposited onto a thin dielectric membrane of low thermal conductivity, which provides good thermal isolation between substrate and the gas-sensitive heated area on the membrane. In this way the power consumption can be kept very low. Since the fabrication process is completely compatible with IC industry, it makes mass production possible and greatly reduces the cost. The working temperature of the new sensor can be reduced as low as 100°C. The low working temperature posse advantages such as lower power consumption, lower thermal induced signal shift as well as safe detection in certain environments where temperature is strictly limited.

Damping control of micromachined lowpass mechanical vibration isolation filters using electrostatic actuation with electronic signal processing

NASA Astrophysics Data System (ADS)

Dean, Robert; Flowers, George; Sanders, Nicole; MacAllister, Ken; Horvath, Roland; Hodel, A. S.; Johnson, Wayne; Kranz, Michael; Whitley, Michael

2005-05-01

Some harsh environments, such as those encountered by aerospace vehicles and various types of industrial machinery, contain high frequency/amplitude mechanical vibrations. Unfortunately, some very useful components are sensitive to these high frequency mechanical vibrations. Examples include MEMS gyroscopes and resonators, oscillators and some micro optics. Exposure of these components to high frequency mechanical vibrations present in the operating environment can result in problems ranging from an increased noise floor to component failure. Passive micromachined silicon lowpass filter structures (spring-mass-damper) have been demonstrated in recent years. However, the performance of these filter structures is typically limited by low damping (especially if operated in near-vacuum environments) and a lack of tunability after fabrication. Active filter topologies, such as piezoelectric, electrostrictive-polymer-film and SMA have also been investigated in recent years. Electrostatic actuators, however, are utilized in many micromachined silicon devices to generate mechanical motion. They offer a number of advantages, including low power, fast response time, compatibility with silicon micromachining, capacitive position measurement and relative simplicity of fabrication. This paper presents an approach for realizing active micromachined mechanical lowpass vibration isolation filters by integrating an electrostatic actuator with the micromachined passive filter structure to realize an active mechanical lowpass filter. Although the electrostatic actuator can be used to adjust the filter resonant frequency, the primary application is for increasing the damping to an acceptable level. The physical size of these active filters is suitable for use in or as packaging for sensitive electronic and MEMS devices, such as MEMS vibratory gyroscope chips.

Centimeter-scale MEMS scanning mirrors for high power laser application

NASA Astrophysics Data System (ADS)

Senger, F.; Hofmann, U.; v. Wantoch, T.; Mallas, C.; Janes, J.; Benecke, W.; Herwig, Patrick; Gawlitza, P.; Ortega-Delgado, M.; Grune, C.; Hannweber, J.; Wetzig, A.

2015-02-01

A higher achievable scan speed and the capability to integrate two scan axes in a very compact device are fundamental advantages of MEMS scanning mirrors over conventional galvanometric scanners. There is a growing demand for biaxial high speed scanning systems complementing the rapid progress of high power lasers for enabling the development of new high throughput manufacturing processes. This paper presents concept, design, fabrication and test of biaxial large aperture MEMS scanning mirrors (LAMM) with aperture sizes up to 20 mm for use in high-power laser applications. To keep static and dynamic deformation of the mirror acceptably low all MEMS mirrors exhibit full substrate thickness of 725 μm. The LAMM-scanners are being vacuum packaged on wafer-level based on a stack of 4 wafers. Scanners with aperture sizes up to 12 mm are designed as a 4-DOF-oscillator with amplitude magnification applying electrostatic actuation for driving a motor-frame. As an example a 7-mm-scanner is presented that achieves an optical scan angle of 32 degrees at 3.2 kHz. LAMM-scanners with apertures sizes of 20 mm are designed as passive high-Q-resonators to be externally excited by low-cost electromagnetic or piezoelectric drives. Multi-layer dielectric coatings with a reflectivity higher than 99.9 % have enabled to apply cw-laser power loads of more than 600 W without damaging the MEMS mirror. Finally, a new excitation concept for resonant scanners is presented providing advantageous shaping of intensity profiles of projected laser patterns without modulating the laser. This is of interest in lighting applications such as automotive laser headlights.

Microfabricated Nickel Based Sensors for Hostile and High Pressure Environments

NASA Astrophysics Data System (ADS)

Holt, Christopher Michael Bjustrom

This thesis outlines the development of two platforms for integrating microfabricated sensors with high pressure feedthroughs for application in hostile high temperature high pressure environments. An application in oil well production logging is explored and two sensors were implemented with these platforms for application in an oil well. The first platform developed involved microfabrication directly onto a cut and polished high pressure feedthrough. This technique enables a system that is more robust than the wire bonded silicon die technique used for MEMS integration in pressure sensors. Removing wire bonds from the traditional MEMS package allows for direct interface of a microfabricated sensor with a hostile high pressure fluid environment which is not currently possible. During the development of this platform key performance metrics included pressure testing to 70MPa and temperature cycling from 20°C to 200°C. This platform enables electronics integration with a variety of microfabricated electrical and thermal based sensors which can be immersed within the oil well environment. The second platform enabled free space fabrication of nickel microfabricated devices onto an array of pins using a thick tin sacrificial layer. This technique allowed microfabrication of metal MEMS that are released by distances of 1cm from their substrate. This method is quite flexible and allows for fabrication to be done on any pin array substrate regardless of surface quality. Being able to place released MEMS sensors directly onto traditional style circuit boards, ceramic circuit boards, electrical connectors, ribbon cables, pin headers, or high pressure feedthroughs greatly improves the variety of possible applications and reduces fabrication costs. These two platforms were then used to fabricate thermal conductivity sensors that showed excellent performance for distinguishing between oil, water, and gas phases. Testing was conducted at various flow rates and performance of the released platform was shown to be better than the performance seen in the anchored sensors while both platforms were significantly better than a simply fabricated wrapped wire sensor. The anchored platform was also used to demonstrate a traditional capacitance based fluid dielectric sensor which was found to work similarly to conventional commercial capacitance probes while being significantly smaller in size.

Faster sensitivity and non-antimonite permanent photoresist for MEMS

NASA Astrophysics Data System (ADS)

Misumi, Koichi; Saito, Koji; Yamanouchi, Atsushi; Senzaki, Takahiro; Okui, Toshiki; Honma, Hideo

2006-03-01

Micro Electro Mechanical Systems (MEMS) is a three-dimensional micro-fabrication technology based on photolithography. The fields of application are extensive and wide-ranging. Among the applications, those that have already acquired a large market include acceleration sensors for airbags of automobiles, pressure sensors for engine control, inkjet printer heads and thin film magnetic heads. The market is expected to further expand in the optic and biology-related fields in the future. In the MEMS field, the packaging accounts for the cost, and it is difficult to standardize due to the low production volume of highly specific technology application. A typical application in the MEMS process would be to conduct plating and etching (Deep RIE) through an intermediate layer of photoresist patterns, but there are cases where the photoresist itself is left therein as a permanent film. A photoresist composed of epoxy resin as the main component can form the permanent film through a catalyst of the optical cationic polymerizating initiator. In general, the optical cationic polymerizating initiator is of onium salt with antimonite as the anion group due to the nature of the hardening rate or the exposure energy. This paper presents the development status of a high sensitivity permanent photoresist made of epoxy resin as the main component with non-antimonite optical cationic polymerizating initiator with concerns to the impact to the environment and material for packaging.

Micro-Mechanical Voltage Tunable Fabry-Perot Filters Formed in (111) Silicon. Degree awarded by Colorado Univ., Boulder, CO

NASA Technical Reports Server (NTRS)

Patterson, James D.

1997-01-01

The MEMS (Micro-Electro-Mechanical-Systems) technology is quickly evolving as a viable means to combine micro-mechanical and micro-optical elements on the same chip. One MEMS technology that has recently gained attention by the research community is the micro-mechanical Fabry-Perot optical filter. A MEMS based Fabry-Perot consists of a vertically integrated structure composed of two mirrors separated by an air gap. Wavelength tuning is achieved by applying a bias between the two mirrors resulting in an attractive electrostatic force which pulls the mirrors closer. In this work, we present a new micro-mechanical Fabry-Perot structure which is simple to fabricate and is integratable with low cost silicon photodetectors and transistors. The structure consists of a movable gold coated oxide cantilever for the top mirror and a stationary Au/Ni plated silicon bottom mirror. The fabrication process is single mask level, self aligned, and requires only one grown or deposited layer. Undercutting of the oxide cantilever is carried out by a combination of RIE and anisotropic KOH etching of the (111) silicon substrate. Metallization of the mirrors is provided by thermal evaporation and electroplating. The optical and electrical characteristics of the fabricated devices were studied and show promissing results. A wavelength shift of 120nm with 53V applied bias was demonstrated by one device geometry using 6.27 micrometer air gap. The finesse of the structure was 2.4. Modulation bandwidths ranging from 91KHz to greater than 920KHz were also observed. Theoretical calculations show that if mirror reflectivity, smoothness, and parallelism are improved, a finesse of 30 is attainable. The predictions also suggest that a reduction of the air gap to 1 micrometer results in an increased wavelength tuning range of 175 nm with a CMOS compatible 4.75V.

Microfabricated Air-Microfluidic Sensor for Personal Monitoring of Airborne Particulate Matter: Design, Fabrication, and Experimental Results

EPA Science Inventory

We present the design and fabrication of a micro electro mechanical systems (MEMS) air-microfluidic particulate matter (PM) sensor, and show experimental results obtained from exposing the sensor to concentrations of tobacco smoke and diesel exhaust, two commonly occurring P...

Contributions to the initial development of a microelectromechanical loop heat pipe, which is based on coherent porous silicon

NASA Astrophysics Data System (ADS)

Cytrynowicz, Debra G.

The research project itself was the initiation of the development of a planar miniature loop heat pipe based on a capillary wick structure made of coherent porous silicon. Work on this project fell into four main categories, which were component fabrication, test system construction, characterization testing and test data collection, performance analysis and thermal modeling. Component fabrication involved the production of various components for the evaporator. When applicable, these components were to be produced by microelectronic and MEMS or microelectromechanical fabrication techniques. Required work involved analyses and, where necessary, modifications to the wafer processing sequence, the photo-electrochemical etching process, system and controlling computer program to make it more reliable, flexible and efficient. The development of more than one wick production process was also extremely necessary in the event of equipment failure. Work on developing this alternative also involved investigations into various details of the photo-electrochemical etching process itself. Test system construction involved the actual assembly of open and closed loop test systems. Characterization involved developing and administering a series of tests to evaluate the performance of the wicks and test systems. Although there were some indications that the devices were operating according to loop heat pipe theory, they were transient and unstable. Performance analysis involved the construction of a transparent evaporator, which enabled the visual observation of the phenomena, which occurred in the evaporator during operation. It also involved investigating the effect of the quartz wool secondary wick on the operation of the device. Observations made during the visualization study indicated that the capillary and boiling limits were being reached at extremely low values of input power. The work was performed in a collaborative effort between the Biomedical Nanotechnology Research Laboratory at the University of Toledo, the Center for Microelectronics and Sensors and MEMS at the University of Cincinnati and the Thermo-Mechanical Systems Branch of the Power and On-Board Propulsion Division at the John H. Glenn Research Center of the National Aeronautics and Space Administration in Cleveland, Ohio. Work on the project produced six publications, which presented various details on component fabrication, tests system construction and characterization and thermal modeling.

MEMS for vibration energy harvesting

NASA Astrophysics Data System (ADS)

Li, Lin; Zhang, Yangjian; San, Haisheng; Guo, Yinbiao; Chen, Xuyuan

2008-03-01

In this paper, a capacitive vibration-to-electrical energy harvester was designed. An integrated process flow for fabricating the designed capacitive harvester is presented. For overcoming the disadvantage of depending on external power source in capacitive energy harvester, two parallel electrodes with different work functions are used as the two electrodes of the capacitor to generate a build-in voltage for initially charging the capacitor. The device is a sandwich structure of silicon layer in two glass layers with area of about 1 cm2. The silicon structure is fabricated by using silicon-on-insulator (SOI) wafer. The glass wafers are anodic bonded on to both sides of the SOI wafer to create a vacuum sealed package.

GRC-2011-C-00579

NASA Image and Video Library

2007-03-28

Photos for Web Feature by Victoria (Tori) Woods; Micro-Electro Mechanical Systems (MEMS) using vacuum technology; fabricating High Temperature Electronics for Harsh Environments using silicon carbide substrates

Thin Film Transistor Control Circuitry for MEMS Acoustic Transducers

NASA Astrophysics Data System (ADS)

Daugherty, Robin

This work seeks to develop a practical solution for short range ultrasonic communications and produce an integrated array of acoustic transmitters on a flexible substrate. This is done using flexible thin film transistor (TFT) and micro electromechanical systems (MEMS). The goal is to develop a flexible system capable of communicating in the ultrasonic frequency range at a distance of 10-100 meters. This requires a great deal of innovation on the part of the FDC team developing the TFT driving circuitry and the MEMS team adapting the technology for fabrication on a flexible substrate. The technologies required for this research are independently developed. The TFT development is driven primarily by research into flexible displays. The MEMS development is driving by research in biosensors and micro actuators. This project involves the integration of TFT flexible circuit capabilities with MEMS micro actuators in the novel area of flexible acoustic transmitter arrays. This thesis focuses on the design, testing and analysis of the circuit components required for this project.

Fabrication and Characterization of a CMOS-MEMS Humidity Sensor.

PubMed

Dennis, John-Ojur; Ahmed, Abdelaziz-Yousif; Khir, Mohd-Haris

2015-07-10

This paper reports on the fabrication and characterization of a Complementary Metal Oxide Semiconductor-Microelectromechanical System (CMOS-MEMS) device with embedded microheater operated at relatively elevated temperatures (40 °C to 80 °C) for the purpose of relative humidity measurement. The sensing principle is based on the change in amplitude of the device due to adsorption or desorption of humidity on the active material layer of titanium dioxide (TiO2) nanoparticles deposited on the moving plate, which results in changes in the mass of the device. The sensor has been designed and fabricated through a standard 0.35 µm CMOS process technology and post-CMOS micromachining technique has been successfully implemented to release the MEMS structures. The sensor is operated in the dynamic mode using electrothermal actuation and the output signal measured using a piezoresistive (PZR) sensor connected in a Wheatstone bridge circuit. The output voltage of the humidity sensor increases from 0.585 mV to 30.580 mV as the humidity increases from 35% RH to 95% RH. The output voltage is found to be linear from 0.585 mV to 3.250 mV as the humidity increased from 35% RH to 60% RH, with sensitivity of 0.107 mV/% RH; and again linear from 3.250 mV to 30.580 mV as the humidity level increases from 60% RH to 95% RH, with higher sensitivity of 0.781 mV/% RH. On the other hand, the sensitivity of the humidity sensor increases linearly from 0.102 mV/% RH to 0.501 mV/% RH with increase in the temperature from 40 °C to 80 °C and a maximum hysteresis of 0.87% RH is found at a relative humidity of 80%. The sensitivity is also frequency dependent, increasing from 0.500 mV/% RH at 2 Hz to reach a maximum value of 1.634 mV/% RH at a frequency of 12 Hz, then decreasing to 1.110 mV/% RH at a frequency of 20 Hz. Finally, the CMOS-MEMS humidity sensor showed comparable response, recovery, and repeatability of measurements in three cycles as compared to a standard sensor that directly measures humidity in % RH.

Fabrication and Characterization of a CMOS-MEMS Humidity Sensor

PubMed Central

Dennis, John-Ojur; Ahmed, Abdelaziz-Yousif; Khir, Mohd-Haris

2015-01-01

This paper reports on the fabrication and characterization of a Complementary Metal Oxide Semiconductor-Microelectromechanical System (CMOS-MEMS) device with embedded microheater operated at relatively elevated temperatures (40 °C to 80 °C) for the purpose of relative humidity measurement. The sensing principle is based on the change in amplitude of the device due to adsorption or desorption of humidity on the active material layer of titanium dioxide (TiO2) nanoparticles deposited on the moving plate, which results in changes in the mass of the device. The sensor has been designed and fabricated through a standard 0.35 µm CMOS process technology and post-CMOS micromachining technique has been successfully implemented to release the MEMS structures. The sensor is operated in the dynamic mode using electrothermal actuation and the output signal measured using a piezoresistive (PZR) sensor connected in a Wheatstone bridge circuit. The output voltage of the humidity sensor increases from 0.585 mV to 30.580 mV as the humidity increases from 35% RH to 95% RH. The output voltage is found to be linear from 0.585 mV to 3.250 mV as the humidity increased from 35% RH to 60% RH, with sensitivity of 0.107 mV/% RH; and again linear from 3.250 mV to 30.580 mV as the humidity level increases from 60% RH to 95% RH, with higher sensitivity of 0.781 mV/% RH. On the other hand, the sensitivity of the humidity sensor increases linearly from 0.102 mV/% RH to 0.501 mV/% RH with increase in the temperature from 40 °C to 80 °C and a maximum hysteresis of 0.87% RH is found at a relative humidity of 80%. The sensitivity is also frequency dependent, increasing from 0.500 mV/% RH at 2 Hz to reach a maximum value of 1.634 mV/% RH at a frequency of 12 Hz, then decreasing to 1.110 mV/% RH at a frequency of 20 Hz. Finally, the CMOS-MEMS humidity sensor showed comparable response, recovery, and repeatability of measurements in three cycles as compared to a standard sensor that directly measures humidity in % RH. PMID:26184204

Nanotechnology: MEMS and NEMS and their applications to smart systems and devices

NASA Astrophysics Data System (ADS)

Varadan, Vijay K.

2003-10-01

The microelectronics industry has seen explosive growth during the last thirty years. Extremely large markets for logic and memory devices have driven the development of new materials, and technologies for the fabrication of even more complex devices with features sizes now down at the sub micron and nanometer level. Recent interest has arisen in employing these materials, tools and technologies for the fabrication of miniature sensors and actuators and their integration with electronic circuits to produce smart devices and systems. This effort offers the promise of: (1) increasing the performance and manufacturability of both sensors and actuators by exploiting new batch fabrication processes developed including micro stereo lithographic and micro molding techniques; (2) developing novel classes of materials and mechanical structures not possible previously, such as diamond like carbon, silicon carbide and carbon nanotubes, micro-turbines and micro-engines; (3) development of technologies for the system level and wafer level integration of micro components at the nanometer precision, such as self-assembly techniques and robotic manipulation; (4) development of control and communication systems for MEMS devices, such as optical and RF wireless, and power delivery systems, etc. A novel composite structure can be tailored by functionalizing carbon nano tubes and chemically bonding them with the polymer matrix e.g. block or graft copolymer, or even cross-linked copolymer, to impart exceptional structural, electronic and surface properties. Bio- and Mechanical-MEMS devices derived from this hybrid composite provide a new avenue for future smart systems. The integration of NEMS (NanoElectroMechanical Systems), MEMS, IDTs (Interdigital Transducers) and required microelectronics and conformal antenna in the multifunctional smart materials and composites results in a smart system suitable for sending and control of a variety functions in automobile, aerospace, marine and civil strutures and food and medical industries. This unique combination of technologies also results in novel conformal sensors that can be remotely sensed by an antenna system with the advantage of no power requirements at the sensor site. This paper provides a brief review of MEMS and NEMS based smart systems for various applications mentioned above. Carbon Nano Tubes (CNT) with their unique structure, have already proven to be valuable in their application as tips for scanning probe microscopy, field emission devices, nanoelectronics, H2-storage, electromagnetic absorbers, ESD, EMI films and coatings and structural composites. For many of these applications, highly purified and functionalized CNT which are compatible with many host polymers are needed. A novel microwave CVD processing technique to meet these requirements has been developed at Penn State Center for the Engineering of Electronic and Acoustic Materials and Devices (CEEAMD). This method enables the production of highly purified carbon nano tubes with variable size (from 5 - 40 nm) at low cost (per gram) and high yield. Whereas, carbon nano tubes synthesized using the laser ablation or arc discharge evaporation method always include impurity due to catalyst or catalyst support. The Penn State research is based on the use of zeolites over other metal/metal oxides in the microwave field for a high production and uniformity of the product. An extended coventional purification method has been employed to purify our products in order to remove left over impurity. A novel composite structure can be tailored by functionalizing carbon nano tubes and chemically bonding them with the polymer matrix e.g. block or graft copolymer, or even cross-linked copolymer, to impart exceptional structural, electronic and surface properties. Bio- and Mechanical-MEMS devices derived from this hybrid composites will be presented.

MEMS- and NEMS-based smart devices and systems

NASA Astrophysics Data System (ADS)

Varadan, Vijay K.

2001-11-01

The microelectronics industry has seen explosive growth during the last thirty years. Extremely large markets for logic and memory devices have driven the development of new materials, and technologies for the fabrication of even more complex devices with features sized now don at the sub micron and nanometer level. Recent interest has arisen in employing these materials, tools and technologies for the fabrication of miniature sensors and actuators and their integration with electronic circuits to produce smart devices and systems. This effort offers the promise of: 1) increasing the performance and manufacturability of both sensors and actuators by exploiting new batch fabrication processes developed including micro stereo lithographic an micro molding techniques; 2) developing novel classes of materials and mechanical structures not possible previously, such as diamond like carbon, silicon carbide and carbon nanotubes, micro-turbines and micro-engines; 3) development of technologies for the system level and wafer level integration of micro components at the nanometer precision, such as self-assembly techniques and robotic manipulation; 4) development of control and communication systems for MEMS devices, such as optical and RF wireless, and power delivery systems, etc. A novel composite structure can be tailored by functionalizing carbon nano tubes and chemically bonding them with the polymer matrix e.g. block or graft copolymer, or even cross-linked copolymer, to impart exceptional structural, electronic and surface properties. Bio- and Mechanical-MEMS devices derived from this hybrid composite provide a new avenue for future smart systems. The integration of NEMS (NanoElectroMechanical Systems), MEMS, IDTs (Interdigital Transducers) and required microelectronics and conformal antenna in the multifunctional smart materials and composites results in a smart system suitable for sensing and control of a variety functions in automobile, aerospace, marine and civil structures and food and medical industries. This unique combination of technologies also results in novel conformal sensors that can be remotely sensed by an antenna system with the advantage of no power requirements at the sensor site. This paper provides a brief review of MEMS and NEMS based smart systems for various applications mentioned above. Carbon Nano Tubes (CNT) with their unique structure, have already proven to be valuable in their application as tips for scanning probe microscopy, field emission devices, nanoelectronics, H2-storage, electromagnetic absorbers, ESD, EMI films and coatings and structural composites. For many of these applications, highly purified and functionalized CNT which are compatible with many host polymers are needed. A novel microwave CVD processing technique to meet these requirements has been developed at Penn State Center for the engineering of Electronic and Acoustic Materials and Devices (CEEAMD). This method enables the production of highly purified carbon nano tubes with variable size (from 5-40 nm) at low cost (per gram) and high yield. Whereas, carbon nano tubes synthesized using the laser ablation or arc discharge evaporation method always include impurity due to catalyst or catalyst support. The Penn State research is based on the use of zeolites over other metal/metal oxides in the microwave field for a high production and uniformity of the product. An extended conventional purification method has been employed to purify our products in order to remove left over impurity. A novel composite structure can be tailored by functionalizing carbon nano tubes and chemically bonding them with the polymer matrix e.g. block or graft copolymer, or even cross- linked copolymer, to impart exceptional structural, electronic and surface properties. Bio- and Mechanical-MEMS devices derived from this hybrid composites will be presented.

Concept for a Micro Autonomous Ultrasonic Instrument (MAUI)

NASA Technical Reports Server (NTRS)

Wilson, William C.; Atkinson, Gary M.

2002-01-01

We investigate a concept for the construction a mobile Micro Optical ElectroMechanical Systems (MOEMS) based laser ultrasonic instrument to serve as a Micro Autonomous Ultrasonic Instrument (MAUI). The system will consist of a laser ultrasonic instrument fabricated using Micro Electro-Mechanical Systems (MEMS) technology, and a MEMS based walking platform like those developed by Pister et al. at Berkeley. This small system will allow for automated remote Non-Destructive Evaluation (NDE) of aerospace vehicles.

Multi-layer plastic/glass microfluidic systems containing electrical and mechanical functionality.

PubMed

Han, Arum; Wang, Olivia; Graff, Mason; Mohanty, Swomitra K; Edwards, Thayne L; Han, Ki-Ho; Bruno Frazier, A

2003-08-01

This paper describes an approach for fabricating multi-layer microfluidic systems from a combination of glass and plastic materials. Methods and characterization results for the microfabrication technologies underlying the process flow are presented. The approach is used to fabricate and characterize multi-layer plastic/glass microfluidic systems containing electrical and mechanical functionality. Hot embossing, heat staking of plastics, injection molding, microstenciling of electrodes, and stereolithography were combined with conventional MEMS fabrication techniques to realize the multi-layer systems. The approach enabled the integration of multiple plastic/glass materials into a single monolithic system, provided a solution for the integration of electrical functionality throughout the system, provided a mechanism for the inclusion of microactuators such as micropumps/valves, and provided an interconnect technology for interfacing fluids and electrical components between the micro system and the macro world.

Development of an all-metal electrothermal actuator and its applications

NASA Astrophysics Data System (ADS)

Luo, JiKui; He, Johnny H.; Flewitt, Andrew J.; Moore, David F.; Spearing, S. Mark; Fleck, Norman A.; Milne, Williams I.

2004-01-01

The in-plane motion of microelectrothermal actuator ("heatuator") has been analysed for Si-based and metallic devices. It was found that the lateral deflection of a heatuator made of a Ni-metal is about ~60% larger than that of a Si-based actuator under the same power consumption. Metals are much better for thermal actuators as they provide a relatively large deflection and large force, for a low operating temperature, and power consumption. Electroplated Ni films were used to fabricate heatuators. The electrical and mechanical properties of electroplated Ni thin films have been investigated as a function of temperature and plating current density, and the process conditions have been optimised to obtain stress-free films suitable for MEMS applications. Lateral thermal actuators have been successfully fabricated, and electrically tested. Microswitches and microtweezers utilising the heatuator have also been fabricated and tested.

Fabrication and Characterization of a Micro Methanol Sensor Using the CMOS-MEMS Technique.

PubMed

Fong, Chien-Fu; Dai, Ching-Liang; Wu, Chyan-Chyi

2015-10-23

A methanol microsensor integrated with a micro heater manufactured using the complementary metal oxide semiconductor (CMOS)-microelectromechanical system (MEMS) technique was presented. The sensor has a capability of detecting low concentration methanol gas. Structure of the sensor is composed of interdigitated electrodes, a sensitive film and a heater. The heater located under the interdigitated electrodes is utilized to provide a working temperature to the sensitive film. The sensitive film prepared by the sol-gel method is tin dioxide doped cadmium sulfide, which is deposited on the interdigitated electrodes. To obtain the suspended structure and deposit the sensitive film, the sensor needs a post-CMOS process to etch the sacrificial silicon dioxide layer and silicon substrate. The methanol senor is a resistive type. A readout circuit converts the resistance variation of the sensor into the output voltage. The experimental results show that the methanol sensor has a sensitivity of 0.18 V/ppm.

Fabrication and Characterization of a Micro Methanol Sensor Using the CMOS-MEMS Technique

PubMed Central

Fong, Chien-Fu; Dai, Ching-Liang; Wu, Chyan-Chyi

2015-01-01

A methanol microsensor integrated with a micro heater manufactured using the complementary metal oxide semiconductor (CMOS)-microelectromechanical system (MEMS) technique was presented. The sensor has a capability of detecting low concentration methanol gas. Structure of the sensor is composed of interdigitated electrodes, a sensitive film and a heater. The heater located under the interdigitated electrodes is utilized to provide a working temperature to the sensitive film. The sensitive film prepared by the sol-gel method is tin dioxide doped cadmium sulfide, which is deposited on the interdigitated electrodes. To obtain the suspended structure and deposit the sensitive film, the sensor needs a post-CMOS process to etch the sacrificial silicon dioxide layer and silicon substrate. The methanol senor is a resistive type. A readout circuit converts the resistance variation of the sensor into the output voltage. The experimental results show that the methanol sensor has a sensitivity of 0.18 V/ppm. PMID:26512671

Using evaporation to control capillary instabilities in micro-systems.

PubMed

Ledesma-Aguilar, Rodrigo; Laghezza, Gianluca; Yeomans, Julia M; Vella, Dominic

2017-12-06

The instabilities of fluid interfaces represent both a limitation and an opportunity for the fabrication of small-scale devices. Just as non-uniform capillary pressures can destroy micro-electrical mechanical systems (MEMS), so they can guide the assembly of novel solid and fluid structures. In many such applications the interface appears during an evaporation process and is therefore only present temporarily. It is commonly assumed that this evaporation simply guides the interface through a sequence of equilibrium configurations, and that the rate of evaporation only sets the timescale of this sequence. Here, we use Lattice-Boltzmann simulations and a theoretical analysis to show that, in fact, the rate of evaporation can be a factor in determining the onset and form of dynamical capillary instabilities. Our results shed light on the role of evaporation in previous experiments, and open the possibility of exploiting diffusive mass transfer to directly control capillary flows in MEMS applications.

Wafer-scale growth of highly textured piezoelectric thin films by pulsed laser deposition for micro-scale sensors and actuators

NASA Astrophysics Data System (ADS)

Nguyen, M. D.; Tiggelaar, R.; Aukes, T.; Rijnders, G.; Roelof, G.

2017-11-01

Piezoelectric lead-zirconate-titanate (PZT) thin films were deposited on 4-inch (111)Pt/Ti/SiO2/Si(001) wafers using large-area pulsed laser deposition (PLD). This study was focused on the homogeneity in film thickness, microstructure, ferroelectric and piezoelectric properties of PZT thin films. The results indicated that the highly textured (001)-oriented PZT thin films with wafer-scale thickness homogeneity (990 nm ± 0.8%) were obtained. The films were fabricated into piezoelectric cantilevers through a MEMS microfabrication process. The measured longitudinal piezoelectric coefficient (d 33f = 210 pm/V ± 1.6%) and piezoelectric transverse coefficient (e 31f = -18.8 C/m2 ± 2.8%) were high and homogeneity across wafers. The high piezoelectric properties on Si wafers will extend industrial application of PZT thin films and further development of piezoMEMS.

Percutaneous intracardiac beating-heart surgery using metal MEMS tissue approximation tools

PubMed Central

Gosline, Andrew H; Vasilyev, Nikolay V; Butler, Evan J; Folk, Chris; Cohen, Adam; Chen, Rich; Lang, Nora; del Nido, Pedro J; Dupont, Pierre E

2013-01-01

Achieving superior outcomes through the use of robots in medical applications requires an integrated approach to the design of the robot, tooling and the procedure itself. In this paper, this approach is applied to develop a robotic technique for closing abnormal communication between the atria of the heart. The goal is to achieve the efficacy of surgical closure as performed on a stopped, open heart with the reduced risk and trauma of a beating-heart catheter-based procedure. In the proposed approach, a concentric tube robot is used to percutaneously access the right atrium and deploy a tissue approximation device. The device is constructed using a metal microelectromechanical system (MEMS) fabrication process and is designed to both fit the manipulation capabilities of the robot as well as to reproduce the beneficial features of surgical closure by suture. The effectiveness of the approach is demonstrated through ex vivo and in vivo experiments. PMID:23750066

A MEMS-based Air Flow Sensor with a Free-standing Micro-cantilever Structure

PubMed Central

Wang, Yu-Hsiang; Lee, Chia-Yen; Chiang, Che-Ming

2007-01-01

This paper presents a micro-scale air flow sensor based on a free-standing cantilever structure. In the fabrication process, MEMS techniques are used to deposit a silicon nitride layer on a silicon wafer. A platinum layer is deposited on the silicon nitride layer to form a piezoresistor, and the resulting structure is then etched to create a freestanding micro-cantilever. When an air flow passes over the surface of the cantilever beam, the beam deflects in the downward direction, resulting in a small variation in the resistance of the piezoelectric layer. The air flow velocity is determined by measuring the change in resistance using an external LCR meter. The experimental results indicate that the flow sensor has a high sensitivity (0.0284 Ω/ms-1), a high velocity measurement limit (45 ms-1) and a rapid response time (0.53 s). PMID:28903233

CROSS-DISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY: Surface Micromachined Adjustable Micro-Concave Mirror for Bio-Detection Applications

NASA Astrophysics Data System (ADS)

Kuo, Ju-Nan; Chen, Wei-Lun; Jywe, Wen-Yuh

2009-08-01

We present a bio-detection system integrated with an adjustable micro-concave mirror. The bio-detection system consists of an adjustable micro-concave mirror, micro flow cytometer chip and optical detection module. The adjustable micro-concave mirror can be fabricated with ease using commercially available MEMS foundry services (such as multiuser MEMS processes, MUMPs) and its curvature can be controlled utilizing thermal or electrical effects. Experimental results show that focal lengths of the micro-concave mirror ranging from 313.5 to 2275.0 μm are achieved. The adjustable micro-concave mirror can be used to increase the efficiency of optical detection and provide a high signal-to-noise ratio. The developed micro-concave mirror is integrated with a micro flow cytometer for cell counting applications. Successful counting of fluorescent-labeled beads is demonstrated using the developed method.

High-uniformity centimeter-wide Si etching method for MEMS devices with large opening elements

NASA Astrophysics Data System (ADS)

Okamoto, Yuki; Tohyama, Yukiya; Inagaki, Shunsuke; Takiguchi, Mikio; Ono, Tomoki; Lebrasseur, Eric; Mita, Yoshio

2018-04-01

We propose a compensated mesh pattern filling method to achieve highly uniform wafer depth etching (over hundreds of microns) with a large-area opening (over centimeter). The mesh opening diameter is gradually changed between the center and the edge of a large etching area. Using such a design, the etching depth distribution depending on sidewall distance (known as the local loading effect) inversely compensates for the over-centimeter-scale etching depth distribution, known as the global or within-die(chip)-scale loading effect. Only a single DRIE with test structure patterns provides a micro-electromechanical systems (MEMS) designer with the etched depth dependence on the mesh opening size as well as on the distance from the chip edge, and the designer only has to set the opening size so as to obtain a uniform etching depth over the entire chip. This method is useful when process optimization cannot be performed, such as in the cases of using standard conditions for a foundry service and of short turn-around-time prototyping. To demonstrate, a large MEMS mirror that needed over 1 cm2 of backside etching was successfully fabricated using as-is-provided DRIE conditions.

Alternative method for steam generation for thermal oxidation of silicon

NASA Astrophysics Data System (ADS)

Spiegelman, Jeffrey J.

2010-02-01

Thermal oxidation of silicon is an important process step in MEMS device fabrication. Thicker oxide layers are often used as structural components and can take days or weeks to grow, causing high gas costs, maintenance issues, and a process bottleneck. Pyrolytic steam, which is generated from hydrogen and oxygen combustion, was the default process, but has serious drawbacks: cost, safety, particles, permitting, reduced growth rate, rapid hydrogen consumption, component breakdown and limited steam flow rates. Results from data collected over a 24 month period by a MEMS manufacturer supports replacement of pyrolytic torches with RASIRC Steamer technology to reduce process cycle time and enable expansion previously limited by local hydrogen permitting. Data was gathered to determine whether Steamers can meet or exceed pyrolytic torch performance. The RASIRC Steamer uses de-ionized water as its steam source, eliminating dependence on hydrogen and oxygen. A non-porous hydrophilic membrane selectively allows water vapor to pass. All other molecules are greatly restricted, so contaminants in water such as dissolved gases, ions, total organic compounds (TOC), particles, and metals can be removed in the steam phase. The MEMS manufacturer improved growth rate by 7% over the growth range from 1μm to 3.5μm. Over a four month period, wafer uniformity, refractive index, wafer stress, and etch rate were tracked with no significant difference found. The elimination of hydrogen generated a four-month return on investment (ROI). Mean time between failure (MTBF) was increased from 3 weeks to 32 weeks based on three Steamers operating over eight months.

Application of MEMS Microphone Array Technology to Airframe Noise Measurements

NASA Technical Reports Server (NTRS)

Humphreys, William M., Jr.; Shams, Qamar A.; Graves, Sharon S.; Sealey, Bradley S.; Bartram, Scott M.; Comeaux, Toby

2005-01-01

Current generation microphone directional array instrumentation is capable of extracting accurate noise source location and directivity data on a variety of aircraft components, resulting in significant gains in test productivity. However, with this gain in productivity has come the desire to install larger and more complex arrays in a variety of ground test facilities, creating new challenges for the designers of array systems. To overcome these challenges, a research study was initiated to identify and develop hardware and fabrication technologies which could be used to construct an array system exhibiting acceptable measurement performance but at much lower cost and with much simpler installation requirements. This paper describes an effort to fabricate a 128-sensor array using commercially available Micro-Electro-Mechanical System (MEMS) microphones. The MEMS array was used to acquire noise data for an isolated 26%-scale high-fidelity Boeing 777 landing gear in the Virginia Polytechnic Institute and State University Stability Tunnel across a range of Mach numbers. The overall performance of the array was excellent, and major noise sources were successfully identified from the measurements.

Development of the micro pixel chamber based on MEMS technology

NASA Astrophysics Data System (ADS)

Takemura, T.; Takada, A.; Kishimoto, T.; Komura, S.; Kubo, H.; Matsuoka, Y.; Miuchi, K.; Miyamoto, S.; Mizumoto, T.; Mizumura, Y.; Motomura, T.; Nakamasu, Y.; Nakamura, K.; Oda, M.; Ohta, K.; Parker, J. D.; Sawano, T.; Sonoda, S.; Tanimori, T.; Tomono, D.; Yoshikawa, K.

2018-02-01

Micro pixel chambers (μ-PIC) are gaseous two-dimensional imaging detectors originally manufactured using printed circuit board (PCB) technology. They are used in MeV gamma-ray astronomy, medicalimaging, neutron imaging, the search for dark matter, and dose monitoring. The position resolution of the present μ-PIC is approximately 120 μm (RMS), however some applications require a fine position resolution of less than 100 μm. To this end, we have started to develop a μ-PIC based on micro electro mechanical system (MEMS) technology, which provides better manufacturing accuracy than PCB technology. Our simulation predicted the gains of MEMS μ-PICs to be twice those of PCB μ-PICs at the same anode voltage. We manufactured two MEMS μ-PICs and tested them to study their behavior. In these experiments, we successfully operated the fabricatedMEMS μ-PICs and we achieved a maximum gain of approximately 7×103 and collected their energy spectra under irradiation of X-rays from 55Fe. However, the measured gains of the MEMS μ-PICs were less than half of the values predicted in the simulations. We postulated that the gains of the MEMS μ-PICs are diminished by the effect of the silicon used as a semiconducting substrate.

Miniaturized diffraction based interferometric distance measurement sensor

NASA Astrophysics Data System (ADS)

Kim, Byungki

In this thesis, new metrology hardware is designed, fabricated, and tested to provide improvements over current MEMS metrology. The metrology system is a micromachined scanning interferometer (muSI) having a sub-nm resolution in a compact design. The proposed microinterferometer forms a phase sensitive diffraction grating with interferomeric sensitivity, while adding the capability of better lateral resolution by focusing the laser to a smaller spot size. A detailed diffraction model of the microinterferometer was developed to simulate the device performance and to suggest the location of photo detectors for integrated optoelectronics. A particular device is fabricated on a fused silica substrate using aluminum to form the deformable diffraction grating fingers and AZ P4620 photo resist (PR) for the microlens. The details of the fabrication processes are presented. The structure also enables optoelectronics to be integrated so that the interferometer with photo detectors can fit in an area that is 1 mm x 1 mm. The scanning results using a fixed grating muSI demonstrated that it could measure vibration profile as well as static vertical (less than a half wave length) and lateral dimension of MEMS. The muSI, which is integrated with photo diodes, demonstrated its operation by scanning a cMUT. The PID control has been tested and resulted in improvement in scanned images. The integrated muSI demonstrated that the deformable grating could be used to tune the measurement keep the interferometer in quadrature for highest sensitivity.

A Ku band 5 bit MEMS phase shifter for active electronically steerable phased array applications

NASA Astrophysics Data System (ADS)

Sharma, Anesh K.; Gautam, Ashu K.; Farinelli, Paola; Dutta, Asudeb; Singh, S. G.

2015-03-01

The design, fabrication and measurement of a 5 bit Ku band MEMS phase shifter in different configurations, i.e. a coplanar waveguide and microstrip, are presented in this work. The development architecture is based on the hybrid approach of switched and loaded line topologies. All the switches are monolithically manufactured on a 200 µm high resistivity silicon substrate using 4 inch diameter wafers. The first three bits (180°, 90° and 45°) are realized using switched microstrip lines and series ohmic MEMS switches whereas the fourth and fifth bits (22.5° and 11.25°) consist of microstrip line sections loaded by shunt ohmic MEMS devices. Individual bits are fabricated and evaluated for performance and the monolithic device is a 5 bit Ku band (16-18 GHz) phase shifter with very low average insertion loss of the order of 3.3 dB and a return loss better than 15 dB over the 32 states with a chip area of 44 mm2. A total phase shift of 348.75° with phase accuracy within 3° is achieved over all of the states. The performance of individual bits has been optimized in order to achieve an integrated performance so that they can be implemented into active electronically steerable antennas for phased array applications.

A sacrificial process for fabrication of biodegradable polymer membranes with submicron thickness.

PubMed

Beardslee, Luke A; Stolwijk, Judith; Khaladj, Dimitrius A; Trebak, Mohamed; Halman, Justin; Torrejon, Karen Y; Niamsiri, Nuttawee; Bergkvist, Magnus

2016-08-01

A new sacrificial molding process using a single mask has been developed to fabricate ultrathin 2-dimensional membranes from several biocompatible polymeric materials. The fabrication process is similar to a sacrificial microelectromechanical systems (MEMS) process flow, where a mold is created from a material that can be coated with a biodegradable polymer and subsequently etched away, leaving behind a very thin polymer membrane. In this work, two different sacrificial mold materials, silicon dioxide (SiO2 ) and Liftoff Resist (LOR) were used. Three different biodegradable materials; polycaprolactone (PCL), poly(lactic-co-glycolic acid) (PLGA), and polyglycidyl methacrylate (PGMA), were chosen as model polymers. We demonstrate that this process is capable of fabricating 200-500 nm thin, through-hole polymer membranes with various geometries, pore-sizes and spatial features approaching 2.5 µm using a mold fabricated via a single contact photolithography exposure. In addition, the membranes can be mounted to support rings made from either SU8 or PCL for easy handling after release. Cell culture compatibility of the fabricated membranes was evaluated with human dermal microvascular endothelial cells (HDMECs) seeded onto the ultrathin porous membranes, where the cells grew and formed confluent layers with well-established cell-cell contacts. Furthermore, human trabecular meshwork cells (HTMCs) cultured on these scaffolds showed similar proliferation as on flat PCL substrates, further validating its compatibility. All together, these results demonstrated the feasibility of our sacrificial fabrication process to produce biocompatible, ultra-thin membranes with defined microstructures (i.e., pores) with the potential to be used as substrates for tissue engineering applications. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1192-1201, 2016. © 2015 Wiley Periodicals, Inc.

Release Resistant Electrical Interconnections For Mems Devices

DOEpatents

Peterson, Kenneth A.; Garrett, Stephen E.; Reber, Cathleen A.

2005-02-22

A release resistant electrical interconnection comprising a gold-based electrical conductor compression bonded directly to a highly-doped polysilicon bonding pad in a MEMS, IMEMS, or MOEMS device, without using any intermediate layers of aluminum, titanium, solder, or conductive adhesive disposed in-between the conductor and polysilicon pad. After the initial compression bond has been formed, subsequent heat treatment of the joint above 363 C creates a liquid eutectic phase at the bondline comprising gold plus approximately 3 wt % silicon, which, upon re-solidification, significantly improves the bond strength by reforming and enhancing the initial bond. This type of electrical interconnection is resistant to chemical attack from acids used for releasing MEMS elements (HF, HCL), thereby enabling the use of a "package-first, release-second" sequence for fabricating MEMS devices. Likewise, the bond strength of an Au--Ge compression bond may be increased by forming a transient liquid eutectic phase comprising Au-12 wt % Ge.

A MEMS sensor for AC electric current

NASA Astrophysics Data System (ADS)

Leland, Eli Sidney

This manuscript describes the development of a new MEMS sensor for the measurement of AC electric current. The sensor is comprised of a MEMS piezoelectric cantilever with a microscale permanent magnet mounted to the cantilever's free end. When placed near a wire carrying AC current, the magnet couples to the oscillating magnetic field surrounding the wire, causing the cantilever to deflect, and piezoelectric coupling produces a sinusoidal voltage proportional to the current in the wire. The sensor is itself passive, requiring no power supply to operate. It also operates on proximity and need only be placed near a current carrier in order to function. The sensor does not need to encircle the current carrier and it therefore can measure current in two-wire zip-cords without necessitating the separation of the two conductors. Applications for tins sensor include measuring residential and commercial electricity use and monitoring electric power distribution networks. An analytical model describing the behavior of the current sensor was developed. This model was also adapted to describe the power output of an energy scavenger coupled to a wire carrying AC current. A mesoscale sensor exhibited a sensitivity of 75 mV/A when measuring AC electric current in a zip-cord. A mesoscale energy scavenger produced 345 muW when coupled to a zip-cord carrying 13 A. MEMS current sensors were fabricated from aluminum nitride piezoelectric cantilevers and composite permanent magnets. The cantilevers were fabricated using a four-mask process. Microscale permanent magnets were dispenser-printed using NdFeB magnetic powder with an epoxy binder. The MEMS AC current sensor was interfaced with amplification circuitry and packaged inside an almninum enclosure. The sensor was also integrated with a mesoscale energy scavenger and power conditioning circuitry to create a fully self-powered current sensor. Unamplified sensitivity of the sensor was 0.1-1.1 mV/A when measuring currents in single wires and zip-cords. The self-powered current sensor operated at a 0.6% duty cycle when coupled to the zip-cord of a 1500 W space heater drawing 13 A. The self-powered sensor's energy scavenger transferred energy to a 10 mF storage capacitor at a rate of 69 muJ/s.

Etching characteristics of Si{110} in 20 wt% KOH with addition of hydroxylamine for the fabrication of bulk micromachined MEMS

NASA Astrophysics Data System (ADS)

Rao, A. V. Narasimha; Swarnalatha, V.; Pal, P.

2017-12-01

Anisotropic wet etching is a most widely employed for the fabrication of MEMS/NEMS structures using silicon bulk micromachining. The use of Si{110} in MEMS is inevitable when a microstructure with vertical sidewall is to be fabricated using wet anisotropic etching. In most commonly employed etchants (i.e. TMAH and KOH), potassium hydroxide (KOH) exhibits higher etch rate and provides improved anisotropy between Si{111} and Si{110} planes. In the manufacturing company, high etch rate is demanded to increase the productivity that eventually reduces the cost of end product. In order to modify the etching characteristics of KOH for the micromachining of Si{110}, we have investigated the effect of hydroxylamine (NH2OH) in 20 wt% KOH solution. The concentration of NH2OH is varied from 0 to 20% and the etching is carried out at 75 °C. The etching characteristics which are studied in this work includes the etch rates of Si{110} and silicon dioxide, etched surface morphology, and undercutting at convex corners. The etch rate of Si{110} in 20 wt% KOH + 15% NH2OH solution is measured to be four times more than that of pure 20 wt% KOH. Moreover, the addition of NH2OH increases the undercutting at convex corners and enhances the etch selectivity between Si and SiO2.

A novel multi-actuation CMOS RF MEMS switch

NASA Astrophysics Data System (ADS)

Lee, Chiung-I.; Ko, Chih-Hsiang; Huang, Tsun-Che

2008-12-01

This paper demonstrates a capacitive shunt type RF MEMS switch, which is actuated by electro-thermal actuator and electrostatic actuator at the same time, and than latching the switching status by electrostatic force only. Since thermal actuators need relative low voltage compare to electrostatic actuators, and electrostatic force needs almost no power to maintain the switching status, the benefits of the mechanism are very low actuation voltage and low power consumption. Moreover, the RF MEMS switch has considered issues for integrated circuit compatible in design phase. So the switch is fabricated by a standard 0.35um 2P4M CMOS process and uses wet etching and dry etching technologies for postprocess. This compatible ability is important because the RF characteristics are not only related to the device itself. If a packaged RF switch and a packaged IC wired together, the parasitic capacitance will cause the problem for optimization. The structure of the switch consists of a set of CPW transmission lines and a suspended membrane. The CPW lines and the membrane are in metal layers of CMOS process. Besides, the electro-thermal actuators are designed by polysilicon layer of the CMOS process. So the RF switch is only CMOS process layers needed for both electro-thermal and electrostatic actuations in switch. The thermal actuator is composed of a three-dimensional membrane and two heaters. The membrane is a stacked step structure including two metal layers in CMOS process, and heat is generated by poly silicon resistors near the anchors of membrane. Measured results show that the actuation voltage of the switch is under 7V for electro-thermal added electrostatic actuation.

Vertical integration of array-type miniature interferometers at wafer level by using multistack anodic bonding

NASA Astrophysics Data System (ADS)

Wang, Wei-Shan; Wiemer, Maik; Froemel, Joerg; Enderlein, Tom; Gessner, Thomas; Lullin, Justine; Bargiel, Sylwester; Passilly, Nicolas; Albero, Jorge; Gorecki, Christophe

2016-04-01

In this work, vertical integration of miniaturized array-type Mirau interferometers at wafer level by using multi-stack anodic bonding is presented. Mirau interferometer is suitable for MEMS metrology and for medical imaging according to its vertical-, lateral- resolutions and working distances. Miniaturized Mirau interferometer can be a promising candidate as a key component of an optical coherence tomography (OCT) system. The miniaturized array-type interferometer consists of a microlens doublet, a Si-based MEMS Z scanner, a spacer for focus-adjustment and a beam splitter. Therefore, bonding technologies which are suitable for heterogeneous substrates are of high interest and necessary for the integration of MEMS/MOEMS devices. Multi-stack anodic bonding, which meets the optical and mechanical requirements of the MOEMS device, is adopted to integrate the array-type interferometers. First, the spacer and the beam splitter are bonded, followed by bonding of the MEMS Z scanner. In the meanwhile, two microlenses, which are composed of Si and glass wafers, are anodically bonded to form a microlens doublet. Then, the microlens doublet is aligned and bonded with the scanner/spacer/beam splitter stack. The bonded array-type interferometer is a 7- wafer stack and the thickness is approximately 5mm. To separate such a thick wafer stack with various substrates, 2-step laser cutting is used to dice the bonded stack into Mirau chips. To simplify fabrication process of each component, electrical connections are created at the last step by mounting a Mirau chip onto a flip chip PCB instead of through wafer vias. Stability of Au/Ti films on the MEMS Z scanner after anodic bonding, laser cutting and flip chip bonding are discussed as well.

Micro hot embossing for high-aspect-ratio structure with materials flow enhancement by polymer sheet

NASA Astrophysics Data System (ADS)

Murakoshi, Yoichi; Shan, Xue-Chuan; Sano, Toshio; Takahashi, Masaharu; Maeda, Ryutaro

2004-04-01

Nano imprinting or Nano embossing process have been introduced to fabricate semiconductor, optical device and Micro Electro Mechanical Systems (MEMS) and the Nano Electro Mechanical Systems (NEMS) to reduce the fabrication cost. In our previous paper, micro hot embossing of Polycarbonate (PC) and Polyetheretherketone (PEEK) for optical switch with 8x8 mirrors was reported. The PC and PEEK sheets were embossed at elevated temperature with an embossing machine designed for the MEMS. In the application, the mirrors on the optical switch had some defects, such as slump, sticking and step at side of the mirror, due to embossing process and process conditions. These defects are attributed to the poor materials flow of plastics into the e Ni mold cavity of complicate shape with different aspect ratio. Therefore, the micro hot embossing is optimized in this paper with PTFE sheet to enhance the materials flow. In this paper, the PC and the PEEK sheets, thickness of 300um, are embossed at elevated temperature with the hot embossing machine with a Nickel mold. To control material flow of the PC or the PEEK sheets, Polytetrafluoroethylene (PTFE) sheet, the thickness of 100um, is placed on the PC or the PEEK sheets at elevated temperature. Mirror shape was transferred with better fidelity on the PC and PEEK sheet, and the thickness of cantilever became thinner than previous embossed structure without the PTFE. Especially, the mirror height and the thickness of cantilever on the PC have been improved at lower embossing temperature.

Low mass MEMS/NEMS switch for a substitute of CMOS transistor using single-walled carbon nanotube thin film

NASA Astrophysics Data System (ADS)

Jang, Min-Woo

Power dissipation is a key factor for mobile devices and other low power applications. Complementary metal oxide semiconductor (CMOS) is the dominant integrated circuit (IC) technology responsible for a large part of this power dissipation. As the minimum feature size of CMOS devices enters into the sub 50 nanometer (nm) regime, power dissipation becomes much worse due to intrinsic physical limits. Many approaches have been studied to reduce power dissipation of deeply scaled CMOS ICs. One possible candidate is the electrostatic electromechanical switch, which could be fabricated with conventional CMOS processing techniques. They have critical advantages compared to CMOS devices such as almost zero standby leakage in the off-state due to the absence of a pn junction and a gate oxide, as well as excellent drive current in the on-state due to a metallic channel. Despite their excellent standby power dissipation, the electrostatic MEMS/NEMS switches have not been considered as a viable replacement for CMOS devices due to their large mechanical delay. Moreover, previous literature reveals that their pull-in voltage and switching speed are strongly proportional to each other. This reduces their potential advantage. However, in this work, we theoretically and experimentally demonstrated that the use of single-walled carbon nanotube (SWNT) with very low mass density and strong mechanical properties could provide a route to move off of the conventional trend with respect to the pull-in voltage / switching speed tradeoff observed in the literature. We fabricated 2-terminal fixed- beam switches with aligned composite SWNT thin films. In this work, layer-by-layer (LbL) self-assembly and dielectrophoresis were selected for aligned-composite SWNT thin film deposition. The dense membranes were successfully patterned to form submicron beams by e-beam lithography and oxygen plasma etching. Fixed-fixed beam switches using these membranes successfully operated with approximately 600 psec switching delay and as low as a 3 V dc pull-in. From this we confirmed that the SWNT-based thin films have the potential to make fast MEMS switches with a low operation voltage due to its low mass density and high stiffness. However, the copolymer caused a serious reliability issue and a copolymer-free SWNT film deposition method was developed by replacing positive copolymer with a dispersion of positively functionalized SWNTs. The electrical and physical properties of pure single-walled carbon nanotube thin films deposited through a copolymer-free LbL self-assembly process are then discussed. The film thickness was proportional to the number of dipping cycles. The film resistivity was estimated as 2.19x10-3 Ω-cm after thermal treatments were performed. The estimated specific contact resistance to gold electrodes was 6.33x10-9 Ω-m2 from contact chain measurements. The fabricated 3-terminal MEMS switches using these films functioned as a beam for multiple switching cycles with a 4.5V pull-in voltage, which was operated like a 2-input NAND gate. The SWNT-based thin film switch is promising for a variety of applications to high-end nanoelectronics and high- performance MEMS/NEMS.

On the Fabrication and Behavior of Diamond Microelectromechanical Sensors (DMEMS)

NASA Technical Reports Server (NTRS)

Holmes, K.; Davidson, J. L.; Kang, W. P.; Howell, M.

2001-01-01

CVD (chemically vapor deposited) diamond films can be processed similar to "conventional" semiconductor device fabrication and as such can be used to achieve microelectromechanical structures (MEMS) also similar to, for example, silicon technology. Very small cantilever beams, membranes, stripes, tips, etc. can be constructed in doped and undoped diamond films and offer an array of choices in diamond with its known superior properties such as elastic modulus, high temperature semiconduction, high thermal conductivity, very low coefficient of expansion and numerous other diamond parameters. This paper will review the construction and behavior of the second generation DMEMS devices comprised as an accelerometer with a diamond diaphragm for use in very high G applications and a diamond pressure sensor for very high temperature and frequency response.

MEMS-based non-rotatory circumferential scanning optical probe for endoscopic optical coherence tomography

NASA Astrophysics Data System (ADS)

Xu, Yingshun; Singh, Janak; Siang, Teo Hui; Ramakrishna, Kotlanka; Premchandran, C. S.; Sheng, Chen Wei; Kuan, Chuah Tong; Chen, Nanguang; Olivo, Malini C.; Sheppard, Colin J. R.

2007-07-01

In this paper, we present a non-rotatory circumferential scanning optical probe integrated with a MEMS scanner for in vivo endoscopic optical coherence tomography (OCT). OCT is an emerging optical imaging technique that allows high resolution cross-sectional imaging of tissue microstructure. To extend its usage to endoscopic applications, a miniaturized optical probe based on Microelectromechanical Systems (MEMS) fabrication techniques is currently desired. A 3D electrothermally actuated micromirror realized using micromachining single crystal silicon (SCS) process highlights its very large angular deflection, about 45 degree, with low driving voltage for safety consideration. The micromirror is integrated with a GRIN lens into a waterproof package which is compatible with requirements for minimally invasive endoscopic procedures. To implement circumferential scanning substantially for diagnosis on certain pathological conditions, such as Barret's esophagus, the micromirror is mounted on 90 degree to optical axis of GRIN lens. 4 Bimorph actuators that are connected to the mirror on one end via supporting beams and springs are selected in this micromirror design. When actuators of the micromirror are driven by 4 channels of sinusoidal waveforms with 90 degree phase differences, beam focused by a GRIN is redirected out of the endoscope by 45 degree tilting mirror plate and achieve circumferential scanning pattern. This novel driving method making full use of very large angular deflection capability of our micromirror is totally different from previously developed or developing micromotor-like rotatory MEMS device for circumferential scanning.

MEMS fabrication and frequency sweep for suspending beam and plate electrode in electrostatic capacitor

NASA Astrophysics Data System (ADS)

Zhu, Jianxiong; Song, Weixing

2018-01-01

We report a MEMS fabrication and frequency sweep for a high-order mode suspending beam and plate layer in electrostatic micro-gap semiconductor capacitor. This suspended beam and plate was designed with silicon oxide (SiO2) film which was fabricated using bulk silicon micromachining technology on both side of a silicon substrate. The designed semiconductor capacitors were driven by a bias direct current (DC) and a sweep frequency alternative current (AC) in a room temperature for an electrical response test. Finite element calculating software was used to evaluate the deformation mode around its high-order response frequency. Compared a single capacitor with a high-order response frequency (0.42 MHz) and a 1 × 2 array parallel capacitor, we found that the 1 × 2 array parallel capacitor had a broader high-order response range. And it concluded that a DC bias voltage can be used to modulate a high-order response frequency for both a single and 1 × 2 array parallel capacitors.

Self-assembly micro optical filter

NASA Astrophysics Data System (ADS)

Zhang, Ping (Cerina); Le, Kevin; Malalur-Nagaraja-Rao, Smitha; Hsu, Lun-Chen; Chiao, J.-C.

2006-01-01

Optical communication and sensor industry face critical challenges in manufacturing for system integration. Due to the assembly complexity and integration platform variety, micro optical components require costly alignment and assembly procedures, in which many required manual efforts. Consequently, self-assembly device architectures have become a great interest and could provide major advantages over the conventional optical devices. In this paper, we discussed a self-assembly integration platform for micro optical components. To demonstrate the adaptability and flexibility of the proposed optical device architectures, we chose a commercially available MEMS fabrication foundry service - MUMPs (Multi-User MEMS Process). In this work, polysilicon layers of MUMPS are used as the 3-D structural material for construction of micro component framework and actuators. However, because the polysilicon has high absorption in the visible and near infrared wavelength ranges, it is not suitable for optical interaction. To demonstrate the required optical performance, hybrid integration of materials was proposed and implemented. Organic compound materials were applied on the silicon-based framework to form the required optical interfaces. Organic compounds provide good optical transparency, flexibility to form filters or lens and inexpensive manufacturing procedures. In this paper, we have demonstrated a micro optical filter integrated with self-assembly structures. We will discuss the self-assembly mechanism, optical filter designs, fabrication issues and results.

Micro-masonry for 3D Additive Micromanufacturing

PubMed Central

Keum, Hohyun; Kim, Seok

2014-01-01

Transfer printing is a method to transfer solid micro/nanoscale materials (herein called ‘inks’) from a substrate where they are generated to a different substrate by utilizing elastomeric stamps. Transfer printing enables the integration of heterogeneous materials to fabricate unexampled structures or functional systems that are found in recent advanced devices such as flexible and stretchable solar cells and LED arrays. While transfer printing exhibits unique features in material assembly capability, the use of adhesive layers or the surface modification such as deposition of self-assembled monolayer (SAM) on substrates for enhancing printing processes hinders its wide adaptation in microassembly of microelectromechanical system (MEMS) structures and devices. To overcome this shortcoming, we developed an advanced mode of transfer printing which deterministically assembles individual microscale objects solely through controlling surface contact area without any surface alteration. The absence of an adhesive layer or other modification and the subsequent material bonding processes ensure not only mechanical bonding, but also thermal and electrical connection between assembled materials, which further opens various applications in adaptation in building unusual MEMS devices. PMID:25146178

Optimized micromirror arrays for adaptive optics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Michalicek, M. Adrian

This paper describes the design, layout, fabrication, and surface characterization of highly optimized surface micromachined micromirror devices. Design considerations and fabrication capabilities are presented. These devices are fabricated in the state-of-the-art, four-level, planarized, ultra-low-stress polysilicon process available at Sandia National Laboratories known as the Sandia Ultra-planar Multi-level MEMS Technology (SUMMiT). This enabling process permits the development of micromirror devices with near-ideal characteristics that have previously been unrealizable in standard three-layer polysilicon processes. The reduced 1 {mu}m minimum feature sizes and 0.1 {mu}m mask resolution make it possible to produce dense wiring patterns and irregularly shaped flexures. Likewise, mirror surfaces canmore » be uniquely distributed and segmented in advanced patterns and often irregular shapes in order to minimize wavefront error across the pupil. The ultra-low-stress polysilicon and planarized upper layer allow designers to make larger and more complex micromirrors of varying shape and surface area within an array while maintaining uniform performance of optical surfaces. Powerful layout functions of the AutoCAD editor simplify the design of advanced micromirror arrays and make it possible to optimize devices according to the capabilities of the fabrication process. Micromirrors fabricated in this process have demonstrated a surface variance across the array from only 2{endash}3 nm to a worst case of roughly 25 nm while boasting active surface areas of 98{percent} or better. Combining the process planarization with a {open_quotes}planarized-by-design{close_quotes} approach will produce micromirror array surfaces that are limited in flatness only by the surface deposition roughness of the structural material. Ultimately, the combination of advanced process and layout capabilities have permitted the fabrication of highly optimized micromirror arrays for adaptive optics. {copyright} {ital 1999 American Institute of Physics.}« less

Finite Ground Coplanar Waveguide Shunt MEMS Switches for Switched Line Phase Shifters

NASA Technical Reports Server (NTRS)

Ponchak, George E.; Simons, Rainee N.; Scardelletti, Maximillian; Varaljay, Nicholas C.

2000-01-01

Switches with low insertion loss and high isolation are required for switched line phase shifters and the transmit/receive switch at the front end of communication systems. A Finite Ground Coplanar (FGC) waveguide capacitive, shunt MEMS switch has been implemented on high resistivity Si. The switch has demonstrated an insertion loss of less than 0.3 dB and a return loss greater than 15 dB from 10 to 20, GHz. The switch design, fabrication, and characteristics are presented.

Miniature Inchworm Actuators Fabricated by Use of LIGA

NASA Technical Reports Server (NTRS)

Yang, Eui-Hyeok

2003-01-01

Miniature inchworm actuators that would have relatively simple designs have been proposed for applications in which there are requirements for displacements of the order of microns or tens of microns and for the ability to hold their positions when electric power is not applied. The proposed actuators would be members of the class of microelectromechanical systems (MEMS), but would be designed and fabricated following an approach that is somewhat unusual for MEMS. Like other MEMS actuators, the proposed inchworm actuators could utilize thermoplastic, bimetallic, shape-memory-alloy, or piezoelectric actuation principles. The figure depicts a piezoelectric inchworm actuator according to the proposal. As in other inchworm actuators, linear motion of an extensible member would be achieved by lengthening and shortening the extensible member in synchronism with alternately clamping and releasing one and then the other end of the member. In this case, the moving member would be the middle one; the member would be piezoelectric and would be shortened by applying a voltage to it. The two outer members would also be piezoelectric; the release of the clamps on the upper or lower end would be achieved by applying a voltage to the electrodes on the upper or lower ends, respectively, of these members. Usually, MEMS actuators cannot be fabricated directly on the side walls of silicon wafers, yet the geometry of this actuator necessitates such fabrication. The solution, according to the proposal, would be to use the microfabrication technique known by the German acronym LIGA - "lithographie, galvanoformung, abformung," which means lithography, electroforming, molding. LIGA involves x-ray lithography of a polymer film followed by selective removal of material to form a three-dimensional pattern from which a mold is made. Among the advantages of LIGA for this purpose are that it is applicable to a broad range of materials, can be used to implement a variety of designs, including those of structures >1 mm high, affords submicron precision, and is amenable to mass production at relatively low unit cost. Fabrication of the proposed actuators would involve some technological risks - in particular, in the integration of electrode connection lines and placement of actuator elements. It will also be necessary to perform an intensive study of the feasibility of growing piezoelectric crystals onto LIGA molds.

Meso-scale controlled motion for a microfluidic drop ejector.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Galambos, Paul C.; Givler, Richard C.; Pohl, Kenneth Roy

2004-12-01

The objective of this LDRD was to develop a uniquely capable, novel droplet solution based manufacturing system built around a new MEMS drop ejector. The development all the working subsystems required was completed, leaving the integration of these subsystems into a working prototype still left to accomplish. This LDRD report will focus on the three main subsystems: (1) MEMS drop ejector--the MEMS ''sideshooter'' effectively ejected 0.25 pl drops at 10 m/s, (2) packaging--a compact ejector package based on a modified EMDIP (Electro-Microfluidic Dual In-line Package--SAND2002-1941) was fabricated, and (3) a vision/stage system allowing precise ejector package positioning in 3 dimensionsmore » above a target was developed.« less

Design and Characterization of Next-Generation Micromirrors Fabricated in a Four-Level, Planarized Surface-Micromachined Polycrystalline Silicon Process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Michalicek, M.A.; Comtois, J.H.; Barron, C.C.

This paper describes the design and characterization of several types of micromirror devices to include process capabilities, device modeling, and test data resulting in deflection versus applied potential curves. These micromirror devices are the first to be fabricated in the state-of-the-art four-level planarized polysilicon process available at Sandia National Laboratories known as the Sandia Ultra-planar Multi-level MEMS Technology (SUMMiT). This enabling process permits the development of micromirror devices with near-ideal characteristics which have previously been unrealizable in standard three-layer polysilicon processes. This paper describes such characteristics as elevated address electrodes, individual address wiring beneath the device, planarized mirror surfaces usingmore » Chemical Mechanical Polishing (CMP), unique post-process metallization, and the best active surface area to date. This paper presents the design, fabrication, modeling, and characterization of several variations of Flexure-Beam (FBMD) and Axial-Rotation Micromirror Devices (ARMD). The released devices are first metallized using a standard sputtering technique relying on metallization guards and masks that are fabricated next to the devices. Such guards are shown to enable the sharing of bond pads between numerous arrays of micromirrors in order to maximize the number of on-chip test arrays. The devices are modeled and then empirically characterized using a laser interferometer setup located at the Air Force Institute of Technology (AFIT) at Wright-Patterson AFB in Dayton, Ohio. Unique design considerations for these devices and the process are also discussed.« less

Wavelength specific excitation of gold nanoparticle thin-films

NASA Astrophysics Data System (ADS)

Lucas, Thomas M.; James, Kurtis T.; Beharic, Jasmin; Moiseeva, Evgeniya V.; Keynton, Robert S.; O'Toole, Martin G.; Harnett, Cindy K.

2014-01-01

Advances in microelectromechanical systems (MEMS) continue to empower researchers with the ability to sense and actuate at the micro scale. Thermally driven MEMS components are often used for their rapid response and ability to apply relatively high forces. However, thermally driven MEMS often have high power consumption and require physical wiring to the device. This work demonstrates a basis for designing light-powered MEMS with a wavelength specific response. This is accomplished by patterning surface regions with a thin film containing gold nanoparticles that are tuned to have an absorption peak at a particular wavelength. The heating behavior of these patterned surfaces is selected by the wavelength of laser directed at the sample. This method also eliminates the need for wires to power a device. The results demonstrate that gold nanoparticle films are effective wavelength-selective absorbers. This "hybrid" of infrared absorbent gold nanoparticles and MEMS fabrication technology has potential applications in light-actuated switches and other mechanical structures that must bend at specific regions. Deposition methods and surface chemistry will be integrated with three-dimensional MEMS structures in the next phase of this work. The long-term goal of this project is a system of light-powered microactuators for exploring cellular responses to mechanical stimuli, increasing our fundamental understanding of tissue response to everyday mechanical stresses at the molecular level.

Linear frequency tuning in an LC-resonant system using a C-V response controllable MEMS varactor

NASA Astrophysics Data System (ADS)

Han, Chang-Hoon; Yoon, Yong-Hoon; Ko, Seung-Deok; Seo, Min-Ho; Yoon, Jun-Bo

2017-12-01

This paper proposes a device level solution to achieve linear frequency tuning with respect to a tuning voltage ( V tune ) sweep in an inductor ( L)-capacitor ( C) resonant system. Since the linearity of the resonant frequency vs. tuning voltage ( f- V) relationship in an LC-resonant system is closely related to the C- V response characteristic of the varactor, we propose a C- V response tunable varactor to realize the linear frequency tuning. The proposed varactor was fabricated using microelectromechanical system (MEMS) surface micromachining. The fabricated MEMS varactor has the ability to dynamically change the C- V response characteristic according to a curve control voltage ( V curve- control ). When V curve- control was increased from zero to 9 V, the C- V response curve was changed from a linear to a concave form (i.e., the capacitance decreased quickly in the low tuning voltage region and slowly in the high tuning voltage region). This change in the C- V response characteristic resulted in a change in the f- V relationship, and we successfully demonstrated almost perfectly linear frequency tuning in the LC-resonant system, with a linearity factor of 99.95%.

Transmission-enabled fiber Fabry-Perot cavity based on a deeply etched slotted micromirror.

PubMed

Othman, Muhammad A; Sabry, Yasser M; Sadek, Mohamed; Nassar, Ismail M; Khalil, Diaa A

2018-06-01

In this work, we report the analysis, fabrication, and characterization of an optical cavity built using a Bragg-coated fiber (BCF) mirror and a metal-coated microelectromechanical systems (MEMS) slotted micromirror, where the latter allows transmission output from the cavity. Theoretical modeling, using Fourier optics analysis for the cavity response based on tracing the propagation of light back and forth between the mirrors, is presented. Detailed simulation analysis is carried out for the spectral response of the cavity under different design conditions. MEMS chips of the slotted micromirror are fabricated using deep reactive ion etching of a silicon-on-insulator substrate with different device-etching depths of 150 μm and 80 μm with aluminum and gold metal coating, respectively. The cavity is characterized as an optical filter using a BCF with reflectivity that is larger than 95% in a 300 nm range across the E-band and the L-band. Versatile filter characteristics were obtained for different values of the MEMS micromirror slit width and cavity length. A free spectral range (FSR) of about 33 nm and a quality factor of about 196 were obtained for a 5.5 μm width aluminum slit, while an FSR of about 148 nm and a quality factor of about 148 were obtained for a 1.5 μm width gold slit. The presented structure opens the door for wide spectral response transmission-type MEMS filters.

A Laboratory Project on the Theory, Fabrication, and Characterization of a Silicon-on-Insulator Micro-Comb Drive Actuator with Fixed-Fixed Beams

ERIC Educational Resources Information Center

Abbas, K.; Leseman, Z. C.

2012-01-01

A laboratory course on the theory, fabrication, and characterization of microelectromechanical systems (MEMS) devices for a multidisciplinary audience of graduate students at the University of New Mexico, Albuquerque, has been developed. Hands-on experience in the cleanroom has attracted graduate students from across the university's engineering…

A low feed-through 3D vacuum packaging technique with silicon vias for RF MEMS resonators

NASA Astrophysics Data System (ADS)

Zhao, Jicong; Yuan, Quan; Kan, Xiao; Yang, Jinling; Yang, Fuhua

2017-01-01

This paper presents a wafer-level three-dimensional (3D) vacuum packaging technique for radio frequency microelectromechanical systems (RF MEMS) resonators. A Sn-rich Au-Sn solder bonding is employed to provide a vacuum encapsulation as well as electrical conductions. Vertical silicon vias are micro-fabricated by glass reflow process. The optimized grounding, via pitch, and all-round shielding effectively reduce feed-through capacitance. Thus the signal-to-background ratios (SBRs) of the transmission signals increase from 17 dB to 20 dB, and the quality factor (Q) values of the packaged resonators go from around 8000 up to more than 9500. The measured average leak rate and shear strength are (2.55  ±  0.9)  ×  10-8 atm-cc s-1 and 42.53  ±  4.19 MPa, respectively. Furthermore, thermal cycling test between  -40 °C and 100 °C and high temperature storage test at 150 °C show that the resonant-frequency drifts are less than  ±7 ppm. In addition, the SBRs and the Q values have no obvious change after the tests. The experimental results demonstrated that the proposed encapsulation technique is well suited for the applications of RF MEMS devices.

A MEMS torsion magnetic sensor with reflective blazed grating integration

NASA Astrophysics Data System (ADS)

Long, Liang; Zhong, Shaolong

2016-07-01

A novel magnetic sensor based on a permanent magnet and blazed grating is presented in this paper. The magnetic field is detected by measuring the diffracted wavelength of the blazed grating which is changed by the torsion motion of a torsion sensitive micro-electromechanical system (MEMS) structure with a permanent magnet attached. A V-shape grating structure is obtained by wet etching on a (1 0 0) SOI substrate. When the magnet is magnetized in different directions, the in-plane or out-of-plane magnetic field is detected by a sensor. The MEMS magnetic sensor with a permanent magnet is fabricated after analytical design and bulk micromachining processes. The magnetic-sensing capability of the sensor is tested by fiber-optic detection system. The result shows the sensitivities of the in-plane and out-of-plane magnetic fields are 3.6 pm μT-1 and 5.7 pm μT-1, respectively. Due to utilization of the permanent magnet and fiber-optic detection, the sensor shows excellent capability of covering the high-resolution detection of low-frequency signals. In addition, the sensitive direction of the magnetic sensor can be easily switched by varying the magnetized direction of the permanent magnet, which offers a simple way to achieve tri-axis magnetic sensor application.

Fabrication and Characterization of CMOS-MEMS Magnetic Microsensors

PubMed Central

Hsieh, Chen-Hsuan; Dai, Ching-Liang; Yang, Ming-Zhi

2013-01-01

This study investigates the design and fabrication of magnetic microsensors using the commercial 0.35 μm complementary metal oxide semiconductor (CMOS) process. The magnetic sensor is composed of springs and interdigitated electrodes, and it is actuated by the Lorentz force. The finite element method (FEM) software CoventorWare is adopted to simulate the displacement and capacitance of the magnetic sensor. A post-CMOS process is utilized to release the suspended structure. The post-process uses an anisotropic dry etching to etch the silicon dioxide layer and an isotropic dry etching to remove the silicon substrate. When a magnetic field is applied to the magnetic sensor, it generates a change in capacitance. A sensing circuit is employed to convert the capacitance variation of the sensor into the output voltage. The experimental results show that the output voltage of the magnetic microsensor varies from 0.05 to 1.94 V in the magnetic field range of 5–200 mT. PMID:24172287

Manufacture of a Polyaniline Nanofiber Ammonia Sensor Integrated with a Readout Circuit Using the CMOS-MEMS Technique

PubMed Central

Liu, Mao-Chen; Dai, Ching-Liang; Chan, Chih-Hua; Wu, Chyan-Chyi

2009-01-01

This study presents the fabrication of a polyaniline nanofiber ammonia sensor integrated with a readout circuit on a chip using the commercial 0.35 μm complementary metal oxide semiconductor (CMOS) process and a post-process. The micro ammonia sensor consists of a sensing resistor and an ammonia sensing film. Polyaniline prepared by a chemical polymerization method was adopted as the ammonia sensing film. The fabrication of the ammonia sensor needs a post-process to etch the sacrificial layers and to expose the sensing resistor, and then the ammonia sensing film is coated on the sensing resistor. The ammonia sensor, which is of resistive type, changes its resistance when the sensing film adsorbs or desorbs ammonia gas. A readout circuit is employed to convert the resistance of the ammonia sensor into the voltage output. Experimental results show that the sensitivity of the ammonia sensor is about 0.88 mV/ppm at room temperature. PMID:22399944

Manufacture of a Polyaniline Nanofiber Ammonia Sensor Integrated with a Readout Circuit Using the CMOS-MEMS Technique.

PubMed

Liu, Mao-Chen; Dai, Ching-Liang; Chan, Chih-Hua; Wu, Chyan-Chyi

2009-01-01

This study presents the fabrication of a polyaniline nanofiber ammonia sensor integrated with a readout circuit on a chip using the commercial 0.35 μm complementary metal oxide semiconductor (CMOS) process and a post-process. The micro ammonia sensor consists of a sensing resistor and an ammonia sensing film. Polyaniline prepared by a chemical polymerization method was adopted as the ammonia sensing film. The fabrication of the ammonia sensor needs a post-process to etch the sacrificial layers and to expose the sensing resistor, and then the ammonia sensing film is coated on the sensing resistor. The ammonia sensor, which is of resistive type, changes its resistance when the sensing film adsorbs or desorbs ammonia gas. A readout circuit is employed to convert the resistance of the ammonia sensor into the voltage output. Experimental results show that the sensitivity of the ammonia sensor is about 0.88 mV/ppm at room temperature.

Modeling of two-hot-arm horizontal thermal actuator

NASA Astrophysics Data System (ADS)

Yan, Dong; Khajepour, Amir; Mansour, Raafat

2003-03-01

Electrothermal actuators have a very promising future in MEMS applications since they can generate large deflection and force with low actuating voltages and small device areas. In this study, a lumped model of a two-hot-arm horizontal thermal actuator is presented. In order to prove the accuracy of the lumped model, finite element analysis (FEA) and experimental results are provided. The two-hot-arm thermal actuator has been fabricated using the MUMPs process. Both the experimental and FEA results are in good agreement with the results of lumped modeling.

Development and Demonstration of Manufacturing Processes for Fabricating Graphite/LARC 160 Polyimide Structural Elements.

DTIC Science & Technology

1981-12-01

microporous mem - brane over the preform bleeder surface and secure in place, wrinkle-free, with pressure sensitive tape on the backside of the mandrel...0 ,1 - a)Q w ( w0O0 aO)W Q)W~ toIt o m 04 0r 0 0 - -0 - -. ’ F0 E-tO 000 F00 H0 OHp oi0 -o 0 0 H *H H H -A P to HH HZ *H HHP o~ 0I 4- m H 044 u It

Deeply-etched micromirror with vertical slit and metallic coating enabling transmission-type optical MEMS filters

NASA Astrophysics Data System (ADS)

Othman, Muhammad A.; Sabry, Yasser M.; Sadek, Mohamed; Nassar, Ismail M.; Khalil, Diaa A.

2016-03-01

In this work we report a novel optical MEMS deeply-etched mirror with metallic coating and vertical slot, where the later allows reflection and transmission by the micromirror. The micromirror as well as fiber grooves are fabricated using deep reactive ion etching technology, where the optical axis is in-plane and the components are self-aligned. The etching depth is 150 μm chosen to improve the micromirror optical throughput. The vertical optical structure is Al metal coated using the shadow mask technique. A fiber-coupled Fabry-Pérot filter is successfully realized using the fabricated structure. Experimental measurements were obtained based on a dielectric-coated optical fiber inserted into a fiber groove facing the slotted micromirror. A versatile performance in terms of the free spectral range and 3-dB bandwidth is achieved.

A preliminary study of a miniature planar 6-cell PEMFC stack combined with a small hydrogen storage canister

NASA Astrophysics Data System (ADS)

Zhang, Xigui; Zheng, Dan; Wang, Tao; Chen, Cong; Cao, Jianyu; Yan, Jian; Wang, Wenming; Liu, Juanying; Liu, Haohan; Tian, Juan; Li, Xinxin; Yang, Hui; Xia, Baojia

The fabrication and performance evaluation of a miniature 6-cell PEMFC stack based on Micro-Electronic-Mechanical-System (MEMS) technology is presented in this paper. The stack with a planar configuration consists of 6-cells in serial interconnection by spot welding one cell anode with another cell cathode. Each cell was made by sandwiching a membrane-electrode-assembly (MEA) between two flow field plates fabricated by a classical MEMS wet etching method using silicon wafer as the original material. The plates were made electrically conductive by sputtering a Ti/Pt/Au composite metal layer on their surfaces. The 6-cells lie in the same plane with a fuel buffer/distributor as their support, which was fabricated by the MEMS silicon-glass bonding technology. A small hydrogen storage canister was used as fuel source. Operating on dry H 2 at a 40 ml min -1 flow rate and air-breathing conditions at room temperature and atmospheric pressure, the linear polarization experiment gave a measured peak power of 0.9 W at 250 mA cm -2 for the stack and average power density of 104 mW cm -2 for each cell. The results suggested that the stack has reasonable performance benefiting from an even fuel supply. But its performance tended to deteriorate with power increase, which became obvious at 600 mW. This suggests that the stack may need some power assistance, from say supercapacitors to maintain its stability when operated at higher power.

A quartz-based micro catalytic methane sensor by high resolution screen printing

NASA Astrophysics Data System (ADS)

Lu, Wenshuai; Jing, Gaoshan; Bian, Xiaomeng; Yu, Hongyan; Cui, Tianhong

2016-02-01

A micro catalytic methane sensor was proposed and fabricated on a bulk fused quartz substrate using a high resolution screen printing technique for the first time, with reduced power consumption and optimized sensitivity. The sensor was designed by the finite element method and quartz was chosen as the substrate material and alumina support with optimized dimensions. Fabrication of the sensor consisted of two MEMS processes, lift-off and high resolution screen printing, with the advantages of high yield and uniformity. When the sensor’s regional working temperature changes from 250 °C to 470 °C, its sensitivity increases, as well as the power consumption. The highest sensitivity can reach 1.52 mV/% CH4. A temperature of 300 °C was chosen as the optimized working temperature, and the sensor’s sensitivity, power consumption, nonlinearity and response time are 0.77 mV/% CH4, 415 mW, 2.6%, and 35 s, respectively. This simple, but highly uniform fabrication process and the reliable performance of this sensor may lead to wide applications for methane detection.

A Two-Axis Direct Fluid Shear Stress Sensor

NASA Technical Reports Server (NTRS)

Adcock, Edward E.; Scott, Michael A.; Bajikar, Sateesh S.

2010-01-01

This innovation is a miniature or micro sized semiconductor sensor design that provides two axis direct non-intrusive measurement of skin friction or wall shear stress in fluid flow. The sensor is fabricated by micro-electro-mechanical system (MEMS) technology, enabling small size and low cost reproductions. The sensors have been fabricated by utilizing MEMS fabrication processes to bond a sensing element wafer to a fluid coupling wafer. This layering technique provides for an out of plane dimension that is on the same order of length as the inplane dimensions. The sensor design has the following characteristics: a shear force collecting plate with dimensions that can be tailored to various application specific requirements such as spatial resolution, temporal resolution and shear force range and resolution. This plate is located coplanar to both the sensor body and flow boundary, and is connected to a dual axis gimbal structure by a connecting column or lever arm. The dual axis gimbal structure has torsional hinges with embedded piezoresistive torsional strain gauges which provide a voltage output that is correlated to the applied shear stress (and excitation current) on force collection plate that is located on the flow boundary surface (hence the transduction method). This combination of design elements create a force concentration and resolution structure that enables the generation of a large stress on the strain gauge from the small shear stress on the flow boundary wall. This design as well as the use of back side electrical contacts establishes a non-intrusive method to quantitatively measure the shear force vector on aerodynamic bodies.

Fracture toughness study on LIGA fabricated microstructures

NASA Astrophysics Data System (ADS)

Oropeza, Catherine; Lian, Kun; Wang, Wanjun

2003-01-01

One of the major difficulties faced by MEMS researchers today is the lack of data regarding properties of electroplated metals or alloys at micro-levels as those produced by the LIGA and the LIGA related process. These mechanical properties are not well known and they cannot be extrapolated from macro-scale data without experimental verification. This lack of technical information about physical properties at microscale has affected the consistency and reliability of batch-fabricated components and leads to very low rates of successful fabrication. Therefore, this material issue is of vital importance to the development of LIGA technology and to its industrial applications. The research work reported in this paper focuses on the development of a new capability based on design, fabrication, and testing of groups of UV-LIGA fabricated nickel microspecimens for the evaluation of fracture strength. The devised testing mechanism demonstrated compatibility with the fabricated samples and capability of performing the desired experimentation by generating resistance-to-fracture values of the nickel specimens. The average fracture strength value obtained, expressed with a 95% confidence interval, was 315 +/- 54 Mpa. Further data acquisition, especially involving tensile specimen testing, and material analysis is needed to fully understand the implications of the information obtained.

The rectenna design on contact lens for wireless powering of the active intraocular pressure monitoring system.

PubMed

Cheng, H W; Jeng, B M; Chen, C Y; Huang, H Y; Chiou, J C; Luo, C H

2013-01-01

This paper proposed a wireless power harvesting system with micro-electro-mechanical-systems (MEMS) fabrication for noninvasive intraocular pressure (IOP) measurement on soft contact lens substructure. The power harvesting IC consists of a loop antenna, an impedance matching network and a rectifier. The proposed IC has been designed and fabricated by CMOS 0.18 um process that operates at the ISM band of 5.8 GHz. The antenna and the power harvesting IC would be bonded together by using flip chip bonding technologies without extra wire interference. The circuit utilized an impedance transformation circuit to boost the input RF signal that improves the circuit performance. The proposed design achieves an RF-to-DC conversion efficiency of 35% at 5.8 GHz.

Fabrication and characterization of a piezoelectric energy harvester with clamped-clamped beams

NASA Astrophysics Data System (ADS)

Cui, Yan; Yu, Menglin; Gao, Shiqiao; Kong, Xiangxin; Gu, Wang; Zhang, Ran; Liu, Bowen

2018-05-01

This work presents a piezoelectric energy harvester with clamped-clamped beams, and it is fabricated with MEMS process. When excited by sinusoidal vibration, the energy harvester has a sharp jumping down phenomenon and the measured frequency responses of the clamped-clamped beams structure show a larger bandwidth which is about 56Hz, more efficient than that with cantilever beams. When the exciting acceleration ac is 12m/s2, the energy harvester achieves to a maximum open-circuit voltage of 94mV on one beam. The load voltage is proportional to the load resistance, and it increased with the increase of load resistance. Connected four beams in series, the output power reaches the maximum value of 730 nW and the optimal load is 15KΩ to one beam.

Dynamic focus-tracking MEMS scanning micromirror with low actuation voltages for endoscopic imaging.

PubMed

Strathman, Matthew; Liu, Yunbo; Li, Xingde; Lin, Lih Y

2013-10-07

We demonstrate a 3-D scanning micromirror device that combines 2-D beam scanning with focus control in the same device using micro-electro-mechanical-systems (MEMS) technology. 2-D beam scanning is achieved with a biaxial gimbal structure and focus control is obtained with a deformable mirror membrane surface. The micromirror with 800 micrometer diameter is designed to be sufficiently compact and efficient so that it can be incorporated into an endoscopic imaging probe in the future. The design, fabrication and characterization of the device are described in this paper. Using the focus-tracking MEMS scanning mirror, we achieved an optical scanning range of >16 degrees with <40 V actuation voltage at resonance and a tunable focal length between infinity and 25 mm with <100V applied bias.

MEMS Microshutter Arrays for James Webb Space Telescope

NASA Technical Reports Server (NTRS)

Li, Mary J.; Beamesderfer, Michael; Babu, Sachi; Bajikar, Sateesh; Ewin, Audrey; Franz, Dave; Hess, Larry; Hu, Ron; Jhabvala, Murzy; Kelly, Dan;

Resonant capacitive MEMS acoustic emission transducers

NASA Astrophysics Data System (ADS)

Ozevin, D.; Greve, D. W.; Oppenheim, I. J.; Pessiki, S. P.

2006-12-01

We describe resonant capacitive MEMS transducers developed for use as acoustic emission (AE) detectors, fabricated in the commercial three-layer polysilicon surface micromachining process (MUMPs). The 1 cm square device contains six independent transducers in the frequency range between 100 and 500 kHz, and a seventh transducer at 1 MHz. Each transducer is a parallel plate capacitor with one plate free to vibrate, thereby causing a capacitance change which creates an output signal in the form of a current under a dc bias voltage. With the geometric proportions we employed, each transducer responds with two distinct resonant frequencies. In our design the etch hole spacing was chosen to limit squeeze film damping and thereby produce an underdamped vibration when operated at atmospheric pressure. Characterization experiments obtained by capacitance and admittance measurements are presented, and transducer responses to physically simulated AE source are discussed. Finally, we report our use of the device to detect acoustic emissions associated with crack initiation and growth in weld metal.

Design and performance test of a MEMS vibratory gyroscope with a novel AGC force rebalance control

NASA Astrophysics Data System (ADS)

Sung, Woon-Tahk; Sung, Sangkyung; Lee, Jang Gyu; Kang, Taesam

2007-10-01

In this paper, the development and performance test results of a laterally oscillating MEMS gyroscope using a novel force rebalance control strategy are presented. The micromachined structure and electrodes are fabricated using the deep reactive ion etching (DRIE) and anodic wafer bonding process. The high quality factor required for the resonance-based sensor is achieved using a vacuum-sealed device package. A systematic design approach of the force rebalance control is applied via a modified automatic gain control (AGC) method. The rebalance control design takes advantages of a novel AGC loop modification, which allows the approximation of the system's dynamics into a simple linear form. Using the proposed modification of AGC and the rebalance strategy that maintains a biased oscillation, a number of performance improvements including bandwidth extension and widened operating range were observed to be achieved. Finally, the experimental results of the gyroscope's practical application verify the feasibility and performance of the developed sensor.

Development of optical MEMS CO2 sensors

NASA Astrophysics Data System (ADS)

McNeal, Mark P.; Moelders, Nicholas; Pralle, Martin U.; Puscasu, Irina; Last, Lisa; Ho, William; Greenwald, Anton C.; Daly, James T.; Johnson, Edward A.; George, Thomas

2002-09-01

Inexpensive optical MEMS gas and chemical sensors offer chip-level solutions to environmental monitoring, industrial health and safety, indoor air quality, and automobile exhaust emissions monitoring. Previously, Ion Optics, Inc. reported on a new design concept exploiting Si-based suspended micro-bridge structures. The devices are fabricated using conventional CMOS compatible processes. The use of photonic bandgap (PBG) crystals enables narrow band IR emission for high chemical selectivity and sensitivity. Spectral tuning was accomplished by controlling symmetry and lattice spacing of the PBG structures. IR spectroscopic studies were used to characterize transmission, absorption and emission spectra in the 2 to 20 micrometers wavelength range. Prototype designs explored suspension architectures and filament geometries. Device characterization studies measured drive and emission power, temperature uniformity, and black body detectivity. Gas detection was achieved using non-dispersive infrared (NDIR) spectroscopic techniques, whereby target gas species were determined from comparison to referenced spectra. A sensor system employing the emitter/detector sensor-chip with gas cell and reflective optics is demonstrated and CO2 gas sensitivity limits are reported.

Micro environmental sensing device

DOEpatents

Polosky, Marc A.; Lukens, Laurance L.

2006-05-02

A microelectromechanical (MEM) acceleration switch is disclosed which includes a proof mass flexibly connected to a substrate, with the proof mass being moveable in a direction substantially perpendicular to the substrate in response to a sensed acceleration. An electrode on the proof mass contacts one or more electrodes located below the proof mass to provide a switch closure in response to the sensed acceleration. Electrical latching of the switch in the closed position is possible with an optional latching electrode. The MEM acceleration switch, which has applications for use as an environmental sensing device, can be fabricated using micromachining.

Design and analysis of MEMS MWCNT/epoxy strain sensor using COMSOL

NASA Astrophysics Data System (ADS)

Sapra, Gaurav; Sharma, Preetika

2017-07-01

The design and performance of piezoresistive MEMS-based MWCNT/epoxy composite strain sensor using COMSOL Multiphysics Toolbox has been investigated. The proposed sensor design comprises su-8 based U-shaped cantilever beam with MWCNT/epoxy composite film as an active sensing element. A point load in microscale has been applied at the tip of the cantilever beam to observe its deflection in the proposed design. Analytical simulations have been performed to optimize various design parameters of the proposed sensor, which will be helpful at the time of fabrication.

Low-voltage high-reliability MEMS switch for millimeter wave 5G applications

NASA Astrophysics Data System (ADS)

Shekhar, Sudhanshu; Vinoy, K. J.; Ananthasuresh, G. K.

2018-07-01

Lack of reliability of radio-frequency microelectromechanical systems (RF MEMS) switches has inhibited their commercial success. Dielectric stiction/breakdown and mechanical shock due to high actuation voltage are common impediments in capacitive MEMS switches. In this work, we report low-actuation voltage RF MEMS switch and its reliability test. Experimental characterization of fabricated devices demonstrate that proposed MEMS switch topology needs very low voltage (4.8 V) for actuation. The mechanical resonant frequency, f 0, quality factor, Q, and switching time are measured to be 8.35 kHz, 1.2, and 33 microsecond, respectively. These MEMS switches have high reliability in terms of switching cycles. Measurements are performed using pulse waveform of magnitude of 6 V under hot-switching condition. Temperature measurement results confirm that the reported switch topology has good thermal stability. The robustness in terms of the measured pull-in voltage shows a variation of 0.08 V °C‑1. Lifetime measurement results after 10 million switching cycles demonstrate insignificant change in the RF performance without any failure. Experimental results show that low voltage improves the lifetime. Low insertion loss (less than 0.6 dB) and improved isolation (above 40 dB) in the frequency range up to 60 GHz have been reported. Measured RF characteristics in the frequency range from 10 MHz to 60 GHz support that these MEMS switches are favorable choice for mm-wave 5G applications.

Projection displays and MEMS: timely convergence for a bright future

NASA Astrophysics Data System (ADS)

Hornbeck, Larry J.

1995-09-01

Projection displays and microelectromechanical systems (MEMS) have evolved independently, occasionally crossing paths as early as the 1950s. But the commercially viable use of MEMS for projection displays has been illusive until the recent invention of Texas Instruments Digital Light Processing TM (DLP) technology. DLP technology is based on the Digital Micromirror DeviceTM (DMD) microchip, a MEMS technology that is a semiconductor digital light switch that precisely controls a light source for projection display and hardcopy applications. DLP technology provides a unique business opportunity because of the timely convergence of market needs and technology advances. The world is rapidly moving to an all- digital communications and entertainment infrastructure. In the near future, most of the technologies necessary for this infrastrucutre will be available at the right performance and price levels. This will make commercially viable an all-digital chain (capture, compression, transmission, reception decompression, hearing, and viewing). Unfortunately, the digital images received today must be translated into analog signals for viewing on today's televisions. Digital video is the final link in the all-digital infrastructure and DLP technoogy provides that link. DLP technology is an enabler for digital, high-resolution, color projection displays that have high contrast, are bright, seamless, and have the accuracy of color and grayscale that can be achieved only by digital control. This paper contains an introduction to DMD and DLP technology, including the historical context from which to view their developemnt. The architecture, projection operation, and fabrication are presented. Finally, the paper includes an update about current DMD business opportunities in projection displays and hardcopy.

Integrated MEMS-tunable VCSELs for reconfigurable optical interconnects

NASA Astrophysics Data System (ADS)

Kögel, Benjamin; Debernardi, Pierluigi; Westbergh, Petter; Gustavsson, Johan S.; Haglund, Åsa; Haglund, Erik; Bengtsson, Jörgen; Larsson, Anders

2012-03-01

A simple and low-cost technology for tunable vertical-cavity surface-emitting lasers (VCSELs) with curved movable micromirror is presented. The micro-electro-mechanical system (MEMS) is integrated with the active optical component (so-called half-VCSEL) by means of surface-micromachining using a reflown photoresist droplet as sacrificial layer. The technology is demonstrated for electrically pumped, short-wavelength (850 nm) tunable VCSELs. Fabricated devices with 10 μm oxide aperture are singlemode with sidemode suppression >35 dB, tunable over 24 nm with output power up to 0.5mW, and have a beam divergence angle <6 °. An improved high-speed design with reduced parasitic capacitance enables direct modulation with 3dB-bandwidths up to 6GHz and error-free data transmission at 5Gbit/s. The modulation response of the MEMS under electrothermal actuation has a bandwidth of 400 Hz corresponding to switching times of about 10ms. The thermal crosstalk between MEMS and half-VCSEL is negligible and not degrading the device performance. With these characteristics the integrated MEMS-tunable VCSELs are basically suitable for use in reconfigurable optical interconnects and ready for test in a prototype system. Schemes for improving output power, tuning speed, and modulation bandwidth are briefly discussed.

HARM processing techniques for MEMS and MOEMS devices using bonded SOI substrates and DRIE

NASA Astrophysics Data System (ADS)

Gormley, Colin; Boyle, Anne; Srigengan, Viji; Blackstone, Scott C.

2000-08-01

Silicon-on-Insulator (SOI) MEMS devices (1) are rapidly gaining popularity in realizing numerous solutions for MEMS, especially in the optical and inertia application fields. BCO recently developed a DRIE trench etch, utilizing the Bosch process, and refill process for high voltage dielectric isolation integrated circuits on thick SOI substrates. In this paper we present our most recently developed DRIE processes for MEMS and MOEMS devices. These advanced etch techniques are initially described and their integration with silicon bonding demonstrated. This has enabled process flows that are currently being utilized to develop optical router and filter products for fiber optics telecommunications and high precision accelerometers.

MEMS Cantilever Sensor for THz Photoacoustic Chemical Sensing and Spectroscopy

DTIC Science & Technology

2013-12-26

meaning the detector didn’t have to be cryogenically cooled. Piezoresistive cantilever style sensor designs have been fabricated for wind and...made a two cantilever pizeoresistive wind speed sensor that utilized a Wheatstone bridge configuration. The designed cantilevers, etched out of...Murakami et al. in Japan fabricated diaphragm and cantilever PZT microphone sensors for anomaly detection in machines such as turbines or engines

Tunable Infrared Metasurface on a Soft Polymer Scaffold.

PubMed

Reeves, Jeremy B; Jayne, Rachael K; Stark, Thomas J; Barrett, Lawrence K; White, Alice E; Bishop, David J

2018-05-09

The fabrication of metallic electromagnetic meta-atoms on a soft microstructured polymer scaffold using a MEMS-based stencil lithography technique is demonstrated. Using this technique, complex metasurfaces that are generally impossible to fabricate with traditional photolithographic techniques are created. By engineering the mechanical deformation of the polymer scaffold, the metasurface reflectivity in the mid-infrared can be tuned by the application of moderate strains.

Miniature thermoacoustic cryocooler driven by a vertical comb-drive

NASA Astrophysics Data System (ADS)

Hao, Zhili; Fowler, Mark; Hammer, Jay A.; Whitley, Michael R.; Brown, David

2003-01-01

In this paper, we propose a novel miniature MEMS based thermoacoustic cryo-cooler for thermal management of cryogenic electronic devices. The basic idea is to exploit a new way to realize a highly-reliable miniature cryo-cooler, which would allow integration of a cryogenic cooling system directly into a cryogenic electronic device. A vertical comb-drive is proposed as the means to provide an acoustic source through a driving plate to a resonant tube. By exciting a standing wave within the resonant tube, a temperature difference develops across the stack in the tube, thereby enabling heat exchange between two heat exchangers. The use of gray scale technology to fabricate tapered resonant tube provides a way to improve the efficiency of the cooling system, compared with a simple cylinder configuration. Furthermore, a tapered tube leads to extremely strong standing waves with relatively pure waveforms and reduces possible harmonics. The working principle of this device is described here. The fabrication of this device is considered, which is compatible with current MEMS fabrication technology. Finally, the theoretical analysis of key components of this cryo-cooler is presented.

An SOI CMOS-Based Multi-Sensor MEMS Chip for Fluidic Applications.

PubMed

Mansoor, Mohtashim; Haneef, Ibraheem; Akhtar, Suhail; Rafiq, Muhammad Aftab; De Luca, Andrea; Ali, Syed Zeeshan; Udrea, Florin

2016-11-04

An SOI CMOS multi-sensor MEMS chip, which can simultaneously measure temperature, pressure and flow rate, has been reported. The multi-sensor chip has been designed keeping in view the requirements of researchers interested in experimental fluid dynamics. The chip contains ten thermodiodes (temperature sensors), a piezoresistive-type pressure sensor and nine hot film-based flow rate sensors fabricated within the oxide layer of the SOI wafers. The silicon dioxide layers with embedded sensors are relieved from the substrate as membranes with the help of a single DRIE step after chip fabrication from a commercial CMOS foundry. Very dense sensor packing per unit area of the chip has been enabled by using technologies/processes like SOI, CMOS and DRIE. Independent apparatuses were used for the characterization of each sensor. With a drive current of 10 µA-0.1 µA, the thermodiodes exhibited sensitivities of 1.41 mV/°C-1.79 mV/°C in the range 20-300 °C. The sensitivity of the pressure sensor was 0.0686 mV/(V excit kPa) with a non-linearity of 0.25% between 0 and 69 kPa above ambient pressure. Packaged in a micro-channel, the flow rate sensor has a linearized sensitivity of 17.3 mV/(L/min) -0.1 in the tested range of 0-4.7 L/min. The multi-sensor chip can be used for simultaneous measurement of fluid pressure, temperature and flow rate in fluidic experiments and aerospace/automotive/biomedical/process industries.

An SOI CMOS-Based Multi-Sensor MEMS Chip for Fluidic Applications †

PubMed Central

Mansoor, Mohtashim; Haneef, Ibraheem; Akhtar, Suhail; Rafiq, Muhammad Aftab; De Luca, Andrea; Ali, Syed Zeeshan; Udrea, Florin

2016-01-01

An SOI CMOS multi-sensor MEMS chip, which can simultaneously measure temperature, pressure and flow rate, has been reported. The multi-sensor chip has been designed keeping in view the requirements of researchers interested in experimental fluid dynamics. The chip contains ten thermodiodes (temperature sensors), a piezoresistive-type pressure sensor and nine hot film-based flow rate sensors fabricated within the oxide layer of the SOI wafers. The silicon dioxide layers with embedded sensors are relieved from the substrate as membranes with the help of a single DRIE step after chip fabrication from a commercial CMOS foundry. Very dense sensor packing per unit area of the chip has been enabled by using technologies/processes like SOI, CMOS and DRIE. Independent apparatuses were used for the characterization of each sensor. With a drive current of 10 µA–0.1 µA, the thermodiodes exhibited sensitivities of 1.41 mV/°C–1.79 mV/°C in the range 20–300 °C. The sensitivity of the pressure sensor was 0.0686 mV/(Vexcit kPa) with a non-linearity of 0.25% between 0 and 69 kPa above ambient pressure. Packaged in a micro-channel, the flow rate sensor has a linearized sensitivity of 17.3 mV/(L/min)−0.1 in the tested range of 0–4.7 L/min. The multi-sensor chip can be used for simultaneous measurement of fluid pressure, temperature and flow rate in fluidic experiments and aerospace/automotive/biomedical/process industries. PMID:27827904

Fabrication and characterization of an SU-8 gripper actuated by a shape memory alloy thin film

NASA Astrophysics Data System (ADS)

Roch, I.; Bidaud, Ph; Collard, D.; Buchaillot, L.

2003-03-01

In this paper, we present the fabrication process of a shape memory alloy (SMA) thin film in both monolithic and hybrid configurations. This provides an effective actuation part for a gripper made of SU-8 thick photoresist. We also extensively describe and discuss the assembly of the SMA thin film with the SU-8 mechanism. Measurements show that the SU-8 gripper is able to achieve an opening action of 500 mum in amplitude at a frequency of 1 Hz. Finite element model simulations indicate that a force of 50 mN, corresponding to 400 mum of opening amplitude, should be produced by the SMA actuator. Although the assembly of the TiNi SMA thin film with the SU-8 mechanism is demonstrated, the bond reliability needs further development in order to improve the thermal behavior of the interface. In this paper, we show that SU-8 is well suited as a structural material for microelectromechanical systems (MEMS) applications. An attractive feature in the MEMS design is that the SMA generated force is well matched with the elastic properties of SU-8. From the application point of view, a SMA-actuated SU-8 high-aspect-ratio microgripper can serve as a secure means to transport microelectronics device, because it provides good grasping and safe insulation. This is also a preliminary result for the future development of biogrippers.

Additively manufactured MEMS multiplexed coaxial electrospray sources for high-throughput, uniform generation of core-shell microparticles.

PubMed

Olvera-Trejo, D; Velásquez-García, L F

2016-10-18

This study reports the first MEMS multiplexed coaxial electrospray sources in the literature. Coaxial electrospraying is a microencapsulation technology based on electrohydrodynamic jetting of two immiscible liquids, which allows precise control with low size variation of the geometry of the core-shell particles it generates, which is of great importance in numerous biomedical and engineering applications, e.g., drug delivery and self-healing composites. By implementing monolithic planar arrays of miniaturized coaxial electrospray emitters that work uniformly in parallel, the throughput of the compound microdroplet source is greatly increased, making the microencapsulation technology compatible with low-cost commercial applications. Miniaturized core-shell particle generators with up to 25 coaxial electrospray emitters (25 emitters cm -2 ) were fabricated via stereolithography, which is an additive manufacturing process that can create complex microfluidic devices at a small fraction of the cost per device and fabrication time associated with silicon-based counterparts. The characterization of devices with the same emitter structure but different array sizes demonstrates uniform array operation. Moreover, the data demonstrate that the per-emitter current is approximately proportional to the square root of the flow rate of the driving liquid, and it is independent of the flow rate of the driven liquid, as predicted by the theory. The core/shell diameters and the size distribution of the generated compound microparticles can be modulated by controlling the flow rates fed to the emitters.

MEMS tactile display: from fabrication to characterization

NASA Astrophysics Data System (ADS)

Miki, Norihisa; Kosemura, Yumi; Watanabe, Junpei; Ishikawa, Hiroaki

2014-03-01

We report fabrication and characterization of MEMS-based tactile display that can display users various tactile information, such as Braille codes and surface textures. The display consists of 9 micro-actuators that are equipped with hydraulic displacement amplification mechanism (HDAM) to achieve large enough displacement to stimulate the human tactile receptors. HDAM encapsulates incompressible liquids. We developed a liquid encapsulation process, which we termed as Bonding-in-Liquid Technique, where bonding with a UV-curable resin in glycerin is conducted in the liquid, which prevented interfusion of air bubbles and deformation of the membrane during the bonding. HDAM successfully amplified the displacement generated by piezoelectric actuators by a factor of 6. The display could virtually produce "rough" and "smooth" surfaces, by controlling the vibration frequency, displacement, and the actuation periods of an actuator until the adjacent actuator was driven. We introduced a sample comparison method to characterize the surfaces, which involves human tactile sensation. First, we prepared samples whose mechanical properties are known. We displayed a surface texture to the user by controlling the parameters and then, the user selects a sample that has the most similar surface texture. By doing so, we can correlate the parameters with the mechanical properties of the sample as well as find the sets of the parameters that can provide similar tactile information to many users. The preliminary results with respect to roughness and hardness is presented.

A Novel Silicone-Magnetite Composite Material Used in the Fabrication of Biomimetic Cilia

NASA Astrophysics Data System (ADS)

Carstens, B. L.; Evans, B. A.; Shields, A. R.; Su, J.; Washburn, S.; Falvo, M. R.; Superfine, R.

2008-10-01

We have developed a novel polymer-magnetite composite that we use to fabricate arrays of magnetically actuable biomimetic cilia. Biomimetic cilia are flexible nanorods 750 nm in diameter and 25 microns tall. They generate fluid flows similar to those produced by biological cilia. Polymer-magnetic nanoparticle materials such as ours are becoming increasingly useful in biomedical applications and microelectromechanical systems (MEMS). Comprised of magnetite (Fe3O4), the nanoparticles have a diameter of 5-7 nm and are complexed with a silicone copolymer and crosslinked into a flexible, magnetic solid. Amine groups make up 6-7 percent of the silicone copolymer, providing a simple means of functionalization. We present a detailed mechanical and magnetic analysis of our bulk crosslinked material. The high-aspect ratio biomimetic cilia we create with this magnetite-copolymer complex may have applications in microfluidic mixing, biofouling, and MEMS.

C-MEMS for bio-sensing applications

NASA Astrophysics Data System (ADS)

Song, Yin; Agrawal, Richa; Wang, Chunlei

2015-05-01

Developing highly sensitive, selective, and reproducible miniaturized bio-sensing platforms require reliable biointerface which should be compatible with microfabrication techniques. In this study, we have fabricated pyrolyzed carbon arrays with high surface area as a bio-sensing electrode, and developed the surface functionalization methods to increase biomolecules immobilization efficiency and further understand electrochemical phenomena at biointerfaces. The carbon microelectrode arrays with high aspect ratio have been fabricated by carbon microelectromechanical systems (C-MEMS) and nanomaterials such as graphene have been integrated to further increase surface area. To achieve the efficient covalent immobilization of biomolecules, various oxidation and reduction functionalization methods have been investigated. The oxidation treatment in this study includes vacuum ultraviolet, electrochemical activation, UV/Ozone and oxygen RIE. The reduction treatment includes direct amination and diazonium grafting. The developed bio-sensing platform was then applied for several applications, such as: DNA sensor; H2O2 sensor; aptamer sensor and HIV sensor.

A Compact and Low-Cost MEMS Loudspeaker for Digital Hearing Aids.

PubMed

Sang-Soo Je; Rivas, F; Diaz, R E; Jiuk Kwon; Jeonghwan Kim; Bakkaloglu, B; Kiaei, S; Junseok Chae

2009-10-01

A microelectromechanical-systems (MEMS)-based electromagnetically actuated loudspeaker to reduce form factor, cost, and power consumption, and increase energy efficiency in hearing-aid applications is presented. The MEMS loudspeaker has multilayer copper coils, an NiFe soft magnet on a thin polyimide diaphragm, and an NdFeB permanent magnet on the perimeter. The coil impedance is measured at 1.5 Omega, and the resonant frequency of the diaphragm is located far from the audio frequency range. The device is driven by a power-scalable, 0.25-mum complementary metal-oxide semiconductor class-D SigmaDelta amplifier stage. The class-D amplifier is formed by a differential H-bridge driven by a single bit, pulse-density-modulated SigmaDelta bitstream at a 1.2-MHz clock rate. The fabricated MEMS loudspeaker generates more than 0.8-mum displacement, equivalent to 106-dB sound pressure level (SPL), with 0.13-mW power consumption. Driven by the SigmaDelta class-D amplifier, the MEMS loudspeaker achieves measured 65-dB total harmonic distortion (THD) with a measurement uncertainty of less than 10%. Energy-efficient and cost-effective advanced hearing aids would benefit from further miniaturization via MEMS technology. The results from this study appear very promising for developing a compact, mass-producible, low-power loudspeaker with sufficient sound generation for hearing-aid applications.

Fabrication and Characterization of CMOS-MEMS Thermoelectric Micro Generators

PubMed Central

Kao, Pin-Hsu; Shih, Po-Jen; Dai, Ching-Liang; Liu, Mao-Chen

2010-01-01

This work presents a thermoelectric micro generator fabricated by the commercial 0.35 μm complementary metal oxide semiconductor (CMOS) process and the post-CMOS process. The micro generator is composed of 24 thermocouples in series. Each thermocouple is constructed by p-type and n-type polysilicon strips. The output power of the generator depends on the temperature difference between the hot and cold parts in the thermocouples. In order to prevent heat-receiving in the cold part in the thermocouples, the cold part is covered with a silicon dioxide layer with low thermal conductivity to insulate the heat source. The hot part of the thermocouples is suspended and connected to an aluminum plate, to increases the heat-receiving area in the hot part. The generator requires a post-CMOS process to release the suspended structures. The post-CMOS process uses an anisotropic dry etching to remove the oxide sacrificial layer and an isotropic dry etching to etch the silicon substrate. Experimental results show that the micro generator has an output voltage of 67 μV at the temperature difference of 1 K. PMID:22205869

MEMS Reliability Assurance Activities at JPL

NASA Technical Reports Server (NTRS)

Kayali, S.; Lawton, R.; Stark, B.

2000-01-01

An overview of Microelectromechanical Systems (MEMS) reliability assurance and qualification activities at JPL is presented along with the a discussion of characterization of MEMS structures implemented on single crystal silicon, polycrystalline silicon, CMOS, and LIGA processes. Additionally, common failure modes and mechanisms affecting MEMS structures, including radiation effects, are discussed. Common reliability and qualification practices contained in the MEMS Reliability Assurance Guideline are also presented.

Large-area low-temperature ultrananocrystaline diamond (UNCD) films and integration with CMOS devices for monolithically integrated diamond MEMD/NEMS-CMOS systems.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sumant, A.V.; Auciello, O.; Yuan, H.-C

2009-05-01

Because of exceptional mechanical, chemical, and tribological properties, diamond has a great potential to be used as a material for the development of high-performance MEMS and NEMS such as resonators and switches compatible with harsh environments, which involve mechanical motion and intermittent contact. Integration of such MEMS/NEMS devices with complementary metal oxide semiconductor (CMOS) microelectronics will provide a unique platform for CMOS-driven commercial MEMS/NEMS. The main hurdle to achieve diamond-CMOS integration is the relatively high substrate temperatures (600-800 C) required for depositing conventional diamond thin films, which are well above the CMOS operating thermal budget (400 C). Additionally, a materialsmore » integration strategy has to be developed to enable diamond-CMOS integration. Ultrananocrystalline diamond (UNCD), a novel material developed in thin film form at Argonne, is currently the only microwave plasma chemical vapor deposition (MPCVD) grown diamond film that can be grown at 400 C, and still retain exceptional mechanical, chemical, and tribological properties comparable to that of single crystal diamond. We have developed a process based on MPCVD to synthesize UNCD films on up to 200 mm in diameter CMOS wafers, which will open new avenues for the fabrication of monolithically integrated CMOS-driven MEMS/NEMS based on UNCD. UNCD films were grown successfully on individual Si-based CMOS chips and on 200 mm CMOS wafers at 400 C in a MPCVD system, using Ar-rich/CH4 gas mixture. The CMOS devices on the wafers were characterized before and after UNCD deposition. All devices were performing to specifications with very small degradation after UNCD deposition and processing. A threshold voltage degradation in the range of 0.08-0.44V and transconductance degradation in the range of 1.5-9% were observed.« less

Micro-supercapacitors from carbide derived carbon (CDC) films on silicon chips

NASA Astrophysics Data System (ADS)

Huang, Peihua; Heon, Min; Pech, David; Brunet, Magali; Taberna, Pierre-Louis; Gogotsi, Yury; Lofland, Samuel; Hettinger, Jeffrey D.; Simon, Patrice

2013-03-01

Interdigitated on-chip micro-supercapacitors based on Carbide Derived Carbon (CDC) films were fabricated and tested. A titanium carbide (TiC) film was patterned and treated with chlorine to obtain a TiC derived carbon (TiC-CDC) film, followed by the deposition of two types of current collectors (Ti/Au and Al) using standard micro-fabrication processes. CDC based micro-supercapacitors were electrochemically characterized by cyclic voltammetry and impedance spectroscopy using a 1 M tetraethylammonium tetrafluoroborate, NEt4BF4, in propylene carbonate (PC) electrolyte. A capacitance of 0.78 mF for the device and 1.5 mF cm-2 as the specific capacitance for the footprint of the device was measured for a 2 V potential range at 100 mV s-1. A specific energy of 3.0 mJ cm-2 and a specific power of 84 mW cm-2 were calculated for the devices. These devices provide a pathway for fabricating pure carbon-based micro-supercapacitors by micro-fabrication, and can be used for powering micro-electromechanical systems (MEMS) and electronic devices.

Rapid prototyping of 2D glass microfluidic devices based on femtosecond laser assisted selective etching process

NASA Astrophysics Data System (ADS)

Kim, Sung-Il; Kim, Jeongtae; Koo, Chiwan; Joung, Yeun-Ho; Choi, Jiyeon

2018-02-01

Microfluidics technology which deals with small liquid samples and reagents within micro-scale channels has been widely applied in various aspects of biological, chemical, and life-scientific research. For fabricating microfluidic devices, a silicon-based polymer, PDMS (Polydimethylsiloxane), is widely used in soft lithography, but it has several drawbacks for microfluidic applications. Glass has many advantages over PDMS due to its excellent optical, chemical, and mechanical properties. However, difficulties in fabrication of glass microfluidic devices that requires multiple skilled steps such as MEMS technology taking several hours to days, impedes broad application of glass based devices. Here, we demonstrate a rapid and optical prototyping of a glass microfluidic device by using femtosecond laser assisted selective etching (LASE) and femtosecond laser welding. A microfluidic droplet generator was fabricated as a demonstration of a microfluidic device using our proposed prototyping. The fabrication time of a single glass chip containing few centimeter long and complex-shaped microfluidic channels was drastically reduced in an hour with the proposed laser based rapid and simple glass micromachining and hermetic packaging technique.

MMI-based MOEMS FT spectrometer for visible and IR spectral ranges

NASA Astrophysics Data System (ADS)

Al-Demerdash, Bassem M.; Medhat, Mostafa; Sabry, Yasser M.; Saadany, Bassam; Khalil, Diaa

2014-03-01

MEMS spectrometers have very strong potential in future healthcare and environmental monitoring applications, where Michelson interferometers are the core optical engine. Recently, MEMS Michelson interferometers based on using silicon interface as a beam splitter (BS) has been proposed [7, 8]. This allows having a monolithically-integrated on-chip FTIR spectrometer. However silicon BS exhibits high absorption loss in the visible range and high material dispersion in the near infrared (NIR) range. For this reason, we propose in this work a novel MOEMS interferometer allowing operation over wider spectral range covering both the infrared (IR) and the visible ranges. The proposed architecture is based on spatial splitting and combining of optical beams using the imaging properties of Multi-Mode Interference MMI waveguide. The proposed structure includes an optical splitter for spatial splitting an input beam into two beams and a combiner for spatial combining the two interferometer beams. A MEMS moveable mirror is provided to produce an optical path difference between the two beams. The new interferometer is fabricated using DRIE technology on an SOI wafer. The movable mirror is metalized and attached to a comb-drive actuator fabricated in the same lithography step in a self-aligned manner on chip. The novel interferometer is tested as a Fourier transform spectrometer. Red laser, IR laser and absorption spectra of different materials are measured with a resolution of 2.5 nm at 635-nm wavelength. The structure is a very compact one that allows its integration and fabrication on a large scale with very low cost.

Dynamic focus-tracking MEMS scanning micromirror with low actuation voltages for endoscopic imaging

PubMed Central

Strathman, Matthew; Liu, Yunbo; Li, Xingde; Lin, Lih Y.

2013-01-01

We demonstrate a 3-D scanning micromirror device that combines 2-D beam scanning with focus control in the same device using micro-electro-mechanical-systems (MEMS) technology. 2-D beam scanning is achieved with a biaxial gimbal structure and focus control is obtained with a deformable mirror membrane surface. The micromirror with 800 micrometer diameter is designed to be sufficiently compact and efficient so that it can be incorporated into an endoscopic imaging probe in the future. The design, fabrication and characterization of the device are described in this paper. Using the focus-tracking MEMS scanning mirror, we achieved an optical scanning range of >16 degrees with <40 V actuation voltage at resonance and a tunable focal length between infinity and 25 mm with <100V applied bias. PMID:24104304

Radio Frequency (RF) Micro-Electromechanical Systems (MEMS) Switches for Space Communications

NASA Technical Reports Server (NTRS)

Simons, Rainee N.; Ponchak, George E.; Scardelletti, Maximillian C.; Varaljay, Nicholas C.

2000-01-01

Micro-electromechanical systems (MEMS) is an emerging technology for radio frequency (RF) systems because it has the potential to dramatically decrease loss and improve efficiency. In this paper, we address the design and fabrication of novel MEMS switches being developed at NASA Glenn Research Center. Two types of switches are being developed: a microstrip series single pole single throw (SPST) switch and a coplanar waveguide (CPW) series SPST and single pole double throw (SPDT) switches. These are being fabricated as an integral part of 50 Ohm microstrip and CPW RF integrated circuits using microfabrication techniques. The construction of the switch relies on a cantilever beam that is partially supported by a dielectric post. The cantilever beam is electro-magnetically actuated. To decrease stiction, a Si3N4 thin film is deposited over the contact area. Thus, when the switch is closed, the ON-state insertion loss is governed by the parallel plate capacitance formed by the two contacts. The isolation in the OFF-state is governed by the parasitic capacitance when the cantilever is in the up position. RF MEMS switches have been demonstrated with 80% lower insertion loss than conventional solid state devices (GaAs Metal Semiconductor Field Effect Transistors (MESFETs) and Silicon PIN diodes) based switches. For example, a conventional GaAs five-bit phase shifter which is required for beam steering in a phased array antenna has approximately 7 dB of insertion loss at 26.5 GHz where as a comparable MEMS based phase shifter is expected to have only 2 dB of insertion loss. This translates into 56% lower power dissipation and therefore decreases the thermal load on the spacecraft and also reduces the power amplifier requirements. These benefits will enable NASA to build the next generation of deep space science crafts and micro/nano satellites.

Wearable Wireless Telemetry System for Implantable BioMEMS Sensors

NASA Technical Reports Server (NTRS)

Simons, Rainee N.; Miranda, Felix A.; Wilson, Jeffrey D.; Simons, Renita E.

2008-01-01

Telemetry systems of a type that have been proposed for the monitoring of physiological functions in humans would include the following subsystems: Surgically implanted or ingested units that would comprise combinations of microelectromechanical systems (MEMS)- based sensors [bioMEMS sensors] and passive radio-frequency (RF) readout circuits that would include miniature loop antennas. Compact radio transceiver units integrated into external garments for wirelessly powering and interrogating the implanted or ingested units. The basic principles of operation of these systems are the same as those of the bioMEMS-sensor-unit/external-RFpowering- and-interrogating-unit systems described in "Printed Multi-Turn Loop Antennas for Biotelemetry" (LEW-17879-1) NASA Tech Briefs, Vol. 31, No. 6 (June 2007), page 48, and in the immediately preceding article, "Hand-Held Units for Short-Range Wireless Biotelemetry" (LEW-17483-1). The differences between what is reported here and what was reported in the cited prior articles lie in proposed design features and a proposed mode of operation. In a specific system of the type now proposed, the sensor unit would comprise mainly a capacitive MEMS pressure sensor located in the annular region of a loop antenna (more specifically, a square spiral inductor/ antenna), all fabricated as an integral unit on a high-resistivity silicon chip. The capacitor electrodes, the spiral inductor/antenna, and the conductor lines interconnecting them would all be made of gold. The dimensions of the sensor unit have been estimated to be about 110.4 mm. The external garment-mounted powering/ interrogating unit would include a multi-turn loop antenna and signal-processing circuits. During operation, this external unit would be positioned in proximity to the implanted or ingested unit to provide for near-field, inductive coupling between the loop antennas, which we have as the primary and secondary windings of an electrical transformer.

Development of a Multi-Channel Piezoelectric Acoustic Sensor Based on an Artificial Basilar Membrane

PubMed Central

Jung, Youngdo; Kwak, Jun-Hyuk; Lee, Young Hwa; Kim, Wan Doo; Hur, Shin

2014-01-01

In this research, we have developed a multi-channel piezoelectric acoustic sensor (McPAS) that mimics the function of the natural basilar membrane capable of separating incoming acoustic signals mechanically by their frequency and generating corresponding electrical signals. The McPAS operates without an external energy source and signal processing unit with a vibrating piezoelectric thin film membrane. The shape of the vibrating membrane was chosen to be trapezoidal such that different locations of membrane have different local resonance frequencies. The length of the membrane is 28 mm and the width of the membrane varies from 1 mm to 8 mm. Multiphysics finite element analysis (FEA) was carried out to predict and design the mechanical behaviors and piezoelectric response of the McPAS model. The designed McPAS was fabricated with a MEMS fabrication process based on the simulated results. The fabricated device was tested with a mouth simulator to measure its mechanical and piezoelectrical frequency response with a laser Doppler vibrometer and acoustic signal analyzer. The experimental results show that the as fabricated McPAS can successfully separate incoming acoustic signals within the 2.5 kHz–13.5 kHz range and the maximum electrical signal output upon acoustic signal input of 94 dBSPL was 6.33 mVpp. The performance of the fabricated McPAS coincided well with the designed parameters. PMID:24361926

Packaging of MEMS/MOEMS and nanodevices: reliability, testing, and characterization aspects

NASA Astrophysics Data System (ADS)

Tekin, Tolga; Ngo, Ha-Duong; Wittler, Olaf; Bouhlal, Bouchaib; Lang, Klaus-Dieter

2011-02-01

The last decade witnessed an explosive growth in research and development efforts devoted to MEMS devices and packaging. The successfully developed MEMS devices are, for example inkjet, pressure sensors, silicon microphones, accelerometers, gyroscopes, MOEMS, micro fuel cells and emerging MEMS. For the next decade, MEMS/MOEMS and nanodevice based products will penetrate into IT, telecommunications, automotive, defense, life sciences, medical and implantable applications. Forecasts say the MEMS market to be $14 billion by 2012. The packaging cost of MEMS/MOEMS products in general is about 70 percent. Unlike today's electronics IC packaging, their packaging are custom-built and difficult due to the moving structural elements. In order for the moving elements of a MEMS device to move effectively in a well-controlled atmosphere, hermetic sealing of the MEMS device in a cap is necessary. For some MEMS devices, such as resonators and gyroscopes, vacuum packaging is required. Usually, the cap is processed at the wafer level, and thus MEMS packaging is truly a wafer level packaging. In terms of MEMS/MOEMS and nanodevice packaging, there are still many critical issues need to be addressed due to the increasing integration density supported by 3D heterogeneous integration of multi-physic components/layers consisting of photonics, electronics, rf, plasmonics, and wireless. The infrastructure of MEMS/MOEMS and nanodevices and their packaging is not well established yet. Generic packaging platform technologies are not available. Some of critical issues have been studied intensively in the last years. In this paper we will discuss about processes, reliability, testing and characterization of MEMS/MOEMS and nanodevice packaging.

CMUT Fabrication Based On A Thick Buried Oxide Layer.

PubMed

Kupnik, Mario; Vaithilingam, Srikant; Torashima, Kazutoshi; Wygant, Ira O; Khuri-Yakub, Butrus T

2010-10-01

We introduce a versatile fabrication process for direct wafer-bonded CMUTs. The objective is a flexible fabrication platform for single element transducers, 1D and 2D arrays, and reconfigurable arrays. The main process features are: A low number of litho masks (five for a fully populated 2D array); a simple fabrication sequence on standard MEMS tools without complicated wafer handling (carrier wafers); an improved device reliability; a wide design space in terms of operation frequency and geometric parameters (cell diameter, gap height, effective insulation layer thickness); and a continuous front face of the transducer (CMUT plate) that is connected to ground (shielding for good SNR and human safety in medical applications). All of this is achieved by connecting the hot electrodes individually through a thick buried oxide layer, i.e. from the handle layer of an SOI substrate to silicon electrodes located in each CMUT cell built in the device layer. Vertical insulation trenches are used to isolate these silicon electrodes from the rest of the substrate. Thus, the high electric field is only present where required - in the evacuated gap region of the device and not in the insulation layer of the post region. Array elements (1D and 2D) are simply defined be etching insulation trenches into the handle wafer of the SOI substrate.

CMUT Fabrication Based On A Thick Buried Oxide Layer

PubMed Central

Kupnik, Mario; Vaithilingam, Srikant; Torashima, Kazutoshi; Wygant, Ira O.; Khuri-Yakub, Butrus T.

2010-01-01

We introduce a versatile fabrication process for direct wafer-bonded CMUTs. The objective is a flexible fabrication platform for single element transducers, 1D and 2D arrays, and reconfigurable arrays. The main process features are: A low number of litho masks (five for a fully populated 2D array); a simple fabrication sequence on standard MEMS tools without complicated wafer handling (carrier wafers); an improved device reliability; a wide design space in terms of operation frequency and geometric parameters (cell diameter, gap height, effective insulation layer thickness); and a continuous front face of the transducer (CMUT plate) that is connected to ground (shielding for good SNR and human safety in medical applications). All of this is achieved by connecting the hot electrodes individually through a thick buried oxide layer, i.e. from the handle layer of an SOI substrate to silicon electrodes located in each CMUT cell built in the device layer. Vertical insulation trenches are used to isolate these silicon electrodes from the rest of the substrate. Thus, the high electric field is only present where required – in the evacuated gap region of the device and not in the insulation layer of the post region. Array elements (1D and 2D) are simply defined be etching insulation trenches into the handle wafer of the SOI substrate. PMID:22685377

Reliable before-fabrication forecasting of normal and touch mode MEMS capacitive pressure sensor: modeling and simulation

NASA Astrophysics Data System (ADS)

Jindal, Sumit Kumar; Mahajan, Ankush; Raghuwanshi, Sanjeev Kumar

2017-10-01

An analytical model and numerical simulation for the performance of MEMS capacitive pressure sensors in both normal and touch modes is required for expected behavior of the sensor prior to their fabrication. Obtaining such information should be based on a complete analysis of performance parameters such as deflection of diaphragm, change of capacitance when the diaphragm deflects, and sensitivity of the sensor. In the literature, limited work has been carried out on the above-stated issue; moreover, due to approximation factors of polynomials, a tolerance error cannot be overseen. Reliable before-fabrication forecasting requires exact mathematical calculation of the parameters involved. A second-order polynomial equation is calculated mathematically for key performance parameters of both modes. This eliminates the approximation factor, and an exact result can be studied, maintaining high accuracy. The elimination of approximation factors and an approach of exact results are based on a new design parameter (δ) that we propose. The design parameter gives an initial hint to the designers on how the sensor will behave once it is fabricated. The complete work is aided by extensive mathematical detailing of all the parameters involved. Next, we verified our claims using MATLAB® simulation. Since MATLAB® effectively provides the simulation theory for the design approach, more complicated finite element method is not used.

A fully wafer-level packaged RF MEMS switch with low actuation voltage using a piezoelectric actuator

NASA Astrophysics Data System (ADS)

Park, Jae-Hyoung; Lee, Hee-Chul; Park, Yong-Hee; Kim, Yong-Dae; Ji, Chang-Hyeon; Bu, Jonguk; Nam, Hyo-Jin

2006-11-01

In this paper, a fully wafer-level packaged RF MEMS switch has been demonstrated, which has low operation voltage, using a piezoelectric actuator. The piezoelectric actuator was designed to operate at low actuation voltage for application to advanced mobile handsets. The dc contact type RF switch was packaged using the wafer-level bonding process. The CPW transmission lines and piezoelectric actuators have been fabricated on separate wafers and assembled together by the wafer-level eutectic bonding process. A gold and tin composite was used for eutectic bonding at a low temperature of 300 °C. Via holes interconnecting the electrical contact pads through the wafer were filled completely with electroplated copper. The fully wafer-level packaged RF MEMS switch showed an insertion loss of 0.63 dB and an isolation of 26.4 dB at 5 GHz. The actuation voltage of the switch was 5 V. The resonant frequency of the piezoelectric actuator was 38.4 kHz and the spring constant of the actuator was calculated to be 9.6 N m-1. The size of the packaged SPST (single-pole single-through) switch was 1.2 mm × 1.2 mm including the packaging sealing rim. The effect of the proposed package structure on the RF performance was characterized with a device having CPW through lines and vertical feed lines excluding the RF switches. The measured packaging loss was 0.2 dB and the return loss was 33.6 dB at 5 GHz.

Methods for fabricating a micro heat barrier

DOEpatents

Marshall, Albert C.; Kravitz, Stanley H.; Tigges, Chris P.; Vawter, Gregory A.

2004-01-06

Methods for fabricating a highly effective, micron-scale micro heat barrier structure and process for manufacturing a micro heat barrier based on semiconductor and/or MEMS fabrication techniques. The micro heat barrier has an array of non-metallic, freestanding microsupports with a height less than 100 microns, attached to a substrate. An infrared reflective membrane (e.g., 1 micron gold) can be supported by the array of microsupports to provide radiation shielding. The micro heat barrier can be evacuated to eliminate gas phase heat conduction and convection. Semi-isotropic, reactive ion plasma etching can be used to create a microspike having a cusp-like shape with a sharp, pointed tip (<0.1 micron), to minimize the tip's contact area. A heat source can be placed directly on the microspikes. The micro heat barrier can have an apparent thermal conductivity in the range of 10.sup.-6 to 10.sup.-7 W/m-K. Multiple layers of reflective membranes can be used to increase thermal resistance.

Power Mems Development

DTIC Science & Technology

2010-11-30

testing and analysis in ONR laboratories. Task 1.2 Contributors: Sunny Kedia, Shinzo Onishi , Scott Samson, Drew Hanser Task 1.2 Deliverable...Priscila Spagnol, Shinzo Onishi , Drew Hanser, Weidong Wang, Sunny Kedia, John Bumgarner Deliverable: Prototype device fabricated on a thin-film diamond

The Effects of Boron Doping on Residual Stress of Hfcvd Diamond Film for Mems Applications

NASA Astrophysics Data System (ADS)

Zhao, Tianqi; Wang, Xinchang; Sun, Fanghong

In this study, the residual stress of boron-doped diamond (BDD) films is investigated as a function of boron doping level using X-ray diffraction (XRD) analysis. Boron doping level is controlled from 1000ppm to 9000ppm by dissolving trimethyl borate into acetone. BDD films are deposited on silicon wafers using a bias-enhanced hot filament chemical vapor deposition (BE-HFCVD) system. Residual stress calculated by sin2 ψ method varies linearly from -2.4GPa to -1.1GPa with increasing boron doping level. On the BDD film of -1.75GPa, free standing BDD cantilevers are fabricated by photolithography and ICP-RIE processes, then tested by laser Doppler vibrometer (LDV). A cantilever with resonant frequency of 183KHz and Q factor of 261 in the air is fabricated.

Towards microscale electrohydrodynamic three-dimensional printing

NASA Astrophysics Data System (ADS)

He, Jiankang; Xu, Fangyuan; Cao, Yi; Liu, Yaxiong; Li, Dichen

2016-02-01

It is challenging for the existing three-dimensional (3D) printing techniques to fabricate high-resolution 3D microstructures with low costs and high efficiency. In this work we present a solvent-based electrohydrodynamic 3D printing technique that allows fabrication of microscale structures like single walls, crossed walls, lattice and concentric circles. Process parameters were optimized to deposit tiny 3D patterns with a wall width smaller than 10 μm and a high aspect ratio of about 60. Tight bonding among neighbour layers could be achieved with a smooth lateral surface. In comparison with the existing microscale 3D printing techniques, the presented method is low-cost, highly efficient and applicable to multiple polymers. It is envisioned that this simple microscale 3D printing strategy might provide an alternative and innovative way for application in MEMS, biosensor and flexible electronics.

The fabrication of thermoelectric La0.95Sr0.05CoO3 nanofibers and Seebeck coefficient measurement.

PubMed

Xu, Weihe; Shi, Yong; Hadim, Hamid

2010-10-01

The P-type perovskite oxides La(1-x)Sr(x)CoO(3) are a promising group of complex oxide thermoelectric (TE) materials. The thermoelectric properties of these oxides are expected to be significantly improved when their critical dimensions are reduced to the nanoscale. In this paper, the La(0.95)Sr(0.05)CoO(3) nanofibers, with diameters in the range of approximately 35 nm, were successfully prepared by the electrospinning process. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to characterize these thermoelectric nanofibers. A micro-electromechanical (MEMS) tester was designed and fabricated to measure the Seebeck coefficient of the nanofibers. The measured voltage output was as large as 1.7 mV and the obtained Seebeck coefficient of the nanofibers reached 650 microV K(-1).

Optimized piranha etching process for SU8-based MEMS and MOEMS construction

PubMed Central

Holmes, Matthew; Keeley, Jared; Hurd, Katherine; Schmidt, Holger; Hawkins, Aaron

2011-01-01

We demonstrate the optimization of the concentration, temperature and cycling of a piranha (H2O2:H2SO4) mixture that produces high yields while quickly etching hollow structures made using a highly crosslinked SU8 polymer sacrificial core. The effects of the piranha mixture on the thickness, refractive index and roughness of common micro-electromechanical systems and micro-opto-electromechanical systems fabrication materials (SiN, SiO2 and Si) were determined. The effectiveness of the optimal piranha mixture was demonstrated in the construction of hollow anti-resonant reflecting optical waveguides. PMID:21423840

Optimized piranha etching process for SU8-based MEMS and MOEMS construction.

PubMed

Holmes, Matthew; Keeley, Jared; Hurd, Katherine; Schmidt, Holger; Hawkins, Aaron

2010-11-01

We demonstrate the optimization of the concentration, temperature and cycling of a piranha (H(2)O(2):H(2)SO(4)) mixture that produces high yields while quickly etching hollow structures made using a highly crosslinked SU8 polymer sacrificial core. The effects of the piranha mixture on the thickness, refractive index and roughness of common micro-electromechanical systems and micro-opto-electromechanical systems fabrication materials (SiN, SiO(2) and Si) were determined. The effectiveness of the optimal piranha mixture was demonstrated in the construction of hollow anti-resonant reflecting optical waveguides.

Optimized piranha etching process for SU8-based MEMS and MOEMS construction

NASA Astrophysics Data System (ADS)

Holmes, Matthew; Keeley, Jared; Hurd, Katherine; Schmidt, Holger; Hawkins, Aaron

2010-11-01

We demonstrate the optimization of the concentration, temperature and cycling of a piranha (H2O2:H2SO4) mixture that produces high yields while quickly etching hollow structures made using a highly crosslinked SU8 polymer sacrificial core. The effects of the piranha mixture on the thickness, refractive index and roughness of common micro-electromechanical systems and micro-opto-electromechanical systems fabrication materials (SiN, SiO2 and Si) were determined. The effectiveness of the optimal piranha mixture was demonstrated in the construction of hollow anti-resonant reflecting optical waveguides.

Encapsulants for protecting MEMS devices during post-packaging release etch

DOEpatents

Peterson, Kenneth A.

2005-10-18

The present invention relates to methods to protect a MEMS or microsensor device through one or more release or activation steps in a "package first, release later" manufacturing scheme: This method of fabrication permits wirebonds, other interconnects, packaging materials, lines, bond pads, and other structures on the die to be protected from physical, chemical, or electrical damage during the release etch(es) or other packaging steps. Metallic structures (e.g., gold, aluminum, copper) on the device are also protected from galvanic attack because they are protected from contact with HF or HCL-bearing solutions.

Applications of Non-linearities in RF MEMS Switches and Resonators

NASA Astrophysics Data System (ADS)

Vummidi Murali, Krishna Prasad

The 21st century is emerging into an era of wireless ubiquity. To support this trend, the RF (Radio Frequency) front end must be capable of processing a range of wireless signals (cellular phone, data connectivity, broadcast TV, GPS positioning, etc.) spanning a total bandwidth of nearly 6 GHz. This warrants the need for multi-band/multi-mode radio architectures. For such architectures to satisfy the constraints on size, battery life, functionality and cost, the radio front-end must be made reconfigurable. RF-MEMS (RF Micro-Electro-Mechanical Systems) are seen as an enabling technology for such reconfigurable radios. RF-MEMS mainly include micromechanical switches (used in phase shifters, switched capacitor banks, impedance tuners etc.) and micromechanical resonators (used in tunable filters, oscillators, reference clocks etc.). MEMS technology also has the potential to be directly integrated into CMOS (Complementary metal-oxide semiconductor) ICs (Integrated Circuits) leading to further potential reductions of cost and size. However, RF-MEMS face challenges that must be addressed before they can gain widespread commercial acceptance. Relatively low switching speed, power handling, and high-voltage drive are some of the key issues in MEMS switches. Phase noise influenced by non-linearities, need for temperature compensation (especially Si based resonators), large start-up times, and aging are the key issues in Si MEMS Resonators. In this work potential solutions are proposed to address some of these key issues, specifically the reduction of high voltage drives in switches and the reduction of phase noise in MEMS resonators for timing applications. MEMS devices that are electrostatically actuated exhibit significant non-linearities. The origins of the non-linearities are both electrical (electrostatic actuation) and mechanical (dimensions and material properties). The influence of spring non-linearities (cubic and quadratic) on the performance of switches and resonators are studied. Gold electroplated fixed-fixed beams were fabricated to test the phenomenon of dynamic (or resonant) pull-in in shunt switches. The dynamic pull-in phenomenon was also tested on commercially fabricated lateral switches. It is shown that the resonant pull-in technique reduces the overall voltage required to actuate the switch. There is an additional reduction of total actuation voltage possible via applying an AC actuation signal at the correct non-linear resonant frequency. The demonstrated best case savings from operating at the non-linear resonance is 50% (for the lateral switch) and 60% (for the vertical switch) as compared to 25% and 40% respectively using a fixed frequency approach. However, the timing response for resonant pull-in has been experimentally shown to be slower than the static actuation. To reduce the switching time, a shifted-frequency method is proposed where the excitation frequency is shifted up or down by a discrete amount deltaO after a brief hold time. It was theoretically shown that the shifted-frequency method enables a minimum realizable switching time comparable to the static switching time for a given set of actuation frequencies. The influence of VDC on the effective non-linearities of a fixed-fixed beam is also studied. Based on the dimensions of the resonator and the type of resonance there is a certain VDC,Lin where the response is near linear (S ≈ 0). In the near-linear domain, the dynamic pull-in is the only upper bound to the amplitude of vibrations, and hence the amplitude of output current, thereby maximizing the power handling capacity of the resonator. Apart from maximizing the output current, it is essential to reduce the amplitude and phase variations of the displacement response which are due to noise mixing into frequency of interest, and are eventually manifested as output phase noise due to capacitive current nonlinearity. Two major aliasing schemes were analyzed and it was shown that the capacitive force non-linearity is the major source of mixing that causes the up-conversion of 1/f frequency into signal sidebands. The resonator's periodic response (displacement) is defined by a set of two first-order nonlinear ordinary differential equations that describe the modulation of amplitude and phase of the response. Frequency response curves of amplitude and frequency are determined from these modulation equations. The zero slope point on the amplitude resonance curve is the peak of the resonance curve where the phase (gammadc) of the response is +/-pi/2. For a strongly non-linear system, the resonance curves are skewed based on the amount of total non-linearity S. For systems that are strongly non-linear, the best region to operate the resonator is the fixed point that correspond to infinite slope (gammadc = +/-2pi/3) in the frequency response of the system. The best case phase noise response was analytically developed for such a fixed point. Theoretically at this fixed point, phase noise will have contributions only from 1/ fnoise and not from 1/f2 and 1/ f3. The resonators phase can be set by controlling the rest of the phase in the loop such that the total phase around the loop is zero or 2pi. In addition, this work has also developed an analytical model for a lateral MEMS switch fabricated in a commercial foundry that has the potential to be processed as MEMS on CMOS. This model accounts for trapezoidal cross sections of the electrodes and springs and also models electrostatic fringing as a function of the moving gap. The analytical model matches closely with the Finite Element (FEA) model.

MEMS-based silicon cantilevers with integrated electrothermal heaters for airborne ultrafine particle sensing

NASA Astrophysics Data System (ADS)

Wasisto, Hutomo Suryo; Merzsch, Stephan; Waag, Andreas; Peiner, Erwin

2013-05-01

The development of low-cost and low-power MEMS-based cantilever sensors for possible application in hand-held airborne ultrafine particle monitors is described in this work. The proposed resonant sensors are realized by silicon bulk micromachining technology with electrothermal excitation, piezoresistive frequency readout, and electrostatic particle collection elements integrated and constructed in the same sensor fabrication process step of boron diffusion. Built-in heating resistor and full Wheatstone bridge are set close to the cantilever clamp end for effective excitation and sensing, respectively, of beam deflection. Meanwhile, the particle collection electrode is located at the cantilever free end. A 300 μm-thick, phosphorus-doped silicon bulk wafer is used instead of silicon-on-insulator (SOI) as the starting material for the sensors to reduce the fabrication costs. To etch and release the cantilevers from the substrate, inductively coupled plasma (ICP) cryogenic dry etching is utilized. By controlling the etching parameters (e.g., temperature, oxygen content, and duration), cantilever structures with thicknesses down to 10 - 20 μm are yielded. In the sensor characterization, the heating resistor is heated and generating thermal waves which induce thermal expansion and further cause mechanical bending strain in the out-of-plane direction. A resonant frequency of 114.08 +/- 0.04 kHz and a quality factor of 1302 +/- 267 are measured in air for a fabricated rectangular cantilever (500x100x13.5 μm3). Owing to its low power consumption of a few milliwatts, this electrothermal cantilever is suitable for replacing the current external piezoelectric stack actuator in the next generation of the miniaturized cantilever-based nanoparticle detector (CANTOR).

A capacitive power sensor based on the MEMS cantilever beam fabricated by GaAs MMIC technology

NASA Astrophysics Data System (ADS)

Yi, Zhenxiang; Liao, Xiaoping

2013-03-01

In this paper, a novel capacitive power sensor based on the microelectromechanical systems (MEMS) cantilever beam at 8-12 GHz is proposed, fabricated and tested. The presented design can not only realize a cantilever beam instead of the conventional fixed-fixed beam, but also provide fine compatibility with the GaAs monolithic microwave integrated circuit (MMIC) process. When the displacement of the cantilever beam is very small compared with the initial height of the air gap, the capacitance change between the measuring electrode and the cantilever beam has an approximately linear dependence on the incident radio frequency (RF) power. Impedance compensating technology, by modifying the slot width of the coplanar waveguide transmission line, is adopted to minimize the effect of the cantilever beam on the power sensor; its validity is verified by the simulation of high frequency structure simulator software. The power sensor has been fabricated successfully by Au surface micromachining using polyimide as the sacrificial layer on the GaAs substrate. Optimization of the design with impedance compensating technology has resulted in a measured return loss of less than -25 dB and an insertion loss of around 0.1 dB at 8-12 GHz, which shows the slight effect of the cantilever beam on the microwave performance of this power sensor. The measured capacitance change starts from 0.7 fF to 1.3 fF when the incident RF power increases from 100 to 200 mW and an approximate linear dependence has been obtained. The measured sensitivities of the sensor are about 6.16, 6.27 and 6.03 aF mW-1 at 8, 10 and 12 GHz, respectively.

Development of a MEMS device for acoustic emission testing

NASA Astrophysics Data System (ADS)

Ozevin, Didem; Pessiki, Stephen P.; Jain, Akash; Greve, David W.; Oppenheim, Irving J.

2003-08-01

Acoustic emission testing is an important technology for evaluating structural materials, and especially for detecting damage in structural members. Significant new capabilities may be gained by developing MEMS transducers for acoustic emission testing, including permanent bonding or embedment for superior coupling, greater density of transducer placement, and a bundle of transducers on each device tuned to different frequencies. Additional advantages include capabilities for maintenance of signal histories and coordination between multiple transducers. We designed a MEMS device for acoustic emission testing that features two different mechanical types, a hexagonal plate design and a spring-mass design, with multiple detectors of each type at ten different frequencies in the range of 100 kHz to 1 MHz. The devices were fabricated in the multi-user polysilicon surface micromachining (MUMPs) process and we have conducted electrical characterization experiments and initial experiments on acoustic emission detection. We first report on C(V) measurements and perform a comparison between predicted (design) and measured response. We next report on admittance measurements conducted at pressures varying from vacuum to atmospheric, identifying the resonant frequencies and again providing a comparison with predicted performance. We then describe initial calibration experiments that compare the performance of the detectors to other acoustic emission transducers, and we discuss the overall performance of the device as a sensor suite, as contrasted to the single-channel performance of most commercial transducers.

An implantable integrated low-power amplifier-microelectrode array for Brain-Machine Interfaces.

PubMed

Patrick, Erin; Sankar, Viswanath; Rowe, William; Sanchez, Justin C; Nishida, Toshikazu

2010-01-01

One of the important challenges in designing Brain-Machine Interfaces (BMI) is to build implantable systems that have the ability to reliably process the activity of large ensembles of cortical neurons. In this paper, we report the design, fabrication, and testing of a polyimide-based microelectrode array integrated with a low-power amplifier as part of the Florida Wireless Integrated Recording Electrode (FWIRE) project at the University of Florida developing a fully implantable neural recording system for BMI applications. The electrode array was fabricated using planar micromachining MEMS processes and hybrid packaged with the amplifier die using a flip-chip bonding technique. The system was tested both on bench and in-vivo. Acute and chronic neural recordings were obtained from a rodent for a period of 42 days. The electrode-amplifier performance was analyzed over the chronic recording period with the observation of a noise floor of 4.5 microVrms, and an average signal-to-noise ratio of 3.8.

Complete Fabrication of a Traversable 3 µm Thick NbN Film Superconducting Coil with Cu plated layer of 42m in Length in a Spiral Three-Storied Trench Engraved in a Si Wafer of 76.2 mm in Diameter Formed by MEMS Technology for a Compact SMES with High Energy Storage Volume Density

NASA Astrophysics Data System (ADS)

Suzuki, Yasuhiro; Iguchi, Nobuhiro; Adachi, Kazuhiro; Ichiki, Akihisa; Hioki, Tatsumi; Hsu, Che-Wei; Sato, Ryoto; Kumagai, Shinya; Sasaki, Minoru; Noh, Joo-Hyong; Sakurahara, Yuuske; Okabe, Kyohei; Takai, Osamu; Honma, Hideo; Watanabe, Hideo; Sakoda, Hitoshi; Sasagawa, Hiroaki; Doy, Hideyuki; Zhou, Shuliang; Hori, H.; Nishikawa, Shigeaki; Nozaki, Toshihiro; Sugimoto, Noriaki; Motohiro, Tomoyoshi

2017-09-01

Based on the concept of a novel approach to make a compact SMES unit composed of a stack of Si wafers using MEMS process proposed previously, a complete fabrication of a traversable 3 µam thick NbN film superconducting coil lined with Cu plated layer of 42m in length in a spiral three-storied trench engraved in and extended over a whole Si-wafer of 76.2 mm in diameter was attained for the first time. With decrease in temperature, the DC resistivity showed a metallic decrease indicating the current pass was in the Cu plated layer and then made a sudden fall to residual contact resistance indicating the shift of current pass from the Cu plated layer to the NbN film at the critical temperature Tc of 15.5K by superconducting transition. The temperature dependence of I-V curve showed the increase in the critical current with decrease in the temperature and the highest critical current measured was 220 mA at 4K which is five times as large as that obtained in the test fabrication as the experimental proof of concept presented in the previous report. This completion of a one wafer superconducting NbN coil is an indispensable step for the next proof of concept of fabrication of series-connected two wafer coils via superconductive joint which will read to series connected 600 wafer coils finally, and for replacement of NbN by high Tc superconductor such as YBa2Cu3O7-x for operation under the cold energy of liquid hydrogen or liquid nitrogen.

Vertical electrostatic force in MEMS cantilever IR sensor

NASA Astrophysics Data System (ADS)

Rezadad, Imen; Boroumand Azad, Javaneh; Smith, Evan M.; Alhasan, Ammar; Peale, Robert E.

2014-06-01

A MEMS cantilever IR detector that repetitively lifts from the surface under the influence of a saw-tooth electrostatic force, where the contact duty cycle is a measure of the absorbed IR radiation, is analyzed. The design is comprised of three parallel conducting plates. Fixed buried and surface plates are held at opposite potential. A moveable cantilever is biased the same as the surface plate. Calculations based on energy methods with position-dependent capacity and electrostatic induction coefficients demonstrate the upward sign of the force on the cantilever and determine the force magnitude. 2D finite element method calculations of the local fields confirm the sign of the force and determine its distribution across the cantilever. The upward force is maximized when the surface plate is slightly larger than the other two. The electrostatic repulsion is compared with Casimir sticking force to determine the maximum useful contact area. MEMS devices were fabricated and the vertical displacement of the cantilever was observed in a number of experiments. The approach may be applied also to MEMS actuators and micromirrors.

Development of a wavelength tunable filter using MEMS technology

NASA Astrophysics Data System (ADS)

Liu, Junting

Microelectromechanical systems (MEMS) for optical applications have received intensive attention in recent years because of their potential applications in optical telecommunication. Traditional wavelength division multiplexing (WDM) offers high capacity but requires the fabrication of selective add-drop filters. MEMS technology offers an effective way to fabricate these components at low cost. This thesis presents the development of a device that tunes the Bragg wavelength by coupling into the evanescent field of the grating. A Bragg grating is a periodic perturbation of the refractive index along a fiber or a periodic perturbation of the structure of a planar waveguide. The Bragg wavelength can be tuned by changing the degree to which a dielectric slab couples into the evanescent field. The result is a change in the effective index of the grating, and thus a change in the wavelength that which it reflects. In this thesis Bragg gratings were successfully written into an optical fiber using phase mask technique. Mechanical polishing was used to side-polish the fiber and remove cladding to expose the core. Grating structures were also fabricated in planar waveguide using E-beam writing and dry etching. In order to achieve the smoothest possible morphology of the waveguide, plasma dry etching of transparent substrates was studied in great detail. It is found that the pre-etch cleaning procedure greatly influences the ability to obtain a smooth etched surface. Upper limits of evanescent field tuning were investigated by applying different index liquids such as D. I. water and index matching oils or by positioning different dielectric materials such as glass and silicon close to the grating. Planar waveguides were found to be more sensitive to effective index change. Two kinds of computer simulation were carried out to understand the mode profile and to estimate the value of effective index of planar waveguide under "dry" and "wet" conditions. The first one used an average depth of grating approximation. The second explicitly considered the corrugated structure of the waveguide. Results of both simulations were compared with the experimental results in order to find the proper simulation approach. The fiber or planar waveguide gratings were "device" integrated and their pro and cons were compared. Devices using an optical fiber employed a microactuator driven by electrothermal vibromotor to change the degree of coupling between fiber and "tuning block". Device using planar waveguides used an electrostatic force actuated membrane, flip-chip mounted atop the waveguide. All devices were fabricated using polysilicon surface micromachining processes. I concluded that devices driven by electrostatic force were easier to actuate and their integration with waveguide less challenging.

Ku to V-band 4-bit MEMS phase shifter bank using high isolation SP4T switches and DMTL structures

NASA Astrophysics Data System (ADS)

Dey, Sukomal; Koul, Shiban K.; Poddar, Ajay K.; Rohde, Ulrich L.

2017-10-01

This work presents a micro-electro-mechanical system (MEMS) based on a wide-band 4-bit phase shifter using two back-to-back single-pole-four-throw (SP4T) switches and four different distributed MEMS transmission line (DMTL) structures that are implemented on 635 µm alumina substrate using surface micromachining process. An SP4T switch is designed with a series-shunt configuration and it demonstrates an average return loss of  >17 dB, an insertion loss of  <1.97 dB and maximum isolation of  >28 dB up to 60 GHz. A maximum area of the SP4T switch is ~0.76 mm2. Single-pole-single-throw and SP4T switches are capable of handling 1 W of radio frequency (RF) power up to  >100 million cycles at 25° C; they can even sustained up to  >70 million cycles with 1 W at 85 °C. The proposed wide-band phase shifter works at 17 GHz (Ku-band), 25 GHz (K-band), 35 GHz (Ka-band) and 60 GHz (V-band) frequencies. Finally,a 4-bit phase shifter demonstrates an average insertion loss of  <6 dB, return loss of  >10 dB and maximum phase error of ~3.8° at 60 GHz frequency over 500 MHz bandwidth. Total area of the fabricated device is ~11 mm2. In addition, the proposed device works well up to  >107 cycles with 1 W of RF power. To the best of the author’s knowledge, this is the best reported wide-band MEMS 4-bit phase shifter in the literature that works with a constant resolution.

Microactuateur electrothermique bistable: Etude d'implementation avec une technologie standard CMOS

NASA Astrophysics Data System (ADS)

Ressejac, Isabelle

The general objective of this Ph.D. thesis was to study the implementation of a new type of eletrothermal microactuator. This actuator presents the advantages to be bistable and fabricated in a standard CMOS process, allowing the integration of a microelectronics addressing circuit on the same substrate. Experimental research work, presented in this thesis, relate to the different steps carried out in order to implement this CMOS MEMS device: its theoretical conception, its fabrication with a standard CMOS technology, its micromachining as a post-process, its characterization and its electro-thermo-mechanical modeling. The device was designed and fabricated by using Mitel 1,5 mum CMOS technology and the Can-MEMS service which are both available via the Canadian Microelectronics Corporation. Fabricated monolithically within a standard CMOS process, our microactuator is suitable for large-scale integration due to its small dimensions (length ˜1000 mum and width ˜150 mum). It constitutes the basic component of a N by N matrix controlled by a microelectronic addressing system built on the same substrate. Initially, only one micromachining technique (involving TMAH) was used, and long etching times (>9 h) were requires} in order to release the microstructures. However, the passivation layer from the CMOS process could protect the underlying metal from the TMAH for a sufficient time (only ˜1--2 h). Consequently, we had to develop a micromachining strategy with shorter etching times to allow the complete release of the microstructures without damaging them. Post-processing begins with deposition (by sputtering) of a platinum layer intended to protect the abutment from subsequent etching. Our micromachining strategy is mainly based on the use of a hybrid etching process starting with a first anisotropic TMAH etching followed by a XeF2 isotropic etching. After micromachining, the released microactuator has a significant initial deflection with its tip reaching a height up to a hundred times higher than its thickness. This natural deflection results from the relaxation of internal stresses inside the thin films which are part of the microactuator. These internal stresses are intrinsics to the host CMOS process. We have developed a model of the microactuator's initial deflection using mechanical properties of thin films and dimensions of the structure. Actuation experiments were performed in order to characterize the deflection of the microactuator with respect to the heating of the bilayers (separately and together). We have developed a thermal actuation analytical model for an n-layers multimorph structure, which takes into account the initial deflection resulting from the relaxation of stresses as well as the deflection due to the temperature increase during the electrothermal activation of the bilayers. (Abstract shortened by UMI.)

Manufacturability: from design to SPC limits through "corner-lot" characterization

NASA Astrophysics Data System (ADS)

Hogan, Timothy J.; Baker, James C.; Wesneski, Lisa; Black, Robert S.; Rothenbury, Dave

2004-12-01

Texas Instruments" Digital Micro-mirror Device, is used in a wide variety of optical display applications ranging from fixed and portable projectors to high-definition television (HDTV) to digital cinema projection systems. A new DMD pixel architecture, called "FTP", was designed and qualified by Texas Instruments DLPTMTM Group in 2003 to meet increased performance objectives for brightness and contrast ratio. Coordination between design, test and fabrication groups was required to balance pixel performance requirements and manufacturing capability. "Corner Lot" designed experiments (DOE) were used to verify "fabrication space" available for the pixel design. The corner lot technique allows confirmation of manufacturability projections early in the design/qualification cycle. Through careful design and analysis of the corner-lot DOE, a balance of critical dimension (cd) "budgets" is possible so that specification and process control limits can be established that meet both customer and factory requirements. The application of corner-lot DOE is illustrated in a case history of the DMD "FTP" pixel. The process for balancing test parameter requirements with multiple critical dimension budgets is shown. MEMS/MOEMS device design and fabrication can use similar techniques to achieve agressive design-to-qualification goals.

Manufacturability: from design to SPC limits through "corner-lot" characterization

NASA Astrophysics Data System (ADS)

Hogan, Timothy J.; Baker, James C.; Wesneski, Lisa; Black, Robert S.; Rothenbury, Dave

2005-01-01

Texas Instruments" Digital Micro-mirror Device, is used in a wide variety of optical display applications ranging from fixed and portable projectors to high-definition television (HDTV) to digital cinema projection systems. A new DMD pixel architecture, called "FTP", was designed and qualified by Texas Instruments DLPTMTM Group in 2003 to meet increased performance objectives for brightness and contrast ratio. Coordination between design, test and fabrication groups was required to balance pixel performance requirements and manufacturing capability. "Corner Lot" designed experiments (DOE) were used to verify "fabrication space" available for the pixel design. The corner lot technique allows confirmation of manufacturability projections early in the design/qualification cycle. Through careful design and analysis of the corner-lot DOE, a balance of critical dimension (cd) "budgets" is possible so that specification and process control limits can be established that meet both customer and factory requirements. The application of corner-lot DOE is illustrated in a case history of the DMD "FTP" pixel. The process for balancing test parameter requirements with multiple critical dimension budgets is shown. MEMS/MOEMS device design and fabrication can use similar techniques to achieve agressive design-to-qualification goals.

Two-Axis Direct Fluid Shear Stress Sensor for Aerodynamic Applications

NASA Technical Reports Server (NTRS)

Bajikar, Sateesh S.; Scott, Michael A.; Adcock, Edward E.

2011-01-01

This miniature or micro-sized semiconductor sensor design provides direct, nonintrusive measurement of skin friction or wall shear stress in fluid flow situations in a two-axis configuration. The sensor is fabricated by microelectromechanical system (MEMS) technology, enabling small size and multiple, low-cost reproductions. The sensors may be fabricated by bonding a sensing element wafer to a fluid-coupling element wafer. Using this layered machine structure provides a truly three-dimensional device.

Commercial-Off-The-Shelf Microelectromechanical Systems (MEMS) Flow-Measurement Probes Fabricated And Assembled

NASA Technical Reports Server (NTRS)

Redding, Chip

2002-01-01

As an alternative to conventional tubing instrumentation for measuring airflow, designers and technicians at the NASA Glenn Research Center have been fabricating packaging components and assembling a set of unique probes using commercial-off-the-shelf microelectromechanical systems (MEMS) integrated circuits (computer chips). Using MEMS as an alternative has some compelling advantages over standard measurement devices. Sensor technologies have matured through high-production usage in industries such as automotive and aircraft manufacturers. Currently, MEMS are the choice in applications such as tire pressure monitors, altimeters, pneumatic controls, cable leak detectors, and consumer appliances. Conventional instrumentation uses tubing buried in the model aerodynamic surfaces or wind tunnel walls. The measurements are made when pressure is introduced at the tube opening. The pressure then must travel the tubing for lengths ranging from 20 to hundreds of feet before reaching an electronic signal conditioner. This condition causes a considerable amount of damping and requires measurements to be made only after the test rig has reached steady-state operation. The electronic MEMS pressure sensor is able to take readings continuously under dynamic states in nearly real time. The use of stainless steel tubing for pressure measurements requires many tubes to be cleaned, cut to length, carefully installed, and delicately deburred and spliced for use. A cluster of a few hundred 1/16-in.- (0.0625-in.-) diameter tubes (not uncommon in research testing facilities) can be several inches in diameter and may weigh enough to require two men to handle. Replacing hard tubing with electronic chips can eliminate much of the bulk. Each sensor would fit on the tip of the 1/16-in. tubing with room to spare. The P592 piezoresistive silicon pressure sensor (Lucas NovaSensor, Fremont, CA) was chosen for this project because of its cost, availability, and tolerance to extreme ambient conditions. The chip is 1 mm square by 0.6 mm thick (0.039 by 0.023 in.) with 0.12-mm (0.005-in.) wire connection tabs. Three MEMS chips were used to build the first type of flow-angularity probe. This MEMS probe will be demonstrated as an alternative to a standard tube type "Cobra Probe" now used routinely in wind tunnel and aeronautical hardware applications. The response time and accuracy would allow the probe to be translated on an actuator across a flow field, yielding precision dynamic measurements not possible with conventional instrumentation. The low profile, the minimal power requirement, the rugged construction, and the moderate cost all contribute to making MEMS sensors the enticing choice instrument in future research measurement needs. The MEMS probe efforts are a continuation of work initiated by Brian Willis, without whose foresight and efforts this project would never have been realized. This task was funded through cooperation with the NASA Electronic Parts and Packaging (NEPP) program at the Jet Propulsion Laboratory.

A review of MEMS micropropulsion technologies for CubeSats and PocketQubes

NASA Astrophysics Data System (ADS)

Silva, Marsil A. C.; Guerrieri, Daduí C.; Cervone, Angelo; Gill, Eberhard

2018-02-01

CubeSats have been extensively used in the past decade as scientific tools, technology demonstrators and for education. Recently, PocketQubes have emerged as an interesting and even smaller alternative to CubeSats. However, both satellite types often lack some key capabilities, such as micropropulsion, in order to further extend the range of applications of these small satellites. This paper reviews the current development status of micropropulsion systems fabricated with MEMS (micro electro-mechanical systems) and silicon technology intended to be used in CubeSat or PocketQube missions and compares different technologies with respect to performance parameters such as thrust, specific impulse, and power as well as in terms of operational complexity. More than 30 different devices are analyzed and divided into 7 main categories according to the working principle. A specific outcome of the research is the identification of the current status of MEMS technologies for micropropulsion including key opportunities and challenges.

Diffusion Bonding of Silicon Carbide for MEMS-LDI Applications

NASA Technical Reports Server (NTRS)

Halbig, Michael C.; Singh, Mrityunjay; Shpargel, Tarah P.; Kiser, J. Douglas

2007-01-01

A robust joining approach is critically needed for a Micro-Electro-Mechanical Systems-Lean Direct Injector (MEMS-LDI) application which requires leak free joints with high temperature mechanical capability. Diffusion bonding is well suited for the MEMS-LDI application. Diffusion bonds were fabricated using titanium interlayers between silicon carbide substrates during hot pressing. The interlayers consisted of either alloyed titanium foil or physically vapor deposited (PVD) titanium coatings. Microscopy shows that well adhered, crack free diffusion bonds are formed under optimal conditions. Under less than optimal conditions, microcracks are present in the bond layer due to the formation of intermetallic phases. Electron microprobe analysis was used to identify the reaction formed phases in the diffusion bond. Various compatibility issues among the phases in the interlayer and substrate are discussed. Also, the effects of temperature, pressure, time, silicon carbide substrate type, and type of titanium interlayer and thickness on the microstructure and composition of joints are discussed.

Novel On-wafer Radiation Pattern Measurement Technique for MEMS Actuator Based Reconfigurable Patch Antennas

NASA Technical Reports Server (NTRS)

Simons, Rainee N.

2002-01-01

The paper presents a novel on-wafer, antenna far field pattern measurement technique for microelectromechanical systems (MEMS) based reconfigurable patch antennas. The measurement technique significantly reduces the time and the cost associated with the characterization of printed antennas, fabricated on a semiconductor wafer or dielectric substrate. To measure the radiation patterns, the RF probe station is modified to accommodate an open-ended rectangular waveguide as the rotating linearly polarized sampling antenna. The open-ended waveguide is attached through a coaxial rotary joint to a Plexiglas(Trademark) arm and is driven along an arc by a stepper motor. Thus, the spinning open-ended waveguide can sample the relative field intensity of the patch as a function of the angle from bore sight. The experimental results include the measured linearly polarized and circularly polarized radiation patterns for MEMS-based frequency reconfigurable rectangular and polarization reconfigurable nearly square patch antennas, respectively.

Nanocharacterization of the adhesion effect and bending stiffness in optical MEMS

NASA Astrophysics Data System (ADS)

Pustan, Marius; Birleanu, Corina; Dudescu, Cristian

2017-11-01

The scope of this paper is the reliability design and testing of flexible MEMS components as clamp-clamp beams for the out-of-plane displacement. The field of implementation of such structures is in optical relevant applications such as the optical microsensors or optical microswitches. Moreover these structures can be successfully implemented in RF switches or in the other MEMS applications. The research studies presented in this paper consider the analytical and numerical analysis follow by the experimental validation. The mechanical and tribological characteristics such as the sample static response under an applied force and the adhesion effect between the flexible structure and substrate are investigated. The samples under test are fabricated from a reflective material - gold. Experimental investigations are performed by atomic force microscopy in order to determine the response of the gold microbridges under an applied force. Moreover, to identify the proper geometry that is less sensitive to a thermal gradient, different geometrical configurations of microbridges are tested under different temperatures. An etalon structure is considered as a reference beam and it is compared with the other samples fabricated in the same geometrical dimensions but with some additional rectangular holes performed on the flexible plate. The scope of holes is to reduce the temperature influence on the mechanical behaviour of clamp-clamp beam from application where a thermal gradient occurs. During numerical analysis and experimental investigations, the temperature of samples is increased from 20 °C to 100 °C and the sample response is monitored. A comparison between numerical and experimental results is provided at the end of paper. The research results are useful for designers to predict the behaviour of material and structure from optical or thermal applications in order to improve the reliability and the MEMS lifetime.

Heat convection in a micro impinging jet system

NASA Astrophysics Data System (ADS)

Mai, John Dzung Hoang

2000-10-01

This thesis covers the development of an efficient micro impinging jet heat exchanger, using MEMS technology, to provide localized cooling for present and next generation microelectronic computer chips. Before designing an efficient localized heat exchanger, it is necessary to investigate fluid dynamics and heat transfer in the micro scale. MEMS technology has been used in this project because it is the only tool currently available that can provide a large array of batch-fabricated, micro-scale nozzles for localized cooling. Our investigation of potential MEMS heat exchanger designs begins with experiments that measure the pressure drops and temperature changes in a micro scale tubing system that will be necessary to carry fluid to the impingement point. Our basic MEMS model is a freestanding micro channel with integrated temperature microsensors. The temperature distribution along the channel in a vacuum is measured. The measured flow rates are compared with an analytical model developed for capillary flow that accounts for 2-D, slip and compressibility effects. The work is focused on obtaining correlations in the form of the Nussult number, the Reynolds number and a H/d geometric factor. A set of single MEMS nozzles have been designed to test heat transfer effectiveness as a function of nozzle diameter, ranging from 1.0 mm to 250 um. In addition, nozzle and slot array MEMS devices have been fabricated. In order to obtain quantitative measurements from these micron scale devices, a series of target temperature sensor chips were custom made and characterized for these experiments. The heat transfer characteristics of various MEMS nozzle configurations operating at various steady inlet pressures, at different heights above the heated substrate, have been characterized. These steady results showed that the average heat transfer coefficient, averaged over a 1 cm2 test area, was usually less than 0.035 W/cm 2K for any situation. However, the local heat transfer coefficient, as measured by a single 4mum x 4mum temperature sensor, was as high as 0.5 W/cm2K. Using a mechanical valve and piezo actuator to perturb the flow at frequencies from 10 Hz to 1 kHz, we identify that enhanced heat transfer can occur in an unsteady forced jet. The functional dependence of the enhanced heat transfer on the mean jet speed, perturbation level and perturbing frequency has been established. The expected trend that increased heat transfer at higher values of St number was noticed. In addition the effect of a confined and free jet geometry on an unsteady flow was observed.

Fabrication and characterization of three-dimensional carbon electrodes for lithium-ion batteries

NASA Astrophysics Data System (ADS)

Teixidor, Genis Turon; Zaouk, Rabih B.; Park, Benjamin Y.; Madou, Marc J.

This paper presents fabrication and testing results of three-dimensional carbon anodes for lithium-ion batteries, which are fabricated through the pyrolysis of lithographically patterned epoxy resins. This technique, known as Carbon-MEMS, provides great flexibility and an unprecedented dimensional control in shaping carbon microstructures. Variations in the pattern density and in the pyrolysis conditions result in anodes with different specific and gravimetric capacities, with a three to six times increase in specific capacity with respect to the current thin-film battery technology. Newly designed cross-shaped Carbon-MEMS arrays have a much higher mechanical robustness (as given by their moment of inertia) than the traditionally used cylindrical posts, but the gravimetric analysis suggests that new designs with thinner features are required for better carbon utilization. Pyrolysis at higher temperatures and slower ramping up schedules reduces the irreversible capacity of the carbon electrodes. We also analyze the addition of Meso-Carbon Micro-Beads (MCMB) particles on the reversible and irreversible capacities of new three-dimensional, hybrid electrodes. This combination results in a slight increase in reversible capacity and a big increase in the irreversible capacity of the carbon electrodes, mostly due to the non-complete attachment of the MCMB particles.

The 18 mm[superscript 2] Laboratory: Teaching MEMS Development with the SUMMiT Foundry Process

ERIC Educational Resources Information Center

Dallas, T.; Berg, J. M.; Gale, R. O.

2012-01-01

This paper describes the goals, pedagogical system, and educational outcomes of a three-semester curriculum in microelectromechanical systems (MEMS). The sequence takes engineering students with no formal MEMS training and gives them the skills to participate in cutting-edge MEMS research and development. The evolution of the curriculum from…

Impact of Reflow on the Output Characteristics of Piezoelectric Microelectromechanical System Devices

NASA Astrophysics Data System (ADS)

Nogami, Hirofumi; Kobayashi, Takeshi; Okada, Hironao; Masuda, Takashi; Maeda, Ryutaro; Itoh, Toshihiro

2012-09-01

An animal health monitoring system and a wireless sensor node aimed at preventing the spread of animal-transmitted diseases and improving pastoral efficiency which are especially suitable for chickens, were developed. The sensor node uses a piezoelectric microelectromechanical system (MEMS) device and an event-driven system that is activated by the movements of a chicken. The piezoelectric MEMS device has two functions: a) it measures the activity of a chicken and b) switches the micro-control unit (MCU) of the wireless sensor node from the sleep mode. The piezoelectric MEMS device is required to produce high output voltages when the chicken moves. However, after the piezoelectric MEMS device was reflowed to the wireless sensor node, the output voltages of the piezoelectric MEMS device decreased. The main reason for this might be the loss of residual polarization, which is affected by the thermal load during the reflow process. After the reflow process, we were not able to apply a voltage to the piezoelectric MEMS device; thus, the piezoelectric output voltage was not increased by repoling the piezoelectric MEMS device. To address the thermal load of the reflow process, we established a thermal poling treatment, which achieves a higher temperature than the reflow process. We found that on increasing the thermal poling temperature, the piezoelectric output voltages did not decreased low significantly. Thus, we considered that a thermal poling temperature higher than that of the reflow process prevents the piezoelectric output voltage reduction caused by the thermal load.

A capacitive CMOS-MEMS sensor designed by multi-physics simulation for integrated CMOS-MEMS technology

NASA Astrophysics Data System (ADS)

Konishi, Toshifumi; Yamane, Daisuke; Matsushima, Takaaki; Masu, Kazuya; Machida, Katsuyuki; Toshiyoshi, Hiroshi

2014-01-01

This paper reports the design and evaluation results of a capacitive CMOS-MEMS sensor that consists of the proposed sensor circuit and a capacitive MEMS device implemented on the circuit. To design a capacitive CMOS-MEMS sensor, a multi-physics simulation of the electromechanical behavior of both the MEMS structure and the sensing LSI was carried out simultaneously. In order to verify the validity of the design, we applied the capacitive CMOS-MEMS sensor to a MEMS accelerometer implemented by the post-CMOS process onto a 0.35-µm CMOS circuit. The experimental results of the CMOS-MEMS accelerometer exhibited good agreement with the simulation results within the input acceleration range between 0.5 and 6 G (1 G = 9.8 m/s2), corresponding to the output voltages between 908.6 and 915.4 mV, respectively. Therefore, we have confirmed that our capacitive CMOS-MEMS sensor and the multi-physics simulation will be beneficial method to realize integrated CMOS-MEMS technology.

Demonstration of a wireless driven MEMS pond skater that uses EWOD technology

NASA Astrophysics Data System (ADS)

Mita, Y.; Li, Y.; Kubota, M.; Morishita, S.; Parkes, W.; Haworth, L. I.; Flynn, B. W.; Terry, J. G.; Tang, T.-B.; Ruthven, A. D.; Smith, S.; Walton, A. J.

2009-07-01

A silicon swimming robot or pond skating device has been demonstrated. It floats on liquid surfaces using surface tension and is capable of movement using electrowetting on dielectric (EWOD) based propulsion. Its dimensions are 6 × 9 mm and the driving mechanism involves first trapping air bubbles within the liquid onto the hydrophobic surface of the device. The air bubbles are then moved using EWOD, which provides the propulsion. The device employs a recently reported TaO EWOD technology enabling a driving voltage of ≈15 V, which is low enough for RF power transmission, thus facilitating wire-free movement. A wired version has been measured to move 1.35 mm in 168 ms (a speed of 8 mm s -1). This low voltage-EWOD (<15 V) device, fabricated using a CMOS compatible process, is believed to be the world's smallest swimming MEMS device that has no mechanical moving parts. The paper also reports results of EWOD droplet operation driven by wireless power transmission and demonstrates that such a wireless design can be successfully mounted on a floating EWOD device to produce movement.

Mechanical Characterization of Polysilicon MEMS: A Hybrid TMCMC/POD-Kriging Approach.

PubMed

Mirzazadeh, Ramin; Eftekhar Azam, Saeed; Mariani, Stefano

2018-04-17

Microscale uncertainties related to the geometry and morphology of polycrystalline silicon films, constituting the movable structures of micro electro-mechanical systems (MEMS), were investigated through a joint numerical/experimental approach. An on-chip testing device was designed and fabricated to deform a compliant polysilicon beam. In previous studies, we showed that the scattering in the input–output characteristics of the device can be properly described only if statistical features related to the morphology of the columnar polysilicon film and to the etching process adopted to release the movable structure are taken into account. In this work, a high fidelity finite element model of the device was used to feed a transitional Markov chain Monte Carlo (TMCMC) algorithm for the estimation of the unknown parameters governing the aforementioned statistical features. To reduce the computational cost of the stochastic analysis, a synergy of proper orthogonal decomposition (POD) and kriging interpolation was adopted. Results are reported for a batch of nominally identical tested devices, in terms of measurement error-affected probability distributions of the overall Young’s modulus of the polysilicon film and of the overetch depth.

Planar MEMS bio-chip for recording ion-channel currents in biological cells

NASA Astrophysics Data System (ADS)

Pandey, Santosh; Ferdous, Zannatul; White, Marvin H.

2003-10-01

We describe a planar MEMS silicon structure to record ion-channel currents in biological cells. The conventional method of performing an electrophysiological experiment, 'patch-clamping,' employs a glass micropipette. Despite careful treatments of the micropipette tip, such as fire polishing and surface coating, the latter is a source of thermal noise because of its inherent, tapered, conical structure, which gives rise to a large pipette resistance. This pipette resistance, when coupled with the self-capacitance of the biological cell, limits the available bandwidth and processing of fast transient, ion channel current pulses. In this work, we reduce considerably the pipette resistance with a planar micropipette on a silicon chip to permit the resolution of sub-millisecond, ion-channel pulses. We discuss the design topology of the device, describe the fabrication sequence, and highlight important critical issues. The design of an integrated on-chip CMOS instrumentation amplifier is described, which has a low-noise front-end, input-offset cancellation, correlated double sampling (CDS), and an ultra-high gain in the order of 1012V/A.

A 3D Model of the Thermoelectric Microwave Power Sensor by MEMS Technology.

PubMed

Yi, Zhenxiang; Liao, Xiaoping

2016-06-21

In this paper, a novel 3D model is proposed to describe the temperature distribution of the thermoelectric microwave power sensor. In this 3D model, the heat flux density decreases from the upper surface to the lower surface of the GaAs substrate while it was supposed to be a constant in the 2D model. The power sensor is fabricated by a GaAs monolithic microwave integrated circuit (MMIC) process and micro-electro-mechanical system (MEMS) technology. The microwave performance experiment shows that the S11 is less than -26 dB over the frequency band of 1-10 GHz. The power response experiment demonstrates that the output voltage increases from 0 mV to 27 mV, while the incident power varies from 1 mW to 100 mW. The measured sensitivity is about 0.27 mV/mW, and the calculated result from the 3D model is 0.28 mV/mW. The relative error has been reduced from 7.5% of the 2D model to 3.7% of the 3D model.

A 3D Model of the Thermoelectric Microwave Power Sensor by MEMS Technology

PubMed Central

Yi, Zhenxiang; Liao, Xiaoping

2016-01-01

In this paper, a novel 3D model is proposed to describe the temperature distribution of the thermoelectric microwave power sensor. In this 3D model, the heat flux density decreases from the upper surface to the lower surface of the GaAs substrate while it was supposed to be a constant in the 2D model. The power sensor is fabricated by a GaAs monolithic microwave integrated circuit (MMIC) process and micro-electro-mechanical system (MEMS) technology. The microwave performance experiment shows that the S11 is less than −26 dB over the frequency band of 1–10 GHz. The power response experiment demonstrates that the output voltage increases from 0 mV to 27 mV, while the incident power varies from 1 mW to 100 mW. The measured sensitivity is about 0.27 mV/mW, and the calculated result from the 3D model is 0.28 mV/mW. The relative error has been reduced from 7.5% of the 2D model to 3.7% of the 3D model. PMID:27338395

Surface-micromachined and high-aspect ratio electrostatic actuators for aeronautic and space applications: design and lifetime considerations

NASA Astrophysics Data System (ADS)

Vescovo, P.; Joseph, E.; Bourbon, G.; Le Moal, P.; Minotti, P.; Hibert, C.; Pont, G.

2003-09-01

This paper focuses on recent advances in the field of MEMS-based actuators and distributed microelectromechanical systems (MEMS). IC-processed actuators (e.g. actuators that are machined using integrated circuit batch processes) are expected to open a wide range of industrial applications on the near term. The most promising investigations deal with high-aspect ratio electric field driven microactuators suitable for use in numerous technical fields such as aeronautics and space industry. Because the silicon micromachining technology have the potential to integrate both mechanical components and control circuits within a single process, MEMS-based active control of microscopic and macroscopic structures appears to be one of the most promising challenges for the next decade. As a first step towards new generations of MEMS-based smart structures, recent investigations dealing with silicon mechanisms involving MEMS-based actuators are briefly discussed in this paper.

MEMS based ion beams for fusion

NASA Astrophysics Data System (ADS)

Persaud, A.; Seidl, P. A.; Ji, Q.; Waldron, W. L.; Schenkel, T.; Ardanuc, S.; Vinayakumar, K. B.; Schaffer, Z. A.; Lal, A.

2016-10-01

Micro-Electro-Mechanical Systems (MEMS) fabrication provides an exciting opportunity to shrink existing accelerator concepts to smaller sizes and to reduce cost by orders of magnitude. We revisit the concept of a Multiple Electrostatic Quadrupole Array Linear Accelerator (MEQALAC) and show how, with current technologies, the concept can be downsized from gap distances of several cm to distances in the sub-mm regime. The basic concept implements acceleration gaps using radio frequency (RF) fields and electrostatic quadrupoles (ESQ) on silicon wafers. First results from proof-of-concept experiments using printed circuit boards to realize the MEQALAC structures are presented. We show results from accelerating structures that were used in an array of nine (3x3) parallel beamlets with He ions at 15 keV. We will also present results from an ESQ focusing lattice using the same beamlet layout showing beam transport and matching. We also will discuss our progress in fabricating MEMS devices in silicon wafers for both the RF and ESQ structures and integration of necessary RF-circuits on-chip. The concept can be scaled up to thousands of beamlets providing high power beams at low cost and can be used to form and compress a plasma for the development of magnetized target fusion approaches. This work was supported by the Office of Science of the US Department of Energy through the ARPA-e ALPHA program under contracts DE-AC0205CH11231 (LBNL).

Gold-based thin multilayers for ohmic contacts in RF-MEMS switches

NASA Astrophysics Data System (ADS)

Mulloni, V.; Iannacci, J.; Bartali, R.; Micheli, V.; Colpo, S.; Laidani, N.; Margesin, B.

2011-06-01

In RF-MEMS switches many reliability issues are related to the metal contacts in the switching area. The characteristics of this contact influence not only contact resistance and insertion loss, but also the most relevant switch failure mechanisms that are wear of ohmic contact, adhesion and stiction. Gold is widely used for this purpose because of its good conductivity and chemical inertness, but is a soft metal, and the development of hard contact materials with low resistivity is of great interest for RF-MEMS switch reliability. It is possible to increase the contact hardness preserving the convenient gold properties alternating gold layers with thin layers of different metals. The material becomes harder not only by simple alloying but also by the presence of interfaces which act as barriers for mechanical dislocation migration. A detailed study of mechanical, electrical and morphological properties of gold-chromium, gold-platinum and gold-palladium multilayers is presented and discussed. It is found that the annealing treatments are important for tuning hardness values, and a careful choice of the alloying metal is essential when the material is inserted in a real switch fabrication cycle, because hardness improvements can vanish during oxygen plasma treatments usually involved in RF-switches fabrication. Platinum is the only metal tested that is unaffected by oxidation, and also modifies the chromium adhesion layer diffusion on the contact surface.

MEMS Reliability Assurance Guidelines for Space Applications

NASA Technical Reports Server (NTRS)

Stark, Brian (Editor)

1999-01-01

This guide is a reference for understanding the various aspects of microelectromechanical systems, or MEMS, with an emphasis on device reliability. Material properties, failure mechanisms, processing techniques, device structures, and packaging techniques common to MEMS are addressed in detail. Design and qualification methodologies provide the reader with the means to develop suitable qualification plans for the insertion of MEMS into the space environment.

Micro-Thermoelectric Generation Modules Fabricated with Low-Cost Mechanical Machining Processes

NASA Astrophysics Data System (ADS)

Liu, Dawei; Jin, A. J.; Peng, Wenbo; Li, Qiming; Gao, Hu; Zhu, Lianjun; Li, Fu; Zhu, Zhixiang

2017-05-01

Micro/small-scale thermoelectric generation modules are able to produce continuous, noise-free and reliable electricity power using low temperature differences that widely exist in nature or industry. These advantages bring them great application prospects in the fields of remote monitoring, microelectronics/micro-electromechanical systems (MEMS), medical apparatus and smart management system, which often require a power source free of maintenance and vibration. In this work, a prototypical thermoelectric module (12 mm × 12 mm × 0.8 mm) with 15 pairs of micro-scale thermoelectric legs (0.2 mm in width and 0.6 mm in height for each leg) is fabricated using a low-cost mechanical machining process. In this process, cutting and polishing are the main methods for the preparation of thermoelectric pairs from commercial polycrystalline materials and for the fabrication of electrode patterns. The as-fabricated module is tested for its power generation properties with the hot side heated by an electrical heater and the cold side by cold air. With the heater temperature of 375 K, the thermoelectric potential is about 9.1 mV, the short circuit current is about 14.5 mA, and the maximum output power is about 32.8 μW. The finite element method is applied to analyze the heat transfer of the module during our test. The temperature difference and heat flux are simulated, according to which the output powers at different temperatures are calculated, and the result is relatively consistent compared to the test results.

A 2D Rods-in-Air Square-Lattice Photonic Crystal Optical Switch

DTIC Science & Technology

2009-03-01

4] Tao Chu, Hirohito Yamada, Satomi Ishida, Yasuhiko Arakawa, Thermooptic switch based on photonic-crystal line-defect waveguides, IEEE Photon...Ishida, Yasuhiko Arakawa, Hiroyuki Fujita, Hiroshi Toshiyoshi, Design and fabrication on MEMS optical mod- ulators integrated with Phc waveguide, in

MEMS cantilever sensor for THz photoacoustic chemical sensing and pectroscopy

NASA Astrophysics Data System (ADS)

Glauvitz, Nathan E.

Sensitive Microelectromechanical System (MEMS) cantilever designs were modeled, fabricated, and tested to measure the photoacoustic (PA) response of gasses to terahertz (THz) radiation. Surface and bulk micromachining technologies were employed to create the extremely sensitive devices that could detect very small changes in pressure. Fabricated devices were then tested in a custom made THz PA vacuum test chamber where the cantilever deflections caused by the photoacoustic effect were measured with a laser interferometer and iris beam clipped methods. The sensitive cantilever designs achieved a normalized noise equivalent absorption coefficient of 2.83x10-10 cm-1 W Hz-½ using a 25 microW radiation source power and a 1 s sampling time. Traditional gas phase molecular spectroscopy absorption cells are large and bulky. The outcome of this research resulted was a photoacoustic detection method that was virtually independent of the absorption path-length, which allowed the chamber dimensions to be greatly reduced, leading to the possibility of a compact, portable chemical detection and spectroscopy system

An optical MEMS accelerometer fabricated using double-sided deep reactive ion etching on silicon-on-insulator wafer

NASA Astrophysics Data System (ADS)

Teo, Adrian J. T.; Li, Holden; Tan, Say Hwa; Yoon, Yong-Jin

2017-06-01

Optical MEMS devices provide fast detection, electromagnetic resilience and high sensitivity. Using this technology, an optical gratings based accelerometer design concept was developed for seismic motion detection purposes that provides miniaturization, high manufacturability, low costs and high sensitivity. Detailed in-house fabrication procedures of a double-sided deep reactive ion etching (DRIE) on a silicon-on-insulator (SOI) wafer for a micro opto electro mechanical system (MOEMS) device are presented and discussed. Experimental results obtained show that the conceptual device successfully captured motion similar to a commercial accelerometer with an average sensitivity of 13.6 mV G-1, and a highest recorded sensitivity of 44.1 mV G-1. A noise level of 13.5 mV was detected due to experimental setup limitations. This is the first MOEMS accelerometer developed using double-sided DRIE on SOI wafer for the application of seismic motion detection, and is a breakthrough technology platform to open up options for lower cost MOEMS devices.

Applications of Ferro-Nanofluid on a Micro-Transformer

PubMed Central

Tsai, Tsung-Han; Kuo, Long-Sheng; Chen, Ping-Hei; Lee, Da-sheng; Yang, Chin-Ting

2010-01-01

An on-chip transformer with a ferrofluid magnetic core has been developed and tested. The transformer consists of solenoid-type coil and a magnetic core of ferrofluid, with the former fabricated by MEMS technology and the latter by a chemical co-precipitation method. The performance of the MEMS transformer with a ferrofluid magnetic core was measured and simulated with frequencies ranging from 100 kHz to 100 MHz. Experimental results reveal that the presence of the ferrofluid increases the inductance of coils and the coupling coefficient of transformer; however, it also increases the resistance owing to the lag between the external magnetic field and the magnetization of the material. PMID:22163647

Applications of ferro-nanofluid on a micro-transformer.

PubMed

Tsai, Tsung-Han; Kuo, Long-Sheng; Chen, Ping-Hei; Lee, Da-Sheng; Yang, Chin-Ting

2010-01-01

An on-chip transformer with a ferrofluid magnetic core has been developed and tested. The transformer consists of solenoid-type coil and a magnetic core of ferrofluid, with the former fabricated by MEMS technology and the latter by a chemical co-precipitation method. The performance of the MEMS transformer with a ferrofluid magnetic core was measured and simulated with frequencies ranging from 100 kHz to 100 MHz. Experimental results reveal that the presence of the ferrofluid increases the inductance of coils and the coupling coefficient of transformer; however, it also increases the resistance owing to the lag between the external magnetic field and the magnetization of the material.

GaAs-based resonant tunneling diode (RTD) epitaxy on Si for highly sensitive strain gauge applications.

PubMed

Li, Jie; Guo, Hao; Liu, Jun; Tang, Jun; Ni, Haiqiao; Shi, Yunbo; Xue, Chenyang; Niu, Zhichuan; Zhang, Wendong; Li, Mifeng; Yu, Ying

2013-05-08

As a highly sensitive strain gauge element, GaAs-based resonant tunneling diode (RTD) has already been applied in microelectromechanical system (MEMS) sensors. Due to poor mechanical properties and high cost, GaAs-based material has been limited in applications as the substrate for MEMS. In this work, we present a method to fabricate the GaAs-based RTD on Si substrate. From the experimental results, it can be concluded that the piezoresistive coefficient achieved with this method reached 3.42 × 10-9 m2/N, which is about an order of magnitude higher than the Si-based semiconductor piezoresistors.

CNES reliability approach for the qualification of MEMS for space

NASA Astrophysics Data System (ADS)

Pressecq, Francis; Lafontan, Xavier; Perez, Guy; Fortea, Jean-Pierre

2001-10-01

This paper describes the reliability approach performs at CNES to evaluate MEMS for space application. After an introduction and a detailed state of the art on the space requirements and on the use of MEMS for space, different approaches for taking into account MEMS in the qualification phases are presented. CNES proposes improvement to theses approaches in term of failure mechanisms identification. Our approach is based on a design and test phase deeply linked with a technology study. This workflow is illustrated with an example: the case of a variable capacitance processed with MUMPS process is presented.

A thickness-mode piezoelectric micromachined ultrasound transducer annular array using a PMN–PZT single crystal

NASA Astrophysics Data System (ADS)

Kang, Woojin; Jung, Joontaek; Lee, Wonjun; Ryu, Jungho; Choi, Hongsoo

2018-07-01

Micro-electromechanical system (MEMS) technologies were used to develop a thickness-mode piezoelectric micromachined ultrasonic transducer (Tm-pMUT) annular array utilizing a lead magnesium niobate–lead zirconate titanate (PMN–PZT) single crystal prepared by the solid-state single-crystal-growth method. Dicing is a conventional processing method for PMN–PZT single crystals, but MEMS technology can be adopted for the development of Tm-pMUT annular arrays and has various advantages, including fabrication reliability, repeatability, and a curved element shape. An inductively coupled plasma–reactive ion etching process was used to etch a brittle PMN–PZT single crystal selectively. Using this process, eight ring-shaped elements were realized in an area of 1  ×  1 cm2. The resonance frequency and effective electromechanical coupling coefficient of the Tm-pMUT annular array were 2.66 (±0.04) MHz, 3.18 (±0.03) MHz, and 30.05%, respectively, in the air. The maximum positive acoustic pressure in water, measured at a distance of 7.27 mm, was 40 kPa from the Tm-pMUT annular array driven by a 10 Vpp sine wave at 2.66 MHz without beamforming. The proposed Tm-pMUT annular array using a PMN–PZT single crystal has the potential for various applications, such as a fingerprint sensor, and for ultrasonic cell stimulation and low-intensity tissue stimulation.

Reactive sputter deposition of piezoelectric Sc 0.12Al 0.88N for contour mode resonators

DOE PAGES

Henry, Michael David; Young, Travis Ryan; Douglas, Erica Ann; ...

2018-05-11

Substitution of Al by Sc has been predicted and demonstrated to improve the piezoelectric response in AlN for commercial market applications in radio frequency filter technologies. Although cosputtering with multiple targets have achieved Sc incorporation in excess of 40%, industrial processes requiring stable single target sputtering are currently limited. A major concern with sputter deposition of ScAl is the control over the presence of non-c-axis oriented crystal growth, referred to as inclusions here, while simultaneously controlling film stress for suspended microelectromechanical systems (MEMS) structures. In this paper, we describe 12.5% ScAl single target reactive sputter deposition process and establishes amore » direct relationship between the inclusion occurrences and compressive film stress allowing for the suppression of the c-axis instability on silicon (100) and Ti/TiN/AlCu seeding layers. An initial high film stress, for suppressing inclusions, is then balanced with a lower film stress deposition to control total film stress to prevent Euler buckling of suspended MEMS devices. Contour mode resonators fabricated using these films demonstrate effective coupling coefficients up to 2.7% with figures of merit of 42. Finally, this work provides a method to establish inclusion free films in ScAlN piezoelectric films for good quality factor devices.« less

Reactive sputter deposition of piezoelectric Sc 0.12Al 0.88N for contour mode resonators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Henry, Michael David; Young, Travis Ryan; Douglas, Erica Ann

Substitution of Al by Sc has been predicted and demonstrated to improve the piezoelectric response in AlN for commercial market applications in radio frequency filter technologies. Although cosputtering with multiple targets have achieved Sc incorporation in excess of 40%, industrial processes requiring stable single target sputtering are currently limited. A major concern with sputter deposition of ScAl is the control over the presence of non-c-axis oriented crystal growth, referred to as inclusions here, while simultaneously controlling film stress for suspended microelectromechanical systems (MEMS) structures. In this paper, we describe 12.5% ScAl single target reactive sputter deposition process and establishes amore » direct relationship between the inclusion occurrences and compressive film stress allowing for the suppression of the c-axis instability on silicon (100) and Ti/TiN/AlCu seeding layers. An initial high film stress, for suppressing inclusions, is then balanced with a lower film stress deposition to control total film stress to prevent Euler buckling of suspended MEMS devices. Contour mode resonators fabricated using these films demonstrate effective coupling coefficients up to 2.7% with figures of merit of 42. Finally, this work provides a method to establish inclusion free films in ScAlN piezoelectric films for good quality factor devices.« less

Reactive sputter deposition of piezoelectric Sc 0.12Al 0.88N for contour mode resonators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Henry, Michael David; Young, Travis Ryan; Douglas, Erica Ann

Substitution of Al by Sc has been predicted and demonstrated to improve the piezoelectric response in AlN for commercial market applications in radio frequency filter technologies. Although cosputtering with multiple targets have achieved Sc incorporation in excess of 40%, industrial processes requiring stable single target sputtering are currently limited. A major concern with sputter deposition of ScAl is the control over the presence of non-c-axis oriented crystal growth, referred to as inclusions here, while simultaneously controlling film stress for suspended microelectromechanical systems (MEMS) structures. This work describes 12.5% ScAl single target reactive sputter deposition process and establishes a direct relationshipmore » between the inclusion occurrences and compressive film stress allowing for the suppression of the c-axis instability on silicon (100) and Ti/TiN/AlCu seeding layers. An initial high film stress, for suppressing inclusions, is then balanced with a lower film stress deposition to control total film stress to prevent Euler buckling of suspended MEMS devices. Contour mode resonators fabricated using these films demonstrate effective coupling coefficients up to 2.7% with figures of merit of 42. Furthermore, this work provides a method to establish inclusion free films in ScAlN piezoelectric films for good quality factor devices.« less

A novel MEMS inertial switch with a reinforcing rib structure and electrostatic power assist to prolong the contact time

NASA Astrophysics Data System (ADS)

Li, Jian; Wang, Yan; Yang, Zhuoqing; Ding, Guifu; Zhao, Xiaolin; Wang, Hong

2018-03-01

The MEMS inertial switch is widely used in various industries owing to its advantage of small size, high integration, low power consumption and low costs, especially in the timing of Internet of things, such as toys, handheld devices, accessories and vibration testing. This paper provided a novel inertial switch with a reinforcing rib structure and electrostatic power assist. The designed inertial switch can reduce the complexity of the post-processing circuit and broaden its application prospect. The continuous electrostatic force can extend the contact time of the designed inertia switch before the leakage of electricity ends. The moving electrode with a reinforcing rib structure can effectively restrain the bending of the lower surface of moving electrode caused by residual stress. The array-type fixed electrode can ensure stable contact between the electrodes when the device is sensitive to external shocks. The dynamic displacement-time curve can be simulated by the COMSOL finite element simulation software. The laminated plating process is used to produce the designed inertial switch and the drop hammer acceleration monitoring system is used to test the fabricated device. The results indicate that, compared with the traditional design, the bouncing phenomenon can be prevented and extend the contact time to 336μs.

Growth and Etch Rate Study of Low Temperature Anodic Silicon Dioxide Thin Films

PubMed Central

Ashok, Akarapu; Pal, Prem

2014-01-01

Silicon dioxide (SiO2) thin films are most commonly used insulating films in the fabrication of silicon-based integrated circuits (ICs) and microelectromechanical systems (MEMS). Several techniques with different processing environments have been investigated to deposit silicon dioxide films at temperatures down to room temperature. Anodic oxidation of silicon is one of the low temperature processes to grow oxide films even below room temperature. In the present work, uniform silicon dioxide thin films are grown at room temperature by using anodic oxidation technique. Oxide films are synthesized in potentiostatic and potentiodynamic regimes at large applied voltages in order to investigate the effect of voltage, mechanical stirring of electrolyte, current density and the water percentage on growth rate, and the different properties of as-grown oxide films. Ellipsometry, FTIR, and SEM are employed to investigate various properties of the oxide films. A 5.25 Å/V growth rate is achieved in potentiostatic mode. In the case of potentiodynamic mode, 160 nm thickness is attained at 300 V. The oxide films developed in both modes are slightly silicon rich, uniform, and less porous. The present study is intended to inspect various properties which are considered for applications in MEMS and Microelectronics. PMID:24672287

High Volume Manufacturing and Field Stability of MEMS Products

NASA Astrophysics Data System (ADS)

Martin, Jack

Low volume MEMS/NEMS production is practical when an attractive concept is implemented with business, manufacturing, packaging, and test support. Moving beyond this to high volume production adds requirements on design, process control, quality, product stability, market size, market maturity, capital investment, and business systems. In a broad sense, this chapter uses a case study approach: It describes and compares the silicon-based MEMS accelerometers, pressure sensors, image projection systems, and gyroscopes that are in high volume production. Although they serve several markets, these businesses have common characteristics. For example, the manufacturing lines use automated semiconductor equipment and standard material sets to make consistent products in large quantities. Standard, well controlled processes are sometimes modified for a MEMS product. However, novel processes that cannot run with standard equipment and material sets are avoided when possible. This reliance on semiconductor tools, as well as the organizational practices required to manufacture clean, particle-free products partially explains why the MEMS market leaders are integrated circuit manufacturers. There are other factors. MEMS and NEMS are enabling technologies, so it can take several years for high volume applications to develop. Indeed, market size is usually a strong function of price. This becomes a vicious circle, because low price requires low cost - a result that is normally achieved only after a product is in high volume production. During the early years, IC companies reduced cost and financial risk by using existing facilities for low volume MEMS production. As a result, product architectures are partially determined by capabilities developed for previous products. This chapter includes a discussion of MEMS product architecture with particular attention to the impact of electronic integration, packaging, and surfaces. Packaging and testing are critical, because they are significant factors in MEMS product cost. These devices have extremelyhigh surface/volume ratios, so performance and stability may depend on the control of surface characteristics after packaging. Looking into the future, the competitive advantage of IC suppliers will decrease as small companies learn to integrate MEMS/NEMS devices on CMOS foundry wafers. Packaging challenges still remain, because most MEMS/NEMS products must interact with the environment without degrading stability or reliability. Generic packaging solutions are unlikely. However, packaging subcontractors recognize that MEMS/NEMS is a growth opportunity. They will spread the overhead burden of high-capital-cost-facilities by developing flexible processes in order to package several types of moderate volume integrated MEMS/NEMS products on the same equipment.

High Volume Manufacturing and Field Stability of MEMS Products

NASA Astrophysics Data System (ADS)

Martin, Jack

Low volume MEMS/NEMS production is practical when an attractive concept is implemented with business, manufacturing, packaging, and test support. Moving beyond this to high volume production adds requirements on design, process control, quality, product stability, market size, market maturity, capital investment, and business systems. In a broad sense, this chapter uses a case study approach: It describes and compares the silicon-based MEMS accelerometers, pressure sensors, image projection systems, and gyroscopes that are in high volume production. Although they serve several markets, these businesses have common characteristics. For example, the manufacturing lines use automated semiconductor equipment and standard material sets to make consistent products in large quantities. Standard, well controlled processes are sometimes modified for a MEMS product. However, novel processes that cannot run with standard equipment and material sets are avoided when possible. This reliance on semiconductor tools, as well as the organizational practices required to manufacture clean, particle-free products partially explains why the MEMS market leaders are integrated circuit manufacturers. There are other factors. MEMS and NEMS are enabling technologies, so it can take several years for high volume applications to develop. Indeed, market size is usually a strong function of price. This becomes a vicious circle, because low price requires low cost - a result that is normally achieved only after a product is in high volume production. During the early years, IC companies reduced cost and financial risk by using existing facilities for low volume MEMS production. As a result, product architectures are partially determined by capabilities developed for previous products. This chapter includes a discussion of MEMS product architecture with particular attention to the impact of electronic integration, packaging, and surfaces. Packaging and testing are critical, because they are significant factors in MEMS product cost. These devices have extremely high surface/volume ratios, so performance and stability may depend on the control of surface characteristics after packaging. Looking into the future, the competitive advantage of IC suppliers will decrease as small companies learn to integrate MEMS/NEMS devices on CMOS foundry wafers. Packaging challenges still remain, because most MEMS/NEMS products must interact with the environment without degrading stability or reliability. Generic packaging solutions are unlikely. However, packaging subcontractors recognize that MEMS/NEMS is a growth opportunity. They will spread the overhead burden of high-capital-cost-facilities by developing flexible processes in order to package several types of moderate volume integrated MEMS/NEMS products on the same equipment.

An absorptive single-pole four-throw switch using multiple-contact MEMS switches and its application to a monolithic millimeter-wave beam-forming network

NASA Astrophysics Data System (ADS)

Lee, Sanghyo; Kim, Jong-Man; Kim, Yong-Kweon; Kwon, Youngwoo

2009-01-01

In this paper, a new absorptive single-pole four-throw (SP4T) switch based on multiple-contact switching is proposed and integrated with a Butler matrix to demonstrate a monolithic beam-forming network at millimeter waves (mm waves). In order to simplify the switching driving circuit and reduce the number of unit switches in an absorptive SP4T switch, the individual switches were replaced with long-span multiple-contact switches using stress-free single-crystalline-silicon MEMS technology. This approach improves the mechanical stability as well as the manufacturing yield, thereby allowing successful integration into a monolithic beam former. The fabricated absorptive SP4T MEMS switch shows insertion loss less than 1.3 dB, return losses better than 11 dB at 30 GHz and wideband isolation performance higher than 39 dB from 20 to 40 GHz. The absorptive SP4T MEMS switch is integrated with a 4 × 4 Butler matrix on a single chip to implement a monolithic beam-forming network, directing beam into four distinct angles. Array factors from the measured data show that the proposed absorptive SPnT MEMS switch can be effectively used for high-performance mm-wave beam-switching systems. This work corresponds to the first demonstration of a monolithic beam-forming network using switched beams.

RF-MEMS for future mobile applications: experimental verification of a reconfigurable 8-bit power attenuator up to 110 GHz

NASA Astrophysics Data System (ADS)

Iannacci, J.; Tschoban, C.

2017-04-01

RF-MEMS technology is proposed as a key enabling solution for realising the high-performance and highly reconfigurable passive components that future communication standards will demand. In this work, we present, test and discuss a novel design concept for an 8-bit reconfigurable power attenuator, manufactured using the RF-MEMS technology available at the CMM-FBK, in Italy. The device features electrostatically controlled MEMS ohmic switches in order to select/deselect the resistive loads (both in series and shunt configuration) that attenuate the RF signal, and comprises eight cascaded stages (i.e. 8-bit), thus implementing 256 different network configurations. The fabricated samples are measured (S-parameters) from 10 MHz to 110 GHz in a wide range of different configurations, and modelled/simulated with Ansys HFSS. The device exhibits attenuation levels (S21) in the range from  -10 dB to  -60 dB, up to 110 GHz. In particular, S21 shows flatness from 15 dB down to 3-5 dB and from 10 MHz to 50 GHz, as well as fewer linear traces up to 110 GHz. A comprehensive discussion is developed regarding the voltage standing wave ratio, which is employed as a quality indicator for the attenuation levels. The margins of improvement at design level which are needed to overcome the limitations of the presented RF-MEMS device are also discussed.

Flexible Chip Scale Package and Interconnect for Implantable MEMS Movable Microelectrodes for the Brain

PubMed Central

Jackson, Nathan; Muthuswamy, Jit

2009-01-01

We report here a novel approach called MEMS microflex interconnect (MMFI) technology for packaging a new generation of Bio-MEMS devices that involve movable microelectrodes implanted in brain tissue. MMFI addresses the need for (i) operating space for movable parts and (ii) flexible interconnects for mechanical isolation. We fabricated a thin polyimide substrate with embedded bond-pads, vias, and conducting traces for the interconnect with a backside dry etch, so that the flexible substrate can act as a thin-film cap for the MEMS package. A double gold stud bump rivet bonding mechanism was used to form electrical connections to the chip and also to provide a spacing of approximately 15–20 µm for the movable parts. The MMFI approach achieved a chip scale package (CSP) that is lightweight, biocompatible, having flexible interconnects, without an underfill. Reliability tests demonstrated minimal increases of 0.35 mΩ, 0.23 mΩ and 0.15 mΩ in mean contact resistances under high humidity, thermal cycling, and thermal shock conditions respectively. High temperature tests resulted in an increase in resistance of > 90 mΩ when aluminum bond pads were used, but an increase of ~ 4.2 mΩ with gold bond pads. The mean-time-to-failure (MTTF) was estimated to be at least one year under physiological conditions. We conclude that MMFI technology is a feasible and reliable approach for packaging and interconnecting Bio-MEMS devices. PMID:20160981

MEMS-Based Satellite Micropropulsion Via Catalyzed Hydrogen Peroxide Decomposition

NASA Technical Reports Server (NTRS)

Hitt, Darren L.; Zakrzwski, Charles M.; Thomas, Michael A.; Bauer, Frank H. (Technical Monitor)

2001-01-01

Micro-electromechanical systems (MEMS) techniques offer great potential in satisfying the mission requirements for the next generation of "micro-scale" satellites being designed by NASA and Department of Defense agencies. More commonly referred to as "nanosats", these miniature satellites feature masses in the range of 10-100 kg and therefore have unique propulsion requirements. The propulsion systems must be capable of providing extremely low levels of thrust and impulse while also satisfying stringent demands on size, mass, power consumption and cost. We begin with an overview of micropropulsion requirements and some current MEMS-based strategies being developed to meet these needs. The remainder of the article focuses the progress being made at NASA Goddard Space Flight Center towards the development of a prototype monopropellant MEMS thruster which uses the catalyzed chemical decomposition of high concentration hydrogen peroxide as a propulsion mechanism. The products of decomposition are delivered to a micro-scale converging/diverging supersonic nozzle which produces the thrust vector; the targeted thrust level approximately 500 N with a specific impulse of 140-180 seconds. Macro-scale hydrogen peroxide thrusters have been used for satellite propulsion for decades; however, the implementation of traditional thruster designs on a MEMS scale has uncovered new challenges in fabrication, materials compatibility, and combustion and hydrodynamic modeling. A summary of the achievements of the project to date is given, as is a discussion of remaining challenges and future prospects.

An integrated microcombustor and photonic crystal emitter for thermophotovoltaics

NASA Astrophysics Data System (ADS)

Chan, Walker R.; Stelmakh, Veronika; Allmon, William R.; Waits, Christopher M.; Soljacic, Marin; Joannopoulos, John D.; Celanovic, Ivan

2016-11-01

Thermophotovoltaic (TPV) energy conversion is appealing for portable millimeter- scale generators because of its simplicity, but it relies on a high temperatures. The performance and reliability of the high-temperature components, a microcombustor and a photonic crystal emitter, has proven challenging because they are subjected to 1000-1200°C and stresses arising from thermal expansion mismatches. In this paper, we adopt the industrial process of diffusion brazing to fabricate an integrated microcombustor and photonic crystal by bonding stacked metal layers. Diffusion brazing is simpler and faster than previous approaches of silicon MEMS and welded metal, and the end result is more robust.

Novel Vertical Interconnects With 180 Degree Phase Shift for Amplifiers, Filters, and Integrated Antennas

NASA Technical Reports Server (NTRS)

Goverdhanam, Kavita; Simons, Rainee N.; Katehi, Linda P. B.; Burke, Thomas P. (Technical Monitor)

2001-01-01

In this paper, novel low loss, wide-band coplanar stripline technology for RF/microwave integrated circuits is demonstrated on high resistivity silicon wafer. In particular, the fabrication process for the deposition of spin-on-glass (SOG) as a dielectric layer, the etching of microvias for the vertical interconnects, the design methodology for the multiport circuits and their measured/simulated characteristics are graphically illustrated. The study shows that circuits with very low loss, large bandwidth and compact size are feasible using this technology. This multilayer planar technology has potential to significantly enhance RF/microwave IC performance when combined with semiconductor devices and microelectromechanical systems (MEMS).

Lithographic microfabrication of biocompatible polymers for tissue engineering and lab-on-a-chip applications

NASA Astrophysics Data System (ADS)

Balciunas, Evaldas; Jonusauskas, Linas; Valuckas, Vytautas; Baltriukiene, Daiva; Bukelskiene, Virginija; Gadonas, Roaldas; Malinauskas, Mangirdas

2012-06-01

In this work, a combination of Direct Laser Writing (DLW), PoliDiMethylSiloxane (PDMS) soft lithography and UV lithography was used to create cm- scale microstructured polymer scaolds for cell culture experiments out of dierent biocompatible materials: novel hybrid organic-inorganic SZ2080, PDMS elastomer, biodegradable PEG- DA-258 and SU-8. Rabbit muscle-derived stem cells were seeded on the fabricated dierent periodicity scaolds to evaluate if the relief surface had any eect on cell proliferation. An array of microlenses was fabricated using DLW out of SZ2080 and replicated in PDMS and PEG-DA-258, showing good potential applicability of the used techniques in many other elds like micro- and nano- uidics, photonics, and MicroElectroMechanical Systems (MEMS). The synergetic employment of three dierent fabrication techniques allowed to produce desired objects with low cost, high throughput and precision as well as use materials that are dicult to process by other means (PDMS and PEG-DA-258). DLW is a relatively slow fabrication method, since the object has to be written point-by-point. By applying PDMS soft lithography, we were enabled to replicate laser-fabricated scaolds for stem cell growth and micro-optical elements for lab-on-a-chip applications with high speed, low cost and good reproducible quality.

Integrative Bioengineering Institute

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eddington, David; Magin,L,Richard; Hetling, John

2009-01-09

Microfabrication enables many exciting experimental possibilities for medicine and biology that are not attainable through traditional methods. However, in order for microfabricated devices to have an impact they must not only provide a robust solution to a current unmet need, but also be simple enough to seamlessly integrate into standard protocols. Broad dissemination of bioMEMS has been stymied by the common aim of replacing established and well accepted protocols with equally or more complex devices, methods, or materials. The marriage of a complex, difficult to fabricate bioMEMS device with a highly variable biological system is rarely successful. Instead, the designmore » philosophy of my lab aims to leverage a beneficial microscale phenomena (e.g. fast diffusion at the microscale) within a bioMEMS device and adapt to established methods (e.g. multiwell plate cell culture) and demonstrate a new paradigm for the field (adapt instead of replace). In order for the field of bioMEMS to mature beyond novel proof-of-concept demonstrations, researchers must focus on developing systems leveraging these phenomena and integrating into standard labs, which have largely been ignored. Towards this aim, the Integrative Bioengineering Institute has been established.« less

Temperature-dependent mechanical behavior of silicon dioxide, gold and gold-vanadium thin films for VLSI integrated circuits and MicroElectroMechanical systems (MEMs)

NASA Astrophysics Data System (ADS)

Lin, Ming-Tzer

The Semiconductor Industry has grown rapidly in the last twenty years. The national technology roadmap for semiconductors plans for developing the complexity and packing density of semiconductor devices into the next decade, allowing ever smaller and more densely packed structures to be fabricated. Recently, MEMS (Micro-Electro-Mechanical Systems) have become important in modern technology. The goal of MEMs is to integrate many types of miniature devices on a single chip, creating a new micro-world. The oxidation of silicon is one of the most important processes in semiconductor technology. Producing high-quality IC's and MEMS devices requires an understanding of the basic oxidation mechanism. In addition, for the reliability of IC's and MEMS devices, the mechanical properties of the oxide play a critical role. There has been an apparent convergence of opinion on the relevant mechanism leading to the "standard computational model" for stress effects on silicon oxidation. This model has recently become suspect. Most of the reasonably direct experimental data on the flow properties of SiO 2 thin film do not support a stress-dependent viscosity of the sort envisioned by the model. Gold and gold vanadium alloys are used in electrical interconnections and in radio frequency switch contacts for the semiconductor industry, MEMs sensors for the aerospace industry and also in brain probes by the bioelectronics mechanical industry. Despite the strong potential usage of gold and gold vanadium thin films at the small scale, very little is known about their mechanical properties. Our goal was to experimentally investigate stress and its influence on SiO2 thin films and the mechanical properties of gold and gold vanadium thin films at room temperature and at elevated temperature of different vanadium concentration. We found that the application of relatively small amounts of bending to an oxidizing silicon substrate leads to significant decreases in oxide thickness in the ultrathin oxide regime. Both tensile and compressive bending retard oxide growth, although compressive bending results in somewhat thinner oxides than does tensile bending. We also determined the modulus of gold and gold vanadium, and discovered that there is some evidence for a vanadium concentration dependence of the mechanical properties.

Microelectromechanical Systems

NASA Technical Reports Server (NTRS)

Gabriel, Kaigham J.

1995-01-01

Micro-electromechanical systems (MEMS) is an enabling technology that merges computation and communication with sensing and actuation to change the way people and machines interact with the physical world. MEMS is a manufacturing technology that will impact widespread applications including: miniature inertial measurement measurement units for competent munitions and personal navigation; distributed unattended sensors; mass data storage devices; miniature analytical instruments; embedded pressure sensors; non-invasive biomedical sensors; fiber-optics components and networks; distributed aerodynamic control; and on-demand structural strength. The long term goal of ARPA's MEMS program is to merge information processing with sensing and actuation to realize new systems and strategies for both perceiving and controlling systems, processes, and the environment. The MEMS program has three major thrusts: advanced devices and processes, system design, and infrastructure.

Pre-release plastic packaging of MEMS and IMEMS devices

DOEpatents

Peterson, Kenneth A.; Conley, William R.

2002-01-01

A method is disclosed for pre-release plastic packaging of MEMS and IMEMS devices. The method can include encapsulating the MEMS device in a transfer molded plastic package. Next, a perforation can be made in the package to provide access to the MEMS elements. The non-ablative material removal process can include wet etching, dry etching, mechanical machining, water jet cutting, and ultrasonic machining, or any combination thereof. Finally, the MEMS elements can be released by using either a wet etching or dry plasma etching process. The MEMS elements can be protected with a parylene protective coating. After releasing the MEMS elements, an anti-stiction coating can be applied. The perforating step can be applied to both sides of the device or package. A cover lid can be attached to the face of the package after releasing any MEMS elements. The cover lid can include a window for providing optical access. The method can be applied to any plastic packaged microelectronic device that requires access to the environment, including chemical, pressure, or temperature-sensitive microsensors; CCD chips, photocells, laser diodes, VCSEL's, and UV-EPROMS. The present method places the high-risk packaging steps ahead of the release of the fragile portions of the device. It also provides protection for the die in shipment between the molding house and the house that will release the MEMS elements and subsequently treat the surfaces.

Sputtered highly oriented PZT thin films for MEMS applications

NASA Astrophysics Data System (ADS)

Kalpat, Sriram S.

Recently there has been an explosion of interest in the field of micro-electro-mechanical systems (MEMS). MEMS device technology has become critical in the growth of various fields like medical, automotive, chemical, and space technology. Among the many applications of ferroelectric thin films in MEMS devices, microfluidics is a field that has drawn considerable amount of research from bio-technology industries as well as chemical and semiconductor manufacturing industries. PZT thin films have been identified as best suited materials for micro-actuators and micro-sensors used in MEMS devices. A promising application for piezoelectric thin film based MEMS devices is disposable drug delivery systems that are capable of sensing biological parameters, mixing and delivering minute and precise amounts of drugs using micro-pumps or micro mixers. These devices call for low driving voltages, so that they can be battery operated. Improving the performance of the actuator material is critical in achieving battery operated disposal drug delivery systems. The device geometry and power consumption in MEMS devices largely depends upon the piezoelectric constant of the films, since they are most commonly used to convert electrical energy into a mechanical response of a membrane or cantilever and vice versa. Phenomenological calculation on the crystal orientation dependence of piezoelectric coefficients for PZT single crystal have reported a significant enhancement of the piezoelectric d33 constant by more than 3 times along [001] in the rhombohedral phase as compared to the conventionally used orientation PZT(111) since [111] is the along the spontaneous polarization direction. This could mean considerable improvement in the MEMS device performance and help drive the operating voltages lower. The motivation of this study is to investigate the crystal orientation dependence of both dielectric and piezoelectric coefficients of PZT thin films in order to select the appropriate orientation that could improve the MEMS device performance. Potential application of these devices is as battery operated disposable drug delivery systems. This work will also investigate the fabrication of a flexural plate wave based microfluidic device using the PZT thin film of appropriate orientation that would enhance the device performance. (Abstract shortened by UMI.)

Design and grayscale fabrication of beamfanners in a silicon substrate

NASA Astrophysics Data System (ADS)

Ellis, Arthur Cecil

2001-11-01

This dissertation addresses important first steps in the development of a grayscale fabrication process for multiple phase diffractive optical elements (DOS's) in silicon. Specifically, this process was developed through the design, fabrication, and testing of 1-2 and 1-4 beamfanner arrays for 5-micron illumination. The 1-2 beamfanner arrays serve as a test-of- concept and basic developmental step toward the construction of the 1-4 beamfanners. The beamfanners are 50 microns wide, and have features with dimensions of between 2 and 10 microns. The Iterative Annular Spectrum Approach (IASA) method, developed by Steve Mellin of UAH, and the Boundary Element Method (BEM) are the design and testing tools used to create the beamfanner profiles and predict their performance. Fabrication of the beamfanners required the techniques of grayscale photolithography and reactive ion etching (RIE). A 2-3micron feature size 1-4 silicon beamfanner array was fabricated, but the small features and contact photolithographic techniques available prevented its construction to specifications. A second and more successful attempt was made in which both 1-4 and 1-2 beamfanner arrays were fabricated with a 5-micron minimum feature size. Photolithography for the UAH array was contracted to MEMS-Optical of Huntsville, Alabama. A repeatability study was performed, using statistical techniques, of 14 photoresist arrays and the subsequent RIE process used to etch the arrays in silicon. The variance in selectivity between the 14 processes was far greater than the variance between the individual etched features within each process. Specifically, the ratio of the variance of the selectivities averaged over each of the 14 etch processes to the variance of individual feature selectivities within the processes yielded a significance level below 0.1% by F-test, indicating that good etch-to-etch process repeatability was not attained. One of the 14 arrays had feature etch-depths close enough to design specifications for optical testing, but 5- micron IR illumination of the 1-4 and 1-2 beamfanners yielded no convincing results of beam splitting in the detector plane 340 microns from the surface of the beamfanner array.

Surface chemistry and tribology of MEMS.

PubMed

Maboudian, Roya; Carraro, Carlo

2004-01-01

The microscopic length scale and high surface-to-volume ratio, characteristic of microelectro-mechanical systems (MEMS), dictate that surface properties are of paramount importance. This review deals with the effects of surface chemical treatments on tribological properties (adhesion, friction, and wear) of MEMS devices. After a brief review of materials and processes that are utilized in MEMS technology, the relevant tribological and chemical issues are discussed. Various MEMS microinstruments are discussed, which are commonly employed to perform adhesion, friction, and wear measurements. The effects of different surface treatments on the reported tribological properties are discussed.

Fabrication technology of CNT-Nickel Oxide based planar pseudocapacitor for MEMS and NEMS

NASA Astrophysics Data System (ADS)

Lebedev, E. A.; Kitsyuk, E. P.; Gavrilin, I. M.; Gromov, D. G.; Gruzdev, N. E.; Gavrilov, S. A.; Dronov, A. A.; Pavlov, A. A.

2015-11-01

Fabrication technology of planar pseudocapacitor (PsC) based on carbon nanotube (CNT) forest, synthesized using plasma enhanced chemical vapor deposition (PECVD) method, covered with thin nickel oxide layer deposited by successive ionic layer adsorption and reaction (SILAR) method, is demonstrated. Dependences of deposited oxide layers thickness on device specific capacities is studied. It is shown that pseudocapacity of nickel oxide thin layer increases specific capacity of the CNT's based device up to 2.5 times.

Structure and Fabrication of a Microscale Flow-Rate/Skin Friction Sensor

NASA Technical Reports Server (NTRS)

Chandrasekharan, Vijay (Inventor); Sells, Jeremy (Inventor); Sheplak, Mark (Inventor); Arnold, David P. (Inventor)

2014-01-01

A floating element shear sensor and method for fabricating the same are provided. According to an embodiment, a microelectromechanical systems (MEMS)-based capacitive floating element shear stress sensor is provided that can achieve time-resolved turbulence measurement. In one embodiment, a differential capacitive transduction scheme is used for shear stress measurement. The floating element structure for the differential capacitive transduction scheme incorporates inter digitated comb fingers forming differential capacitors, which provide electrical output proportional to the floating element deflection.

3D Microfabrication Using Emulsion Mask Grayscale Photolithography Technique

NASA Astrophysics Data System (ADS)

Lee, Tze Pin; Mohamed, Khairudin

2016-02-01

Recently, the rapid development of technology such as biochips, microfluidic, micro-optical devices and micro-electromechanical-systems (MEMS) demands the capability to create complex design of three-dimensional (3D) microstructures. In order to create 3D microstructures, the traditional photolithography process often requires multiple photomasks to form 3D pattern from several stacked photoresist layers. This fabrication method is extremely time consuming, low throughput, costly and complicated to conduct for high volume manufacturing scale. On the other hand, next generation lithography such as electron beam lithography (EBL), focused ion beam lithography (FIB) and extreme ultraviolet lithography (EUV) are however too costly and the machines require expertise to setup. Therefore, the purpose of this study is to develop a simplified method in producing 3D microstructures using single grayscale emulsion mask technique. By using this grayscale fabrication method, microstructures of thickness as high as 500μm and as low as 20μm are obtained in a single photolithography exposure. Finally, the fabrication of 3D microfluidic channel has been demonstrated by using this grayscale photolithographic technique.

Nondestructive surface profiling of hidden MEMS using an infrared low-coherence interferometric microscope

NASA Astrophysics Data System (ADS)

Krauter, Johann; Osten, Wolfgang

2018-03-01

There are a wide range of applications for micro-electro-mechanical systems (MEMS). The automotive and consumer market is the strongest driver for the growing MEMS industry. A 100 % test of MEMS is particularly necessary since these are often used for safety-related purposes such as the ESP (Electronic Stability Program) system. The production of MEMS is a fully automated process that generates 90 % of the costs during the packaging and dicing steps. Nowadays, an electrical test is carried out on each individual MEMS component before these steps. However, after encapsulation, MEMS are opaque to visible light and other defects cannot be detected. Therefore, we apply an infrared low-coherence interferometer for the topography measurement of those hidden structures. A lock-in algorithm-based method is shown to calculate the object height and to reduce ghost steps due to the 2π -unambiguity. Finally, measurements of different MEMS-based sensors are presented.

Recent Advances in High-Resolution MEMS DM Fabrication and Integration

DTIC Science & Technology

2010-09-01

MOEMS , [8], 031308-031308, (2009). [2] Macintosh B, Graham J, Palmer D, Doyon R, Gavel D, Larkin J, Oppenheimer B, Saddlemyer L, Wallace JK, Bauman B... MOEMS , [8], 033040-033014, (2009). [6] Smith JC, Sanchez DJ, Oesch DW, Engstrom N, AgrguelloLoretta, Tewksbury-Christle CM, Vitayaudom KP, Kelly PR

Carbon nanoparticle doped micro-patternable nano-composites for wearable sensing applications (Conference Presentation)

NASA Astrophysics Data System (ADS)

Khosla, Ajit

2017-04-01

This talk focuses on preparation, characterization and micropatterning of electrically conducting KETJENBLACK carbon black nanoparticle (80 nm-diameter) doped Polydimethylsiloxane (PDMS) by employing extrusion mixing. Previously, we had reported fabrication of various micropatternable nanocomposites for wearable sensing applications vis solvent assisted ultrasonic mixing technique[1-16] . Extrusion mixing has an advantage as no organic solvents are used and homogenous dispersion of carbon nanoparticles is observed, which is confirmed by SEM analysis. The developed nanocomposite can be micropatterened using standard microfabrication techniques. It is also observed that percolation threshold occurs at 0.51 wt% of carbon nanoparticles in polymer matrix. Examples of developed nano-composites for wearable sensing applications for precision medicine will also be discussed. References: 1.http://summit.sfu.ca/item/12017 A. Khosla. Micropatternable multifunctional nanocomposite polymers for flexible soft MEMS applications. Diss. Applied Science: School of Engineering Science, 2011. 2. A. Khosla ; B. L. Gray; Fabrication of multiwalled carbon nanotube polydimethylsiloxne nanocomposite polymer flexible microelectrodes for microfluidics and MEMS. Proc. SPIE 7642, Electroactive Polymer Actuators and Devices (EAPAD) 2010, 76421V (April 09, 2010); doi:10.1117/12.847292. 3. Ang Li ; Ajit Khosla ; Connie Drewbrook ; Bonnie L. Gray; Fabrication and testing of thermally responsive hydrogel-based actuators using polymer heater elements for flexible microvalves. Proc. SPIE 7929, Microfluidics, BioMEMS, and Medical Microsystems IX, 79290G (February 14, 2011); doi:10.1117/12.873197. 4. Khosla, A. and Gray, B. L. (2010), Preparation, Micro-Patterning and Electrical Characterization of Functionalized Carbon-Nanotube Polydimethylsiloxane Nanocomposite Polymer. Macromol. Symp., 297: 210-218. doi:10.1002/masy.200900165 5. A. Khosla ; D. Hilbich ; C. Drewbrook ; D. Chung ; B. L. Gray; Large scale micropatterning of multi-walled carbon nanotube/polydimethylsiloxane nanocomposite polymer on highly flexible 12×24 inch substrates. Proc. SPIE 7926, Micromachining and Microfabrication Process Technology XVI, 79260L (February 15, 2011); doi:10.1117/12.876738. 6. A. Khosla, and Bonnie L. Gray. "(Invited) Micropatternable Multifunctional Nanocomposite Polymers for Flexible Soft NEMS and MEMS Applications." ECS Transactions 45.3 (2012): 477-494. doi: 10.1149/1.3700913 7. Khosla, Ajit. "Nanoparticle-doped electrically-conducting polymers for flexible nano-micro Systems." Electrochemical Society Interface 21.3-4 (2012): 67-70. 8. Ajit Khosla; Smart garments in chronic disease management: progress and challenges. Proc. SPIE 8548, Nanosystems in Engineering and Medicine, 85482O (October 24, 2012); doi:10.1117/12.979667. 9. D. Chung ; A. Khosla ; B. L. Gray; Screen printable flexible conductive nanocomposite polymer with applications to wearable sensors. Proc. SPIE 9060, Nanosensors, Biosensors, and Info-Tech Sensors and Systems 2014, 90600U (April 16, 2014); doi:10.1117/12.2046548. 10. Daehan Chung ; Sam Seyfollahi ; Ajit Khosla ; Bonnie Gray ; Ash Parameswaran ; Ramani Ramaseshan ; Kirpal Kohli; Initial experiments with flexible conductive electrodes for potential applications in cancer tissue screening. Proc. SPIE 7929, Microfluidics, BioMEMS, and Medical Microsystems IX, 79290Z (February 14, 2011); doi:10.1117/12.875563. 11. A. Khosla ; B. L. Gray; New technologies for large-scale micropatterning of functional nanocomposite polymers. Proc. SPIE 8344, Nanosensors, Biosensors, and Info-Tech Sensors and Systems 2012, 83440W (April 26, 2012); doi:10.1117/12.915178. 12. A. Khosla, B.L. Gray, Preparation, characterization and micromolding of multi-walled carbon nanotube polydimethylsiloxane conducting nanocomposite polymer, Materials Letters, Volume 63, Issues 13-14, 31 May 2009, Pages 1203-1206, ISSN 0167-577X, http://dx.doi.org/10.1016/j.matlet.2009.02.043. 13. Giassa, M., Khosla, A., Gray, B. et al. J Electron Test (2010) 26: 139. doi:10.1007/s10836-009-5125-3 14.Ozhikandathil, Jayan, Ajit Khosla, and Muthukumaran Packirisamy. "Electrically Conducting PDMS Nanocomposite Using In Situ Reduction of Gold Nanostructures and Mechanical Stimulation of Carbon Nanotubes and Silver Nanoparticles." ECS Journal of Solid State Science and Technology 4.10 (2015): S3048-S3052. doi:10.1149/2.0091510jss 15. Kassegne, Sam, Maria Vomero, Roberto Gavuglio, Mieko Hirabayashi, Emre Özyilmaz, Sebastien Nguyen, Jesus Rodriguez, Eda Özyilmaz, Pieter van Niekerk, and Ajit Khosla. "Electrical impedance, electrochemistry, mechanical stiffness, and hardness tunability in glassy carbon MEMS μECoG electrodes." Microelectronic Engineering 133 (2015): 36-44. 16. A. Khosla ; B. L. Gray; Fabrication and properties of conductive micromoldable thermosetting polymer for electronic routing in highly flexible microfluidic systems. Proc. SPIE 7593, Microfluidics, BioMEMS, and Medical Microsystems VIII, 759314 (February 17, 2010); doi:10.1117/12.840911.