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Sample records for active semiconductor devices

  1. Unitary lens semiconductor device

    DOEpatents

    Lear, K.L.

    1997-05-27

    A unitary lens semiconductor device and method are disclosed. The unitary lens semiconductor device is provided with at least one semiconductor layer having a composition varying in the growth direction for unitarily forming one or more lenses in the semiconductor layer. Unitary lens semiconductor devices may be formed as light-processing devices such as microlenses, and as light-active devices such as light-emitting diodes, photodetectors, resonant-cavity light-emitting diodes, vertical-cavity surface-emitting lasers, and resonant cavity photodetectors. 9 figs.

  2. Unitary lens semiconductor device

    DOEpatents

    Lear, Kevin L.

    1997-01-01

    A unitary lens semiconductor device and method. The unitary lens semiconductor device is provided with at least one semiconductor layer having a composition varying in the growth direction for unitarily forming one or more lenses in the semiconductor layer. Unitary lens semiconductor devices may be formed as light-processing devices such as microlenses, and as light-active devices such as light-emitting diodes, photodetectors, resonant-cavity light-emitting diodes, vertical-cavity surface-emitting lasers, and resonant cavity photodetectors.

  3. Interconnected semiconductor devices

    DOEpatents

    Grimmer, Derrick P.; Paulson, Kenneth R.; Gilbert, James R.

    1990-10-23

    Semiconductor layer and conductive layer formed on a flexible substrate, divided into individual devices and interconnected with one another in series by interconnection layers and penetrating terminals.

  4. Introduction to Semiconductor Devices

    NASA Astrophysics Data System (ADS)

    Brennan, Kevin F.

    2005-03-01

    This volume offers a solid foundation for understanding the most important devices used in the hottest areas of electronic engineering today, from semiconductor fundamentals to state-of-the-art semiconductor devices in the telecommunications and computing industries. Kevin Brennan describes future approaches to computing hardware and RF power amplifiers, and explains how emerging trends and system demands of computing and telecommunications systems influence the choice, design and operation of semiconductor devices. In addition, he covers MODFETs and MOSFETs, short channel effects, and the challenges faced by continuing miniaturization. His book is both an excellent senior/graduate text and a valuable reference for practicing engineers and researchers.

  5. Survey of cryogenic semiconductor devices

    SciTech Connect

    Talarico, L.J.; McKeever, J.W.

    1996-04-01

    Improved reliability and electronic performance can be achieved in a system operated at cryogenic temperatures because of the reduction in mechanical insult and in disruptive effects of thermal energy on electronic devices. Continuing discoveries of new superconductors with ever increasing values of T{sub c} above that of liquid nitrogen temperature (LNT) have provided incentive for developing semiconductor electronic systems that may also operate in the superconductor`s liquid nitrogen bath. Because of the interest in high-temperature superconductor (HTS) devices, liquid nitrogen is the cryogen of choice and LNT is the temperature on which this review is focused. The purpose of this survey is to locate and assemble published information comparing the room temperature (298 K), performance of commercially available conventional and hybrid semiconductor device with their performance at LNT (77K), to help establish their candidacy as cryogenic electronic devices specifically for use at LNT. The approach to gathering information for this survey included the following activities. Periodicals and proceedings were searched for information on the behavior of semiconductor devices at LNT. Telephone calls were made to representatives of semiconductor industries, to semiconductor subcontractors, to university faculty members prominent for their research in the area of cryogenic semiconductors, and to representatives of the National Aeronautics and Space Administration (NASA) and NASA subcontractors. The sources and contacts are listed with their responses in the introduction, and a list of references appears at the end of the survey.

  6. Field-induced activation of metal oxide semiconductor for low temperature flexible transparent electronic device applications

    NASA Astrophysics Data System (ADS)

    Pudasaini, Pushpa Raj; Noh, Joo Hyon; Wong, Anthony; Haglund, Amada; Ward, Thomas Zac; Mandrus, David; Rack, Philip

    Amorphous metal-oxide semiconductors have been extensively studied as an active channel material in thin film transistors due to their high carrier mobility, and excellent large-area uniformity. Here, we report the athermal activation of amorphous indium gallium zinc oxide semiconductor channels by an electric field-induced oxygen migration via gating through an ionic liquid. Using field-induced activation, a transparent flexible thin film transistor is demonstrated on a polyamide substrate with transistor characteristics having a current ON-OFF ratio exceeding 108, and saturation field effect mobility of 8.32 cm2/(V.s) without a post-deposition thermal treatment. This study demonstrates the potential of field-induced activation as an athermal alternative to traditional post-deposition thermal annealing for metal oxide electronic devices suitable for transparent and flexible polymer substrates. Materials Science and Technology Division, ORBL, Oak Ridge, TN 37831, USA.

  7. Ionic Liquid Activation of Amorphous Metal-Oxide Semiconductors for Flexible Transparent Electronic Devices

    DOE PAGES

    Pudasaini, Pushpa Raj; Noh, Joo Hyon; Wong, Anthony T.; Ovchinnikova, Olga S.; Haglund, Amanda V.; Dai, Sheng; Ward, Thomas Zac; Mandrus, David; Rack, Philip D.

    2016-02-09

    To begin this abstract, amorphous metal-oxide semiconductors offer the high carrier mobilities and excellent large-area uniformity required for high performance, transparent, flexible electronic devices; however, a critical bottleneck to their widespread implementation is the need to activate these materials at high temperatures which are not compatible with flexible polymer substrates. The highly controllable activation of amorphous indium gallium zinc oxide semiconductor channels using ionic liquid gating at room temperature is reported. Activation is controlled by electric field-induced oxygen migration across the ionic liquid-semiconductor interface. In addition to activation of unannealed devices, it is shown that threshold voltages of a transistormore » can be linearly tuned between the enhancement and depletion modes. Finally, the first ever example of transparent flexible thin film metal oxide transistor on a polyamide substrate created using this simple technique is demonstrated. Finally, this study demonstrates the potential of field-induced activation as a promising alternative to traditional postdeposition thermal annealing which opens the door to wide scale implementation into flexible electronic applications.« less

  8. Synchronous semiconductor memory device

    SciTech Connect

    Onno, C.; Hirata, M.

    1989-11-21

    This patent describes a synchronous semiconductor memory device. It comprises: first latch means for latching a write command in synchronism with clock signal; second latch means for latching a write data in synchronism with the clock signal and for outputting two write process signals based on the write data latched thereby; pulse generating means for generating an internal write pulse signal based on the write command latched by the first latch means. The internal write pulse signal having a semiconductor memory device; write control means supplied with the internal write pulse signal and the write process signals for controlling write and read operations of the synchronous semiconductor memory device; memory means for storing the write data latched by the second latch means; and noise preventing means coupled to the second latch means and the write control means for supplying the write process signals to the write control means only in the write mode responsive to the internal write pulse signal and for setting the write process signals to fixed potentials during a time other than the write mode.

  9. Semiconductor structure and devices

    NASA Technical Reports Server (NTRS)

    Dinkel, Nancy A. (Inventor); Goldstein, Bernard (Inventor); Ettenberg, Michael (Inventor)

    1987-01-01

    Semiconductor devices such as lasers which include a substrate with a channel therein with a clad layer overlying the substrate and filling the channel exhibit irregularities such as terraces in the surface of the clad layer which are detrimental to device performance. These irregularities are substantially eliminated by forming the channel in a surface of a buffer layer greater than about 4 micrometers thick on the substrate and forming the clad layer over the buffer layer and the channel. CW lasers incorporating the principles of the invention exhibit the highest output power in a single spatial mode and maximum output power which have been observed to date.

  10. Simulating nanoscale semiconductor devices.

    SciTech Connect

    Salinger, Andrew Gerhard; Zhao, P.; Woolard, D. L.; Kelley, C. Tim; Lasater, Matthew S.

    2005-03-01

    The next generation of electronic devices will be developed at the nanoscale and molecular level, where quantum mechanical effects are observed. These effects must be accounted for in the design process for such small devices. One prototypical nanoscale semiconductor device under investigation is a resonant tunneling diode (RTD). Scientists are hopeful the quantum tunneling effects present in an RTD can be exploited to induce and sustain THz frequency current oscillations. To simulate the electron transport within the RTD, the Wigner-Poisson equations are used. These equations describe the time evolution of the electrons distribution within the device. In this paper, this model and a parameter study using this model will be presented. The parameter study involves calculating the steady-state current output from the RTD as a function of an applied voltage drop across the RTD and also calculating the stability of that solution. To implement the parameter study, the computational model was connected to LOCA (Library of Continuation Algorithms), a part of Sandia National Laboratories parallel solver project, Trilinos. Numerical results will be presented.

  11. Active photonic devices based on colloidal semiconductor nanocrystals and organometallic halide perovskites

    NASA Astrophysics Data System (ADS)

    Suárez Alvarez, Isaac

    2016-10-01

    Semiconductor nanocrystals have arisen as outstanding materials to develop a new generation of optoelectronic devices. Their fabrication under simple and low cost colloidal chemistry methods results in cheap nanostructures able to provide a wide range of optical functionalities. Their attractive optical properties include a high absorption cross section below the band gap, a high quantum yield emission at room temperature, or the capability of tuning the band-gap with the size or the base material. In addition, their solution process nature enables an easy integration on several substrates and photonic structures. As a consequence, these nanoparticles have been extensively proposed to develop several photonic applications, such as detection of light, optical gain, generation of light or sensing. This manuscript reviews the great effort undertaken by the scientific community to construct active photonic devices based on these nanoparticles. The conditions to demonstrate stimulated emission are carefully studied by comparing the dependence of the optical properties of the nanocrystals with their size, shape and composition. In addition, this paper describes the design of different photonic architectures (waveguides and cavities) to enhance the generation of photoluminescence, and hence to reduce the threshold of optical gain. Finally, semiconductor nanocrystals are compared to organometallic halide perovskites, as this novel material has emerged as an alternative to colloidal nanoparticles.

  12. High-speed semiconductor devices

    NASA Astrophysics Data System (ADS)

    Sze, S. M.

    An introduction to the physical principles and operational characteristics of high-speed semiconductor devices is presented. Consideration is given to materials and technologies for high-speed devices, device building blocks, the submicron MOSFET, homogeneous field-effect transistors, and heterostructure field-effect transistors. Also considered are quantum-effect devices, microwave diodes, and high-speed photonic devices.

  13. Semiconductor active plasmonics

    NASA Astrophysics Data System (ADS)

    Mendach, Stefan; Nötzel, Richard

    2013-12-01

    Plasmonics is a research area in nanophotonics attracting increasing interest due to the potential applications in sensing and detecting, sub-wavelength confinement of light, integrated circuits, and many others. In particular, when plasmonic structures such as metal nanostructures or highly doped semiconductor particles are combined with active semiconductor materials and nanostructures, novel exciting physics and applications arise. This special section on semiconductor active plasmonics covers several of the most important and complementary directions in the field. First is the modification of the optical properties of a semiconductor nanostructure due to the close proximity of a metallic film or nanostructure. These arise from the formation hybrid plasmon/exciton states and may lead to enhanced spontaneous emission rates, directional far field emission patterns, strong coupling phenomena, and many more. Second is the realization of sub-wavelength scale nanolasers by coupling a semiconductor gain medium with a plasmonic metallic cavity. Particular emphasis is given on the major technical challenges in the fabrication of these nanolasers, such as device patterning, surface passivation, and metal deposition. While the above topics address mainly active structures and devices operating in the visible or near-infrared wavelength region, in the third, the enhanced THz extinction by periodic arrays of semiconductor particles is discussed. This is based on the build-up of surface plasmon resonances in the doped semiconductor particles which can be resonantly coupled and widely tuned by the carrier density in the semiconductor. We believe these highly diverse aspects give insight into the wide variety of new physics and applications that semiconductor active plasmonics is offering. Finally, we would like to thank the IOP editorial staff, in particular Alice Malhador, for their support, and we would also like to thank the contributors for their efforts and participation

  14. Advanced Semiconductor Devices

    NASA Astrophysics Data System (ADS)

    Shur, Michael S.; Maki, Paul A.; Kolodzey, James

    2007-06-01

    I. Wide band gap devices. Wide-Bandgap Semiconductor devices for automotive applications / M. Sugimoto ... [et al.]. A GaN on SiC HFET device technology for wireless infrastructure applications / B. Green ... [et al.]. Drift velocity limitation in GaN HEMT channels / A. Matulionis. Simulations of field-plated and recessed gate gallium nitride-based heterojunction field-effect transistors / V. O. Turin, M. S. Shur and D. B. Veksler. Low temperature electroluminescence of green and deep green GaInN/GaN light emitting diodes / Y. Li ... [et al.]. Spatial spectral analysis in high brightness GaInN/GaN light emitting diodes / T. Detchprohm ... [et al.]. Self-induced surface texturing of Al2O3 by means of inductively coupled plasma reactive ion etching in Cl2 chemistry / P. Batoni ... [et al.]. Field and termionic field transport in aluminium gallium arsenide heterojunction barriers / D. V. Morgan and A. Porch. Electrical characteristics and carrier lifetime measurements in high voltage 4H-SiC PiN diodes / P. A. Losee ... [et al.]. Geometry and short channel effects on enhancement-mode n-Channel GaN MOSFETs on p and n- GaN/sapphire substrates / W. Huang, T. Khan and T. P. Chow. 4H-SiC Vertical RESURF Schottky Rectifiers and MOSFETs / Y. Wang, P. A. Losee and T. P. Chow. Present status and future Directions of SiGe HBT technology / M. H. Khater ... [et al.]Optical properties of GaInN/GaN multi-quantum Wells structure and light emitting diode grown by metalorganic chemical vapor phase epitaxy / J. Senawiratne ... [et al.]. Electrical comparison of Ta/Ti/Al/Mo/Au and Ti/Al/Mo/Au Ohmic contacts on undoped GaN HEMTs structure with AlN interlayer / Y. Sun and L. F. Eastman. Above 2 A/mm drain current density of GaN HEMTs grown on sapphire / F. Medjdoub ... [et al.]. Focused thermal beam direct patterning on InGaN during molecular beam epitaxy / X. Chen, W. J. Schaff and L. F. Eastman -- II. Terahertz and millimeter wave devices. Temperature-dependent microwave performance of

  15. Semiconductors for high temperature active devices: silicon, GaAs, and GaP. [For use in geothermal wells

    SciTech Connect

    Coquat, J.A.

    1980-01-01

    This paper reviews developments during the past three years in the area of high-temperature active semiconductor devices for use at 275/sup 0/C in instrumentation needed to characterize geothermal resources. Surveys of silicon bipolar, MOS, and JFET devices operated at high temperature and development work on high temperature silicon CMOS logic and DI analog circuits are reviewed. The initial results of developmental work on GaAs and GaP diodes are discussed. These efforts have identified several promising devices for high temperature applications; however, further development is required to resolve such problems as excessive leakage currents, metallization degradation, device stability, and long term aging.

  16. Radiation Effects on Semiconductor Devices

    NASA Astrophysics Data System (ADS)

    Liu, Guangyu

    In order to observe and analyze the behavior of semiconductor devices under radiation exposure, a real time measurement system has been built so that investigations can be carried out before, during, and after radiation exposure. The system consists of an IBM personal computer with IEEE488 I/O interface board and various Hewlett-Packard instruments. Real time measurement and device parameter characterization programs have been written to accommodate the study. Such a system provides the ability to do not only direct and dynamic measurements, but also comprehensive parameter analyses for semiconductor devices. It is well known that MOS devices are vulnerable to radiation produced ionization. Many MOS device parameters are radiation sensitive. Based on real time measurement results and the mathematical model of a CMOS inverter, a radiation hardening design method has been developed. With the example of noise margin optimization, the concept of desensitizing device parameters is expected to minimize radiation damage to MOS integrated circuits.

  17. Mechanical scriber for semiconductor devices

    DOEpatents

    Lin, P.T.

    1985-03-05

    A mechanical scriber using a scribing tip, such as a diamond, provides controlled scriber forces with a spring-loaded compound lever arrangement. The scribing force and range of scribing depth are adjusted by a pair of adjustable micrometer heads. A semiconductor device, such as a multilayer solar cell, can be formed into scribed strips at each layer. 5 figs.

  18. Mechanical scriber for semiconductor devices

    DOEpatents

    Lin, Peter T.

    1985-01-01

    A mechanical scriber using a scribing tip, such as a diamond, provides controlled scriber forces with a spring-loaded compound lever arrangement. The scribing force and range of scribing depth are adjusted by a pair of adjustable micrometer heads. A semiconductor device, such as a multilayer solar cell, can be formed into scribed strips at each layer.

  19. Integrated devices including cleaved semiconductor lasers

    SciTech Connect

    Chen, C.Y.

    1987-11-17

    A process for fabricating a semiconductor device is described comprising semiconductor laser on a semiconductor substrate in which prior to cleaving the semiconductor substrate to form a facet of the semiconductor laser a hole is made in the substrate along the cleave plane so as to produce a stop cleave facet.

  20. Complex-envelope alternating-direction-implicit FDTD method for simulating active photonic devices with semiconductor/solid-state media.

    PubMed

    Singh, Gurpreet; Ravi, Koustuban; Wang, Qian; Ho, Seng-Tiong

    2012-06-15

    A complex-envelope (CE) alternating-direction-implicit (ADI) finite-difference time-domain (FDTD) approach to treat light-matter interaction self-consistently with electromagnetic field evolution for efficient simulations of active photonic devices is presented for the first time (to our best knowledge). The active medium (AM) is modeled using an efficient multilevel system of carrier rate equations to yield the correct carrier distributions, suitable for modeling semiconductor/solid-state media accurately. To include the AM in the CE-ADI-FDTD method, a first-order differential system involving CE fields in the AM is first set up. The system matrix that includes AM parameters is then split into two time-dependent submatrices that are then used in an efficient ADI splitting formula. The proposed CE-ADI-FDTD approach with AM takes 22% of the time as the approach of the corresponding explicit FDTD, as validated by semiconductor microdisk laser simulations.

  1. Semiconductor devices having a recessed electrode structure

    DOEpatents

    Palacios, Tomas Apostol; Lu, Bin; Matioli, Elison de Nazareth

    2015-05-26

    An electrode structure is described in which conductive regions are recessed into a semiconductor region. Trenches may be formed in a semiconductor region, such that conductive regions can be formed in the trenches. The electrode structure may be used in semiconductor devices such as field effect transistors or diodes. Nitride-based power semiconductor devices are described including such an electrode structure, which can reduce leakage current and otherwise improve performance.

  2. Physical Modeling of Activation Energy in Organic Semiconductor Devices based on Energy and Momentum Conservations.

    PubMed

    Mao, Ling-Feng; Ning, H; Hu, Changjun; Lu, Zhaolin; Wang, Gaofeng

    2016-04-22

    Field effect mobility in an organic device is determined by the activation energy. A new physical model of the activation energy is proposed by virtue of the energy and momentum conservation equations. The dependencies of the activation energy on the gate voltage and the drain voltage, which were observed in the experiments in the previous independent literature, can be well explained using the proposed model. Moreover, the expression in the proposed model, which has clear physical meanings in all parameters, can have the same mathematical form as the well-known Meyer-Neldel relation, which lacks of clear physical meanings in some of its parameters since it is a phenomenological model. Thus it not only describes a physical mechanism but also offers a possibility to design the next generation of high-performance optoelectronics and integrated flexible circuits by optimizing device physical parameter.

  3. Physical Modeling of Activation Energy in Organic Semiconductor Devices based on Energy and Momentum Conservations

    PubMed Central

    Mao, Ling-Feng; Ning, H.; Hu, Changjun; Lu, Zhaolin; Wang, Gaofeng

    2016-01-01

    Field effect mobility in an organic device is determined by the activation energy. A new physical model of the activation energy is proposed by virtue of the energy and momentum conservation equations. The dependencies of the activation energy on the gate voltage and the drain voltage, which were observed in the experiments in the previous independent literature, can be well explained using the proposed model. Moreover, the expression in the proposed model, which has clear physical meanings in all parameters, can have the same mathematical form as the well-known Meyer-Neldel relation, which lacks of clear physical meanings in some of its parameters since it is a phenomenological model. Thus it not only describes a physical mechanism but also offers a possibility to design the next generation of high-performance optoelectronics and integrated flexible circuits by optimizing device physical parameter. PMID:27103586

  4. Physical Modeling of Activation Energy in Organic Semiconductor Devices based on Energy and Momentum Conservations

    NASA Astrophysics Data System (ADS)

    Mao, Ling-Feng; Ning, H.; Hu, Changjun; Lu, Zhaolin; Wang, Gaofeng

    2016-04-01

    Field effect mobility in an organic device is determined by the activation energy. A new physical model of the activation energy is proposed by virtue of the energy and momentum conservation equations. The dependencies of the activation energy on the gate voltage and the drain voltage, which were observed in the experiments in the previous independent literature, can be well explained using the proposed model. Moreover, the expression in the proposed model, which has clear physical meanings in all parameters, can have the same mathematical form as the well-known Meyer-Neldel relation, which lacks of clear physical meanings in some of its parameters since it is a phenomenological model. Thus it not only describes a physical mechanism but also offers a possibility to design the next generation of high-performance optoelectronics and integrated flexible circuits by optimizing device physical parameter.

  5. Heating device for semiconductor wafers

    DOEpatents

    Vosen, S.R.

    1999-07-27

    An apparatus for heat treating semiconductor wafers is disclosed. The apparatus includes a heating device which contains an assembly of light energy sources for emitting light energy onto a wafer. In particular, the light energy sources are positioned such that many different radial heating zones are created on a wafer being heated. For instance, in one embodiment, the light energy sources form a spiral configuration. In an alternative embodiment, the light energy sources appear to be randomly dispersed with respect to each other so that no discernible pattern is present. In a third alternative embodiment of the present invention, the light energy sources form concentric rings. Tuning light sources are then placed in between the concentric rings of light. 4 figs.

  6. Heating device for semiconductor wafers

    DOEpatents

    Vosen, Steven R.

    1999-01-01

    An apparatus for heat treating semiconductor wafers is disclosed. The apparatus includes a heating device which contains an assembly of light energy sources for emitting light energy onto a wafer. In particular, the light energy sources are positioned such that many different radial heating zones are created on a wafer being heated. For instance, in one embodiment, the light energy sources form a spiral configuration. In an alternative embodiment, the light energy sources appear to be randomly dispersed with respect to each other so that no discernable pattern is present. In a third alternative embodiment of the present invention, the light energy sources form concentric rings. Tuning light sources are then placed in between the concentric rings of light.

  7. Continuous Monitoring of Electrical Activity of Pancreatic β-Cells Using Semiconductor-Based Biosensing Devices

    NASA Astrophysics Data System (ADS)

    Sakata, Toshiya; Sugimoto, Haruyo

    2011-02-01

    The electrical activity of rat pancreatic β-cells caused by introduction of glucose was directly and noninvasively detected using a cell-based field-effect transistor (FET). Rat pancreatic β-cells were adhered to the gate sensing surface of the cell-based FET. The principle of cell-based FETs is based on the detection of charge density changes such as pH variation at the interface between the cell membrane and the gate surface. The gate surface potential of pancreatic β-cell-based FET increased continuously after introduction of glucose at a high concentration of 10 mg/ml. This result indicates that the electrical activity of β-cells was successfully monitored on the basis of pH changes, i.e., increase in the concentration of hydrogen ions, at the cell/gate interface using the pancreatic β-cell-based FET. We assume that the pH variation based on hydrogen ion accumulation at the cell/gate interface was induced by activation of respiration accompanied by insulin secretion process following glucose addition. The platform based on the field-effect devices is suitable for application in a real-time, noninvasive, and label-free detection system for cell functional analyses.

  8. Improved Thermoelectric Devices: Advanced Semiconductor Materials for Thermoelectric Devices

    SciTech Connect

    2009-12-11

    Broad Funding Opportunity Announcement Project: Phononic Devices is working to recapture waste heat and convert it into usable electric power. To do this, the company is using thermoelectric devices, which are made from advanced semiconductor materials that convert heat into electricity or actively remove heat for refrigeration and cooling purposes. Thermoelectric devices resemble computer chips, and they manage heat by manipulating the direction of electrons at the nanoscale. These devices aren’t new, but they are currently too inefficient and expensive for widespread use. Phononic Devices is using a high-performance, cost-effective thermoelectric design that will improve the device’s efficiency and enable electronics manufacturers to more easily integrate them into their products.

  9. Radiation-Hardness Data For Semiconductor Devices

    NASA Technical Reports Server (NTRS)

    Price, W. E.; Nichols, D. K.; Brown, S. F.; Gauthier, M. K.; Martin, K. E.

    1984-01-01

    Document presents data on and analysis of radiation hardness of various semiconductor devices. Data specifies total-dose radiation tolerance of devices. Volume 1 of report covers diodes, bipolar transistors, field effect transistors, silicon controlled rectifiers and optical devices. Volume 2 covers integrated circuits. Volume 3 provides detailed analysis of data in volumes 1 and 2.

  10. Library Analog Semiconductor Devices SPICE Simulators

    SciTech Connect

    Deveney, Michael F.; Archer, Wendel; Bogdan, Carolyn W.

    1996-07-23

    SPICE-SANDIA.LIB is a library of parameter sets and macromodels of semiconductor devices. They are used with Spice-based (SPICE is a program for electronic circuit analysis) simulators to simulate electronic circuits.

  11. Efficient semiconductor light-emitting device and method

    DOEpatents

    Choquette, K.D.; Lear, K.L.; Schneider, R.P. Jr.

    1996-02-20

    A semiconductor light-emitting device and method are disclosed. The semiconductor light-emitting device is provided with at least one control layer or control region which includes an annular oxidized portion thereof to channel an injection current into the active region, and to provide a lateral refractive index profile for index guiding the light generated within the device. A periodic composition grading of at least one of the mirror stacks in the device provides a reduced operating voltage of the device. The semiconductor light-emitting device has a high efficiency for light generation, and may be formed either as a resonant-cavity light-emitting diode (RCLED) or as a vertical-cavity surface-emitting laser (VCSEL). 12 figs.

  12. Efficient semiconductor light-emitting device and method

    DOEpatents

    Choquette, Kent D.; Lear, Kevin L.; Schneider, Jr., Richard P.

    1996-01-01

    A semiconductor light-emitting device and method. The semiconductor light-emitting device is provided with at least one control layer or control region which includes an annular oxidized portion thereof to channel an injection current into the active region, and to provide a lateral refractive index profile for index guiding the light generated within the device. A periodic composition grading of at least one of the mirror stacks in the device provides a reduced operating voltage of the device. The semiconductor light-emitting device has a high efficiency for light generation, and may be formed either as a resonant-cavity light-emitting diode (RCLED) or as a vertical-cavity surface-emitting laser (VCSEL).

  13. Optical processing for semiconductor device fabrication

    NASA Technical Reports Server (NTRS)

    Sopori, Bhushan L.

    1994-01-01

    A new technique for semiconductor device processing is described that uses optical energy to produce local heating/melting in the vicinity of a preselected interface of the device. This process, called optical processing, invokes assistance of photons to enhance interface reactions such as diffusion and melting, as compared to the use of thermal heating alone. Optical processing is performed in a 'cold wall' furnace, and requires considerably lower energies than furnace or rapid thermal annealing. This technique can produce some device structures with unique properties that cannot be produced by conventional thermal processing. Some applications of optical processing involving semiconductor-metal interfaces are described.

  14. Optical devices featuring nonpolar textured semiconductor layers

    DOEpatents

    Moustakas, Theodore D; Moldawer, Adam; Bhattacharyya, Anirban; Abell, Joshua

    2013-11-26

    A semiconductor emitter, or precursor therefor, has a substrate and one or more textured semiconductor layers deposited onto the substrate in a nonpolar orientation. The textured layers enhance light extraction, and the use of nonpolar orientation greatly enhances internal quantum efficiency compared to conventional devices. Both the internal and external quantum efficiencies of emitters of the invention can be 70-80% or higher. The invention provides highly efficient light emitting diodes suitable for solid state lighting.

  15. Whatever happened to silicon carbide. [semiconductor devices

    NASA Technical Reports Server (NTRS)

    Campbell, R. B.

    1981-01-01

    The progress made in silicon carbide semiconductor devices in the 1955 to 1975 time frame is examined and reasons are given for the present lack of interest in the material. Its physical and chemical properties and methods of preparation are discussed. Fabrication techniques and the characteristics of silicon carbide devices are reviewed. It is concluded that a combination of economic factors and the lack of progress in fabrication techniques leaves no viable market for SiC devices in the near future.

  16. Nanoscale Semiconductor Devices as New Biomaterials

    PubMed Central

    Zimmerman, John; Parameswaran, Ramya; Tian, Bozhi

    2016-01-01

    Research on nanoscale semiconductor devices will elicit a novel understanding of biological systems. First, we discuss why it is necessary to build interfaces between cells and semiconductor nanoelectronics. Second, we describe some recent molecular biophysics studies with nanowire field effect transistor sensors. Third, we present the use of nanowire transistors as electrical recording devices that can be integrated into synthetic tissues and targeted intra- or extracellularly to study single cells. Lastly, we discuss future directions and challenges in further developing this area of research, which will advance biology and medicine. PMID:27213041

  17. Architectures for Improved Organic Semiconductor Devices

    NASA Astrophysics Data System (ADS)

    Beck, Jonathan H.

    Advancements in the microelectronics industry have brought increasing performance and decreasing prices to a wide range of users. Conventional silicon-based electronics have followed Moore's law to provide an ever-increasing integrated circuit transistor density, which drives processing power, solid-state memory density, and sensor technologies. As shrinking conventional integrated circuits became more challenging, researchers began exploring electronics with the potential to penetrate new applications with a low price of entry: "Electronics everywhere." The new generation of electronics is thin, light, flexible, and inexpensive. Organic electronics are part of the new generation of thin-film electronics, relying on the synthetic flexibility of carbon molecules to create organic semiconductors, absorbers, and emitters which perform useful tasks. Organic electronics can be fabricated with low energy input on a variety of novel substrates, including inexpensive plastic sheets. The potential ease of synthesis and fabrication of organic-based devices means that organic electronics can be made at very low cost. Successfully demonstrated organic semiconductor devices include photovoltaics, photodetectors, transistors, and light emitting diodes. Several challenges that face organic semiconductor devices are low performance relative to conventional devices, long-term device stability, and development of new organic-compatible processes and materials. While the absorption and emission performance of organic materials in photovoltaics and light emitting diodes is extraordinarily high for thin films, the charge conduction mobilities are generally low. Building highly efficient devices with low-mobility materials is one challenge. Many organic semiconductor films are unstable during fabrication, storage, and operation due to reactions with water, oxygen and hydroxide. A final challenge facing organic electronics is the need for new processes and materials for electrodes

  18. Thermovoltaic semiconductor device including a plasma filter

    DOEpatents

    Baldasaro, Paul F.

    1999-01-01

    A thermovoltaic energy conversion device and related method for converting thermal energy into an electrical potential. An interference filter is provided on a semiconductor thermovoltaic cell to pre-filter black body radiation. The semiconductor thermovoltaic cell includes a P/N junction supported on a substrate which converts incident thermal energy below the semiconductor junction band gap into electrical potential. The semiconductor substrate is doped to provide a plasma filter which reflects back energy having a wavelength which is above the band gap and which is ineffectively filtered by the interference filter, through the P/N junction to the source of radiation thereby avoiding parasitic absorption of the unusable portion of the thermal radiation energy.

  19. International Semiconductor Device Research Symposium (ISDRS-93)

    NASA Astrophysics Data System (ADS)

    Shur, Michael

    1994-04-01

    The goal of this second biannual international meeting was to provide a congenial forum for the exchange of information and new ideas for researchers from university, industry and government laboratories in the field of semiconductor devices and device physics. To this end, we have an unusually short period between the submission of papers and the conference, a speedy publication of the proceedings, poster sessions, panel discussions, and a wide dissemination of the conference proceedings. Our other goal is to make this conference truly international. To achieve this, the symposium has sub-committees in Asia, Europe and the former Soviet Union. This conference is organized in cooperation with the IEEE MTT Society, the European Physical Society, the United States National Committee of URSI and the Russian Physical Society. Generous financial support has been provided by the Army Research Office, the Office of Naval Research, the NASA Ames Research Center and the Soros International Science Foundation. Papers cover a broad range of topics, including novel and ultrasmall devices, photonics and optoelectronics, heterostructure and cryogenic devices, wide band gap semiconductors, thin film transistors, MOSFET technology and devices, carrier transport phenomena, materials and device characterization, simulation and modeling. It is hoped that such a broad range of topics will foster a cross-fertilization of the different fields related to semiconductor materials and devices.

  20. International Semiconductor Device Research Symposium (ISDRS-91)

    NASA Astrophysics Data System (ADS)

    Shur, Michael; Money, John M.

    1992-03-01

    The First International Semiconductor Device Research Symposium took place in Charlottesville, VA, on 4-6 Dec. 1991 for the purpose of providing a convenient forum for the exchange of information and new ideas for researchers from industry, university, and government laboratories with leading researchers from the US, Canada, Europe, Asia, and the former Soviet Union. As the first international conference of its kind to take place after the Aug. 1991 coup attempt in the Soviet Union, it was unique with the presence of an unusually large contingent of Russian scientists. The emphasis of the program was on advanced semiconductor technologies still in their infancy whose tangible technological outcomes are not expected for another five to ten years. Some of the technologies discussed at the symposium included bandgap engineering, large area semiconductor electronics, new millimeter wave and optoelectronic technologies, and silicon carbide and diamond devices.

  1. International Semiconductor Device Research Symposium (ISDRS-91)

    NASA Astrophysics Data System (ADS)

    Shur, Michael

    1992-03-01

    The First International Semiconductor Device Research Symposium (ISDRS-91) took place in Charlottesville, Va on December 4-6, 1991 for the purpose of providing a convenient forum for the exchange of information and new ideas for researchers from industry, university, and government laboratories with leading researchers from the United States, Canada, Europe, Asia, and the former Soviet Union. As the first international conference of its kind to take place after the August 1991 coup attempt in the Soviet Union, it was unique with the presence of an unusually large contingent of Russian scientists. The emphasis of the program was on novel ideas such as advanced semiconductor technologies still in their infancy whose tangible technological outcomes are not expected for another five to ten years. Some of the technologies discussed at the symposium included bandgap engineering, large area semiconductor electronics, new millimeter wave and opto-electronics technologies, and silicon carbide and diamond devices.

  2. Ferromagnet/semiconductor based spintronic devices

    NASA Astrophysics Data System (ADS)

    Saha, Dipankar

    Spintronics is an emerging field which is great interest for its potential to provide high-speed and low-power novel devices and eventually replace and/or complement conventional silicon-based metal-oxide-semiconductor (MOS) devices. Spin-based optoelectronic devices provide improved laser performance and polarized light sources for secure communication. Spintronics has therefore received a lot of interest with the potential for conventional and novel applications. Spintronics has been investigated both in all-metal and semiconductor based platforms. Spin-based ferromagnet/semiconductor heterojunction devices are particularly attractive compared to all-metal spintronic devices due to the versatility and the long electron spin coherence time in semiconductors. Here we have investigated semiconductor based spintronic devices for logic, memory and communication applications. We have demonstrated electrical injection and detection of spin in a MnAs/GaAs lateral spin valve. A peak magnetoresistance of 3.6% at 10 K and 1.1% at 125 K have been measured in these devices. Spin polarization in semiconductors is usually very small and difficult to detect. We have therefore theoretically designed and experimentally demonstrated a spin-current amplifier to alleviate this problem. A spin polarization of 100% has been measured at 150 K in these devices. We have emphasized the importance of finite sizes of ferromagnetic contact pads in terms of two-dimensional spin-diffusion in lateral spintronic devices, which enhances spin-polarization. We have discovered a new phenomenon observing electrically driven spin-dynamics of paramagnetic impurities. We have demonstrated a spin-capacitor using this novel phenomenon. In this study we have also demonstrated a spin-polarized quantum dot spin-laser which is a fundamental spin-based optoelectronic device. An output circular polarization of 8% and threshold current reduction of 14% have been measured at 200 K. We have also demonstrated

  3. Semiconductor device PN junction fabrication using optical processing of amorphous semiconductor material

    SciTech Connect

    Sopori, Bhushan; Rangappan, Anikara

    2014-11-25

    Systems and methods for semiconductor device PN junction fabrication are provided. In one embodiment, a method for fabricating an electrical device having a P-N junction comprises: depositing a layer of amorphous semiconductor material onto a crystalline semiconductor base, wherein the crystalline semiconductor base comprises a crystalline phase of a same semiconductor as the amorphous layer; and growing the layer of amorphous semiconductor material into a layer of crystalline semiconductor material that is epitaxially matched to the lattice structure of the crystalline semiconductor base by applying an optical energy that penetrates at least the amorphous semiconductor material.

  4. General Electronics Technician: Semiconductor Devices and Circuits.

    ERIC Educational Resources Information Center

    Hilley, Robert

    These instructional materials include a teacher's guide designed to assist instructors in organizing and presenting an introductory course in general electronics focusing on semiconductor devices and circuits and a student guide. The materials are based on the curriculum-alignment concept of first stating the objectives, developing instructional…

  5. Semiconductors: In Situ Processing of Photovoltaic Devices

    NASA Technical Reports Server (NTRS)

    Curreri, Peter A.

    1998-01-01

    The possible processing of semiconductor photovoltaic devices is discussed. The requirements for lunar PV cells is reviewed, and the key challenges involved in their manufacturing are investigated. A schematic diagram of a passivated emitter and rear cell (PERC) is presented. The possible fabrication of large photovoltaic arrays in space from lunar materials is also discussed.

  6. Power semiconductor device with negative thermal feedback

    NASA Technical Reports Server (NTRS)

    Borky, J. M.; Thornton, R. D.

    1970-01-01

    Composite power semiconductor avoids second breakdown and provides stable operation. It consists of an array of parallel-connected integrated circuits fabricated in a single chip. The output power device and associated low-level amplifier are closely coupled thermally, so that they have a predetermined temperature relationship.

  7. Methods and devices for fabricating and assembling printable semiconductor elements

    DOEpatents

    Nuzzo, Ralph G.; Rogers, John A.; Menard, Etienne; Lee, Keon Jae; Khang, Dahl-Young; Sun, Yugang; Meitl, Matthew; Zhu, Zhengtao

    2009-11-24

    The invention provides methods and devices for fabricating printable semiconductor elements and assembling printable semiconductor elements onto substrate surfaces. Methods, devices and device components of the present invention are capable of generating a wide range of flexible electronic and optoelectronic devices and arrays of devices on substrates comprising polymeric materials. The present invention also provides stretchable semiconductor structures and stretchable electronic devices capable of good performance in stretched configurations.

  8. Methods and devices for fabricating and assembling printable semiconductor elements

    DOEpatents

    Nuzzo, Ralph G; Rogers, John A; Menard, Etienne; Lee, Keon Jae; Khang, Dahl-Young; Sun, Yugang; Meitl, Matthew; Zhu, Zhengtao

    2014-03-04

    The invention provides methods and devices for fabricating printable semiconductor elements and assembling printable semiconductor elements onto substrate surfaces. Methods, devices and device components of the present invention are capable of generating a wide range of flexible electronic and optoelectronic devices and arrays of devices on substrates comprising polymeric materials. The present invention also provides stretchable semiconductor structures and stretchable electronic devices capable of good performance in stretched configurations.

  9. Methods and devices for fabricating and assembling printable semiconductor elements

    DOEpatents

    Nuzzo, Ralph G; Rogers, John A; Menard, Etienne; Lee, Keon Jae; Khang, Dahl-Young; Sun, Yugang; Meitl, Matthew; Zhu, Zhengtao

    2013-05-14

    The invention provides methods and devices for fabricating printable semiconductor elements and assembling printable semiconductor elements onto substrate surfaces. Methods, devices and device components of the present invention are capable of generating a wide range of flexible electronic and optoelectronic devices and arrays of devices on substrates comprising polymeric materials. The present invention also provides stretchable semiconductor structures and stretchable electronic devices capable of good performance in stretched configurations.

  10. Methods and devices for fabricating and assembling printable semiconductor elements

    DOEpatents

    Nuzzo, Ralph G.; Rogers, John A.; Menard, Etienne; Lee, Keon Jae; Khang, Dahl-Young; Sun, Yugang; Meitl, Matthew; Zhu, Zhengtao

    2011-07-19

    The invention provides methods and devices for fabricating printable semiconductor elements and assembling printable semiconductor elements onto substrate surfaces. Methods, devices and device components of the present invention are capable of generating a wide range of flexible electronic and optoelectronic devices and arrays of devices on substrates comprising polymeric materials. The present invention also provides stretchable semiconductor structures and stretchable electronic devices capable of good performance in stretched configurations.

  11. Refrigeration penalties for crycooling power semiconductor devices

    SciTech Connect

    Ramalingam, M.L.; Donovan, B.D.; Mahefkey, T.

    1995-12-31

    There has been recent interest in the potential applications of cryogenically cooled power electronics, capacitors, and inductors. There are potentially many military and commercial uses for these devices. Preliminary feasibility studies, based on refrigeration thermodynamics, have been conducted for candidate power semiconductor and power conditioning components. While superconducting devices operate at 77K or lower, the present analysis indicates that significant benefits cannot be derived by cooling the various power conditioning components to such low temperatures. It was found that, by operating the power semiconductor component at 150K instead of at 77K, the overall system efficiency was not jeopardized by way of large input power requirements to dissipate small refrigerator loads. This is an acute problem as current cryogenic refrigeration systems allow for very low levels of energy dissipation while performing at about 7 to 10% of the Carnot coefficients of performance (COP) between 300K and 77K.

  12. Semiconductor-based, large-area, flexible, electronic devices

    DOEpatents

    Goyal, Amit

    2011-03-15

    Novel articles and methods to fabricate the same resulting in flexible, large-area, triaxially textured, single-crystal or single-crystal-like, semiconductor-based, electronic devices are disclosed. Potential applications of resulting articles are in areas of photovoltaic devices, flat-panel displays, thermophotovoltaic devices, ferroelectric devices, light emitting diode devices, computer hard disc drive devices, magnetoresistance based devices, photoluminescence based devices, non-volatile memory devices, dielectric devices, thermoelectric devices and quantum dot laser devices.

  13. Semiconductor Device Analysis on Personal Computers

    1993-02-08

    PC-1D models the internal operation of bipolar semiconductor devices by solving for the concentrations and quasi-one-dimensional flow of electrons and holes resulting from either electrical or optical excitation. PC-1D uses the same detailed physical models incorporated in mainframe computer programs, yet runs efficiently on personal computers. PC-1D was originally developed with DOE funding to analyze solar cells. That continues to be its primary mode of usage, with registered copies in regular use at more thanmore » 100 locations worldwide. The program has been successfully applied to the analysis of silicon, gallium-arsenide, and indium-phosphide solar cells. The program is also suitable for modeling bipolar transistors and diodes, including heterojunction devices. Its easy-to-use graphical interface makes it useful as a teaching tool as well.« less

  14. Semiconductor devices incorporating multilayer interference regions

    DOEpatents

    Biefeld, R.M.; Drummond, T.J.; Gourley, P.L.; Zipperian, T.E.

    1987-08-31

    A semiconductor high reflector comprising a number of thin alternating layers of semiconductor materials is electrically tunable and may be used as a temperature insensitive semiconductor laser in a Fabry-Perot configuration. 8 figs.

  15. Semiconductor devices incorporating multilayer interference regions

    DOEpatents

    Biefeld, Robert M.; Drummond, Timothy J.; Gourley, Paul L.; Zipperian, Thomas E.

    1990-01-01

    A semiconductor high reflector comprising a number of thin alternating layers of semiconductor materials is electrically tunable and may be used as a temperature insensitive semiconductor laser in a Fabry-Perot configuration.

  16. Method for fabricating an interconnected array of semiconductor devices

    DOEpatents

    Grimmer, Derrick P.; Paulson, Kenneth R.; Gilbert, James R.

    1989-10-10

    Semiconductor layer and conductive layer formed on a flexible substrate, divided into individual devices and interconnected with one another in series by interconnection layers and penetrating terminals.

  17. Coated semiconductor devices for neutron detection

    DOEpatents

    Klann, Raymond T.; McGregor, Douglas S.

    2002-01-01

    A device for detecting neutrons includes a semi-insulated bulk semiconductor substrate having opposed polished surfaces. A blocking Schottky contact comprised of a series of metals such as Ti, Pt, Au, Ge, Pd, and Ni is formed on a first polished surface of the semiconductor substrate, while a low resistivity ("ohmic") contact comprised of metals such as Au, Ge, and Ni is formed on a second, opposed polished surface of the substrate. In one embodiment, n-type low resistivity pinout contacts comprised of an Au/Ge based eutectic alloy or multi-layered Pd/Ge/Ti/Au are also formed on the opposed polished surfaces and in contact with the Schottky and ohmic contacts. Disposed on the Schottky contact is a neutron reactive film, or coating, for detecting neutrons. The coating is comprised of a hydrogen rich polymer, such as a polyolefin or paraffin; lithium or lithium fluoride; or a heavy metal fissionable material. By varying the coating thickness and electrical settings, neutrons at specific energies can be detected. The coated neutron detector is capable of performing real-time neutron radiography in high gamma fields, digital fast neutron radiography, fissile material identification, and basic neutron detection particularly in high radiation fields.

  18. Skutterudite Compounds For Power Semiconductor Devices

    NASA Technical Reports Server (NTRS)

    Fleurial, Jean-Pierre; Caillat, Thierry; Borshchevsky, Alexander; Vandersande, Jan

    1996-01-01

    New semiconducting materials with p-type carrier mobility values much higher than state-of-art semiconductors discovered. Nine compounds, antimonides CoSb(sub3), RhSb(sub3), IrSb(sub3), arsenides CoAs(sub3), RhAs(sub3), IrAs(sub3), and phosphides CoP(sub3), RhP(sub3) and IrP(sub3), exhibit same skutterudite crystallographic structure and form solid solutions of general composition Co(1-x-y)RH(x)Ir(y)P(1-w-z)As(w)Sb(z). Materials exhibit high hole mobilities, high doping levels, and high electronic figures of merit. Some compositions show great potential for application to thermoelectric devices.

  19. Semiconductor device modeling on a workstation

    SciTech Connect

    Diegert, C.

    1985-09-01

    We choose to move from large mainframe computers to workstations to gain the interactive graphics we need to prepare and to analyze semiconductor device modeling problems. Given this much on a workstation, it is convenient to attempt to solve the entire problem there. We find that a top-of-the-line Apollo 660 workstation, with bit-slice processor, pipelined arithmetic processor, and 4 megabytes of real memory, is surprisingly effective in finding solutions when running the Pisces II device modeling code. In our experiment we find where the workstation bogs down when running these problems. We both analyze the Pisces CPU time log and we sample the executing program to accumulate a histogram of execution time as distributed over the source code. Results suggest how Pisces could be adapted to solve somewhat larger problems entirely on the workstation. Evolution of a trusted derivative of Pisces, to be used on supercomputers without interactivity, is suggested to complement our success with Pisces on workstations. 4 refs.

  20. Zinc Alloys for the Fabrication of Semiconductor Devices

    NASA Technical Reports Server (NTRS)

    Ryu, Yungryel; Lee, Tae S.

    2009-01-01

    ZnBeO and ZnCdSeO alloys have been disclosed as materials for the improvement in performance, function, and capability of semiconductor devices. The alloys can be used alone or in combination to form active photonic layers that can emit over a range of wavelength values. Materials with both larger and smaller band gaps would allow for the fabrication of semiconductor heterostructures that have increased function in the ultraviolet (UV) region of the spectrum. ZnO is a wide band-gap material possessing good radiation-resistance properties. It is desirable to modify the energy band gap of ZnO to smaller values than that for ZnO and to larger values than that for ZnO for use in semiconductor devices. A material with band gap energy larger than that of ZnO would allow for the emission at shorter wavelengths for LED (light emitting diode) and LD (laser diode) devices, while a material with band gap energy smaller than that of ZnO would allow for emission at longer wavelengths for LED and LD devices. The amount of Be in the ZnBeO alloy system can be varied to increase the energy bandgap of ZnO to values larger than that of ZnO. The amount of Cd and Se in the ZnCdSeO alloy system can be varied to decrease the energy band gap of ZnO to values smaller than that of ZnO. Each alloy formed can be undoped or can be p-type doped using selected dopant elements, or can be n-type doped using selected dopant elements. The layers and structures formed with both the ZnBeO and ZnCdSeO semiconductor alloys - including undoped, p-type-doped, and n-type-doped types - can be used for fabricating photonic and electronic semiconductor devices for use in photonic and electronic applications. These devices can be used in LEDs, LDs, FETs (field effect transistors), PN junctions, PIN junctions, Schottky barrier diodes, UV detectors and transmitters, and transistors and transparent transistors. They also can be used in applications for lightemitting display, backlighting for displays, UV and

  1. Optoelectronic semiconductor device and method of fabrication

    DOEpatents

    Cui, Yi; Zhu, Jia; Hsu, Ching-Mei; Fan, Shanhui; Yu, Zongfu

    2014-11-25

    An optoelectronic device comprising an optically active layer that includes a plurality of domes is presented. The plurality of domes is arrayed in two dimensions having a periodicity in each dimension that is less than or comparable with the shortest wavelength in a spectral range of interest. By virtue of the plurality of domes, the optoelectronic device achieves high performance. A solar cell having high energy-conversion efficiency, improved absorption over the spectral range of interest, and an improved acceptance angle is presented as an exemplary device.

  2. Methods of measurement for semiconductor materials, process control, and devices

    NASA Technical Reports Server (NTRS)

    Bullis, W. M. (Editor)

    1972-01-01

    Activities directed toward the development of methods of measurement for semiconductor materials, process control, and devices are described. Topics investigated include: measurements of transistor delay time; application of the infrared response technique to the study of radiation-damaged, lithium-drifted silicon detectors; and identification of a condition that minimizes wire flexure and reduces the failure rate of wire bonds in transistors and integrated circuits under slow thermal cycling conditions. Supplementary data concerning staff, standards committee activities, technical services, and publications are included as appendixes.

  3. Iterative solution of the semiconductor device equations

    SciTech Connect

    Bova, S.W.; Carey, G.F.

    1996-12-31

    Most semiconductor device models can be described by a nonlinear Poisson equation for the electrostatic potential coupled to a system of convection-reaction-diffusion equations for the transport of charge and energy. These equations are typically solved in a decoupled fashion and e.g. Newton`s method is used to obtain the resulting sequences of linear systems. The Poisson problem leads to a symmetric, positive definite system which we solve iteratively using conjugate gradient. The transport equations lead to nonsymmetric, indefinite systems, thereby complicating the selection of an appropriate iterative method. Moreover, their solutions exhibit steep layers and are subject to numerical oscillations and instabilities if standard Galerkin-type discretization strategies are used. In the present study, we use an upwind finite element technique for the transport equations. We also evaluate the performance of different iterative methods for the transport equations and investigate various preconditioners for a few generalized gradient methods. Numerical examples are given for a representative two-dimensional depletion MOSFET.

  4. Optical devices featuring textured semiconductor layers

    DOEpatents

    Moustakas, Theodore D.; Cabalu, Jasper S.

    2011-10-11

    A semiconductor sensor, solar cell or emitter, or a precursor therefor, has a substrate and one or more textured semiconductor layers deposited onto the substrate. The textured layers enhance light extraction or absorption. Texturing in the region of multiple quantum wells greatly enhances internal quantum efficiency if the semiconductor is polar and the quantum wells are grown along the polar direction. Electroluminescence of LEDs of the invention is dichromatic, and results in variable color LEDs, including white LEDs, without the use of phosphor.

  5. Optical devices featuring textured semiconductor layers

    DOEpatents

    Moustakas, Theodore D.; Cabalu, Jasper S.

    2012-08-07

    A semiconductor sensor, solar cell or emitter, or a precursor therefor, has a substrate and one or more textured semiconductor layers deposited onto the substrate. The textured layers enhance light extraction or absorption. Texturing in the region of multiple quantum wells greatly enhances internal quantum efficiency if the semiconductor is polar and the quantum wells are grown along the polar direction. Electroluminescence of LEDs of the invention is dichromatic, and results in variable color LEDs, including white LEDs, without the use of phosphor.

  6. Photovoltaic healing of non-uniformities in semiconductor devices

    DOEpatents

    Karpov, Victor G.; Roussillon, Yann; Shvydka, Diana; Compaan, Alvin D.; Giolando, Dean M.

    2006-08-29

    A method of making a photovoltaic device using light energy and a solution to normalize electric potential variations in the device. A semiconductor layer having nonuniformities comprising areas of aberrant electric potential deviating from the electric potential of the top surface of the semiconductor is deposited onto a substrate layer. A solution containing an electrolyte, at least one bonding material, and positive and negative ions is applied over the top surface of the semiconductor. Light energy is applied to generate photovoltage in the semiconductor, causing a redistribution of the ions and the bonding material to the areas of aberrant electric potential. The bonding material selectively bonds to the nonuniformities in a manner such that the electric potential of the nonuniformities is normalized relative to the electric potential of the top surface of the semiconductor layer. A conductive electrode layer is then deposited over the top surface of the semiconductor layer.

  7. A Semiconductor Device Noise Model: A Deterministic Approach to Semiconductor Device Current Noise for Semiclassical Transport

    SciTech Connect

    Noaman, B. A.; Korman, C. E.

    2009-04-23

    In this paper, we present a deterministic approach to calculate terminal current noise characteristics in semiconductor devices in the framework of semiclassical transport based on the spherical harmonics of the Boltzmann Transport Equation. The model relies on the solution of the Boltzmann equation in the frequency domain with special initial and boundary conditions. The terminal current fluctuation is directly related to scattering without the additional Langevin noise term added to the calculation. Simulation results are presented for the terminal current spectral density for a 1-D n{sup +}nn{sup +} structure due to elastic-acoustic and intervally scattering.

  8. SPICE-SANDIA.LIB. Library Analog Semiconductor Devices SPICE Simulators

    SciTech Connect

    Deveney, M.F.; Archer, W.; Bogdan, C.

    1996-06-06

    SPICE-SANDIA.LIB is a library of parameter sets and macromodels of semiconductor devices. They are used with Spice-based (SPICE is a program for electronic circuit analysis) simulators to simulate electronic circuits.

  9. Separating semiconductor devices from substrate by etching graded composition release layer disposed between semiconductor devices and substrate including forming protuberances that reduce stiction

    SciTech Connect

    Tauke-Pedretti, Anna; Nielson, Gregory N; Cederberg, Jeffrey G; Cruz-Campa, Jose Luis

    2015-05-12

    A method includes etching a release layer that is coupled between a plurality of semiconductor devices and a substrate with an etch. The etching includes etching the release layer between the semiconductor devices and the substrate until the semiconductor devices are at least substantially released from the substrate. The etching also includes etching a protuberance in the release layer between each of the semiconductor devices and the substrate. The etch is stopped while the protuberances remain between each of the semiconductor devices and the substrate. The method also includes separating the semiconductor devices from the substrate. Other methods and apparatus are also disclosed.

  10. Simulation of neutron radiation damage in silicon semiconductor devices.

    SciTech Connect

    Shadid, John Nicolas; Hoekstra, Robert John; Hennigan, Gary Lee; Castro, Joseph Pete Jr.; Fixel, Deborah A.

    2007-10-01

    A code, Charon, is described which simulates the effects that neutron damage has on silicon semiconductor devices. The code uses a stabilized, finite-element discretization of the semiconductor drift-diffusion equations. The mathematical model used to simulate semiconductor devices in both normal and radiation environments will be described. Modeling of defect complexes is accomplished by adding an additional drift-diffusion equation for each of the defect species. Additionally, details are given describing how Charon can efficiently solve very large problems using modern parallel computers. Comparison between Charon and experiment will be given, as well as comparison with results from commercially-available TCAD codes.

  11. Monolayer-Mediated Growth of Organic Semiconductor Films with Improved Device Performance.

    PubMed

    Huang, Lizhen; Hu, Xiaorong; Chi, Lifeng

    2015-09-15

    Increased interest in wearable and smart electronics is driving numerous research works on organic electronics. The control of film growth and patterning is of great importance when targeting high-performance organic semiconductor devices. In this Feature Article, we summarize our recent work focusing on the growth, crystallization, and device operation of organic semiconductors intermediated by ultrathin organic films (in most cases, only a monolayer). The site-selective growth, modified crystallization and morphology, and improved device performance of organic semiconductor films are demonstrated with the help of the inducing layers, including patterned and uniform Langmuir-Blodgett monolayers, crystalline ultrathin organic films, and self-assembled polymer brush films. The introduction of the inducing layers could dramatically change the diffusion of the organic semiconductors on the surface and the interactions between the active layer with the inducing layer, leading to improved aggregation/crystallization behavior and device performance. PMID:25992464

  12. Active terahertz metamaterial devices.

    PubMed

    Chen, Hou-Tong; Padilla, Willie J; Zide, Joshua M O; Gossard, Arthur C; Taylor, Antoinette J; Averitt, Richard D

    2006-11-30

    The development of artificially structured electromagnetic materials, termed metamaterials, has led to the realization of phenomena that cannot be obtained with natural materials. This is especially important for the technologically relevant terahertz (1 THz = 10(12) Hz) frequency regime; many materials inherently do not respond to THz radiation, and the tools that are necessary to construct devices operating within this range-sources, lenses, switches, modulators and detectors-largely do not exist. Considerable efforts are underway to fill this 'THz gap' in view of the useful potential applications of THz radiation. Moderate progress has been made in THz generation and detection; THz quantum cascade lasers are a recent example. However, techniques to control and manipulate THz waves are lagging behind. Here we demonstrate an active metamaterial device capable of efficient real-time control and manipulation of THz radiation. The device consists of an array of gold electric resonator elements (the metamaterial) fabricated on a semiconductor substrate. The metamaterial array and substrate together effectively form a Schottky diode, which enables modulation of THz transmission by 50 per cent, an order of magnitude improvement over existing devices. PMID:17136089

  13. Method for fabricating an interconnected array of semiconductor devices

    NASA Technical Reports Server (NTRS)

    Grimmer, Derrick P. (Inventor)

    1995-01-01

    A method of forming an array of interconnected solar cells. A flexible substrate carrying semiconductor and conductive layers is divided into individual devices by slitting the substrate along the web length. The individual devices are then connected with one another in series by laminating the substrate onto an insulating backing and by depositing conducting interconnection layers which join the lower conductor of one device with the top conductor of the adjoining device.

  14. Tapered rib fiber coupler for semiconductor optical devices

    DOEpatents

    Vawter, Gregory A.; Smith, Robert Edward

    2001-01-01

    A monolithic tapered rib waveguide for transformation of the spot size of light between a semiconductor optical device and an optical fiber or from the fiber into the optical device. The tapered rib waveguide is integrated into the guiding rib atop a cutoff mesa type semiconductor device such as an expanded mode optical modulator or and expanded mode laser. The tapered rib acts to force the guided light down into the mesa structure of the semiconductor optical device instead of being bound to the interface between the bottom of the guiding rib and the top of the cutoff mesa. The single mode light leaving or entering the output face of the mesa structure then can couple to the optical fiber at coupling losses of 1.0 dB or less.

  15. A Thermal and Electrical Analysis of Power Semiconductor Devices

    NASA Technical Reports Server (NTRS)

    Vafai, Kambiz

    1997-01-01

    The state-of-art power semiconductor devices require a thorough understanding of the thermal behavior for these devices. Traditional thermal analysis have (1) failed to account for the thermo-electrical interaction which is significant for power semiconductor devices operating at high temperature, and (2) failed to account for the thermal interactions among all the levels involved in, from the entire device to the gate micro-structure. Furthermore there is a lack of quantitative studies of the thermal breakdown phenomenon which is one of the major failure mechanisms for power electronics. This research work is directed towards addressing. Using a coupled thermal and electrical simulation, in which the drift-diffusion equations for the semiconductor and the energy equation for temperature are solved simultaneously, the thermo-electrical interactions at the micron scale of various junction structures are thoroughly investigated. The optimization of gate structure designs and doping designs is then addressed. An iterative numerical procedure which incorporates the thermal analysis at the device, chip and junction levels of the power device is proposed for the first time and utilized in a BJT power semiconductor device. In this procedure, interactions of different levels are fully considered. The thermal stability issue is studied both analytically and numerically in this research work in order to understand the mechanism for thermal breakdown.

  16. Fabrication of optically reflecting ohmic contacts for semiconductor devices

    DOEpatents

    Sopori, B.L.

    1995-07-04

    A method is provided to produce a low-resistivity ohmic contact having high optical reflectivity on one side of a semiconductor device. The contact is formed by coating the semiconductor substrate with a thin metal film on the back reflecting side and then optically processing the wafer by illuminating it with electromagnetic radiation of a predetermined wavelength and energy level through the front side of the wafer for a predetermined period of time. This method produces a thin epitaxial alloy layer between the semiconductor substrate and the metal layer when a crystalline substrate is used. The alloy layer provides both a low-resistivity ohmic contact and high optical reflectance. 5 figs.

  17. Fabrication of optically reflecting ohmic contacts for semiconductor devices

    DOEpatents

    Sopori, Bhushan L.

    1995-01-01

    A method is provided to produce a low-resistivity ohmic contact having high optical reflectivity on one side of a semiconductor device. The contact is formed by coating the semiconductor substrate with a thin metal film on the back reflecting side and then optically processing the wafer by illuminating it with electromagnetic radiation of a predetermined wavelength and energy level through the front side of the wafer for a predetermined period of time. This method produces a thin epitaxial alloy layer between the semiconductor substrate and the metal layer when a crystalline substrate is used. The alloy layer provides both a low-resistivity ohmic contact and high optical reflectance.

  18. Method of producing strained-layer semiconductor devices via subsurface-patterning

    DOEpatents

    Dodson, Brian W.

    1993-01-01

    A method is described for patterning subsurface features in a semiconductor device, wherein the semiconductor device includes an internal strained layer. The method comprises creating a pattern of semiconductor material over the semiconductor device, the semiconductor material having a predetermined thickness which stabilizes areas of the strained semiconductor layer that lie beneath the pattern. Subsequently, a heating step is applied to the semiconductor device to cause a relaxation in areas of the strained layer which do not lie beneath the semiconductor material pattern, whereby dislocations result in the relaxed areas and impair electrical transport therethrough.

  19. III-V semiconductor devices integrated with silicon III-V semiconductor devices integrated with silicon

    NASA Astrophysics Data System (ADS)

    Hopkinson, Mark; Martin, Trevor; Smowton, Peter

    2013-09-01

    The integration of III-V semiconductor devices with silicon is one of the most topical challenges in current electronic materials research. The combination has the potential to exploit the unique optical and electronic functionality of III-V technology with the signal processing capabilities and advanced low-cost volume production techniques associated with silicon. Key industrial drivers include the use of high mobility III-V channel materials (InGaAs, InAs, InSb) to extend the performance of Si CMOS, the unification of electronics and photonics by combining photonic components (GaAs, InP) with a silicon platform for next-generation optical interconnects and the exploitation of large-area silicon substrates and high-volume Si processing capabilities to meet the challenges of low-cost production, a challenge which is particularly important for GaN-based devices in both power management and lighting applications. The diverse nature of the III-V and Si device approaches, materials technologies and the distinct differences between industrial Si and III-V processing have provided a major barrier to integration in the past. However, advances over the last decade in areas such as die transfer, wafer fusion and epitaxial growth have promoted widespread renewed interest. It is now timely to bring some of these topics together in a special issue covering a range of approaches and materials providing a snapshot of recent progress across the field. The issue opens a paper describing a strategy for the epitaxial integration of photonic devices where Kataria et al describe progress in the lateral overgrowth of InP/Si. As an alternative, Benjoucef and Reithmaier report on the potential of InAs quantum dots grown direct onto Si surfaces whilst Sandall et al describe the properties of similar InAs quantum dots as an optical modulator device. As an alternative to epitaxial integration approaches, Yokoyama et al describe a wafer bonding approach using a buried oxide concept, Corbett

  20. Methods of Measurement for Semiconductor Materials, Process Control, and Devices

    NASA Technical Reports Server (NTRS)

    Bullis, W. M. (Editor)

    1973-01-01

    The development of methods of measurement for semiconductor materials, process control, and devices is reported. Significant accomplishments include: (1) Completion of an initial identification of the more important problems in process control for integrated circuit fabrication and assembly; (2) preparations for making silicon bulk resistivity wafer standards available to the industry; and (3) establishment of the relationship between carrier mobility and impurity density in silicon. Work is continuing on measurement of resistivity of semiconductor crystals; characterization of generation-recombination-trapping centers, including gold, in silicon; evaluation of wire bonds and die attachment; study of scanning electron microscopy for wafer inspection and test; measurement of thermal properties of semiconductor devices; determination of S-parameters and delay time in junction devices; and characterization of noise and conversion loss of microwave detector diodes.

  1. Silicon superlattices: Theory and application to semiconductor devices

    NASA Technical Reports Server (NTRS)

    Moriarty, J. A.

    1981-01-01

    Silicon superlattices and their applicability to improved semiconductor devices were studied. The device application potential of the atomic like dimension of III-V semiconductor superlattices fabricated in the form of ultrathin periodically layered heterostructures was examined. Whether this leads to quantum size effects and creates the possibility to alter familiar transport and optical properties over broad physical ranges was studied. Applications to improved semiconductor lasers and electrondevices were achieved. Possible application of silicon sperlattices to faster high speed computing devices was examined. It was found that the silicon lattices show features of smaller fundamental energyband gaps and reduced effective masses. The effects correlate strongly with both the chemical and geometrical nature of the superlattice.

  2. Excitons and the lifetime of organic semiconductor devices

    PubMed Central

    Forrest, Stephen R.

    2015-01-01

    While excitons are responsible for the many beneficial optical properties of organic semiconductors, their non-radiative recombination within the material can result in material degradation due to the dumping of energy onto localized molecular bonds. This presents a challenge in developing strategies to exploit the benefits of excitons without negatively impacting the device operational stability. Here, we will briefly review the fundamental mechanisms leading to excitonic energy-driven device ageing in two example devices: blue emitting electrophosphorescent organic light emitting devices (PHOLEDs) and organic photovoltaic (OPV) cells. We describe strategies used to minimize or even eliminate this fundamental device degradation pathway. PMID:25987572

  3. SEMICONDUCTOR DEVICES: CuPc/C60 heterojunction thin film optoelectronic devices

    NASA Astrophysics Data System (ADS)

    Murtaza, Imran; Qazi, Ibrahim; Karimov, Khasan S.

    2010-06-01

    The optoelectronic properties of heterojunction thin film devices with ITO/CuPc/C60/Al structure have been investigated by analyzing their current-voltage characteristics, optical absorption and photocurrent. In this organic photovoltaic device, CuPc acts as an optically active layer, C60 as an electron-transporting layer and ITO and Al as electrodes. It is observed that, under illumination, excitons are formed, which subsequently drift towards the interface with C60, where an internal electric field is present. The excitons that reach the interface are subsequently dissociated into free charge carriers due to the electric field present at the interface. The experimental results show that in this device the total current density is a function of injected carriers at the electrode-organic semiconductor surface, the leakage current through the organic layer and collected photogenerated current that results from the effective dissociation of excitons.

  4. Deep impurity trapping concepts for power semiconductor devices

    NASA Technical Reports Server (NTRS)

    Sundberg, G. R.

    1982-01-01

    High voltage semiconductor switches using deep impurity doped silicon now appear feasible for high voltage (1-100 kV), high power (10 Kw) switching and protection functions for future space power applications. Recent discoveries have demonstrated several practical ways of gating deep impurity doped silicon devices in planar configurations and of electrically controlling their characteristics, leading to a vast array of possible circuit applications. A new family of semiconductor switching devices and transducers are possible based on this technology. New deep impurity devices could be simpler than conventional p-n junction devices and yet use the same basic materials and processing techniques. In addition, multiple functions may be possible on a single device as well as increased ratings.

  5. Methods of forming semiconductor devices and devices formed using such methods

    DOEpatents

    Fox, Robert V; Rodriguez, Rene G; Pak, Joshua

    2013-05-21

    Single source precursors are subjected to carbon dioxide to form particles of material. The carbon dioxide may be in a supercritical state. Single source precursors also may be subjected to supercritical fluids other than supercritical carbon dioxide to form particles of material. The methods may be used to form nanoparticles. In some embodiments, the methods are used to form chalcopyrite materials. Devices such as, for example, semiconductor devices may be fabricated that include such particles. Methods of forming semiconductor devices include subjecting single source precursors to carbon dioxide to form particles of semiconductor material, and establishing electrical contact between the particles and an electrode.

  6. A thermovoltaic semiconductor device including a plasma filter

    SciTech Connect

    Baldasaro, Paul F.

    1997-12-01

    A thermovoltaic energy conversion device and related method for converting thermal energy into an electrical potential are disclosed. An interference filter is provided on a semiconductor thermovoltaic cell to pre-filter black body radiation. The semiconductor thermovoltaic cell includes a P/N junction supported on a substrate which converts incident thermal energy below the semiconductor junction band gap into electrical potential. The semiconductor substrate is doped to provide a plasma filter which reflects back energy having a wavelength which is above the band gap and which is ineffectively filtered by the interference filter, through the P/N junction to the source of radiation thereby avoiding parasitic absorption of the unusable portion of the thermal radiation energy.

  7. Second International Semiconductor Device Research Symposium (ISDRS-1993)

    NASA Astrophysics Data System (ADS)

    Shur, Michael; Money, John M.

    1994-04-01

    The goal of this second biannual international meeting was to provide a congenial forum for the exchange of information and new ideas for researchers from university, industry and government laboratories in the field of semiconductor devices and device physics. To this end, we have an unusually short period between the submission of papers and the conference, a speedy publication of the proceedings, poster sessions, panel discussions, and a wide dissemination of the conference proceedings. Our other goal is to make this conference truly international. To achieve this, the symposium has sub-committees in Asia, Europe and the former Soviet Union. This conference is organized in cooperation with the IEEE MTT Society, the European Physical Society, the United States National Committee of URSI and the Russian Physical Society. Generous financial support has been provided by the Army Research Office, the Office of Naval Research, the NASA Ames Research Center and the Soros International Science Foundation. Papers cover a broad range of topics, including novel and ultrasmall devices, photonics and optoelectronics, heterostructure and cryogenic devices, wide band gap semiconductors, thin film transistors, MOSFET technology and devices, carrier transport phenomena, materials and device characterization, simulation and modeling. It is hoped that such a broad range of topics will foster a cross-fertilization of the different fields related to semiconductor materials and devices.

  8. Porous silicon carbide (SiC) semiconductor device

    NASA Technical Reports Server (NTRS)

    Shor, Joseph S. (Inventor); Kurtz, Anthony D. (Inventor)

    1994-01-01

    A semiconductor device employs at least one layer of semiconducting porous silicon carbide (SiC). The porous SiC layer has a monocrystalline structure wherein the pore sizes, shapes, and spacing are determined by the processing conditions. In one embodiment, the semiconductor device is a p-n junction diode in which a layer of n-type SiC is positioned on a p-type layer of SiC, with the p-type layer positioned on a layer of silicon dioxide. Because of the UV luminescent properties of the semiconducting porous SiC layer, it may also be utilized for other devices such as LEDs and optoelectronic devices.

  9. Improvement of screening methods for silicon planar semiconductor devices

    NASA Technical Reports Server (NTRS)

    Berger, W. M.

    1972-01-01

    The results of the program for the development of a more sensitive method for selecting silicon planar semiconductor devices for long life applications are reported. The manufacturing technologies (MOS and Bipolar) are discussed along with the screening procedures developed as a result of the tests and evaluations, and the effectiveness of the MOS and Bilayer screening procedures are evaluated.

  10. Quantum transport in nanoscale semiconductor devices

    NASA Astrophysics Data System (ADS)

    Jones, Gregory Millington

    Because of technological advancement, transistor dimensions are approaching the length scale of the electron Fermi wavelength, on the order of only nanometers. In this regime, quantum mechanical phenomena will dominate electron transport. Using InAs single quantum wells, we have fabricated Y-shaped electron waveguides whose lengths are smaller than the elastic mean free path. Electron transport in these waveguides is ballistic, a quantum mechanical phenomenon. Coupled to the electron waveguide are two gates used to coherently steer the electron wave. We demonstrate for the first time that gating modifies the electron's wave function, by changing its geometrical resonance in the waveguide. Evidence of this alteration is the observation of anti-correlated, oscillatory transconductances. Our data provides direct evidence of wavefunction steering in a transistor structure and has applications in high-speed, low-power electronics. Quantum computing, if realized, will have a significant impact in computer security. The development of quantum computers has been hindered by challenges in producing the basic building block, the qubit. Qubit approaches using semiconductors promise upscalability and can take the form of a single electron transistor. We have designed, fabricated, and characterized single electron transistors in InAs, and separately in silicon, for the application of quantum computing. With the InAs single electron transistor, we have demonstrated one-electron quantum dots using a single-top-gate transistor configuration on a composite quantum well. Electrical transport data indicates a 15meV charging energy and a 20meV orbital energy spacing, which implies a quantum dot of 20nm in diameter. InAs is attractive due to its large electron Lande g-factor. With the silicon-based single electron transistor, we have demonstrated a structure that is similar to conventional silicon-based metal-oxide-semiconductor field effect transistors. The substrate is undoped and

  11. Release strategies for making transferable semiconductor structures, devices and device components

    SciTech Connect

    Rogers, John A; Nuzzo, Ralph G; Meitl, Matthew; Ko, Heung Cho; Yoon, Jongseung; Menard, Etienne; Baca, Alfred J

    2014-11-25

    Provided are methods for making a device or device component by providing a multilayer structure having a plurality of functional layers and a plurality of release layers and releasing the functional layers from the multilayer structure by separating one or more of the release layers to generate a plurality of transferable structures. The transferable structures are printed onto a device substrate or device component supported by a device substrate. The methods and systems provide means for making high-quality and low-cost photovoltaic devices, transferable semiconductor structures, (opto-)electronic devices and device components.

  12. Release strategies for making transferable semiconductor structures, devices and device components

    DOEpatents

    Rogers, John A.; Nuzzo, Ralph G.; Meitl, Matthew; Ko, Heung Cho; Yoon, Jongseung; Menard, Etienne; Baca, Alfred J.

    2011-04-26

    Provided are methods for making a device or device component by providing a multilayer structure having a plurality of functional layers and a plurality of release layers and releasing the functional layers from the multilayer structure by separating one or more of the release layers to generate a plurality of transferable structures. The transferable structures are printed onto a device substrate or device component supported by a device substrate. The methods and systems provide means for making high-quality and low-cost photovoltaic devices, transferable semiconductor structures, (opto-)electronic devices and device components.

  13. Release strategies for making transferable semiconductor structures, devices and device components

    DOEpatents

    Rogers, John A.; Nuzzo, Ralph G.; Meitl, Matthew; Ko, Heung Cho; Yoon, Jongseung; Menard, Etienne; Baca, Alfred J.

    2016-05-24

    Provided are methods for making a device or device component by providing a multi layer structure having a plurality of functional layers and a plurality of release layers and releasing the functional layers from the multilayer structure by separating one or more of the release layers to generate a plurality of transferable structures. The transferable structures are printed onto a device substrate or device component supported by a device substrate. The methods and systems provide means for making high-quality and low-cost photovoltaic devices, transferable semiconductor structures, (opto-)electronic devices and device components.

  14. Electromagnetic radiation screening of semiconductor devices for long life applications

    NASA Technical Reports Server (NTRS)

    Hall, T. C.; Brammer, W. G.

    1972-01-01

    A review is presented of the mechanism of interaction of electromagnetic radiation in various spectral ranges, with various semiconductor device defects. Previous work conducted in this area was analyzed as to its pertinence to the current problem. The task was studied of implementing electromagnetic screening methods in the wavelength region determined to be most effective. Both scanning and flooding type stimulation techniques are discussed. While the scanning technique offers a considerably higher yield of useful information, a preliminary investigation utilizing the flooding approach is first recommended because of the ease of implementation, lower cost and ability to provide go-no-go information in semiconductor screening.

  15. Semiconductor quantum wells: old technology or new device functionalities

    NASA Astrophysics Data System (ADS)

    Kolbas, R. M.; Lo, Y. C.; Hsieh, K. Y.; Lee, J. H.; Reed, F. E.; Zhang, D.; Zhang, T.

    2009-08-01

    The introduction of semiconductor quantum wells in the 1970s created a revolution in optoelectronic devices. A large fraction of today's lasers and light emitting diodes are based on quantum wells. It has been more than 30 years but novel ideas and new device functions have recently been demonstrated using quantum well heterostructures. This paper provides a brief overview of the subject and then focuses on the physics of quantum wells that the lead author believes holds the key to new device functionalities. The data and figures contained within are not new. They have been assembled from 30 years of work. They are presented to convey the story of why quantum wells continue to fuel the engine that drives the semiconductor optoelectronic business. My apologies in advance to my students and co-workers that contributed so much that could not be covered in such a short manuscript. The explanations provided are based on the simplest models possible rather than the very sophisticated mathematical models that have evolved over many years. The intended readers are those involved with semiconductor optoelectronic devices and are interested in new device possibilities.

  16. Semiconductor optoelectronic devices for free-space optical communications

    NASA Technical Reports Server (NTRS)

    Katz, J.

    1983-01-01

    The properties of individual injection lasers are reviewed, and devices of greater complexity are described. These either include or are relevant to monolithic integration configurations of the lasers with their electronic driving circuitry, power combining methods of semiconductor lasers, and electronic methods of steering the radiation patterns of semiconductor lasers and laser arrays. The potential of AlGaAs laser technology for free-space optical communications systems is demonstrated. These solid-state components, which can generate and modulate light, combine the power of a number of sources and perform at least part of the beam pointing functions. Methods are proposed for overcoming the main drawback of semiconductor lasers, that is, their inability to emit the needed amount of optical power in a single-mode operation.

  17. Screenable contact structure and method for semiconductor devices

    DOEpatents

    Ross, Bernd

    1980-08-26

    An ink composition for deposition upon the surface of a semiconductor device to provide a contact area for connection to external circuitry is disclosed, the composition comprising an ink system containing a metal powder, a binder and vehicle, and a metal frit. The ink is screened onto the semiconductor surface in the desired pattern and is heated to a temperature sufficient to cause the metal frit to become liquid. The metal frit dissolves some of the metal powder and densifies the structure by transporting the dissolved metal powder in a liquid sintering process. The sintering process typically may be carried out in any type of atmosphere. A small amount of dopant or semiconductor material may be added to the ink systems to achieve particular results if desired.

  18. Porous silicon carbide (SIC) semiconductor device

    NASA Technical Reports Server (NTRS)

    Shor, Joseph S. (Inventor); Kurtz, Anthony D. (Inventor)

    1996-01-01

    Porous silicon carbide is fabricated according to techniques which result in a significant portion of nanocrystallites within the material in a sub 10 nanometer regime. There is described techniques for passivating porous silicon carbide which result in the fabrication of optoelectronic devices which exhibit brighter blue luminescence and exhibit improved qualities. Based on certain of the techniques described porous silicon carbide is used as a sacrificial layer for the patterning of silicon carbide. Porous silicon carbide is then removed from the bulk substrate by oxidation and other methods. The techniques described employ a two-step process which is used to pattern bulk silicon carbide where selected areas of the wafer are then made porous and then the porous layer is subsequently removed. The process to form porous silicon carbide exhibits dopant selectivity and a two-step etching procedure is implemented for silicon carbide multilayers.

  19. Nanostructured Semiconductor Device Design in Solar Cells

    NASA Astrophysics Data System (ADS)

    Dang, Hongmei

    We demonstrate the use of embedded CdS nanowires in improving spectral transmission loss and the low mechanical and electrical robustness of planar CdS window layer and thus enhancing the quantum efficiency and the reliability of the CdS-CdTe solar cells. CdS nanowire window layer enables light transmission gain at 300nm-550nm. A nearly ideal spectral response of quantum efficiency at a wide spectrum range provides an evidence for improving light transmission in the window layer and enhancing absorption and carrier generation in absorber. Nanowire CdS/CdTe solar cells with Cu/graphite/silver paste as back contacts, on SnO2/ITO-soda lime glass substrates, yield the highest efficiency of 12% in nanostructured CdS-CdTe solar cells. Reliability is improved by approximately 3 times over the cells with the traditional planar CdS counterpart. Junction transport mechanisms are delineated for advancing the basic understanding of device physics at the interface. Our results prove the efficacy of this nanowire approach for enhancing the quantum efficiency and the reliability in windowabsorber type solar cells (CdS-CdTe, CdS-CIGS and CdS-CZTSSe etc) and other optoelectronic devices. We further introduce MoO3-x as a transparent, low barrier back contact. We design nanowire CdS-CdTe solar cells on flexible foils of metals in a superstrate device structure, which makes low-cost roll-to-roll manufacturing process feasible and greatly reduces the complexity of fabrication. The MoO3 layer reduces the valence band offset relative to the CdTe, and creates improved cell performance. Annealing as-deposited MoO3 in N 2 reduces series resistance from 9.98 O/cm2 to 7.72 O/cm2, and hence efficiency of the nanowire solar cell is improved from 9.9% to 11%, which efficiency comparable to efficiency of planar counterparts. When the nanowire solar cell is illuminated from MoO 3-x /Au side, it yields an efficiency of 8.7%. This reduction in efficiency is attributed to decrease in Jsc from 25.5m

  20. Microwave assisted synthesis and characterisation of a zinc oxide/tobacco mosaic virus hybrid material. An active hybrid semiconductor in a field-effect transistor device.

    PubMed

    Sanctis, Shawn; Hoffmann, Rudolf C; Eiben, Sabine; Schneider, Jörg J

    2015-01-01

    Tobacco mosaic virus (TMV) has been employed as a robust functional template for the fabrication of a TMV/zinc oxide field effect transistor (FET). A microwave based approach, under mild conditions was employed to synthesize stable zinc oxide (ZnO) nanoparticles, employing a molecular precursor. Insightful studies of the decomposition of the precursor were done using NMR spectroscopy and material characterization of the hybrid material derived from the decomposition was achieved using dynamic light scattering (DLS), transmission electron microscopy (TEM), grazing incidence X-ray diffractometry (GI-XRD) and atomic force microscopy (AFM). TEM and DLS data confirm the formation of crystalline ZnO nanoparticles tethered on top of the virus template. GI-XRD investigations exhibit an orientated nature of the deposited ZnO film along the c-axis. FET devices fabricated using the zinc oxide mineralized virus template material demonstrates an operational transistor performance which was achieved without any high-temperature post-processing steps. Moreover, a further improvement in FET performance was observed by adjusting an optimal layer thickness of the deposited ZnO on top of the TMV. Such a bio-inorganic nanocomposite semiconductor material accessible using a mild and straightforward microwave processing technique could open up new future avenues within the field of bio-electronics.

  1. Methods of measurement for semiconductor materials, process control, and devices

    NASA Technical Reports Server (NTRS)

    Bullis, W. M. (Editor)

    1972-01-01

    Significant accomplishments include development of a procedure to correct for the substantial differences of transistor delay time as measured with different instruments or with the same instrument at different frequencies; association of infrared response spectra of poor quality germanium gamma ray detectors with spectra of detectors fabricated from portions of a good crystal that had been degraded in known ways; and confirmation of the excellent quality and cosmetic appearance of ultrasonic bonds made with aluminum ribbon wire. Work is continuing on measurement of resistivity of semiconductor crystals; study of gold-doped silicon, development of the infrared response technique; evaluation of wire bonds and die attachment; and measurement of thermal properties of semiconductor devices, delay time and related carrier transport properties in junction devices, and noise properties of microwave diodes.

  2. Strategies for Radiation Hardness Testing of Power Semiconductor Devices

    NASA Technical Reports Server (NTRS)

    Soltis, James V. (Technical Monitor); Patton, Martin O.; Harris, Richard D.; Rohal, Robert G.; Blue, Thomas E.; Kauffman, Andrew C.; Frasca, Albert J.

    2005-01-01

    Plans on the drawing board for future space missions call for much larger power systems than have been flown in the past. These systems would employ much higher voltages and currents to enable more powerful electric propulsion engines and other improvements on what will also be much larger spacecraft. Long term human outposts on the moon and planets would also require high voltage, high current and long life power sources. Only hundreds of watts are produced and controlled on a typical robotic exploration spacecraft today. Megawatt systems are required for tomorrow. Semiconductor devices used to control and convert electrical energy in large space power systems will be exposed to electromagnetic and particle radiation of many types, depending on the trajectory and duration of the mission and on the power source. It is necessary to understand the often very different effects of the radiations on the control and conversion systems. Power semiconductor test strategies that we have developed and employed will be presented, along with selected results. The early results that we have obtained in testing large power semiconductor devices give a good indication of the degradation in electrical performance that can be expected in response to a given dose. We are also able to highlight differences in radiation hardness that may be device or material specific.

  3. Method of making high breakdown voltage semiconductor device

    DOEpatents

    Arthur, Stephen D.; Temple, Victor A. K.

    1990-01-01

    A semiconductor device having at least one P-N junction and a multiple-zone junction termination extension (JTE) region which uniformly merges with the reverse blocking junction is disclosed. The blocking junction is graded into multiple zones of lower concentration dopant adjacent termination to facilitate merging of the JTE to the blocking junction and placing of the JTE at or near the high field point of the blocking junction. Preferably, the JTE region substantially overlaps the graded blocking junction region. A novel device fabrication method is also provided which eliminates the prior art step of separately diffusing the JTE region.

  4. Molecular detection via hybrid peptide-semiconductor photonic devices

    NASA Astrophysics Data System (ADS)

    Estephan, E.; Saab, M.-b.; Martin, M.; Cloitre, T.; Larroque, C.; Cuisinier, F. J. G.; Malvezzi, A. M.; Gergely, C.

    2011-03-01

    The aim of this work was to investigate the possibilities to support device functionality that includes strongly confined and localized light emission and detection processes within nano/micro-structured semiconductors for biosensing applications. The interface between biological molecules and semiconductor surfaces, yet still under-explored is a key issue for improving biomolecular recognition in devices. We report on the use of adhesion peptides, elaborated via combinatorial phage-display libraries for controlled placement of biomolecules, leading to user-tailored hybrid photonic systems for molecular detection. An M13 bacteriophage library has been used to screen 1010 different peptides against various semiconductors to finally isolate specific peptides presenting a high binding capacity for the target surfaces. When used to functionalize porous silicon microcavities (PSiM) and GaAs/AlGaAs photonic crystals, we observe the formation of extremely thin (<1nm) peptide layers, hereby preserving the nanostructuration of the crystals. This is important to assure the photonic response of these tiny structures when they are functionalized by a biotinylated peptide layer and then used to capture streptavidin. Molecular detection was monitored via both linear and nonlinear optical measurements. Our linear reflectance spectra demonstrate an enhanced detection resolution via PSiM devices, when functionalized with the Si-specific peptide. Molecular capture at even lower concentrations (femtomols) is possible via the second harmonic generation of GaAs/AlGaAs photonic crystals when functionalized with GaAs-specific peptides. Our work demonstrates the outstanding value of adhesion peptides as interface linkers between semiconductors and biological molecules. They assure an enhanced molecular detection via both linear and nonlinear answers of photonic crystals.

  5. An integrated semiconductor device enabling non-optical genome sequencing.

    PubMed

    Rothberg, Jonathan M; Hinz, Wolfgang; Rearick, Todd M; Schultz, Jonathan; Mileski, William; Davey, Mel; Leamon, John H; Johnson, Kim; Milgrew, Mark J; Edwards, Matthew; Hoon, Jeremy; Simons, Jan F; Marran, David; Myers, Jason W; Davidson, John F; Branting, Annika; Nobile, John R; Puc, Bernard P; Light, David; Clark, Travis A; Huber, Martin; Branciforte, Jeffrey T; Stoner, Isaac B; Cawley, Simon E; Lyons, Michael; Fu, Yutao; Homer, Nils; Sedova, Marina; Miao, Xin; Reed, Brian; Sabina, Jeffrey; Feierstein, Erika; Schorn, Michelle; Alanjary, Mohammad; Dimalanta, Eileen; Dressman, Devin; Kasinskas, Rachel; Sokolsky, Tanya; Fidanza, Jacqueline A; Namsaraev, Eugeni; McKernan, Kevin J; Williams, Alan; Roth, G Thomas; Bustillo, James

    2011-07-21

    The seminal importance of DNA sequencing to the life sciences, biotechnology and medicine has driven the search for more scalable and lower-cost solutions. Here we describe a DNA sequencing technology in which scalable, low-cost semiconductor manufacturing techniques are used to make an integrated circuit able to directly perform non-optical DNA sequencing of genomes. Sequence data are obtained by directly sensing the ions produced by template-directed DNA polymerase synthesis using all-natural nucleotides on this massively parallel semiconductor-sensing device or ion chip. The ion chip contains ion-sensitive, field-effect transistor-based sensors in perfect register with 1.2 million wells, which provide confinement and allow parallel, simultaneous detection of independent sequencing reactions. Use of the most widely used technology for constructing integrated circuits, the complementary metal-oxide semiconductor (CMOS) process, allows for low-cost, large-scale production and scaling of the device to higher densities and larger array sizes. We show the performance of the system by sequencing three bacterial genomes, its robustness and scalability by producing ion chips with up to 10 times as many sensors and sequencing a human genome. PMID:21776081

  6. Active cleaning technique device

    NASA Technical Reports Server (NTRS)

    Shannon, R. L.; Gillette, R. B.

    1973-01-01

    The objective of this program was to develop a laboratory demonstration model of an active cleaning technique (ACT) device. The principle of this device is based primarily on the technique for removing contaminants from optical surfaces. This active cleaning technique involves exposing contaminated surfaces to a plasma containing atomic oxygen or combinations of other reactive gases. The ACT device laboratory demonstration model incorporates, in addition to plasma cleaning, the means to operate the device as an ion source for sputtering experiments. The overall ACT device includes a plasma generation tube, an ion accelerator, a gas supply system, a RF power supply and a high voltage dc power supply.

  7. Semiconductor-based, large-area, flexible, electronic devices on {110}<100> oriented substrates

    DOEpatents

    Goyal, Amit

    2014-08-05

    Novel articles and methods to fabricate the same resulting in flexible, oriented, semiconductor-based, electronic devices on {110}<100> textured substrates are disclosed. Potential applications of resulting articles are in areas of photovoltaic devices, flat-panel displays, thermophotovoltaic devices, ferroelectric devices, light emitting diode devices, computer hard disc drive devices, magnetoresistance based devices, photoluminescence based devices, non-volatile memory devices, dielectric devices, thermoelectric devices and quantum dot laser devices.

  8. [100] or [110] aligned, semiconductor-based, large-area, flexible, electronic devices

    DOEpatents

    Goyal, Amit

    2015-03-24

    Novel articles and methods to fabricate the same resulting in flexible, large-area, [100] or [110] textured, semiconductor-based, electronic devices are disclosed. Potential applications of resulting articles are in areas of photovoltaic devices, flat-panel displays, thermophotovoltaic devices, ferroelectric devices, light emitting diode devices, computer hard disc drive devices, magnetoresistance based devices, photoluminescence based devices, non-volatile memory devices, dielectric devices, thermoelectric devices and quantum dot laser devices.

  9. Semiconductor ferroelectric compositions and their use in photovoltaic devices

    DOEpatents

    Rappe, Andrew M; Davies, Peter K; Spanier, Jonathan E; Grinberg, Ilya; West, Don Vincent

    2016-11-01

    Disclosed herein are ferroelectric perovskites characterized as having a band gap, Egap, of less than 2.5 eV. Also disclosed are compounds comprising a solid solution of KNbO3 and BaNi1/2Nb1/2O3-delta, wherein delta is in the range of from 0 to about 1. The specification also discloses photovoltaic devices comprising one or more solar absorbing layers, wherein at least one of the solar absorbing layers comprises a semiconducting ferroelectric layer. Finally, this patent application provides solar cell, comprising: a heterojunction of n- and p-type semiconductors characterized as comprising an interface layer disposed between the n- and p-type semiconductors, the interface layer comprising a semiconducting ferroelectric absorber layer capable of enhancing light absorption and carrier separation.

  10. Radiation hardening of metal-oxide semi-conductor (MOS) devices by boron

    NASA Technical Reports Server (NTRS)

    Danchenko, V.

    1974-01-01

    Technique using boron effectively protects metal-oxide semiconductor devices from ionizing radiation without using shielding materials. Boron is introduced into insulating gate oxide layer at semiconductor-insulator interface.

  11. Women's Presence in the Development of Semiconductor Physics and Semiconductor Devices Research in Cuba (abstract)

    NASA Astrophysics Data System (ADS)

    Vigil, Elena

    2009-04-01

    Physics research did not exist in prerevolutionary Cuba. In 1962, Cuban university programs were reformed and Havana University's School of Physics was created. Equal opportunities for women and science development were made high priorities during university reform. In the early 1960s the growth of physics research began, particularly in semiconductors. This research is reviewed, emphasizing the presence and accomplishments of the women involved. Women physicists havr authored papers regarding the first alloyed semiconductor diode in 1967; IREs and LEDs (discrete, as well as integrated digits) in the 1970s; epitaxial growth in space; and LED and IRE technology transfer to the Cuban semiconductor industry in the 1980s. Women's current active role in solar cell research is also reviewed.

  12. Contact formation and gettering of precipitated impurities by multiple firing during semiconductor device fabrication

    DOEpatents

    Sopori, Bhushan

    2014-05-27

    Methods for contact formation and gettering of precipitated impurities by multiple firing during semiconductor device fabrication are provided. In one embodiment, a method for fabricating an electrical semiconductor device comprises: a first step that includes gettering of impurities from a semiconductor wafer and forming a backsurface field; and a second step that includes forming a front contact for the semiconductor wafer, wherein the second step is performed after completion of the first step.

  13. A quantum energy transport model for semiconductor device simulation

    SciTech Connect

    Sho, Shohiro; Odanaka, Shinji

    2013-02-15

    This paper describes numerical methods for a quantum energy transport (QET) model in semiconductors, which is derived by using a diffusion scaling in the quantum hydrodynamic (QHD) model. We newly drive a four-moments QET model similar with a classical ET model. Space discretization is performed by a new set of unknown variables. Numerical stability and convergence are obtained by developing numerical schemes and an iterative solution method with a relaxation method. Numerical simulations of electron transport in a scaled MOSFET device are discussed. The QET model allows simulations of quantum confinement transport, and nonlocal and hot-carrier effects in scaled MOSFETs.

  14. Methods of measurement for semiconductor materials, process control, and devices

    NASA Technical Reports Server (NTRS)

    Bullis, W. M. (Editor)

    1971-01-01

    The development of methods of measurement for semiconductor materials, process control, and devices is discussed. The following subjects are also presented: (1) demonstration of the high sensitivity of the infrared response technique by the identification of gold in a germanium diode, (2) verification that transient thermal response is significantly more sensitive to the presence of voids in die attachment than steady-state thermal resistance, and (3) development of equipment for determining susceptibility of transistors to hot spot formation by the current-gain technique.

  15. Semiconductor laser devices having lateral refractive index tailoring

    DOEpatents

    Ashby, Carol I. H.; Hadley, G. Ronald; Hohimer, John P.; Owyoung, Adelbert

    1990-01-01

    A broad-area semiconductor laser diode includes an active lasing region interposed between an upper and a lower cladding layer, the laser diode further comprising structure for controllably varying a lateral refractive index profile of the diode to substantially compensate for an effect of junction heating during operation. In embodiments disclosed the controlling structure comprises resistive heating strips or non-radiative linear junctions disposed parallel to the active region. Another embodiment discloses a multi-layered upper cladding region selectively disordered by implanted or diffused dopant impurities. Still another embodiment discloses an upper cladding layer of variable thickness that is convex in shape and symmetrically disposed about a central axis of the active region. The teaching of the invention is also shown to be applicable to arrays of semiconductor laser diodes.

  16. Novel SiGe Semiconductor Devices for Cryogenic Power Electronics

    NASA Astrophysics Data System (ADS)

    Ward, R. R.; Dawson, W. J.; Zhu, L.; Kirschman, R. K.; Niu, G.; Nelms, R. M.; Mueller, O.; Hennessy, M. J.; Mueller, E. K.

    2006-03-01

    It is predicted that systems for electrical power generation, conversion and distribution on ships and aerospace vehicles could be made smaller, lighter, more efficient, more versatile, and lower maintenance by operating these systems—partly or entirely—at cryogenic temperatures. In view of this, we have taken initial steps in the investigation and development of SiGe semiconductor devices for cryogenic power applications. We have (1) simulated, designed, fabricated and characterized SiGe power diodes, and (2) evaluated these SiGe diodes in cryogenic power converters. Our target low-end temperature is 55 K, although we characterize devices and circuits down to approximately 30 K. We have demonstrated, experimentally, favorable characteristics for SiGe power diodes and have shown higher conversion efficiency compared to equivalent Si power diodes in a 100-W boost switching DC-DC power converter, over an ambient temperature range of 300 K down to approximately 30 K.

  17. Development of silicon carbide semiconductor devices for high temperature applications

    NASA Technical Reports Server (NTRS)

    Matus, Lawrence G.; Powell, J. Anthony; Petit, Jeremy B.

    1991-01-01

    The semiconducting properties of electronic grade silicon carbide crystals, such as wide energy bandgap, make it particularly attractive for high temperature applications. Applications for high temperature electronic devices include instrumentation for engines under development, engine control and condition monitoring systems, and power conditioning and control systems for space platforms and satellites. Discrete prototype SiC devices were fabricated and tested at elevated temperatures. Grown p-n junction diodes demonstrated very good rectification characteristics at 870 K. A depletion-mode metal-oxide-semiconductor field-effect transistor was also successfully fabricated and tested at 770 K. While optimization of SiC fabrication processes remain, it is believed that SiC is an enabling high temperature electronic technology.

  18. Contributive research in compound semiconductor material and related devices

    NASA Astrophysics Data System (ADS)

    Twist, James R.

    1988-05-01

    The objective of this program was to provide the Electronic Device Branch (AFWAL/AADR) with the support needed to perform state of the art electronic device research. In the process of managing and performing on the project, UES has provided a wide variety of scientific and engineering talent who worked in-house for the Avionics Laboratory. These personnel worked on many different types of research programs from gas phase microwave driven lasers, CVD and MOCVD of electronic materials to Electronic Device Technology for new devices. The fields of research included MBE and theoretical research in this novel growth technique. Much of the work was slanted towards the rapidly developing technology of GaAs and the general thrust of the research that these tasks started has remained constant. This work was started because the Avionics Laboratory saw a chance to advance the knowledge and level of the current device technology by working in the compounds semiconductor field. UES is pleased to have had the opportunity to perform on this program and is looking forward to future efforts with the Avionics Laboratory.

  19. Comparison of Non-Parabolic Hydrodynamic Simulations for Semiconductor Devices

    NASA Technical Reports Server (NTRS)

    Smith, A. W.; Brennan, K. F.

    1996-01-01

    Parabolic drift-diffusion simulators are common engineering level design tools for semiconductor devices. Hydrodynamic simulators, based on the parabolic band approximation, are becoming more prevalent as device dimensions shrink and energy transport effects begin to dominate device characteristic. However, band structure effects present in state-of-the-art devices necessitate relaxing the parabolic band approximation. This paper presents simulations of ballistic diodes, a benchmark device, of Si and GaAs using two different non-parabolic hydrodynamic formulations. The first formulation uses the Kane dispersion relationship in the derivation of the conservation equations. The second model uses a power law dispersion relation {(hk)(exp 2)/2m = xW(exp Y)}. Current-voltage relations show that for the ballistic diodes considered. the non-parabolic formulations predict less current than the parabolic case. Explanations of this will be provided by examination of velocity and energy profiles. At low bias, the simulations based on the Kane formulation predict greater current flow than the power law formulation. As the bias is increased this trend changes and the power law predicts greater current than the Kane formulation. It will be shown that the non-parabolicity and energy range of the hydrodynamic model based on the Kane dispersion relation are limited due to the binomial approximation which was utilized in the derivation.

  20. Study of total dose effect on semiconductor devices

    NASA Astrophysics Data System (ADS)

    Kanno, Toru

    1993-10-01

    This memorandum describes single event phenomena of power MOS (Metal Oxide Semiconductor) - FET (Field Effect Transistor) and SRAM (Static Random Access Memory), and total dose resistance of 256 k bit EEPROM (Electrically Erasable and Programmable Read Only Memory). The single event is a phenomenon that causes permanent failure and malfunction by a single high energy heavy atom entering into a semiconductor device. This study evaluated power MOS-FET and SRAM for Single Event Burnout (SEB) and Single Event Latchup (SEL) using newly developed Energetic Particle Induced Charge Spectroscopy (EPICS). As a result, influence of LET (Linear Energy Transfer) on avalanche effect and phenomena relating with nuclear reaction/recoil were observed, and mechanism of SEB was suggested. In addition, SEL occurrence probability was determined in wide range of LET using an accelerator of heavy ions. This study evaluated total dose effect of EEPROM, and malfunction site and the total dose mechanism were proposed. However, the total dose resistance was not sufficient to be used in outer space. Because it will require enormous change of processes to improve this device, and because degeneration of peripheral circuits were too fast to be evaluated, development of space ROM (Read Only Memory) seems to be difficult in this stage.

  1. SEMICONDUCTOR DEVICES: Simulation for signal charge transfer of charge coupled devices

    NASA Astrophysics Data System (ADS)

    Zujun, Wang; Yinong, Liu; Wei, Chen; Benqi, Tang; Zhigang, Xiao; Shaoyan, Huang; Minbo, Liu; Yong, Zhang

    2009-12-01

    Physical device models and numerical processing methods are presented to simulate a linear buried channel charge coupled devices (CCDs). The dynamic transfer process of CCD is carried out by a three-phase clock pulse driver. By using the semiconductor device simulation software MEDICI, dynamic transfer pictures of signal charges cells, electron concentration and electrostatic potential are presented. The key parameters of CCD such as charge transfer efficiency (CTE) and dark electrons are numerically simulated. The simulation results agree with the theoretic and experimental results.

  2. Accelerator-based electron beam technologies for modification of bipolar semiconductor devices

    NASA Astrophysics Data System (ADS)

    Pavlov, Y. S.; Surma, A. M.; Lagov, P. B.; Fomenko, Y. L.; Geifman, E. M.

    2016-09-01

    Radiation processing technologies for static and dynamic parameters modification of silicon bipolar semiconductor devices implemented. Devices of different classes with wide range of operating currents (from a few mA to tens kA) and voltages (from a few volts to 8 kV) were processed in large scale including power diodes and thyristors, high-frequency bipolar and IGBT transistors, fast recovery diodes, pulsed switching diodes, precise temperature- compensated Zener diodes (in general more than fifty 50 device types), produced by different enterprises. The necessary changes in electrical parameters and characteristics of devices caused by formation in the device structures of electrically active and stable in the operating temperature range sub-nanoscale recombination centres. Technologies implemented in the air with high efficiency and controllability, and are an alternative to diffusion doping of Au or Pt, γ-ray, proton and low-Z ion irradiation.

  3. Plasma Passivation of Compound Semiconductors for Device Applications.

    NASA Astrophysics Data System (ADS)

    Herman, Jonathan Samuel

    Plasma processing such as PECVD can be used in a variety of ways for both film deposition and surface passivation to improve the performance of solid state devices in both the silicon and compound semiconductor areas. Film properties can be improved over the conventional constant temperature uninterrupted deposition method, and plasma pretreatment can be used to alter the semiconductor surface prior to film deposition. Novel deposition techniques consisting of interrupting the SiO_2 film deposition for in -situ plasma treatments have been developed to improve the electrical behavior of the plasma SiO_2 -Si interface. The most successful of these was the two-temperature method, where the interface was formed at lower temperature than the rest of the film. Low power hydrogen plasmas were used during the temperature ramp to simulate a conventional MOS post-metallization anneal and reduce the interface trap density. Hydrogen sulfide plasmas were used to passivate the surfaces of both GaAs and InP for subsequent dielectric deposition (SiO_2). Plasma processing provides a high degree of reproducibility compared to wet chemical processes through computer control of parameters such as chamber pressure, gas flows, temperature, rf power, and exposure time. The electrical and structural properties of the interfaces were characterized with C-V, XPS, SE and PL. The H_2S treatments were more robust than similar treatments involving nitrogen plasmas. The applicability of these passivation techniques was demonstrated by fabricating metal-insulator-semiconductor FET's on GaAs and InP substrates using a fully ion implaned planar process for both inversion and depletion mode transistors. The sulfide treated samples showed considerable improvement in performance over the control samples.

  4. Analysis of Carbon Nanotube Metal-Semiconductor Diode Device

    NASA Technical Reports Server (NTRS)

    Yamada, Toshishige; Biegel, Bryan (Technical Monitor)

    2002-01-01

    We study recently reported drain current Id-drain voltage Vd characteristics of a carbon nanotube metal semiconductor diode device with the gate voltage Vg applied to modulate the carrier density in the nanotube. The diode was kink-shaped at the metal-semiconductor interface. It was shown that (1) larger negative Vg blocked Id more effectively in the negative Vd region, resulting in the rectifying Id-Vd characteristics, and that (2) positive Vg allowed Id in the both Vd polarities, resulting in the non-rectifying characteristics. The negative Vd was the Schottky reverse direction, judging from the negligible Id behavior for a wide region of -4 V less than Vd less than 0 V, with Vg = -4 V. Such negative Vg would attract positive charges from the metallic electrodes (charge reservoir) to the nanotube and lower the nanotube Fermi energy (EF). With larger negative Vg, the experiment showed that the Schottky forward direction (Vd greater than 0) had a smaller turn-on voltage and the Schottky reverse direction (Vd less than 0) was more resistant to the tunneling breakdown. Therefore, the majority carriers in the transport would be electrons since they can see a lower tunneling barrier (shallower built-in potential) in the forward direction when EF is lowered, and a thicker tunneling barrier (Schottky barrier) in the reverse direction due to the reduction in the electron density when EF is lowered.

  5. Semiconductor Devices Inspired By and Integrated With Biology

    SciTech Connect

    Rogers, John

    2012-04-25

    Biology is curved, soft and elastic; silicon wafers are not. Semiconductor technologies that can bridge this gap in form and mechanics will create new opportunities in devices that adopt biologically inspired designs or require intimate integration with the human body. This talk describes the development of ideas for electronics that offer the performance of state-of-the-art, wafer- based systems but with the mechanical properties of a rubber band. We explain the underlying materials science and mechanics of these approaches, and illustrate their use in (1) bio- integrated, ‘tissue-like’ electronics with unique capabilities for mapping cardiac and neural electrophysiology, and (2) bio-inspired, ‘eyeball’ cameras with exceptional imaging properties enabled by curvilinear, Petzval designs.

  6. Nonequilibrium drift-diffusion model for organic semiconductor devices

    NASA Astrophysics Data System (ADS)

    Felekidis, Nikolaos; Melianas, Armantas; Kemerink, Martijn

    2016-07-01

    Two prevailing formalisms are currently used to model charge transport in organic semiconductor devices. Drift-diffusion calculations, on the one hand, are time effective but assume local thermodynamic equilibrium, which is not always realistic. Kinetic Monte Carlo models, on the other hand, do not require this assumption but are computationally expensive. Here, we present a nonequilibrium drift-diffusion model that bridges this gap by fusing the established multiple trap and release formalism with the drift-diffusion transport equation. For a prototypical photovoltaic system the model is shown to quantitatively describe, with a single set of parameters, experiments probing (1) temperature-dependent steady-state charge transport—space-charge limited currents, and (2) time-resolved charge transport and relaxation of nonequilibrated photocreated charges. Moreover, the outputs of the developed kinetic drift-diffusion model are an order of magnitude, or more, faster to compute and in good agreement with kinetic Monte Carlo calculations.

  7. SEMICONDUCTOR DEVICES: Humidity sensitive organic field effect transistor

    NASA Astrophysics Data System (ADS)

    Murtaza, I.; Karimov, Kh S.; Ahmad, Zubair; Qazi, I.; Mahroof-Tahir, M.; Khan, T. A.; Amin, T.

    2010-05-01

    This paper reports the experimental results for the humidity dependent properties of an organic field effect transistor. The organic field effect transistor was fabricated on thoroughly cleaned glass substrate, in which the junction between the metal gate and the organic channel plays the role of gate dielectric. Thin films of organic semiconductor copper phthalocynanine (CuPc) and semitransparent Al were deposited in sequence by vacuum thermal evaporation on the glass substrate with preliminarily deposited Ag source and drain electrodes. The output and transfer characteristics of the fabricated device were performed. The effect of humidity on the drain current, drain current-drain voltage relationship, and threshold voltage was investigated. It was observed that humidity has a strong effect on the characteristics of the organic field effect transistor.

  8. Rigid band analysis of heavily doped semiconductor devices

    NASA Astrophysics Data System (ADS)

    Marshak, A. H.; Shibib, M. A.; Fossum, J. G.; Lindholm, F. A.

    1981-03-01

    The conventional carrier transport equations used in device analysis must be modified for heavily doped semiconductor regions. The modifications to Shockley's auxiliary equations relating the carrier densities to their corresponding quasi-Fermi levels are derived for the rigid band model. The effects of asymmetric bandgap narrowing and of carrier degeneracy (Fermi-Dirac statistics) are induced. Emphasis is placed on writing the equations in a simple form that indicates the effect of changes in the band structure due to heavy doping. In this form they can serve as a basis for computer-aided analysis and design. It is shown that, in general, the effective intrinsic carrier density as well as the electron and hole current densities depend on the asymmetry in bandgap narrowing.

  9. Conductance matrix of multiterminal semiconductor devices with edge channels

    SciTech Connect

    Danilovskii, E. Yu. Bagraev, N. T.

    2014-12-15

    A method for determining the conductance matrix of multiterminal semiconductor structures with edge channels is proposed. The method is based on the solution of a system of linear algebraic equations based on Kirchhoff equations, made up of potential differences U{sub ij} measured at stabilized currents I{sub kl}, where i, j, k, l are terminal numbers. The matrix obtained by solving the system of equations completely describes the structure under study, reflecting its configuration and homogeneity. This method can find wide application when using the known Landauer-Buttiker formalism to analyze carrier transport in the quantum Hall effect and quantum spin Hall effect modes. Within the proposed method, the contribution of the contact area resistances R{sub c} to the formation of conductance matrix elements is taken into account. The possibilities of practical application of the results obtained in developing analog cryptographic devices are considered.

  10. System for characterizing semiconductor materials and photovoltaic devices through calibration

    DOEpatents

    Sopori, B.L.; Allen, L.C.; Marshall, C.; Murphy, R.C.; Marshall, T.

    1998-05-26

    A method and apparatus are disclosed for measuring characteristics of a piece of material, typically semiconductor materials including photovoltaic devices. The characteristics may include dislocation defect density, grain boundaries, reflectance, external LBIC, internal LBIC, and minority carrier diffusion length. The apparatus includes a light source, an integrating sphere, and a detector communicating with a computer. The measurement or calculation of the characteristics is calibrated to provide accurate, absolute values. The calibration is performed by substituting a standard sample for the piece of material, the sample having a known quantity of one or more of the relevant characteristics. The quantity measured by the system of the relevant characteristic is compared to the known quantity and a calibration constant is created thereby. 44 figs.

  11. System for characterizing semiconductor materials and photovoltaic devices through calibration

    DOEpatents

    Sopori, Bhushan L.; Allen, Larry C.; Marshall, Craig; Murphy, Robert C.; Marshall, Todd

    1998-01-01

    A method and apparatus for measuring characteristics of a piece of material, typically semiconductor materials including photovoltaic devices. The characteristics may include dislocation defect density, grain boundaries, reflectance, external LBIC, internal LBIC, and minority carrier diffusion length. The apparatus includes a light source, an integrating sphere, and a detector communicating with a computer. The measurement or calculation of the characteristics is calibrated to provide accurate, absolute values. The calibration is performed by substituting a standard sample for the piece of material, the sample having a known quantity of one or more of the relevant characteristics. The quantity measured by the system of the relevant characteristic is compared to the known quantity and a calibration constant is created thereby.

  12. Low-temperature optical processing of semiconductor devices using photon effects

    SciTech Connect

    Sopori, B.L.; Cudzinovic, M.; Symko, M.

    1995-08-01

    In an RTA process the primary purpose of the optical energy incident on the semiconductor sample is to increase its temperature rapidly. The activation of reactions involved in processes such as the formation of junctions, metal contacts, deposition of oxides or nitrides, takes place purely by the temperature effects. We describe the observation of a number of new photonic effects that take place within the bulk and at the interfaces of a semiconductor when a semiconductor device is illuminated with a spectrally broad-band light. Such effects include changes in the diffusion properties of impurities in the semiconductor, increased diffusivity of impurities across interfaces, and generation of electric fields that can alter physical and chemical properties of the interface. These phenomena lead to certain unique effects in an RTA process that do not occur during conventional furnace annealing under the same temperature conditions. Of particular interest are observations of low-temperature alloying of Si-Al interfaces, enhanced activation of phosphorus in Si during drive-in, low-temperature oxidation of Si, and gettering of impurities at low-temperatures under optical illumination. These optically induced effects, in general, diminish with an increase in the temperature, thus allowing thermally activated reaction rates to dominate at higher temperatures.

  13. Application of copper-carbon fiber composites to power semiconductor devices

    NASA Technical Reports Server (NTRS)

    Kuniya, Keiichi; Arakawa, Hideo; Sakaue, Tadashi; Minorikawa, Hitoshi; Akeyama, Kenji; Sakamoto, Tatsuji

    1988-01-01

    Copper-carbon composite electrodes are used in a series of power semiconductor devices, i.e., resin molded diodes, button-type diodes, stud-type diodes, power modules, and integrated circuit igniter modules. The properties of these power semiconductor devices compare favorably with those conventional devices using Mo or W electrodes. In thermal fatigue tests, no degradation in the electrical and mechanical characteristics of these devices are observed. The new composite electrode with carbon fibers satisfies all of the major requirements for the electrodes in power semiconductor devices.

  14. Metal-oxide-semiconductor field effect nanostructure spin lattice devices

    NASA Astrophysics Data System (ADS)

    Yang, Jun

    This dissertation explored and developed technologies for silicon based spin lattice devices. Spin lattices are artificial electron spin systems with a periodic structure having one to a few electrons at each site. They are expected to have various magnetic and even superconducting properties when structured at an optimal scale with a specific number i of electrons. Silicon turns out to be a very good material choice in realizing spin lattices. A metal-oxide-semiconductor field-effect nanostructure (MOSFENS) device, which is closely related to a MOS transistor but with a nanostructured oxide-semiconductor interface, can define the spin lattices potential at the interface and alter the occupation i with the gate electrode potential to change the magnetic phase. The MOSFENS spin lattices engineering challenge addressed in this work has come from the practical difficulty of process integration in modifying a transistor fabrication process to accommodate the interface patterning requirements. Two distinct design choices for the fabrication sequences that create the nanostructure have been examined. Patterning the silicon surface before the MOS gate stack layers gives a "nanostructure first" process, and patterning the interface after forming the gate stack gives a "nanostructure last process." Both processes take advantage of a nano-LOCOS (nano-local oxidation of silicon) invention developed in this work. The nano-LOCOS process plays a central role in defining a clean, sharp confining potential for the spin lattice electrons. The MOSFENS process required a basic transistor fabrication process that can accommodate the nanostructures. The process developed for this purpose has a gate stack with a 15 nm polysilicon gate electrode and a 3 nm thermal gate oxide on a p-type silicon substrate. The measured threshold voltage is 0.25 V. Device processes were examined for either isolating the devices with windows in the field oxide or with mesas defined by the etched trenches

  15. Oxide semiconductors for organic opto-electronic devices

    NASA Astrophysics Data System (ADS)

    Sigdel, Ajaya K.

    In this dissertation, I have introduced various concepts on the modulations of various surface, interface and bulk opto-electronic properties of ZnO based semiconductor for charge transport, charge selectivity and optimal device performance. I have categorized transparent semiconductors into two sub groups depending upon their role in a device. Electrodes, usually 200 to 500 nm thick, optimized for good transparency and transporting the charges to the external circuit. Here, the electrical conductivity in parallel direction to thin film, i.e bulk conductivity is important. And contacts, usually 5 to 50 nm thick, are optimized in case of solar cells for providing charge selectivity and asymmetry to manipulate the built in field inside the device for charge separation and collection. Whereas in Organic LEDs (OLEDs), contacts provide optimum energy level alignment at organic oxide interface for improved charge injections. For an optimal solar cell performance, transparent electrodes are designed with maximum transparency in the region of interest to maximize the light to pass through to the absorber layer for photo-generation, plus they are designed for minimum sheet resistance for efficient charge collection and transport. As such there is need for material with high conductivity and transparency. Doping ZnO with some common elements such as B, Al, Ga, In, Ge, Si, and F result in n-type doping with increase in carriers resulting in high conductivity electrode, with better or comparable opto-electronic properties compared to current industry-standard indium tin oxide (ITO). Furthermore, improvement in mobility due to improvement on crystallographic structure also provide alternative path for high conductivity ZnO TCOs. Implementing these two aspects, various studies were done on gallium doped zinc oxide (GZO) transparent electrode, a very promising indium free electrode. The dynamics of the superimposed RF and DC power sputtering was utilized to improve the

  16. III-V aresenide-nitride semiconductor materials and devices

    NASA Technical Reports Server (NTRS)

    Major, Jo S. (Inventor); Welch, David F. (Inventor); Scifres, Donald R. (Inventor)

    1997-01-01

    III-V arsenide-nitride semiconductor crystals, methods for producing such crystals and devices employing such crystals. Group III elements are combined with group V elements, including at least nitrogen and arsenic, in concentrations chosen to lattice match commercially available crystalline substrates. Epitaxial growth of these III-V crystals results in direct bandgap materials, which can be used in applications such as light emitting diodes and lasers. Varying the concentrations of the elements in the III-V crystals varies the bandgaps, such that materials emitting light spanning the visible spectra, as well as mid-IR and near-UV emitters, can be created. Conversely, such material can be used to create devices that acquire light and convert the light to electricity, for applications such as full color photodetectors and solar energy collectors. The growth of the III-V crystals can be accomplished by growing thin layers of elements or compounds in sequences that result in the overall lattice match and bandgap desired.

  17. Activation of molecular catalysts using semiconductor quantum dots

    DOEpatents

    Meyer, Thomas J.; Sykora, Milan; Klimov, Victor I.

    2011-10-04

    Photocatalytic materials based on coupling of semiconductor nanocrystalline quantum dots (NQD) and molecular catalysts. These materials have capability to drive or catalyze non-spontaneous chemical reactions in the presence of visible radiation, ultraviolet radiation, or both. The NQD functions in these materials as a light absorber and charge generator. Following light absorption, the NQD activates a molecular catalyst adsorbed on the surface of the NQD via transfer of one or more charges (either electrons or electron-holes) from the NQD to the molecular catalyst. The activated molecular catalyst can then drive a chemical reaction. A photoelectrolytic device that includes such photocatalytic materials is also described.

  18. Analysis of Carbon Nanotube Metal-Semiconductor Diode Device

    NASA Technical Reports Server (NTRS)

    Yamada, Toshishige; Biegel, Bryan (Technical Monitor)

    2001-01-01

    We study recently reported drain current I(sub d)-drain voltage V(sub d) characteristics of a carbon nanotube metal-semiconductor diode device with the gate voltage V(sub g) applied to modulate the carrier density in the nanotube. The diode was kink-shaped at the metal-semiconductor interface. It was shown that (1) larger negative V(sub g) blocked I(sub d) more effectively in the negative V(sub d) region, resulting in the rectifying I(sub d)-V(sub d) characteristics, and that (2) positive V(sub g) allowed I(sub d) in the both V(sub d) polarities, resulting in the non-rectifying characteristics. The negative V(sub d) was the Schottky reverse direction, judging from the negligible I(sub d) behavior for a wide region of -4 V (is less than) V(sub d) (is less than) 0 V, with V(sub g) = -4 V. Such negative V(sub g) would attract positive charges from the metallic electrodes (charge reservoir) to the nanotube and lower the nanotube Fermi energy (E(sub F)). With larger negative V(sub g), the experiment showed that the Schottky forward direction (V(sub d) (is greater than) 0) had a smaller turn-on voltage and the Schottky reverse direction (V(sub d) (is less than) 0) was more resistant to the tunneling breakdown. Therefore, the majority carriers in the transport would be electrons since they can see a lower tunneling barrier (shallower built-in potential) in the forward direction when E(sub F) is lowered, and a thicker tunneling barrier (Schottky barrier) in the reverse direction due to the reduction in the electron density when E(sub F) is lowered.

  19. An investigation of corrosion in semiconductor bridge explosive devices.

    SciTech Connect

    Klassen, Sandra Ellen; Sorensen, Neil Robert

    2007-05-01

    In the course of a failure investigation, corrosion of the lands was occasionally found in developmental lots of semiconductor bridge (SCB) detonators and igniters. Evidence was found in both detonators and igniters of the gold layer being deposited on top of a corroded aluminum layer, but inspection of additional dies from the same wafer did not reveal any more corroded parts. In some detonators, evidence was found that corrosion of the aluminum layer also happened after the gold was deposited. Moisture and chloride must both be present for aluminum to corrode. A likely source for chloride is the adhesive used to bond the die to the header. Inspection of other SCB devices, both recently manufactured and manufactured about ten years ago, found no evidence for corrosion even in devices that contained SCBs with aluminum lands and no gold. Several manufacturing defects were noted such as stains, gouges in the gold layer due to tooling, and porosity of the gold layer. Results of atmospheric corrosion experiments confirmed that devices with a porous gold layer over the aluminum layer are susceptible to extensive corrosion when both moisture and chlorine are present. The extent of corrosion depends on the level of chlorine contamination, and corrosion did not occur when only moisture was present. Elimination of the gold plating on the lands eliminated corrosion of the lands in these experiments. Some questions remain unanswered, but enough information was gathered to recommend changes to materials and procedures. A second lot of detonators was successfully built using aluminum SCBs, limiting the use of Ablebond{trademark} adhesive, increasing the rigor in controlling exposure to moisture, and adding inspection steps.

  20. Atomically Flat Surfaces Developed for Improved Semiconductor Devices

    NASA Technical Reports Server (NTRS)

    Powell, J. Anthony

    2001-01-01

    New wide bandgap semiconductor materials are being developed to meet the diverse high temperature, -power, and -frequency demands of the aerospace industry. Two of the most promising emerging materials are silicon carbide (SiC) for high-temperature and high power applications and gallium nitride (GaN) for high-frequency and optical (blue-light-emitting diodes and lasers) applications. This past year Glenn scientists implemented a NASA-patented crystal growth process for producing arrays of device-size mesas whose tops are atomically flat (i.e., step-free). It is expected that these mesas can be used for fabricating SiC and GaN devices with major improvements in performance and lifetime. The promising new SiC and GaN devices are fabricated in thin-crystal films (known as epi films) that are grown on commercial single-crystal SiC wafers. At this time, no commercial GaN wafers exist. Crystal defects, known as screw defects and micropipes, that are present in the commercial SiC wafers propagate into the epi films and degrade the performance and lifetime of subsequently fabricated devices. The new technology isolates the screw defects in a small percentage of small device-size mesas on the surface of commercial SiC wafers. This enables atomically flat surfaces to be grown on the remaining defect-free mesas. We believe that the atomically flat mesas can also be used to grow GaN epi films with a much lower defect density than in the GaN epi films currently being grown. Much improved devices are expected from these improved low-defect epi films. Surface-sensitive SiC devices such as Schottky diodes and field effect transistors should benefit from atomically flat substrates. Also, we believe that the atomically flat SiC surface will be an ideal surface on which to fabricate nanoscale sensors and devices. The process for achieving atomically flat surfaces is illustrated. The surface steps present on the "as-received" commercial SiC wafer is also illustrated. because of the

  1. Electroluminescent devices formed using semiconductor nanocrystals as an electron transport media and method of making such electroluminescent devices

    DOEpatents

    Alivisatos, A. Paul; Colvin, Vickie

    1996-01-01

    An electroluminescent device is described, as well as a method of making same, wherein the device is characterized by a semiconductor nanocrystal electron transport layer capable of emitting visible light in response to a voltage applied to the device. The wavelength of the light emitted by the device may be changed by changing either the size or the type of semiconductor nanocrystals used in forming the electron transport layer. In a preferred embodiment the device is further characterized by the capability of emitting visible light of varying wavelengths in response to changes in the voltage applied to the device. The device comprises a hole processing structure capable of injecting and transporting holes, and usually comprising a hole injecting layer and a hole transporting layer; an electron transport layer in contact with the hole processing structure and comprising one or more layers of semiconductor nanocrystals; and an electron injecting layer in contact with the electron transport layer for injecting electrons into the electron transport layer. The capability of emitting visible light of various wavelengths is principally based on the variations in voltage applied thereto, but the type of semiconductor nanocrystals used and the size of the semiconductor nanocrystals in the layers of semiconductor nanometer crystals may also play a role in color change, in combination with the change in voltage.

  2. Direct CVD Graphene Growth on Semiconductors and Dielectrics for Transfer-Free Device Fabrication.

    PubMed

    Wang, Huaping; Yu, Gui

    2016-07-01

    Graphene is the most broadly discussed and studied two-dimensional material because of its preeminent physical, mechanical, optical, and thermal properties. Until now, metal-catalyzed chemical vapor deposition (CVD) has been widely employed for the scalable production of high-quality graphene. However, in order to incorporate the graphene into electronic devices, a transfer process from metal substrates to targeted substrates is inevitable. This process usually results in contamination, wrinkling, and breakage of graphene samples - undesirable in graphene-based technology and not compatible with industrial production. Therefore, direct graphene growth on desired semiconductor and dielectric substrates is considered as an effective alternative. Over the past years, there have been intensive investigations to realize direct graphene growth using CVD methods without the catalytic role of metals. Owing to the low catalytic activity of non-metal substrates for carbon precursor decomposition and graphene growth, several strategies have been designed to facilitate and engineer graphene fabrication on semiconductors and insulators. Here, those developed strategies for direct CVD graphene growth on semiconductors and dielectrics for transfer-free fabrication of electronic devices are reviewed. By employing these methods, various graphene-related structures can be directly prepared on desired substrates and exhibit excellent performance, providing versatile routes for varied graphene-based materials fabrication.

  3. Advanced Numerical Methods and Software Approaches for Semiconductor Device Simulation

    DOE PAGES

    Carey, Graham F.; Pardhanani, A. L.; Bova, S. W.

    2000-01-01

    In this article we concisely present several modern strategies that are applicable to driftdominated carrier transport in higher-order deterministic models such as the driftdiffusion, hydrodynamic, and quantum hydrodynamic systems. The approaches include extensions of “upwind” and artificial dissipation schemes, generalization of the traditional Scharfetter – Gummel approach, Petrov – Galerkin and streamline-upwind Petrov Galerkin (SUPG), “entropy” variables, transformations, least-squares mixed methods and other stabilized Galerkin schemes such as Galerkin least squares and discontinuous Galerkin schemes. The treatment is representative rather than an exhaustive review and several schemes are mentioned only briefly with appropriate reference to the literature. Some of themore » methods have been applied to the semiconductor device problem while others are still in the early stages of development for this class of applications. We have included numerical examples from our recent research tests with some of the methods. A second aspect of the work deals with algorithms that employ unstructured grids in conjunction with adaptive refinement strategies. The full benefits of such approaches have not yet been developed in this application area and we emphasize the need for further work on analysis, data structures and software to support adaptivity. Finally, we briefly consider some aspects of software frameworks. These include dial-an-operator approaches such as that used in the industrial simulator PROPHET, and object-oriented software support such as those in the SANDIA National Laboratory framework SIERRA.« less

  4. Advanced numerical methods and software approaches for semiconductor device simulation

    SciTech Connect

    CAREY,GRAHAM F.; PARDHANANI,A.L.; BOVA,STEVEN W.

    2000-03-23

    In this article the authors concisely present several modern strategies that are applicable to drift-dominated carrier transport in higher-order deterministic models such as the drift-diffusion, hydrodynamic, and quantum hydrodynamic systems. The approaches include extensions of upwind and artificial dissipation schemes, generalization of the traditional Scharfetter-Gummel approach, Petrov-Galerkin and streamline-upwind Petrov Galerkin (SUPG), entropy variables, transformations, least-squares mixed methods and other stabilized Galerkin schemes such as Galerkin least squares and discontinuous Galerkin schemes. The treatment is representative rather than an exhaustive review and several schemes are mentioned only briefly with appropriate reference to the literature. Some of the methods have been applied to the semiconductor device problem while others are still in the early stages of development for this class of applications. They have included numerical examples from the recent research tests with some of the methods. A second aspect of the work deals with algorithms that employ unstructured grids in conjunction with adaptive refinement strategies. The full benefits of such approaches have not yet been developed in this application area and they emphasize the need for further work on analysis, data structures and software to support adaptivity. Finally, they briefly consider some aspects of software frameworks. These include dial-an-operator approaches such as that used in the industrial simulator PROPHET, and object-oriented software support such as those in the SANDIA National Laboratory framework SIERRA.

  5. Active RF Pulse Compression Using An Electrically Controlled Semiconductor Switch

    SciTech Connect

    Guo, Jiquan; Tantawi, Sami; /SLAC

    2007-01-10

    First we review the theory of active pulse compression systems using resonant delay lines. Then we describe the design of an electrically controlled semiconductor active switch. The switch comprises an active window and an overmoded waveguide three-port network. The active window is based on a four-inch silicon wafer which has 960 PIN diodes. These are spatially combined in an overmoded waveguide. We describe the philosophy and design methodology for the three-port network and the active window. We then present the results of using this device to compress 11.4 GHz RF signals with high compression ratios. We show how the system can be used with amplifier like sources, in which one can change the phase of the source by manipulating the input to the source. We also show how the active switch can be used to compress a pulse from an oscillator like sources, which is not possible with passive pulse compression systems.

  6. Resonant activation in bistable semiconductor lasers

    SciTech Connect

    Lepri, Stefano; Giacomelli, Giovanni

    2007-08-15

    We theoretically investigate the possibility of observing resonant activation in the hopping dynamics of two-mode semiconductor lasers. We present a series of simulations of a rate-equation model under random and periodic modulation of the bias current. In both cases, for an optimal choice of the modulation time scale, the hopping times between the stable lasing modes attain a minimum. The simulation data are understood by means of an effective one-dimensional Langevin equation with multiplicative fluctuations. Our conclusions apply to both edge-emitting and vertical cavity lasers, thus opening the way to several experimental tests in such optical systems.

  7. Electrical contacts for a thin-film semiconductor device

    DOEpatents

    Carlson, David E.; Dickson, Charles R.; D'Aiello, Robert V.

    1989-08-08

    A method of fabricating spaced-apart back contacts on a thin film of semiconductor material by forming strips of buffer material on top of the semiconductor material in locations corresponding to the desired dividing lines between back contacts, forming a film of metal substantially covering the semiconductor material and buffer strips, and scribing portions of the metal film overlying the buffer strips with a laser without contacting the underlying semiconductor material to separate the metal layer into a plurality of back contacts. The buffer material serves to protect the underlying semiconductor material from being damaged during the laser scribing. Back contacts and multi-cell photovoltaic modules incorporating such back contacts also are disclosed.

  8. Atomic origin of high-temperature electron trapping in metal-oxide-semiconductor devices

    SciTech Connect

    Shen, Xiao; Dhar, Sarit; Pantelides, Sokrates T.

    2015-04-06

    MOSFETs based on wide-band-gap semiconductors are suitable for operation at high temperature, at which additional atomic-scale processes that are benign at lower temperatures can get activated, resulting in device degradation. Recently, significant enhancement of electron trapping was observed under positive bias in SiC MOSFETs at temperatures higher than 150 °C. Here, we report first-principles calculations showing that the enhanced electron trapping is associated with thermally activated capturing of a second electron by an oxygen vacancy in SiO{sub 2} by which the vacancy transforms into a structure that comprises one Si dangling bond and a bond between a five-fold and a four-fold Si atoms. The results suggest a key role of oxygen vacancies and their structural reconfigurations in the reliability of high-temperature MOS devices.

  9. Accurate analytical modelling of cosmic ray induced failure rates of power semiconductor devices

    NASA Astrophysics Data System (ADS)

    Bauer, Friedhelm D.

    2009-06-01

    A new, simple and efficient approach is presented to conduct estimations of the cosmic ray induced failure rate for high voltage silicon power devices early in the design phase. This allows combining common design issues such as device losses and safe operating area with the constraints imposed by the reliability to result in a better and overall more efficient design methodology. Starting from an experimental and theoretical background brought forth a few yeas ago [Kabza H et al. Cosmic radiation as a cause for power device failure and possible countermeasures. In: Proceedings of the sixth international symposium on power semiconductor devices and IC's, Davos, Switzerland; 1994. p. 9-12, Zeller HR. Cosmic ray induced breakdown in high voltage semiconductor devices, microscopic model and possible countermeasures. In: Proceedings of the sixth international symposium on power semiconductor devices and IC's, Davos, Switzerland; 1994. p. 339-40, and Matsuda H et al. Analysis of GTO failure mode during d.c. blocking. In: Proceedings of the sixth international symposium on power semiconductor devices and IC's, Davos, Switzerland; 1994. p. 221-5], an exact solution of the failure rate integral is derived and presented in a form which lends itself to be combined with the results available from commercial semiconductor simulation tools. Hence, failure rate integrals can be obtained with relative ease for realistic two- and even three-dimensional semiconductor geometries. Two case studies relating to IGBT cell design and planar junction termination layout demonstrate the purpose of the method.

  10. Production of films and powders for semiconductor device applications

    DOEpatents

    Bhattacharya, Raghu Nath; Noufi, Rommel; Wang, Li

    1998-01-01

    A process for chemical bath deposition of selenide and sulfide salts as films and powders employable as precursors for the fabrication of solar cell devices. The films and powders include (1) Cu.sub.x Se.sub.n, wherein x=1-2 and n=1-3; (2) Cu.sub.x Ga.sub.y Se.sub.n, wherein x=1-2, y=0-1 and n=1-3; (3) Cu.sub.x In.sub.y Se.sub.n, wherein x=1-2.27, y=0.72-2 and n=1-3; (4) Cu.sub.x (InGa).sub.y Se.sub.n, wherein x=1-2.17, y=0.96-2 and n=1-3; (5) In.sub.y Se.sub.n, wherein y=1-2.3 and n=1-3; (6) Cu.sub.x S.sub.n, wherein x=1-2 and n=1-3; and (7) Cu.sub.x (InGa).sub.y (SeS).sub.n, wherein x=1-2, y=0.07-2 and n=0.663-3. A reaction vessel containing therein a substrate upon which will form one or more layers of semiconductor material is provided, and relevant solution mixtures are introduced in a sufficient quantity for a sufficient time and under favorable conditions into the vessel to react with each other to produce the resultant salt being prepared and deposited as one or more layers on the substrate and as a powder on the floor of the vessel. Hydrazine is present during all reaction processes producing non-gallium containing products and optionally present during reaction processes producing gallium-containing products to function as a strong reducing agent and thereby enhance reaction processes.

  11. Production of films and powders for semiconductor device applications

    DOEpatents

    Bhattacharya, R.N.; Noufi, R.; Li Wang

    1998-03-24

    A process is described for chemical bath deposition of selenide and sulfide salts as films and powders employable as precursors for the fabrication of solar cell devices. The films and powders include (1) Cu{sub x}Se{sub n}, wherein x=1--2 and n=1--3; (2) Cu{sub x}Ga{sub y}Se{sub n}, wherein x=1--2, y=0--1 and n=1--3; (3) Cu{sub x}In{sub y}Se{sub n}, wherein x=1--2.27, y=0.72--2 and n=1--3; (4) Cu{sub x}(InGa){sub y}Se{sub n}, wherein x=1--2.17, y=0.96--2 and n=1--3; (5) In{sub y}Se{sub n}, wherein y=1--2.3 and n=1--3; (6) Cu{sub x}S{sub n}, wherein x=1--2 and n=1--3; and (7) Cu{sub x}(InGa){sub y}(SeS){sub n}, wherein x=1--2, y=0.07--2 and n=0.663--3. A reaction vessel containing therein a substrate upon which will form one or more layers of semiconductor material is provided, and relevant solution mixtures are introduced in a sufficient quantity for a sufficient time and under favorable conditions into the vessel to react with each other to produce the resultant salt being prepared and deposited as one or more layers on the substrate and as a powder on the floor of the vessel. Hydrazine is present during all reaction processes producing non-gallium containing products and optionally present during reaction processes producing gallium-containing products to function as a strong reducing agent and thereby enhance reaction processes. 4 figs.

  12. EDITORIAL: Semiconductor nanotechnology: novel materials and devices for electronics, photonics and renewable energy applications Semiconductor nanotechnology: novel materials and devices for electronics, photonics and renewable energy applications

    NASA Astrophysics Data System (ADS)

    Goodnick, Stephen; Korkin, Anatoli; Krstic, Predrag; Mascher, Peter; Preston, John; Zaslavsky, Alex

    2010-04-01

    -14 August, Hamilton, Ontario, Canada) and the scope was expanded to include renewable energy research and development. This special issue of Nanotechnology is devoted to a better understanding of the function and design of semiconductor devices that are relevant to information technology (both electronics and photonics based) and renewable energy applications. The papers contained in this special issue are selected from the NGC/CSTC2009 symposium. Among them is a report by Ray LaPierre from McMaster University and colleagues at the University of Waterloo in Canada on the ability to manipulate single spins in nanowire quantum bits. The paper also reports the development of a testbed of a few qubits for general quantum information processing tasks [1]. Lower cost and greater energy conversion efficiency compared with thin film devices have led to a high level of activity in nanowire research related to photovoltaic applications. This special issue also contains results from an impedance spectroscopy study of core-shell GaAs nanowires to throw light on the transport and recombination mechanisms relevant to solar cell research [2]. Information technology research and renewable energy sources are research areas of enormous public interest. This special issue addresses both theoretical and experimental achievements and provides a stimulating outlook for technological developments in these highly topical fields of research. References [1] Caram J, Sandoval C, Tirado M, Comedi D, Czaban J, Thompson D A and LaPierre R R 2101 Nanotechnology 21 134007 [2] Baugh J, Fung J S and LaPierre RR 2010 Nanotechnology 21 134018

  13. Rare-Earth Doped Wide Bandgap Oxide Semiconductor Materials and Devices

    NASA Astrophysics Data System (ADS)

    Wellenius, Ian Patrick

    Amorphous oxide semiconductors composed of indium gallium zinc oxide are transparent to visible light and have higher electron mobilities than conventional amorphous semiconductors, such as amorphous silicon. The advantages of higher switching speed, lack of dangling bonds leading to good electronic stability and visible spectrum transparency of amorphous oxide semiconductor devices are expected to lead to numerous applications, including transparent displays and flexible electronics. In this thesis the integration of transparent thin film transistors with transparent electroluminescent pixels was investigated. Compared with display technologies employing organic semiconductors that degrade with exposure to moisture and ultraviolet light, the all-oxide structure of this device is expected to be environmentally robust. This is believed to be the first demonstration of an integrated active matrix pixel using amorphous oxide semiconductor materials as both the light emitter and addressing circuit elements. The transparent active matrix pixel was designed, fabricated and characterized, that integrated amorphous indium gallium zinc oxide (IGZO) thin film transistors (TFTs) with a europium-doped IGZO thin film electroluminescent (TFEL) device. The integrated circuits were fabricated using room temperature pulsed laser deposition (PLD) of IGZO and ITO thin films onto substrates of Corning 7059 glass, sputter coated with an ITO back contact and subsequent atomic layer deposited ATO high-k dielectric. A second ITO layer is deposited by PLD as a contact and interconnect layer. All deposition steps were carried out at room temperature. In addition to the integration task, an important part of this thesis concerns the investigation of europium as a dopant in different oxide hosts including gallium oxide, gadolinium oxide, and amorphous IGZO. Amorphous IGZO was chosen for the integration task since it could be deposited at room temperature, however it was found that the

  14. {100}<100> or 45.degree.-rotated {100}<100>, semiconductor-based, large-area, flexible, electronic devices

    DOEpatents

    Goyal, Amit

    2012-05-15

    Novel articles and methods to fabricate the same resulting in flexible, {100}<100> or 45.degree.-rotated {100}<100> oriented, semiconductor-based, electronic devices are disclosed. Potential applications of resulting articles are in areas of photovoltaic devices, flat-panel displays, thermophotovoltaic devices, ferroelectric devices, light emitting diode devices, computer hard disc drive devices, magnetoresistance based devices, photoluminescence based devices, non-volatile memory devices, dielectric devices, thermoelectric devices and quantum dot laser devices.

  15. Quantitative temperature measurement of multi-layered semiconductor devices using spectroscopic thermoreflectance microscopy.

    PubMed

    Kim, Dong Uk; Park, Kwan Seob; Jeong, Chan Bae; Kim, Geon Hee; Chang, Ki Soo

    2016-06-27

    Thermoreflectance microscopy is essential in understanding the unpredictable local heating generation that occurs during microelectronic device operation. However, temperature measurements of multi-layered semiconductor devices represent a challenge because the thermoreflectance coefficient is quite small and is dramatically changed by the optical interference inside transparent layers of the device. Therefore, we propose a spectroscopic thermoreflectance microscopy system using a systematic approach for improving the quantitative temperature measurement of multi-layered semiconductor devices. We demonstrate the quantitative measurement of the temperature profile for physical defects on thin-film polycrystalline silicon resistors via thermoreflectance coefficient calibration and effective coefficient κ estimation.

  16. Quantitative temperature measurement of multi-layered semiconductor devices using spectroscopic thermoreflectance microscopy.

    PubMed

    Kim, Dong Uk; Park, Kwan Seob; Jeong, Chan Bae; Kim, Geon Hee; Chang, Ki Soo

    2016-06-27

    Thermoreflectance microscopy is essential in understanding the unpredictable local heating generation that occurs during microelectronic device operation. However, temperature measurements of multi-layered semiconductor devices represent a challenge because the thermoreflectance coefficient is quite small and is dramatically changed by the optical interference inside transparent layers of the device. Therefore, we propose a spectroscopic thermoreflectance microscopy system using a systematic approach for improving the quantitative temperature measurement of multi-layered semiconductor devices. We demonstrate the quantitative measurement of the temperature profile for physical defects on thin-film polycrystalline silicon resistors via thermoreflectance coefficient calibration and effective coefficient κ estimation. PMID:27410553

  17. Silicon active photonic devices

    NASA Astrophysics Data System (ADS)

    Dimitropoulos, Dimitrios

    Active photonic devices utilizing the optical nonlinearities of silicon have emerged in the last 5 years and the effort for commercial photonic devices in the material that has been the workhorse of electronics has been building up since. This dissertation presents the theory for some of these devices. We are concerned herein with CW lasers, amplifiers and wavelength converters that are based on the Raman effect. There have already been cursory experimental demonstrations of these devices and some of their limitations are already apparent. Most of the limitations observed are because of the appearance of effects that are competing with stimulated Raman scattering. Under the high optical powers that are necessary for the Raman effect (tens to hundrends of mW's) the process of optical two-photon (TPA) absorption occurs. The absorption of optical power that it causes itself is weak but in the process electrons and holes are generated which can further absorb light through the free-carrier absorption effect (FCA). The effective "lifetime" that these carriers have determines the magnitude of the FCA loss. We present a model for the carrier lifetime in Silicon-On-Insulator (SOI) waveguides and numerical simulations to understand how this critical parameter varies and how it can be controlled. A p-i-n junction built along SOI waveguides can help achieve lifetime of the order of 20--100 ps but the price one has to pay is on-chip electrical power consumption on the order of 100's of mWs. We model CW Raman lasers and we find that the carrier lifetime reduces the output power. If the carrier lifetime exceeds a certain "critical" value optical losses become overwhelming and lasing is impossible. As we show, in amplifiers, the nonlinear loss does not only result in diminished gain, but also in a higher noise figure. Finally the effect of Coherent anti-Stokes Raman scattering (CARS) is examined. The effect is important because with a pump frequency at 1434nm coherent power

  18. Exploring graphene field effect transistor devices to improve spectral resolution of semiconductor radiation detectors

    SciTech Connect

    Harrison, Richard Karl; Howell, Stephen Wayne; Martin, Jeffrey B.; Hamilton, Allister B.

    2013-12-01

    Graphene, a planar, atomically thin form of carbon, has unique electrical and material properties that could enable new high performance semiconductor devices. Graphene could be of specific interest in the development of room-temperature, high-resolution semiconductor radiation spectrometers. Incorporating graphene into a field-effect transistor architecture could provide an extremely high sensitivity readout mechanism for sensing charge carriers in a semiconductor detector, thus enabling the fabrication of a sensitive radiation sensor. In addition, the field effect transistor architecture allows us to sense only a single charge carrier type, such as electrons. This is an advantage for room-temperature semiconductor radiation detectors, which often suffer from significant hole trapping. Here we report on initial efforts towards device fabrication and proof-of-concept testing. This work investigates the use of graphene transferred onto silicon and silicon carbide, and the response of these fabricated graphene field effect transistor devices to stimuli such as light and alpha radiation.

  19. Biasing, operation and parasitic current limitation in single device equivalent to CMOS, and other semiconductor systems

    DOEpatents

    Welch, James D.

    2003-09-23

    Disclosed are semiconductor devices including at least one junction which is rectifying whether the semiconductor is caused to be N or P-type, by the presence of applied gate voltage field induced carriers in essentially intrinsic, essentially homogeneously simultaneously containing both N and P-type metallurgical dopants at substantially equal doping levels, essentially homogeneously simultaneously containing both N and P-type metallurgical dopants at different doping levels, and containing a single metallurgical doping type, and functional combinations thereof. In particular, inverting and non-inverting gate voltage channel induced semiconductor single devices with operating characteristics similar to conventional multiple device CMOS systems, which can be operated as modulators, are disclosed as are a non-latching SCR and an approach to blocking parasitic currents utilizing material(s) which form rectifying junctions with both N and P-type semiconductor whether metallurigically or field induced.

  20. Accelerated Aging System for Prognostics of Power Semiconductor Devices

    NASA Technical Reports Server (NTRS)

    Celaya, Jose R.; Vashchenko, Vladislav; Wysocki, Philip; Saha, Sankalita

    2010-01-01

    Prognostics is an engineering discipline that focuses on estimation of the health state of a component and the prediction of its remaining useful life (RUL) before failure. Health state estimation is based on actual conditions and it is fundamental for the prediction of RUL under anticipated future usage. Failure of electronic devices is of great concern as future aircraft will see an increase of electronics to drive and control safety-critical equipment throughout the aircraft. Therefore, development of prognostics solutions for electronics is of key importance. This paper presents an accelerated aging system for gate-controlled power transistors. This system allows for the understanding of the effects of failure mechanisms, and the identification of leading indicators of failure which are essential in the development of physics-based degradation models and RUL prediction. In particular, this system isolates electrical overstress from thermal overstress. Also, this system allows for a precise control of internal temperatures, enabling the exploration of intrinsic failure mechanisms not related to the device packaging. By controlling the temperature within safe operation levels of the device, accelerated aging is induced by electrical overstress only, avoiding the generation of thermal cycles. The temperature is controlled by active thermal-electric units. Several electrical and thermal signals are measured in-situ and recorded for further analysis in the identification of leading indicators of failures. This system, therefore, provides a unique capability in the exploration of different failure mechanisms and the identification of precursors of failure that can be used to provide a health management solution for electronic devices.

  1. Active multistable twisting device

    NASA Technical Reports Server (NTRS)

    Schultz, Marc R. (Inventor)

    2008-01-01

    Two similarly shaped, such as rectangular, shells are attached to one another such that they form a resulting thin airfoil-like structure. The resulting device has at least two stable equilibrium shapes. The device can be transformed from one shape to another with a snap-through action. One or more actuators can be used to effect the snap-through; i.e., transform the device from one stable shape to another. Power to the actuators is needed only to transform the device from one shape to another.

  2. Sputtered pin amorphous silicon semi-conductor device and method therefor

    DOEpatents

    Moustakas, Theodore D.; Friedman, Robert A.

    1983-11-22

    A high efficiency amorphous silicon PIN semi-conductor device is constructed by the sequential sputtering of N, I and P layers of amorphous silicon and at least one semi-transparent ohmic electrode. A method of construction produces a PIN device, exhibiting enhanced physical integrity and facilitates ease of construction in a singular vacuum system and vacuum pump down procedure.

  3. Hybrid method of making an amorphous silicon P-I-N semiconductor device

    DOEpatents

    Moustakas, Theodore D.; Morel, Don L.; Abeles, Benjamin

    1983-10-04

    The invention is directed to a hydrogenated amorphous silicon PIN semiconductor device of hybrid glow discharge/reactive sputtering fabrication. The hybrid fabrication method is of advantage in providing an ability to control the optical band gap of the P and N layers, resulting in increased photogeneration of charge carriers and device output.

  4. Semiconductor Devices and Applications. Electronics Module 5. Instructor's Guide.

    ERIC Educational Resources Information Center

    Chappell, John; And Others

    This module is the fifth of 10 modules in the competency-based electronics series. Introductory materials include a listing of competencies addressed in the module, a parts/equipment list, and a cross-reference table of instructional materials. Sixteen instructional units cover: semiconductor materials; diodes; diode applications and…

  5. The structure of constitutive equations for semiconductor devices

    SciTech Connect

    Buchanan, G.R.; Girrens, S.P.; Bennett, J.G.

    1987-01-01

    The fundamental equations that describe carrier transport in semiconductor materials are developed using the methods of continuum mixture theory and Maxwell's equations for electrodynamics. There are five basic equations that govern the behavior of current flux, electrostatic potential, electrons, and holes. The bahavior of the electrical chemical potentials are introduced and their relation to the current flux is discussed.

  6. High Temperature Superconductor/Semiconductor Hybrid Microwave Devices and Circuits

    NASA Technical Reports Server (NTRS)

    Romanofsky, Robert R.; Miranda, Felix A.

    1999-01-01

    Contents include following: film deposition technique; laser ablation; magnetron sputtering; sequential evaporation; microwave substrates; film characterization at microwave frequencies; complex conductivity; magnetic penetration depth; surface impedance; planar single-mode filters; small antennas; antenna arrays phase noise; tunable oscillations; hybrid superconductor/semiconductor receiver front ends; and noise modeling.

  7. Electronic-carrier-controlled photochemical etching process in semiconductor device fabrication

    DOEpatents

    Ashby, C.I.H.; Myers, D.R.; Vook, F.L.

    1988-06-16

    An electronic-carrier-controlled photochemical etching process for carrying out patterning and selective removing of material in semiconductor device fabrication includes the steps of selective ion implanting, photochemical dry etching, and thermal annealing, in that order. In the selective ion implanting step, regions of the semiconductor material in a desired pattern are damaged and the remainder of the regions of the material not implanted are left undamaged. The rate of recombination of electrons and holes is increased in the damaged regions of the pattern compared to undamaged regions. In the photochemical dry etching step which follows ion implanting step, the material in the undamaged regions of the semiconductor are removed substantially faster than in the damaged regions representing the pattern, leaving the ion-implanted, damaged regions as raised surface structures on the semiconductor material. After completion of photochemical dry etching step, the thermal annealing step is used to restore the electrical conductivity of the damaged regions of the semiconductor material.

  8. Electronic-carrier-controlled photochemical etching process in semiconductor device fabrication

    DOEpatents

    Ashby, Carol I. H.; Myers, David R.; Vook, Frederick L.

    1989-01-01

    An electronic-carrier-controlled photochemical etching process for carrying out patterning and selective removing of material in semiconductor device fabrication includes the steps of selective ion implanting, photochemical dry etching, and thermal annealing, in that order. In the selective ion implanting step, regions of the semiconductor material in a desired pattern are damaged and the remainder of the regions of the material not implanted are left undamaged. The rate of recombination of electrons and holes is increased in the damaged regions of the pattern compared to undamaged regions. In the photochemical dry etching step which follows ion implanting step, the material in the undamaged regions of the semiconductor are removed substantially faster than in the damaged regions representing the pattern, leaving the ion-implanted, damaged regions as raised surface structures on the semiconductor material. After completion of photochemical dry etching step, the thermal annealing step is used to restore the electrical conductivity of the damaged regions of the semiconductor material.

  9. Spectroscopy of semiconductor meta-device building blocks (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Butakov, Nikita A.; Schuller, Jon A.

    2015-09-01

    Inspired by the potential of designing highly efficient nanophotonic optical elements, numerous researchers are currently exploring the use of dielectric resonators in constructing meta-devices. A wide range of optical components have been demonstrated, including metasurfaces that act as two-dimensional lenses, gratings, and axicons. At the core of these devices is a dielectric building block, typically a Silicon nano-disk or nano-rod, that supports Mie-like leaky mode excitations with a geometrically tunable amplitude and phase response. Here we present a comprehensive experimental characterization of these building blocks. We elucidate their multipolar mode structure, and explain the dependence on the underlying substrate. We find that fundamentally new buried magnetic modes emerge in high-index substrates, and that Fabry-Perot effects in silicon-on-insulator platforms can be utilized to enhance or suppress specific modes. When individual resonators are arranged into arrays with sub-wavelength periodicities, inter-particle coupling leads to a shift in the resonant response. When the periodicities are on the same order as the operating wavelength, the localized resonances may couple with the global diffraction modes, leading to the possible formation of distinct high-quality-factor surface-lattice-resonant modes, similar to those encountered in plasmonic gratings. We conclude by exploring the behavior of resonators constructed out of active materials, such as polar materials that support phonon-polariton excitations, and phase-change materials with tunable dielectric constants.

  10. Growth of coincident site lattice matched semiconductor layers and devices on crystalline substrates

    DOEpatents

    Norman, Andrew G; Ptak, Aaron J

    2013-08-13

    Methods of fabricating a semiconductor layer or device and said devices are disclosed. The methods include but are not limited to providing a substrate having a crystalline surface with a known lattice parameter (a). The method further includes growing a crystalline semiconductor layer on the crystalline substrate surface by coincident site lattice matched epitaxy, without any buffer layer between the crystalline semiconductor layer and the crystalline surface of the substrate. The crystalline semiconductor layer will be prepared to have a lattice parameter (a') that is related to the substrate lattice parameter (a). The lattice parameter (a') maybe related to the lattice parameter (a) by a scaling factor derived from a geometric relationship between the respective crystal lattices.

  11. Solid state technology: A compilation. [on semiconductor devices

    NASA Technical Reports Server (NTRS)

    1973-01-01

    A compilation, covering selected solid state devices developed and integrated into systems by NASA to improve performance, is presented. Data are also given on device shielding in hostile radiation environments.

  12. Polycrystalline or amorphous semiconductor photovoltaic device having improved collection efficiency

    NASA Technical Reports Server (NTRS)

    Kressel, Henry (Inventor); D'Aiello, Robert Vincent (Inventor); Robinson, Paul Harvey (Inventor)

    1978-01-01

    A body of semiconductor material having a first surface and a second surface spaced from the first surface includes a first layer along the first surface, a second layer along the second surface, a third layer between and contiguous to the first and second layers. The third layer is of a conductivity type opposite that of the first and second layers so as to form first and second P-N junctions respectively therebetween. The thickness of the third layer is at least twice the minority carrier diffusion length of the semiconductor material, so that carriers generated within the third layer have a high probability of being collected by one of the P-N junctions. The body includes means for electrically connecting the first and second P-N junctions and means for transferring the carriers collected at the first P-N junction to a portion of the first surface.

  13. Terahertz optoelectronic devices based on intersubband transitions in III-nitride semiconductors

    NASA Astrophysics Data System (ADS)

    Sudradjat, Faisal Firmansyah

    The terahertz (THz) spectral region, commonly defined as the frequency (wavelength) range between 0.3 and 10 THz (1 mm and 30 µm) has many important applications in the industrial, biomedical, and military sectors. However, due to a lack of practical semiconductor materials with adequately small bandgap energy, the development of THz light sources and photodetectors has so far been limited. In recent years, devices based on intersubband transitions between discrete energy states in quantum heterostructures have been under intense research and development to address this issue. Of particular promise in the THz range are quantum cascade lasers (QCLs) and quantum well infrared photodetectors (QWIPs), which utilize intersubband transitions in specially designed quantum well (QW) structures to emit light and generate photocurrent, respectively. This research work has focused on the development of THz light sources and photodetectors using intersubband transitions in GaN/AlGaN QWs, whose basic materials properties allow for improved spectral coverage and high-temperature operation compared to existing semiconductor devices. To design the active region of QCLs and QWIPs based on inter-conduction-subband transitions in these materials, the necessary numerical tools have first been developed. Sequential tunneling, the key electronic transport mechanism of intersubband light emitters, has then been demonstrated in GaN/AlGaN QC structures. Furthermore, we have measured promising THz electroluminescence spectra from the same devices through the use of lock-in step-scan Fourier transform infrared spectroscopy. In the area of photodetectors, we have developed a novel double-step QW design in order to overcome the material limitations presented by the intrinsic internal electric fields of GaN/AlGaN QWs. With this design approach, we have experimentally demonstrated the operation of a far infrared QWIP with a peak detection wavelength of 23 µm (13 THz frequency), which is the

  14. Device Concepts Based on Spin-dependent Transmission in Semiconductor Heterostructures

    NASA Technical Reports Server (NTRS)

    Ting, David Z. - Y.; Cartoixa, X.

    2004-01-01

    We examine zero-magnetic-field spin-dependent transmission in nonmagnetic semiconductor heterostructures with structural inversion asymmetry (SIA) and bulk inversion asymmetry (BIA), and report spin devices concepts that exploit their properties. Our modeling results show that several design strategies could be used to achieve high spin filtering efficiencies. The current spin polarization of these devices is electrically controllable, and potentially amenable to highspeed spin modulation, and could be integrated in optoelectronic devices for added functionality.

  15. Nonlinear fibre-optic devices pumped by semiconductor disk lasers

    SciTech Connect

    Chamorovskiy, A Yu; Okhotnikov, Oleg G

    2012-11-30

    Semiconductor disk lasers offer a unique combination of characteristics that are particularly attractive for pumping Raman lasers and amplifiers. The advantages of disk lasers include a low relative noise intensity (-150 dB Hz{sup -1}), scalable (on the order of several watts) output power, and nearly diffraction-limited beam quality resulting in a high ({approx}70 % - 90 %) coupling efficiency into a single-mode fibre. Using this technology, low-noise fibre Raman amplifiers operating at 1.3 {mu}m in co-propagation configuration are developed. A hybrid Raman-bismuth doped fibre amplifier is proposed to further increase the pump conversion efficiency. The possibility of fabricating mode-locked picosecond fibre lasers operating under both normal and anomalous dispersion is shown experimentally. We demonstrate the operation of 1.38-{mu}m and 1.6-{mu}m passively mode-locked Raman fibre lasers pumped by 1.29-{mu}m and 1.48-{mu}m semiconductor disk lasers and producing 1.97- and 2.7-ps pulses, respectively. Using a picosecond semiconductor disk laser amplified with an ytterbium-erbium fibre amplifier, the supercontinuum generation spanning from 1.35 {mu}m to 2 {mu}m is achieved with an average power of 3.5 W. (invited paper)

  16. Semiconductor nanowire devices: Novel morphologies and applications to electrogenic biological systems

    NASA Astrophysics Data System (ADS)

    Timko, Brian Paul

    The interface between nanoscale semiconductors and biological systems represents a powerful means for molecular-scale, two-way communication between these two diverse yet complementary systems. In this thesis, I present a general methodology for the synthesis of semiconductor nanowires with rationally-defined material composition and geometry. Specifically, I demonstrate that this technique can be used to fabricate silicon nanowires, hollow nanostructures (e.g. nanotubes, nanocones and branched tubular networks), and Ge/Si heterostructures that exhibit 1D hole gasses. Using bottom-up assembly techniques, nanostructures are subsequently built into arrays containing up to tens of nanowire field-effect transistors (NW-FETs) that exhibit exquisite sensitivity to local charges. Significantly, this robust assembly technique enables integration of disparate materials (e.g. n- and p-type silicon nanowires) on virtually any type of substrate. These arrays are particularly useful for integration with biological systems. I will demonstrate that at the single-cell level, silicon nanowire device arrays can be integrated with mammalian neurons. Discrete hybrid structures enable neuronal stimulation and recording at the axon, dendrite, or soma with high sensitivity and spatial resolution, while aligned arrays containing up to 50 devices can be used to measure the speed and temporal evolution of signals or to interact with a single cell as multiple inputs and outputs. I analyze the shape and magnitude of reported signals, and place within the context of previously reported results. Hybrid interfaces can also be extended to entire organs such as embryonic chicken hearts. NW-FET signals are synchronized with the beating heart, and the signal amplitude is directly related to the device sensitivity. Multiplexed measurements made from NW-FET arrays further show that signal propagation across the myocardium can be mapped, with a potential resolution significantly better than

  17. Device processing of wide bandgap semiconductors - challenges and directions

    SciTech Connect

    Pearton, S.J.; Shul, R.J.; Zolper, J.C.

    1997-10-01

    The wide gap materials SiC, GaN and to a lesser extent diamond are attracting great interest for high power/high temperature electronics. There are a host of device processing challenges presented by these materials because of their physical and chemical stability, including difficulty in achieving stable, low contact resistances, especially for one conductivity type, absence of convenient wet etch recipes, generally slow dry etch rates, the high temperatures needed for implant activation, control of suitable gate dielectrics and the lack of cheap, large diameter conducting and semi-insulating substrates. The relatively deep ionization levels of some of the common dopants (Mg, in GaN; B, Al in SiC; P in diamond) means that carrier densities may be low at room temperature even if the impurity is electrically active - this problem will be reduced at elevated temperature, and thus contact resistances will be greatly improved provided the metallization is stable and reliable. Some recent work with CoSi{sub x} on SiC and W-alloys on GaN show promise for improved ohmic contacts. The issue of unintentional hydrogen passivation of dopants will also be covered - this leads to strong increases in resistivity of p-SiC and GaN, but to large decreases in resistivity of diamond. Recent work on development of wet etches has found recipes for AlN (KOH), while photochemical etching of SiC and GaN has been reported. In the latter cases p-type materials is not etched, which can be a major liability in some devices. The dry etch results obtained with various novel reactors, including ICP, ECR and LE4 will be compared - the high ion densities in the former techniques produce the highest etch rates for strongly-bonded materials, but can lead to preferential loss of N from the nitrides and therefore to a highly conducting surface. This is potentially a major problem for fabrication of dry etched, recessed gate FET structures.

  18. Study on the photoresponse of amorphous In-Ga-Zn-O and zinc oxynitride semiconductor devices by the extraction of sub-gap-state distribution and device simulation.

    PubMed

    Jang, Jun Tae; Park, Jozeph; Ahn, Byung Du; Kim, Dong Myong; Choi, Sung-Jin; Kim, Hyun-Suk; Kim, Dae Hwan

    2015-07-22

    Persistent photoconduction (PPC) is a phenomenon that limits the application of oxide semiconductor thin-film transistors (TFTs) in optical sensor-embedded displays. In the present work, a study on zinc oxynitride (ZnON) semiconductor TFTs based on the combination of experimental results and device simulation is presented. Devices incorporating ZnON semiconductors exhibit negligible PPC effects compared with amorphous In-Ga-Zn-O (a-IGZO) TFTs, and the difference between the two types of materials are examined by monochromatic photonic C-V spectroscopy (MPCVS). The latter method allows the estimation of the density of subgap states in the semiconductor, which may account for the different behavior of ZnON and IGZO materials with respect to illumination and the associated PPC. In the case of a-IGZO TFTs, the oxygen flow rate during the sputter deposition of a-IGZO is found to influence the amount of PPC. Small oxygen flow rates result in pronounced PPC, and large densities of valence band tail (VBT) states are observed in the corresponding devices. This implies a dependence of PPC on the amount of oxygen vacancies (VO). On the other hand, ZnON has a smaller bandgap than a-IGZO and contains a smaller density of VBT states over the entire range of its bandgap energy. Here, the concept of activation energy window (AEW) is introduced to explain the occurrence of PPC effects by photoinduced electron doping, which is likely to be associated with the formation of peroxides in the semiconductor. The analytical methodology presented in this report accounts well for the reduction of PPC in ZnON TFTs, and provides a quantitative tool for the systematic development of phototransistors for optical sensor-embedded interactive displays.

  19. Dynamic detection of electron spin accumulation in ferromagnet–semiconductor devices by ferromagnetic resonance

    PubMed Central

    Liu, Changjiang; Patel, Sahil J.; Peterson, Timothy A.; Geppert, Chad C.; Christie, Kevin D.; Stecklein, Gordon; Palmstrøm, Chris J.; Crowell, Paul A.

    2016-01-01

    A distinguishing feature of spin accumulation in ferromagnet–semiconductor devices is its precession in a magnetic field. This is the basis for detection techniques such as the Hanle effect, but these approaches become ineffective as the spin lifetime in the semiconductor decreases. For this reason, no electrical Hanle measurement has been demonstrated in GaAs at room temperature. We show here that by forcing the magnetization in the ferromagnet to precess at resonance instead of relying only on the Larmor precession of the spin accumulation in the semiconductor, an electrically generated spin accumulation can be detected up to 300 K. The injection bias and temperature dependence of the measured spin signal agree with those obtained using traditional methods. We further show that this approach enables a measurement of short spin lifetimes (<100 ps), a regime that is not accessible in semiconductors using traditional Hanle techniques. PMID:26777243

  20. Reconditioning of semiconductor substrates to remove photoresist during semiconductor device fabrication

    DOEpatents

    Farino, Anthony J.

    2004-01-27

    A method for reconditioning the surface of a semiconductor substrate to remove an unwanted (i.e. defective) layer of photoresist is disclosed. The method adapts a conventional automated spinner which is used to rotate the substrate at high speed while a stream of a first solvent (e.g. acetone) is used to dissolve the photoresist. A stream of a second solvent (e.g. methanol) is then used to clean the substrate at a lower speed, with the substrate being allowed to dry with continued rotation. The method of the present invention can be used within a photolithography track so that the substrates need never leave the track for reconditioning.

  1. SEMICONDUCTOR DEVICES: Guided modes in a rectangular waveguide with semiconductor metamaterial

    NASA Astrophysics Data System (ADS)

    Tingting, Tang; Fushen, Chen; Bao, Sun

    2010-05-01

    The dispersion equations of bulk modes and surface modes in a rectangular waveguide of semiconductor metamaterial are derived by a modified “Marcatili's method". The cutoff frequencies of the lowest TM bulk mode are discussed, and the Brillouin diagrams of different bulk modes are drawn. They demonstrate that different heights correspond to different guidance frequency ranges which have no superposition with each other and a waveguide with a larger height possesses a wider passband of light. In addition, tendencies of degeneracy for different modes are observed. Finally, the existence of surface modes is verified by a graphical method.

  2. Investigation of radiation effects on semiconductor devices and integrated circuits

    NASA Astrophysics Data System (ADS)

    Shanfield, Zef; Srour, Joseph R.; Moriwaki, Melvin; Kitazaki, Kerry S.; Hartmann, Robert A.

    1988-09-01

    Results of a study of radiation effects on electronic materials, devices, and integrated circuits are presented in this report. Emphasis was placed on determining the underlying mechanisms responsible for observed radiation effects with a view toward gaining understanding of value in the development of radiation-hardened devices. Measurements and analyses were made of the effects of single energetic neutrons and protons on silicon integrated circuits. In addition, a detailed description is given of the effects of radiation-induced displacement damage on device depletion regions. Single event upset studies included charge collection and transient current measurements on Si and GaAs devices following a single alpha-particle strike. The angular dependence of charge funneling was also investigated. The mechanisms of ionizing radiation effects on Si MOS devices were explored in detail using the thermally stimulated current technique and other measurement approaches. Data obtained by several techniques show that use of the radiation-induced shift of the capacitance-voltage curve at midgap is not generally valid for determining oxide trapped charge.

  3. PREFACE: Semiconductor Nanostructures towards Electronic and Optoelectronic Device Applications II (Symposium K, E-MRS 2009 Spring Meeting)

    NASA Astrophysics Data System (ADS)

    Nötzel, Richard

    2009-07-01

    This volume of IOP Conference Series: Materials Science and Engineering contains papers that were presented at the special symposium K at the EMRS 2009 Spring Meeting held 8-12 June in Strasbourg, France, which was entitled 'Semiconductor Nanostructures towards Electronic and Optoelectronic Device Applications II'. Thanks to the broad interest a large variety of quantum dots and quantum wires and related nanostructures and their application in devices could be covered. There was significant progress in the epitaxial growth of semiconductor quantum dots seen in the operation of high-power, as well as mode locked laser diodes and the lateral positioning of quantum dots on patterned substrates or by selective area growth for future single quantum dot based optoelectronic and electronic devices. In the field of semiconductor nanowires high quality, almost twin free structures are now available together with a new degree of freedom for band structure engineering based on alternation of the crystal structure. In the search for Si based light emitting structures, nanocrystals and miniband-related near infrared luminescence of Si/Ge quantum dot superlattices with high quantum efficiency were reported. These highlights, among others, and the engaged discussions of the scientists, engineers and students brought together at the symposium emphasize how active the field of semiconductor nanostructures and their applications in devices is, so that we can look forward to the progress to come. Guest Editor Richard Nötzel COBRA Research Institute Department of Applied Physics Eindhoven University of Technology 5600 MB Eindhoven The Netherlands Tel.: +31 40 247 2047; fax: +31 40 246 1339 E-mail address: r.noetzel@tue.nl

  4. Total-dose radiation effects data for semiconductor devices (1989 supplement)

    NASA Technical Reports Server (NTRS)

    Martin, Keith E.; Coss, James R.; Goben, Charles A.; Shaw, David C.; Farmanesh, Sam; Davarpanah, Michael M.; Craft, Leroy H.; Price, William E.

    1990-01-01

    Steady state, total dose radiation test data are provided for electronic designers and other personnel using semiconductor devices in a radiation environment. The data are presented in graphic and narrative formats. Two primary radiation source types were used: Cobalt-60 gamma rays and a Dynamitron electron accelerator capable of delivering 2.5 MeV electrons at a steady rate.

  5. 77 FR 19032 - Certain Semiconductor Integrated Circuit Devices and Products Containing Same Notice of Receipt...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-29

    ...Notice is hereby given that the U.S. International Trade Commission has received a complaint entitled Certain Semiconductor Integrated Circuit Devices and Products Containing Same, DN 2888; the Commission is soliciting comments on any public interest issues raised by the complaint or complainant's filing under section 210.8(b) of the Commission's Rules of Practice and Procedure (19 CFR......

  6. Recent Developments in p-Type Oxide Semiconductor Materials and Devices.

    PubMed

    Wang, Zhenwei; Nayak, Pradipta K; Caraveo-Frescas, Jesus A; Alshareef, Husam N

    2016-05-01

    The development of transparent p-type oxide semiconductors with good performance may be a true enabler for a variety of applications where transparency, power efficiency, and greater circuit complexity are needed. Such applications include transparent electronics, displays, sensors, photovoltaics, memristors, and electrochromics. Hence, here, recent developments in materials and devices based on p-type oxide semiconductors are reviewed, including ternary Cu-bearing oxides, binary copper oxides, tin monoxide, spinel oxides, and nickel oxides. The crystal and electronic structures of these materials are discussed, along with approaches to enhance valence-band dispersion to reduce effective mass and increase mobility. Strategies to reduce interfacial defects, off-state current, and material instability are suggested. Furthermore, it is shown that promising progress has been made in the performance of various types of devices based on p-type oxides. Several innovative approaches exist to fabricate transparent complementary metal oxide semiconductor (CMOS) devices, including novel device fabrication schemes and utilization of surface chemistry effects, resulting in good inverter gains. However, despite recent developments, p-type oxides still lag in performance behind their n-type counterparts, which have entered volume production in the display market. Recent successes along with the hurdles that stand in the way of commercial success of p-type oxide semiconductors are presented. PMID:26879813

  7. Recent Developments in p-Type Oxide Semiconductor Materials and Devices.

    PubMed

    Wang, Zhenwei; Nayak, Pradipta K; Caraveo-Frescas, Jesus A; Alshareef, Husam N

    2016-05-01

    The development of transparent p-type oxide semiconductors with good performance may be a true enabler for a variety of applications where transparency, power efficiency, and greater circuit complexity are needed. Such applications include transparent electronics, displays, sensors, photovoltaics, memristors, and electrochromics. Hence, here, recent developments in materials and devices based on p-type oxide semiconductors are reviewed, including ternary Cu-bearing oxides, binary copper oxides, tin monoxide, spinel oxides, and nickel oxides. The crystal and electronic structures of these materials are discussed, along with approaches to enhance valence-band dispersion to reduce effective mass and increase mobility. Strategies to reduce interfacial defects, off-state current, and material instability are suggested. Furthermore, it is shown that promising progress has been made in the performance of various types of devices based on p-type oxides. Several innovative approaches exist to fabricate transparent complementary metal oxide semiconductor (CMOS) devices, including novel device fabrication schemes and utilization of surface chemistry effects, resulting in good inverter gains. However, despite recent developments, p-type oxides still lag in performance behind their n-type counterparts, which have entered volume production in the display market. Recent successes along with the hurdles that stand in the way of commercial success of p-type oxide semiconductors are presented.

  8. Development of a multi-physics simulation framework for semiconductor materials and devices

    NASA Astrophysics Data System (ADS)

    Almeida, Nuno Sucena

    Modern day semiconductor technology devices face the ever increasing issue of accounting for quantum mechanics effects on their modeling and performance assessment. The objective of this work is to create a user-friendly, extensible and powerful multi-physics simulation blackbox for nano-scale semiconductor devices. By using a graphical device modeller this work will provide a friendly environment were a user without deep knowledge of device physics can create a device, simulate it and extract optical and electrical characteristics deemed of interest to his engineering occupation. Resorting to advanced template C++ object-oriented design from the start, this work was able to implement algorithms to simulate 1,2 and 3D devices which along with scripting using the well known Python language enables the user to create batch simulations, to better optimize device performance. Higher-dimensional semiconductors, like wires and dots, require a huge computational cost. MPI parallel libraries enable the software to tackle complex geometries which otherwise would be unfeasible on a small single-CPU computer. Quantum mechanical phenomena is described by Schrodinger's equation which must be solved self-consistently with Poisson's equation for the electrostatic charge and, if required, make use of piezoelectric charge terms from elasticity constraints. Since the software implements a generic n-dimensional FEM engine, virtually any kind of Partial Differential Equation can be solved and in the future, other required solvers besides the ones already implemented will also be included for easy of use. In particular for the semiconductor device physics, we solve the quantum mechanics effective mass conduction-valence band k·p approximation to the Schrodinger-Poisson, in any crystal growth orientation (C,polar M,A and semi-polar planes or any user defined angle) and also include Piezoelectric effects caused by strain in lattice mismatched layers, where the implemented software

  9. Ferromagnet-semiconductor device with tunable tunnel characteristics

    NASA Astrophysics Data System (ADS)

    Heide, C.

    2000-05-01

    A device is proposed consisting of a GaAs/AlxGa1-xAs heterostructure with a ferromagnetic strip placed on top that has an easy axis of magnetization perpendicular to the underlying two-dimensional electron gas. In addition, the strip is gated to form a combined magnetostatic and electrostatic barrier for the conduction electrons. On the basis of a simple model, which is of the Landauer-Büttiker type, such a structure is shown to have three different regimes of operation. Whereas for a certain regime, electrons can move according to the classical diamagnetic motion, there is also the possibility of tuning the device between nonresonant and resonant tunneling behavior. In the latter case the combined magnetostatic and electrostatic barrier acts as an energy and momentum filter. The proposed device could find application in digital logic circuits as an electromagnetic field-effect transistor.

  10. Wide-Bandgap Semiconductor Devices for Automotive Applications

    NASA Astrophysics Data System (ADS)

    Sugimoto, M.; Ueda, H.; Uesugi, T.; Kachi, T.

    2007-06-01

    In this paper, we discuss requirements of power devices for automotive applications, especially hybrid vehicles and the development of GaN power devices at Toyota. We fabricated AlGaN/GaN HEMTs and measured their characteristics. The maximum breakdown voltage was over 600V. The drain current with a gate width of 31mm was over 8A. A thermograph image of the HEMT under high current operation shows the AlGaN/GaN HEMT operated at more than 300°C. And we confirmed the operation of a vertical GaN device. All the results of the GaN HEMTs are really promising to realize high performance and small size inverters for future automobiles.

  11. Novel compound semiconductor devices based on III-V nitrides

    SciTech Connect

    Pearton, S.J.; Abernathy, C.R.; Ren, F.

    1995-10-01

    New developments in dry and wet etching, ohmic contacts and epitaxial growth of Ill-V nitrides are reported. These make possible devices such as microdisk laser structures and GaAs/AlGaAs heterojunction bipolar transistors with improved InN ohmic contacts.

  12. System for characterizing semiconductor materials and photovoltaic device

    DOEpatents

    Sopori, B.L.

    1996-12-03

    Apparatus for detecting and mapping defects in the surfaces of polycrystalline material in a manner that distinguishes dislocation pits from grain boundaries includes a first laser of a first wavelength for illuminating a wide spot on the surface of the material, a second laser of a second relatively shorter wavelength for illuminating a relatively narrower spot on the surface of the material, a light integrating sphere with apertures for capturing light scattered by etched dislocation pits in an intermediate range away from specular reflection while allowing light scattered by etched grain boundaries in a near range from specular reflection to pass through, and optical detection devices for detecting and measuring intensities of the respective intermediate scattered light and near specular scattered light. A center blocking aperture or filter can be used to screen out specular reflected light, which would be reflected by nondefect portions of the polycrystalline material surface. An X-Y translation stage for mounting the polycrystalline material and signal processing and computer equipment accommodate raster mapping, recording, and displaying of respective dislocation and grain boundary defect densities. A special etch procedure is included, which prepares the polycrystalline material surface to produce distinguishable intermediate and near specular light scattering in patterns that have statistical relevance to the dislocation and grain boundary defect densities. A reflectance measurement of the piece of material is obtained by adding together the signals from the optical detection devices. In the case where the piece of material includes a photovoltaic device, the current induced in the device by the illuminating light can be measured with a current sensing amplifier after the light integrating sphere is moved away from the device. 22 figs.

  13. System for characterizing semiconductor materials and photovoltaic device

    DOEpatents

    Sopori, Bhushan L.

    1996-01-01

    Apparatus for detecting and mapping defects in the surfaces of polycrystalline material in a manner that distinguishes dislocation pits from grain boundaries includes a first laser of a first wavelength for illuminating a wide spot on the surface of the material, a second laser of a second relatively shorter wavelength for illuminating a relatively narrower spot on the surface of the material, a light integrating sphere with apertures for capturing light scattered by etched dislocation pits in an intermediate range away from specular reflection while allowing light scattered by etched grain boundaries in a near range from specular reflection to pass through, and optical detection devices for detecting and measuring intensities of the respective intermediate scattered light and near specular scattered light. A center blocking aperture or filter can be used to screen out specular reflected light, which would be reflected by nondefect portions of the polycrystalline material surface. An X-Y translation stage for mounting the polycrystalline material and signal processing and computer equipment accommodate raster mapping, recording, and displaying of respective dislocation and grain boundary defect densities. A special etch procedure is included, which prepares the polycrystalline material surface to produce distinguishable intermediate and near specular light scattering in patterns that have statistical relevance to the dislocation and grain boundary defect densities. A reflectance measurement of the piece of material is obtained by adding together the signals from the optical detection devices. In the case where the piece of material includes a photovoltaic device, the current induced in the device by the illuminating light can be measured with a current sensing amplifier after the light integrating sphere is moved away from the device.

  14. Oxide charge accumulation in metal oxide semiconductor devices during irradiation

    SciTech Connect

    Lee, D. ); Chan, C. )

    1991-05-15

    An analysis of a simple physical model for radiation induced oxide charge accumulation in the SiO{sub 2} layer of metal oxide semiconductor (MOS) structure has been developed. The model assumes that both electron and hole traps exist in the oxide layer. These traps can capture electrons as well as holes during irradiation. Using this model, final oxide charge distributions in the oxide layer of MOS capacitors exposed to a total dose radiation can be predicted. The resulting charge distribution is calculated to yield the midgap voltage shifts as functions of total dose, bias voltage, and oxide thickness. The results are shown to agree well with the experimental data. Furthermore, the model successfully analyzes the radiation-induced negative oxide charge distribution in an ion-implanted, radiation-hard MOS capacitor. These negative oxide charge distributions not only partially compensate the effects of trapped positive oxide charges but also reduced the density of positive oxide charges trapped near the Si/SiO{sub 2} interface. We found the reduction of the positive oxide charge density near the Si/SiO{sub 2} interface is due to internal electric field modification in the oxide layer.

  15. Novel integration method for III–V semiconductor devices on silicon platform

    NASA Astrophysics Data System (ADS)

    Matsumoto, Keiichi; Kishikawa, Junya; Nishiyama, Tetsuo; Onuki, Yuya; Shimomura, Kazuhiko

    2016-11-01

    A novel integration method for III–V semiconductor devices on a Si platform was demonstrated. Thin-film InP was directly bonded on a Si substrate and metal organic vapor phase epitaxy (MOVPE) growth was performed by using an InP/Si template. A void-free 2-in. InP layer bonded on a Si substrate was realized, and a low interfacial resistance and ohmic contact through the bonded interface were observed. After the MOVPE process, the as-grown structure was optically active and we observed photoluminescence (PL) intensity comparable to that from the same structure grown on InP as a reference. Furthermore, almost no lattice strain was observed from the InP layer. Then, the epitaxial growth of a GaInAsP–InP double-hetero (DH) laser diode (LD) was demonstrated on the substrate and we observed lasing emission at RT in a pulse regime. These results are promising for the integration of InP-based devices on a Si platform for optical interconnection.

  16. New photovoltaic devices based on the sensitization of p-type semiconductors: challenges and opportunities.

    PubMed

    Odobel, Fabrice; Le Pleux, Loïc; Pellegrin, Yann; Blart, Errol

    2010-08-17

    Because solar energy is the most abundant renewable energy resource, the clear connection between human activity and global warming has strengthened the interest in photovoltaic science. Dye-sensitized solar cells (DSSCs) provide a promising low-cost technology for harnessing this energy source. Until recently, much of the research surrounding DSSCs had been focused on the sensitization of n-type semiconductors, such as titanium dioxide (Gratzel cells). In an n-type dye-sensitized solar cell (n-DSSC), an electron is injected into the conduction band of an n-type semiconductor (n-SC) from the excited state of the sensitizer. Comparatively few studies have examined the sensitization of wide bandgap p-type semiconductors. In a p-type DSSC (p-DSSC), the photoexcited sensitizer is reductively quenched by hole injection into the valence band of a p-type semiconductor (p-SC). The study of p-DSSCs is important both to understand the factors that control the rate of hole photoinjection and to aid the rational design of efficient p-DSSCs. In theory, p-DSSCs should be able to work as efficiently as n-DSSCs. In addition, this research provides a method for preparing tandem DSSCs consisting of a TiO(2)-photosensitized anode and a photosensitized p-type SC as a cathode. Tandem DSSCs are particularly important because they represent low-cost photovoltaic devices whose photoconversion efficiencies could exceed 15%. This Account describes recent research results on p-DSSCs. Because these photoelectrochemical devices are the mirror images of conventional n-DSSCs, they share some structural similarities, but they use different materials and have different charge transfer kinetics. In this technology, nickel oxide is the predominant p-SC material used, but much higher photoconversion efficiencies could be achieved with new p-SCs materials with deeper valence band potential. Currently, iodide/triiodide is the main redox mediator of electron transport within these devices, but we expect

  17. Ferroelectric HfO2 for Emerging Ferroelectric Semiconductor Devices

    NASA Astrophysics Data System (ADS)

    Florent, Karine

    The spontaneous polarization in ferroelectrics (FE) makes them particularly attractive for non-volatile memory and logic applications. Non-volatile FRAM memories using perovskite structure materials, such as Lead Zirconate Titanate (PZT) and Strontium Bismuth Tantalate (SBT) have been studied for many years. However, because of their scaling limit and incompatibility with CMOS beyond 130 nm node, floating gate Flash memory technology has been preferred for manufacturing. The recent discovery of ferroelectricity in doped HfO2 in 2011 has opened the door for new ferroelectric based devices compatible with CMOS technology, such as Ferroelectric Field Effect Transistor (FeFET) and Ferroelectric Tunnel Junctions (FTJ). This work began with developing ferroelectric hysteresis characterization capabilities at RIT. Initially reactively sputtered aluminum doped HfO 2 films were investigated. It was observed that the composition control using co-sputtering was not achievable within the existing capabilities. During the course of this study, collaboration was established with the NaMLab group in Germany to investigate Si doped HfO2 deposited by Atomic Layer Deposition (ALD). Metal Ferroelectric Metal (MFM) devices were fabricated using TiN as the top and bottom electrode with Si:HfO2 thickness ranging from 6.4 nm to 22.9 nm. The devices were electrically tested for P-E, C-V and I-V characteristics. Structural characterizations included TEM, EELS, XRR, XRD and XPS/Auger spectroscopy. Higher remanant polarization (Pr) was observed for films of 9.3 nm and 13.1 nm thickness. Thicker film (22.9 nm) showed smaller Pr. Devices with 6.4 nm thick films exhibit tunneling behavior showing a memristor like I-V characteristics. The tunnel current and ferroelectricity showed decrease with cycling indicating a possible change in either the structure or the domain configurations. Theoretical simulations using the improved FE model were carried out to model the ferroelectric behavior of

  18. A technique for optimizing the design of power semiconductor devices

    NASA Technical Reports Server (NTRS)

    Schlegel, E. S.

    1976-01-01

    A technique is described that provides a basis for predicting whether any device design change will improve or degrade the unavoidable trade-off that must be made between the conduction loss and the turn-off speed of fast-switching high-power thyristors. The technique makes use of a previously reported method by which, for a given design, this trade-off was determined for a wide range of carrier lifetimes. It is shown that by extending this technique, one can predict how other design variables affect this trade-off. The results show that for relatively slow devices the design can be changed to decrease the current gains to improve the turn-off time without significantly degrading the losses. On the other hand, for devices having fast turn-off times design changes can be made to increase the current gain to decrease the losses without a proportionate increase in the turn-off time. Physical explanations for these results are proposed.

  19. Metallization and packaging of compound semiconductor devices at Sandia National Laboratories

    SciTech Connect

    Seigal, P.K.; Armendariz, M.G.; Rieger, D.J.; Lear, K.L.; Sullivan, C.T.

    1996-11-01

    Recent advances in compound semiconductor technology utilize a variety of metal thin films fabricated by thermal and electron-beam evaporation, and electroplating. An overview of metal processes used by Sandia`s Compound Semiconductor Research Laboratory is presented. Descriptions of electrical n-type and p-type ohmic contact alloys, interconnect metal, and metal layers specifically included for packaging requirements are addressed. Several illustrations of devices incorporating gold plated air bridges are included. ``Back-end`` processes such as flip-chip under bump metallurgy with fluxless solder reflow and plated solder processes are mentioned as current research areas.

  20. Present status and prospects of R&D of radiation-resistant semiconductor devices at JAEA

    NASA Astrophysics Data System (ADS)

    Itoh, H.

    2013-05-01

    Research and development of radiation resistant semiconductor devices have been performed at Japan Atomic Energy Agency (JAEA) for their application to electronic system used in harsh environments like space, accelerator and nuclear facilities. Such devices are also indispensable for robots and equipment necessary for decommissioning of the damaged reactors at Fukushima Daiichi Nuclear Power Plants. For this purpose, we have fabricated transistors based on a wide band-gap semiconductor SiC and examined their radiation degradation. As a result, SiC-based transistors exhibited no significant degradation up to 1MGy, indicating their excellent radiation resistance. Recent our R&Ds of radiation resistant devices based on SiC are summarized and reviewed.

  1. Method of making suspended thin-film semiconductor piezoelectric devices

    DOEpatents

    Casalnuovo, Stephen A.; Frye-Mason, Gregory C.

    2001-01-01

    A process for forming a very thin suspended layer of piezoelectric material of thickness less than 10 microns. The device is made from a combination of GaAs and AlGaAs layers to form either a sensor or an electronic filter. Onto a GaAs substrate is epitaxially deposited a thin (1-5 micron) sacrificial AlGaAs layer, followed by a thin GaAs top layer. In one embodiment the substrate is selectively etched away from below until the AlGaAs layer is reached. Then a second selective etch removes the sacrificial AlGaAs layer, that has acted here as an etch stop, leaving the thin suspended layer of piezoelectric GaAs. In another embodiment, a pattern of small openings is etched through the thin layer of GaAs on top of the device to expose the sacrificial AlGaAs layer. A second selective etch is done through these openings to remove the sacrificial AlGaAs layer, leaving the top GaAs layer suspended over the GaAs substrate. A novel etchant solution containing a surface tension reducing agent is utilized to remove the AlGaAs while preventing buildup of gas bubbles that would otherwise break the thin GaAs layer.

  2. Total-dose radiation effects data for semiconductor devices, volume 1. [radiation resistance of components for the Galileo Project

    NASA Technical Reports Server (NTRS)

    Price, W. E.; Martin, K. E.; Nichols, D. K.; Gauthier, M. K.; Brown, S. F.

    1981-01-01

    Steady-state, total-dose radiation test data are provided in graphic format, for use by electronic designers and other personnel using semiconductor devices in a radiation environment. Data are presented by JPL for various NASA space programs on diodes, bipolar transistors, field effect transistors, silicon-controlled rectifiers, and optical devices. A vendor identification code list is included along with semiconductor device electrical parameter symbols and abbreviations.

  3. ZnCdMgSe-Based Semiconductors for Intersubband Devices

    SciTech Connect

    Tamargo, Maria C.

    2008-11-13

    This paper presents a review of recent results on the application of ZnCdMgSe-based wide bandgap II-VI compounds to intersubband devices such as quantum cascade lasers and quantum well infrared photodetectors operating in the mid-infrared region. The conduction band offset of ZnCdSe/ZnCdMgSe quantum well structures was determined from contactless electroreflectance measurements to be as high as 1.12 eV. FT-IR was used to measure intersubband absorption in multi-quantum well structures in the mid-IR range. Electroluminescence at 4.8 {mu}m was observed from a quantum cascade emitter structure made from these materials. Preliminary results are also presented on self assembled quantum dots of CdSe on ZnCdMgSe, and novel quantum well structures with metastable binary MgSe barriers.

  4. Investigation of plasma etch induced damage in compound semiconductor devices

    SciTech Connect

    Shul, R.J.; Lovejoy, M.L.; Hetherington, D.L.; Rieger, D.J.; Vawter, G.A.; Klem, J.F.; Melloch, M.R.

    1993-11-01

    We have investigated the electrical performance of mesa-isolated GaAs pn-junction diodes to determine the plasma-induced damage effects from reactive ion and reactive ion beam etching. A variety of plasma chemistries (SiCl{sub 4}, BCl{sub 3}, BCl{sub 3}/Cl{sub 2}, and Cl{sub 2}) and ion energies ranging from 100 to 400 eV were studied. We have observed that many of the RIE BCl{sub 3}/Cl{sub 2} plasmas and RIBE Cl{sub 2} plasmas yield diodes with low reverse-bias currents that are comparable to the electrical characteristics of wet-chemical-etched devices. The reverse-bias leakage currents are independent of surface morphology and sidewall profiles.

  5. Distributed and coupled 2D electro-thermal model of power semiconductor devices

    NASA Astrophysics Data System (ADS)

    Belkacem, Ghania; Lefebvre, Stéphane; Joubert, Pierre-Yves; Bouarroudj-Berkani, Mounira; Labrousse, Denis; Rostaing, Gilles

    2014-05-01

    The development of power electronics in the field of transportations (automotive, aeronautics) requires the use of power semiconductor devices providing protection and diagnostic functions. In the case of series protections power semiconductor devices which provide protection may operate in shortcircuit and act as a current limiting device. This mode of operations is very constraining due to the large dissipation of power. In these particular conditions of operation, electro-thermal models of power semiconductor devices are of key importance in order to optimize their thermal design and increase their reliability. The development of such an electro-thermal model for power MOSFET transistors based on the coupling between two computation softwares (Matlab and Cast3M) is described in this paper. The 2D electro-thermal model is able to predict (i) the temperature distribution on chip surface well as in the volume under short-circuit operations, (ii) the effect of the temperature on the distribution of the current flowing within the die and (iii) the effects of the ageing of the metallization layer on the current density and the temperature. In this paper, the electrical and thermal models are described as well as the implemented coupling scheme.

  6. SEMICONDUCTOR DEVICES: Simulation and optimization of a 6H-SiC metal-semiconductor-metal ultraviolet photodetector

    NASA Astrophysics Data System (ADS)

    Bin, Chen; Yintang, Yang; Yuejin, Li; Hongxia, Liu

    2010-06-01

    Based on thermionic emission theory, a model of a 6H-SiC metal-semiconductor-metal (MSM) ultraviolet photodetector is established with the simulation package ISE-TCAD. A device with 3 μm electrode width (W) and 3 μm electrode spacing (L) is simulated. The findings show that the MSM photodetector has quite a low dark current of 15 pA at 10 V bias and the photocurrent is two orders of magnitude higher than the dark current. The influences of different structures on dark and illuminated current-voltage characteristics of the MSM photodetector are investigated to optimize the device parameters. Simulation results indicate that the maximum photocurrent and the highest ratio of photocurrent to dark current at 15 V bias are 5.3 nA and 327 with device parameters of W = 6 μm, L = 3 μm and W = 3 μm, L = 6 μm, respectively.

  7. Theoretical discovery of stable structures of group III-V monolayers: The materials for semiconductor devices

    SciTech Connect

    Suzuki, Tatsuo

    2015-11-23

    Group III-V compounds are very important as the materials of semiconductor devices. Stable structures of the monolayers of group III-V binary compounds have been discovered by using first-principles calculations. The primitive unit cell of the discovered structures is a rectangle, which includes four group-III atoms and four group-V atoms. A group-III atom and its three nearest-neighbor group-V atoms are placed on the same plane; however, these connections are not the sp{sup 2} hybridization. The bond angles around the group-V atoms are less than the bond angle of sp{sup 3} hybridization. The discovered structure of GaP is an indirect transition semiconductor, while the discovered structures of GaAs, InP, and InAs are direct transition semiconductors. Therefore, the discovered structures of these compounds have the potential of the materials for semiconductor devices, for example, water splitting photocatalysts. The discovered structures may become the most stable structures of monolayers which consist of other materials.

  8. Energy Models for One-Carrier Transport in Semiconductor Devices

    NASA Technical Reports Server (NTRS)

    Jerome, Joseph W.; Shu, Chi-Wang

    1991-01-01

    Moment models of carrier transport, derived from the Boltzmann equation, made possible the simulation of certain key effects through such realistic assumptions as energy dependent mobility functions. This type of global dependence permits the observation of velocity overshoot in the vicinity of device junctions, not discerned via classical drift-diffusion models, which are primarily local in nature. It was found that a critical role is played in the hydrodynamic model by the heat conduction term. When ignored, the overshoot is inappropriately damped. When the standard choice of the Wiedemann-Franz law is made for the conductivity, spurious overshoot is observed. Agreement with Monte-Carlo simulation in this regime required empirical modification of this law, or nonstandard choices. Simulations of the hydrodynamic model in one and two dimensions, as well as simulations of a newly developed energy model, the RT model, are presented. The RT model, intermediate between the hydrodynamic and drift-diffusion model, was developed to eliminate the parabolic energy band and Maxwellian distribution assumptions, and to reduce the spurious overshoot with physically consistent assumptions. The algorithms employed for both models are the essentially non-oscillatory shock capturing algorithms. Some mathematical results are presented and contrasted with the highly developed state of the drift-diffusion model.

  9. Development of molecular beam epitaxy technology for III–V compound semiconductor heterostructure devices

    SciTech Connect

    Cheng, K. Y.

    2013-09-15

    Molecular beam epitaxy (MBE) is a versatile ultrahigh vacuum technique for growing multiple epitaxial layers of semiconductor crystals with high precision. The extreme control of the MBE technique over composition variation, interface sharpness, impurity doping profiles, and epitaxial layer thickness to the atomic level makes it possible to demonstrate a wide variety of novel semiconductor structures. Since its invention nearly 40 years ago, the MBE technique has evolved from a laboratory apparatus for exploring new materials and novel devices to a favored tool for the mass production of III–V high-speed devices. This paper will review some of the past developments in this technology and propose an outlook of future developments.

  10. An efficient method-of-lines simulation procedure for organic semiconductor devices.

    PubMed

    Rogel-Salazar, J; Bradley, D D C; Cash, J R; Demello, J C

    2009-03-14

    We describe an adaptive grid method-of-lines (MOL) solution procedure for modelling charge transport and recombination in organic semiconductor devices. The procedure we describe offers an efficient, robust and versatile means of simulating semiconductor devices that allows for much simpler coding of the underlying equations than alternative simulation procedures. The MOL technique is especially well-suited to modelling the extremely stiff (and hence difficult to solve) equations that arise during the simulation of organic-and some inorganic-semiconductor devices. It also has wider applications in other areas, including reaction kinetics, combustion and aero- and fluid dynamics, where its ease of implementation also makes it an attractive choice. The MOL procedure we use converts the underlying semiconductor equations into a series of coupled ordinary differential equations (ODEs) that can be integrated forward in time using an appropriate ODE solver. The time integration is periodically interrupted, the numerical solution is interpolated onto a new grid that is better matched to the solution profile, and the time integration is then resumed on the new grid. The efficacy of the simulation procedure is assessed by considering a single layer device structure, for which exact analytical solutions are available for the electric potential, the charge distributions and the current-voltage characteristics. Two separate state-of-the-art ODE solvers are tested: the single-step Runge-Kutta solver Radau5 and the multi-step solver ODE15s, which is included as part of the Matlab ODE suite. In both cases, the numerical solutions show excellent agreement with the exact analytical solutions, yielding results that are accurate to one part in 1 x 10(4). The single-step Radau5 solver, however, is found to provide faster convergence since its efficiency is not compromised by the periodic interruption of the time integration when the grid is updated.

  11. Evaluation of semiconductor devices for Electric and Hybrid Vehicle (EHV) ac-drive applications, volume 1

    NASA Technical Reports Server (NTRS)

    Lee, F. C.; Chen, D. Y.; Jovanovic, M.; Hopkins, D. C.

    1985-01-01

    The results of evaluation of power semiconductor devices for electric hybrid vehicle ac drive applications are summarized. Three types of power devices are evaluated in the effort: high power bipolar or Darlington transistors, power MOSFETs, and asymmetric silicon control rectifiers (ASCR). The Bipolar transistors, including discrete device and Darlington devices, range from 100 A to 400 A and from 400 V to 900 V. These devices are currently used as key switching elements inverters for ac motor drive applications. Power MOSFETs, on the other hand, are much smaller in current rating. For the 400 V device, the current rating is limited to 25 A. For the main drive of an electric vehicle, device paralleling is normally needed to achieve practical power level. For other electric vehicle (EV) related applications such as battery charger circuit, however, MOSFET is advantageous to other devices because of drive circuit simplicity and high frequency capability. Asymmetrical SCR is basically a SCR device and needs commutation circuit for turn off. However, the device poses several advantages, i.e., low conduction drop and low cost.

  12. Semiconductor-free hot carrier devices for energy harvesting and photodetection

    NASA Astrophysics Data System (ADS)

    Gong, Tao; Munday, Jeremy

    The maximum efficiency for a single-junction solar cell is around 30% by the Shockley-Queisser (SQ) limit. The energy loss is typically through a thermalization process between the excited high-energy carriers, e.g. hot carriers, and the lattice. Therefore, the collection of the hot carriers before thermalization would allow for reduced power loss. Recently, photodetectors based on metal-semiconductor Schottky junctions have been exploiting hot electron effects to allow sub-bandgap absorption and hence show promise as near IR wavelength detectors. Here we present a simple, semiconductor-free hot carrier device based on transparent conducting oxides (TCO) electrodes. We experimentally demonstrate the hot carrier generation and extraction under monochromatic and broadband light illumination of normal and oblique incidence. Under optimized conditions, a power conversion efficiency >10% is predicted for high-energy photon excitation. The performance of the device shows further improvement by employing nanostructures, which couple the incident light into surface plasmons, leading to absorption enhancement. This semiconductor-free device provides an alternative way of energy harvesting and photodetection.

  13. Low-temperature sintering of nanoscale silver paste for semiconductor device interconnection

    NASA Astrophysics Data System (ADS)

    Bai, Guofeng

    This research has developed a lead-free semiconductor device interconnect technology by studying the processing-microstructure-property relationships of low-temperature sintering of nanoscale silver pastes. The nanoscale silver pastes have been formulated by adding organic components (dispersant, binder and thinner) into nano-silver particles. The selected organic components have the nano-particle polymeric stabilization, paste processing quality adjustment, and non-densifying diffusion retarding functions and thus help the pastes sinter to ˜80% bulk density at temperatures no more than 300°C. It has been found that the low-temperature sintered silver has better electrical, thermal and overall thermomechanical properties compared with the existing semiconductor device interconnecting materials such as solder alloys and conductive epoxies. After solving the organic burnout problems associated with the covered sintering, a lead-free semiconductor device interconnect technology has been designed to be compatible with the existing surface-mounting techniques with potentially low-cost. It has been found that the low-temperature sintered silver joints have high electrical, thermal, and mechanical performance. The reliability of the silver joints has also been studied by the 50-250°C thermal cycling experiment. Finally, the bonging strength drop of the silver joints has been suggested to be ductile fracture in the silver joints as micro-voids nucleated at microscale grain boundaries during the temperature cycling. The low-temperature silver sintering technology has enabled some benchmark packaging concepts and substantial advantages in future applications.

  14. Gene Detection in Complex Biological Media Using Semiconductor Nanorods within an Integrated Microfluidic Device.

    PubMed

    Bi, Xinyan; Adriani, Giulia; Xu, Yang; Chakrabortty, Sabyasachi; Pastorin, Giorgia; Ho, Han Kiat; Ang, Wee Han; Chan, Yinthai

    2015-10-20

    The salient optical properties of highly luminescent semiconductor nanocrystals render them ideal fluorophores for clinical diagnostics, therapeutics, and highly sensitive biochip applications. Microfluidic systems allow miniaturization and integration of multiple biochemical processes in a single device and do not require sophisticated diagnostic tools. Herein, we describe a microfluidic system that integrates RNA extraction, reverse transcription to cDNA, amplification and detection within one integrated device to detect histidine decarboxylase (HDC) gene directly from human white blood cells samples. When anisotropic semiconductor nanorods (NRs) were used as the fluorescent probes, the detection limit was found to be 0.4 ng of total RNA, which was much lower than that obtained using spherical quantum dots (QDs) or organic dyes. This was attributed to the large action cross-section of NRs and their high probability of target capture in a pull-down detection scheme. The combination of large scale integrated microfluidics with highly fluorescent semiconductor NRs may find widespread utility in point-of-care devices and multitarget diagnostics.

  15. P and n-type microcrystalline semiconductor alloy material including band gap widening elements, devices utilizing same

    DOEpatents

    Guha, Subhendu; Ovshinsky, Stanford R.

    1988-10-04

    An n-type microcrystalline semiconductor alloy material including a band gap widening element; a method of fabricating p-type microcrystalline semiconductor alloy material including a band gap widening element; and electronic and photovoltaic devices incorporating said n-type and p-type materials.

  16. Procedure for pressure contact on high-power semiconductor devices free of thermal fatigue

    NASA Technical Reports Server (NTRS)

    Knobloch, J.

    1979-01-01

    To eliminate thermal fatigue, a procedure for manufacturing semiconductor power devices with pure pressure contact without solid binding was developed. Pressure contact without the use of a solid binding to avoid a limitation of the maximum surface in the contact was examined. A silicon wafer covered with a relatively thick metal layer is imbedded with the aid of a soft silver foil between two identically sized hard contact discs (molybdenum or tungsten) which are rotationally symmetrical. The advantages of this concept are shown for large diameters. The pressure contact was tested successfully in many devices in a large variety of applications.

  17. Combining semiconductor quantum dots and bioscaffolds into nanoscale energy transfer devices.

    PubMed

    Spillmann, Christopher M; Stewart, Michael H; Susumu, Kimihiro; Medintz, Igor L

    2015-11-01

    Significant advances have been made in the development of nanoscale devices capable of exciton transport via Förster resonance energy transfer. Several requirements must be met for effective operation, including a reliable energy-harvesting source along with highly organized, precisely placed energy relay elements. For the latter, biological scaffolds such as DNA provide a customizable, symmetric, and stable structure that can be site-specifically modified with organic fluorophores. Here, advancements in nanoscale energy transfer devices incorporating semiconductor nanocrystals and bioscaffolds are reviewed with discussion of biofunctionalization, linker chemistries, design considerations, and concluding with applications in light harvesting, multiplexed biosensing, and optical logic. PMID:26560627

  18. A review of the physics and response models for burnout of semiconductor devices

    NASA Astrophysics Data System (ADS)

    Orvis, W. J.; Khanaka, G. H.; Yee, J. H.

    1984-12-01

    Physical mechanisms that cause semiconductor devices to fail from electrical overstress--particularly, EMP-induced electrical stress--are described in light of the current literature and the authors' own research. A major concern is the cause and effects of second breakdown phenomena in p-n junction devices. Models of failure thresholds are evaluated for their inherent errors and for their ability to represent the relevant physics. Finally, the response models that relate electromagnetic stress parameters to appropriate failure-threshold parameters are discussed.

  19. Semiconductor structure

    NASA Technical Reports Server (NTRS)

    Hovel, Harold J. (Inventor); Woodall, Jerry M. (Inventor)

    1979-01-01

    A technique for fabricating a semiconductor heterostructure by growth of a ternary semiconductor on a binary semiconductor substrate from a melt of the ternary semiconductor containing less than saturation of at least one common ingredient of both the binary and ternary semiconductors wherein in a single temperature step the binary semiconductor substrate is etched, a p-n junction with specific device characteristics is produced in the binary semiconductor substrate by diffusion of a dopant from the melt and a region of the ternary semiconductor of precise conductivity type and thickness is grown by virtue of a change in the melt characteristics when the etched binary semiconductor enters the melt.

  20. Capacitance-voltage characteristics of Si and Ge nanomembrane based flexible metal-oxide-semiconductor devices under bending conditions

    NASA Astrophysics Data System (ADS)

    Cho, Minkyu; Seo, Jung-Hun; Park, Dong-Wook; Zhou, Weidong; Ma, Zhenqiang

    2016-06-01

    Metal-oxide-semiconductor (MOS) device is the basic building block for field effect transistors (FET). The majority of thin-film transistors (TFTs) are FETs. When MOSFET are mechanically bent, the MOS structure will be inevitably subject to mechanical strain. In this paper, flexible MOS devices using single crystalline Silicon (Si) and Germanium (Ge) nanomembranes (NM) with SiO2, SiO, and Al2O3 dielectric layers are fabricated on a plastic substrate. The relationships between semiconductor nanomembranes and various oxide materials are carefully investigated under tensile/compressive strain. The flatband voltage, threshold voltage, and effective charge density in various MOS combinations revealed that Si NM-SiO2 configuration shows the best interface charge behavior, while Ge NM-Al2O3 shows the worst. This investigation of flexible MOS devices can help us understand the impact of charges in the active region of the flexible TFTs and capacitance changes under the tensile/compressive strains on the change in electrical characteristics in flexible NM based TFTs.

  1. Features of the piezo-phototronic effect on optoelectronic devices based on wurtzite semiconductor nanowires.

    PubMed

    Yang, Qing; Wu, Yuanpeng; Liu, Ying; Pan, Caofeng; Wang, Zhong Lin

    2014-02-21

    The piezo-phototronic effect, a three way coupling effect of piezoelectric, semiconductor and photonic properties in non-central symmetric semiconductor materials, utilizing the piezo-potential as a "gate" voltage to tune the charge transport/generation/recombination and modulate the performance of optoelectronic devices, has formed a new field and attracted lots of interest recently. The mechanism was verified in various optoelectronic devices such as light emitting diodes (LEDs), photodetectors and solar cells etc. The fast development and dramatic increasing interest in the piezo-phototronic field not only demonstrate the way the piezo-phototronic effects work, but also indicate the strong need for further research in the physical mechanism and potential applications. Furthermore, it is important to distinguish the contribution of the piezo-phototronic effect from other factors induced by external strain such as piezoresistance, band shifting or contact area change, which also affect the carrier behaviour and device performance. In this perspective, we review our recent progress on piezo-phototronics and especially focus on pointing out the features of piezo-phototronic effect in four aspects: I-V characteristics; c-axis orientation; influence of illumination; and modulation of carrier behaviour. Finally we proposed several criteria for describing the contribution made by the piezo-phototronic effect to the performance of optoelectronic devices. This systematic analysis and comparison will not only help give an in-depth understanding of the piezo-phototronic effect, but also work as guide for the design of devices in related areas.

  2. Demonstration of Y1Ba2Cu3O(7-delta) and complementary metal-oxide-semiconductor device fabrication on the same sapphire substrate

    NASA Technical Reports Server (NTRS)

    Burns, M. J.; De La Houssaye, P. R.; Russell, S. D.; Garcia, G. A.; Clayton, S. R.; Ruby, W. S.; Lee, L. P.

    1993-01-01

    We report the first fabrication of active semiconductor and high-temperature superconducting devices on the same substrate. Test structures of complementary MOS transistors were fabricated on the same sapphire substrate as test structures of Y1Ba2Cu3O(7-delta) flux-flow transistors, and separately, Y1Ba2Cu3O(7-delta) superconducting quantum interference devices utilizing both biepitaxial and step-edge Josephson junctions. Both semiconductor and superconductor devices were operated at 77 K. The cofabrication of devices using these disparate yet complementary electronic technologies on the same substrate opens the door for the fabrication of true semiconductive/superconductive hybrid integrated circuits capable of exploiting the best features of each of these technologies.

  3. Spin polarized state filter based on semiconductor–dielectric–iron–semiconductor multi-nanolayer device

    SciTech Connect

    Makarov, Vladimir I.; Khmelinskii, Igor

    2015-04-15

    Highlights: • Development of a new spintronics device. • Development of quantum spin polarized filters. • Development of theory of quantum spin polarized filter. - Abstract: Presently we report spin-polarized state transport in semiconductor–dielectric–iron–semiconductor (SDIS) four-nanolayer sandwich devices. The exchange-resonance spectra in such devices are quite specific, differing also from spectra observed earlier in other three-nanolayer devices. The theoretical model developed earlier is extended and used to interpret the available experimental results. A detailed ab initio analysis of the magnetic-field dependence of the output magnetic moment is also performed. The model predicts an exchange spectrum comprising a series of peaks, with the spectral structure determined by several factors, discussed in the paper.

  4. Theory of Current Transients in Planar Semiconductor Devices: Insights and Applications to Organic Solar Cells

    NASA Astrophysics Data System (ADS)

    Hawks, Steven A.; Finck, Benjamin Y.; Schwartz, Benjamin J.

    2015-04-01

    Time-domain current measurements are widely used to characterize semiconductor material properties, such as carrier mobility, doping concentration, carrier lifetime, and the static dielectric constant. It is therefore critical that these measurements be theoretically understood if they are to be successfully applied to assess the properties of materials and devices. In this paper, we derive generalized relations for describing current-density transients in planar semiconductor devices at uniform temperature. By spatially averaging the charge densities inside the semiconductor, we are able to provide a rigorous, straightforward, and experimentally relevant way to interpret these measurements. The formalism details several subtle aspects of current transients, including how the electrode charge relates to applied bias and internal space charge, how the displacement current can alter the apparent free-carrier current, and how to understand the integral of a charge-extraction transient. We also demonstrate how the formalism can be employed to derive the current transients arising from simple physical models, like those used to describe charge extraction by linearly increasing voltage (CELIV) and time-of-flight experiments. In doing so, we find that there is a nonintuitive factor-of-2 reduction in the apparent free-carrier concentration that can be easily missed, for example, in the application of charge-extraction models. Finally, to validate our theory and better understand the different current contributions, we perform a full time-domain drift-diffusion simulation of a CELIV trace and compare the results to our formalism. As expected, our analytic equations match precisely with the numerical solutions to the drift-diffusion, Poisson, and continuity equations. Thus, overall, our formalism provides a straightforward and general way to think about how the internal space-charge distribution, the electrode charge, and the externally applied bias translate into a measured

  5. Semiconductor technology program. Progress briefs

    NASA Technical Reports Server (NTRS)

    Bullis, W. M.

    1980-01-01

    Measurement technology for semiconductor materials, process control, and devices is reviewed. Activities include: optical linewidth and thermal resistance measurements; device modeling; dopant density profiles; resonance ionization spectroscopy; and deep level measurements. Standardized oxide charge terminology is also described.

  6. Epitaxial MoS2/GaN structures to enable vertical 2D/3D semiconductor heterostructure devices

    NASA Astrophysics Data System (ADS)

    Ruzmetov, D.; Zhang, K.; Stan, G.; Kalanyan, B.; Eichfeld, S.; Burke, R.; Shah, P.; O'Regan, T.; Crowne, F.; Birdwell, A. G.; Robinson, J.; Davydov, A.; Ivanov, T.

    MoS2/GaN structures are investigated as a building block for vertical 2D/3D semiconductor heterostructure devices that utilize a 3D substrate (GaN) as an active component of the semiconductor device without the need of mechanical transfer of the 2D layer. Our CVD-grown monolayer MoS2 has been shown to be epitaxially aligned to the GaN lattice which is a pre-requisite for high quality 2D/3D interfaces desired for efficient vertical transport and large area growth. The MoS2 coverage is nearly 50 % including isolated triangles and monolayer islands. The GaN template is a double-layer grown by MOCVD on sapphire and allows for measurement of transport perpendicular to the 2D layer. Photoluminescence, Raman, XPS, Kelvin force probe microscopy, and SEM analysis identified high quality monolayer MoS2. The MoS2/GaN structures electrically conduct in the out-of-plane direction and across the van der Waals gap, as measured with conducting AFM (CAFM). The CAFM current maps and I-V characteristics are analyzed to estimate the MoS2/GaN contact resistivity to be less than 4 Ω-cm2 and current spreading in the MoS2 monolayer to be approx. 1 μm in diameter. Epitaxial MoS2/GaN heterostructures present a promising platform for the design of energy-efficient, high-speed vertical devices incorporating 2D layered materials with 3D semiconductors.

  7. Dual control active superconductive devices

    DOEpatents

    Martens, Jon S.; Beyer, James B.; Nordman, James E.; Hohenwarter, Gert K. G.

    1993-07-20

    A superconducting active device has dual control inputs and is constructed such that the output of the device is effectively a linear mix of the two input signals. The device is formed of a film of superconducting material on a substrate and has two main conduction channels, each of which includes a weak link region. A first control line extends adjacent to the weak link region in the first channel and a second control line extends adjacent to the weak link region in the second channel. The current flowing from the first channel flows through an internal control line which is also adjacent to the weak link region of the second channel. The weak link regions comprise small links of superconductor, separated by voids, through which the current flows in each channel. Current passed through the control lines causes magnetic flux vortices which propagate across the weak link regions and control the resistance of these regions. The output of the device taken across the input to the main channels and the output of the second main channel and the internal control line will constitute essentially a linear mix of the two input signals imposed on the two control lines. The device is especially suited to microwave applications since it has very low input capacitance, and is well suited to being formed of high temperature superconducting materials since all of the structures may be formed coplanar with one another on a substrate.

  8. Optically Detected Magnetic Resonance and Thermal Activation Spectroscopy Study of Organic Semiconductors

    SciTech Connect

    Chang-Hwan Kim

    2003-12-12

    Organic electronic materials are a new class of emerging materials. Organic light emitting devices (OLEDs) are the most promising candidates for future flat panel display technologies. The photophysical characterization is the basic research step one must follow to understand this new class of materials and devices. The light emission properties are closely related to the transport properties of these materials. The objective of this dissertation is to probe the relation between transport and photophysical properties of organic semiconductors. The transport characteristics were evaluated by using thermally stimulated current and thermally stimulated luminescence techniques. The photoluminescence detected magnetic resonance and photoluminescence quantum yield studies provide valuable photophysical information on this class of materials. OLEDs are already in the market. However, detailed studies on the degradation mechanisms are still lacking. Since both optically detected magnetic resonance and thermal activation spectroscopy probe long-lived defect-related states in organic semiconductors, the combined study generates new insight on the OLED operation and degradation mechanisms.

  9. Structural and optical properties of silicon metal-oxide-semiconductor light-emitting devices

    NASA Astrophysics Data System (ADS)

    Xu, Kaikai; Zhang, Zhengyuan; Zhang, Zhengping

    2016-01-01

    A silicon p-channel metal oxide semiconductor field-effect transistor (Si-PMOSFET) that is fully compatible with the standard complementary metal oxide semiconductor process is investigated based on the phenomenon of optical radiation observed in the reverse-biased p-n junction in the Si-PMOSFET device. The device can be used either as a two-terminal silicon diode light-emitting device (Si-diode LED) or as a three-terminal silicon gate-controlled diode light-emitting device (Si gate-controlled diode LED). It is seen that the three-terminal operating mode could provide much higher power transfer efficiency than the two-terminal operating mode. A new solution based on the concept of a theoretical quantum efficiency model combined with calculated results is proposed for interpreting the evidence of light intensity reduction at high operating voltages. The Si-LED that can be easily integrated into CMOS fabrication process is an important step toward optical interconnects.

  10. Memory effects in a Al/Ti:HfO2/CuPc metal-oxide-semiconductor device

    NASA Astrophysics Data System (ADS)

    Tripathi, Udbhav; Kaur, Ramneek

    2016-05-01

    Metal oxide semiconductor structured organic memory device has been successfully fabricated. Ti doped hafnium oxide (Ti:HfO2) nanoparticles has been fabricated by precipitation method and further calcinated at 800 °C. Copper phthalocyanine, a hole transporting material has been utilized as an organic semiconductor. The electrical properties of the fabricated device have been studied by measuring the current-voltage and capacitance-voltage characteristics. The amount of charge stored in the nanoparticles has been calculated by using flat band condition. This simple approach for fabricating MOS memory device has opens up opportunities for the development of next generation memory devices.

  11. Total-dose radiation effects data for semiconductor devices: 1985 supplement, volume 1

    NASA Technical Reports Server (NTRS)

    Martin, K. E.; Gauthier, M. K.; Coss, J. R.; Dantas, A. R. V.; Price, W. E.

    1985-01-01

    Steady-state, total-dose radiation test data are provided, in graphic format, for use by electronic designers and other personnel using semiconductor devices in a radiation environment. The data were generated by JPL for various NASA space programs. The document is in two volumes: Volume 1 provides data on diodes, bipolar transistors, field effect transistors, and miscellaneous semiconductor types, and Volume 2 provides total-dose radiation test data on integrated circuits. Volume 1 of this 1985 Supplement contains new total-dose radiation test data generated since the August 1, 1981 release date of the original Volume 1. Publication of Volume 2 of the 1985 Supplement will follow that of Volume 1 by approximately three months.

  12. Implantable micro-optical semiconductor devices for optical theranostics in deep tissue

    NASA Astrophysics Data System (ADS)

    Takehara, Hiroaki; Katsuragi, Yuji; Ohta, Yasumi; Motoyama, Mayumi; Takehara, Hironari; Noda, Toshihiko; Sasagawa, Kiyotaka; Tokuda, Takashi; Ohta, Jun

    2016-04-01

    Optical therapy and diagnostics using photoactivatable molecular tools are promising approaches in medical applications; however, a method for the delivery of light deep inside biological tissues remains a challenge. Here, we present a method of illumination and detection of light using implantable micro-optical semiconductor devices. Unlike in conventional transdermal light delivery methods using low-energy light (>620 nm or near-infrared light), in our method, high-energy light (470 nm) can also be used for illumination. Implanted submillimeter-sized light-emitting diodes were found to provide sufficient illumination (0.6-4.1 mW/cm2), and a complementary metal-oxide-semiconductor image sensor enabled the detection of fluorescence signals.

  13. H+-type and OH--type biological protonic semiconductors and complementary devices

    NASA Astrophysics Data System (ADS)

    Deng, Yingxin; Josberger, Erik; Jin, Jungho; Rousdari, Anita Fadavi; Helms, Brett A.; Zhong, Chao; Anantram, M. P.; Rolandi, Marco

    2013-10-01

    Proton conduction is essential in biological systems. Oxidative phosphorylation in mitochondria, proton pumping in bacteriorhodopsin, and uncoupling membrane potentials by the antibiotic Gramicidin are examples. In these systems, H+ hop along chains of hydrogen bonds between water molecules and hydrophilic residues - proton wires. These wires also support the transport of OH- as proton holes. Discriminating between H+ and OH- transport has been elusive. Here, H+ and OH- transport is achieved in polysaccharide- based proton wires and devices. A H+- OH- junction with rectifying behaviour and H+-type and OH--type complementary field effect transistors are demonstrated. We describe these devices with a model that relates H+ and OH- to electron and hole transport in semiconductors. In turn, the model developed for these devices may provide additional insights into proton conduction in biological systems.

  14. Encoding Active Device Elements at Nanowire Tips.

    PubMed

    No, You-Shin; Gao, Ruixuan; Mankin, Max N; Day, Robert W; Park, Hong-Gyu; Lieber, Charles M

    2016-07-13

    Semiconductor nanowires and other one-dimensional materials are attractive for highly sensitive and spatially confined electrical and optical signal detection in biological and physical systems, although it has been difficult to localize active electronic or optoelectronic device function at one end of such one-dimensional structures. Here we report a new nanowire structure in which the material and dopant are modulated specifically at only one end of nanowires to encode an active two-terminal device element. We present a general bottom-up synthetic scheme for these tip-modulated nanowires and illustrate this with the synthesis of nanoscale p-n junctions. Electron microscopy imaging verifies the designed p-Si nanowire core with SiO2 insulating inner shell and n-Si outer shell with clean p-Si/n-Si tip junction. Electrical transport measurements with independent contacts to the p-Si core and n-Si shell exhibited a current rectification behavior through the tip and no detectable current through the SiO2 shell. Electrical measurements also exhibited an n-type response in conductance versus water-gate voltage with pulsed gate experiments yielding a temporal resolution of at least 0.1 ms and ∼90% device sensitivity localized to within 0.5 μm from the nanowire p-n tip. In addition, photocurrent experiments showed an open-circuit voltage of 0.75 V at illumination power of ∼28.1 μW, exhibited linear dependence of photocurrent with respect to incident illumination power with an estimated responsivity up to ∼0.22 A/W, and revealed localized photocurrent generation at the nanowire tip. The tip-modulated concept was further extended to a top-down/bottom-up hybrid approach that enabled large-scale production of vertical tip-modulated nanowires with a final synthetic yield of >75% with >4300 nanowires. Vertical tip-modulated nanowires were fabricated into >50 individually addressable nanowire device arrays showing diode-like current-voltage characteristics. These tip

  15. Fault localization and analysis in semiconductor devices with optical-feedback infrared confocal microscopy

    SciTech Connect

    Sarmiento, Raymund; Cemine, Vernon Julius; Tagaca, Imee Rose; Salvador, Arnel; Mar Blanca, Carlo; Saloma, Caesar

    2007-11-01

    We report on a cost-effective optical setup for characterizing light-emitting semiconductor devices with optical-feedback confocal infrared microscopy and optical beam-induced resistance change.We utilize the focused beam from an infrared laser diode to induce local thermal resistance changes across the surface of a biased integrated circuit (IC) sample. Variations in the multiple current paths are mapped by scanning the IC across the focused beam. The high-contrast current maps allow accurate differentiation of the functional and defective sites, or the isolation of the surface-emittingp-i-n devices in the IC. Optical beam-induced current (OBIC) is not generated since the incident beam energy is lower than the bandgap energy of the p-i-n device. Inhomogeneous current distributions in the IC become apparent without the strong OBIC background. They are located at a diffraction-limited resolution by referencing the current maps against the confocal reflectance image that is simultaneously acquired via optical-feedback detection. Our technique permits the accurate identification of metal and semiconductor sites as well as the classification of different metallic structures according to thickness, composition, or spatial inhomogeneity.

  16. Two-dimensional device modeling and analysis of GaInAs metal-semiconductor-metal photodiode structures

    NASA Astrophysics Data System (ADS)

    Averin, S.; Sachot, R.; Hugi, J.; de Fays, M.; Ilegems, M.

    1996-08-01

    A two-dimensional self-consistent time-dependent simulation technique has been developed to investigate electron-hole transport processes in the active region of metal-semiconductor-metal (MSM) interdigitated photodiode structures and to analyze their high-speed response. The distribution of the electric field inside the MSM device is determined by numerically solving the two-dimensional Poisson's equation by the modified fast elliptic solver method. A set of superparticles photogenerated at a particular wavelength is analyzed with a given initial distribution of the potential and given boundary conditions, and the evolution of the particles is traced in time through the active region of the MSM device. Circuit loading, electric field effects in the MSM structure with various finger separations, background doping, carrier trapping, and recombination are included in the simulation program. Owing to miniaturization of devices, the classical scaling laws lose their validity while various performance degrading effects appear. The simulations show that the main problem in MSM devices with a small contact separation is the low electric field penetration depth. This results in different electron and hole collection rates and in a poor response time. The trade-off between the high-speed response and the internal quantum efficiency is examined and ways to improve the high-speed response are indicated. Modeling results are compared with experimental data on Ga0.47In0.53As based MSM photodiodes.

  17. Generation and annihilation of traps in metal-oxide-semiconductor devices after negative air corona charging

    NASA Astrophysics Data System (ADS)

    Prasad, Ila; Srivastava, R. S.

    1993-07-01

    Surface and bulk traps along with positive oxide charge accumulation have been found to be generated in metal-oxide-semiconductor capacitors, when subjected to negative air corona discharge at slightly reduced pressure (≂10-1 Torr). The effects are neutralized and device quality improved when annealed at 200 °C in air. The bulk traps and a fraction of oxide charges were annealable when kept at room temperature for several months. The results have been analyzed by Nicollian-Goetzberger's conductance technique and a plausible explanation is given.

  18. Wide-band-gap, alkaline-earth-oxide semiconductor and devices utilizing same

    DOEpatents

    Abraham, Marvin M.; Chen, Yok; Kernohan, Robert H.

    1981-01-01

    This invention relates to novel and comparatively inexpensive semiconductor devices utilizing semiconducting alkaline-earth-oxide crystals doped with alkali metal. The semiconducting crystals are produced by a simple and relatively inexpensive process. As a specific example, a high-purity lithium-doped MgO crystal is grown by conventional techniques. The crystal then is heated in an oxygen-containing atmosphere to form many [Li].degree. defects therein, and the resulting defect-rich hot crystal is promptly quenched to render the defects stable at room temperature and temperatures well above the same. Quenching can be effected conveniently by contacting the hot crystal with room-temperature air.

  19. TOPICAL REVIEW: Strain induced semiconductor nanotubes: from formation process to device applications

    NASA Astrophysics Data System (ADS)

    Li, Xiuling

    2008-10-01

    Semiconductor nanotubes (SNTs) represent a new class of nanotechnology building blocks. They are formed by a combination of bottom-up and top-down approaches, using strain induced self-rolling mechanism from epitaxially grown heterojunction films. This review summarizes several aspects of this emerging field, including the SNT formation process, its dependence on crystal orientation, strain direction and geometry as well as the structural, electronic and optical properties and their implications. The precise controllability of structural and spatial positioning and versatile functionality make SNTs and related three-dimensional (3D) architectures promising candidates for practical applications in next generation nanoelectronic and nanophotonic devices.

  20. Lorentz factor determination for local electric fields in semiconductor devices utilizing hyper-thin dielectrics

    SciTech Connect

    McPherson, J. W.

    2015-11-28

    The local electric field (the field that distorts, polarizes, and weakens polar molecular bonds in dielectrics) has been investigated for hyper-thin dielectrics. Hyper-thin dielectrics are currently required for advanced semiconductor devices. In the work presented, it is shown that the common practice of using a Lorentz factor of L = 1/3, to describe the local electric field in a dielectric layer, remains valid for hyper-thin dielectrics. However, at the very edge of device structures, a rise in the macroscopic/Maxwell electric field E{sub diel} occurs and this causes a sharp rise in the effective Lorentz factor L{sub eff}. At capacitor and transistor edges, L{sub eff} is found to increase to a value 2/3 < L{sub eff} < 1. The increase in L{sub eff} results in a local electric field, at device edge, that is 50%–100% greater than in the bulk of the dielectric. This increase in local electric field serves to weaken polar bonds thus making them more susceptible to breakage by standard Boltzmann and/or current-driven processes. This has important time-dependent dielectric breakdown (TDDB) implications for all electronic devices utilizing polar materials, including GaN devices that suffer from device-edge TDDB.

  1. Non-parabolic hydrodynamic formulations for the simulation of inhomogeneous semiconductor devices

    NASA Technical Reports Server (NTRS)

    Smith, Arlynn W.; Brennan, Kevin F.

    1995-01-01

    Hydrodynamic models are becoming prevalent design tools for small scale devices and other devices in which high energy effects can dominate transport. Most current hydrodynamic models use a parabolic band approximation to obtain fairly simple conservation equations. Interest in accounting for band structure effects in hydrodynamic device simulation has begun to grow since parabolic models can not fully describe the transport in state of the art devices due to the distribution populating non-parabolic states within the band. This paper presents two different non-parabolic formulations of the hydrodynamic model suitable for the simulation of inhomogeneous semiconductor devices. The first formulation uses the Kane dispersion relationship (hk)(exp 2)/2m = W(1 + alpha(W)). The second formulation makes use of a power law ((hk)(exp 2)/2m = xW(sup y)) for the dispersion relation. Hydrodynamic models which use the first formulation rely on the binomial expansion to obtain moment equations with closed form coefficients. This limits the energy range over which the model is valid. The power law formulation readily produces closed form coefficients similar to those obtained using the parabolic band approximation. However, the fitting parameters (x,y) are only valid over a limited energy range. The physical significance of the band non-parabolicity is discussed as well as the advantages/disadvantages and approximations of the two non-parabolic models. A companion paper describes device simulations based on the three dispersion relationships: parabolic, Kane dispersion, and power low dispersion.

  2. Non-Parabolic Hydrodynamic Formulations for the Simulation of Inhomogeneous Semiconductor Devices

    NASA Technical Reports Server (NTRS)

    Smith, A. W.; Brennan, K. F.

    1996-01-01

    Hydrodynamic models are becoming prevalent design tools for small scale devices and other devices in which high energy effects can dominate transport. Most current hydrodynamic models use a parabolic band approximation to obtain fairly simple conservation equations. Interest in accounting for band structure effects in hydrodynamic device simulation has begun to grow since parabolic models cannot fully describe the transport in state of the art devices due to the distribution populating non-parabolic states within the band. This paper presents two different non-parabolic formulations or the hydrodynamic model suitable for the simulation of inhomogeneous semiconductor devices. The first formulation uses the Kane dispersion relationship ((hk)(exp 2)/2m = W(1 + alphaW). The second formulation makes use of a power law ((hk)(exp 2)/2m = xW(exp y)) for the dispersion relation. Hydrodynamic models which use the first formulation rely on the binomial expansion to obtain moment equations with closed form coefficients. This limits the energy range over which the model is valid. The power law formulation readily produces closed form coefficients similar to those obtained using the parabolic band approximation. However, the fitting parameters (x,y) are only valid over a limited energy range. The physical significance of the band non-parabolicity is discussed as well as the advantages/disadvantages and approximations of the two non-parabolic models. A companion paper describes device simulations based on the three dispersion relationships; parabolic, Kane dispersion and power law dispersion.

  3. Design and fabrication of 6.1-.ANG. family semiconductor devices using semi-insulating A1Sb substrate

    DOEpatents

    Sherohman, John W.; Coombs, III, Arthur W.; Yee, Jick Hong; Wu, Kuang Jen J.

    2007-05-29

    For the first time, an aluminum antimonide (AlSb) single crystal substrate is utilized to lattice-match to overlying semiconductor layers. The AlSb substrate establishes a new design and fabrication approach to construct high-speed, low-power electronic devices while establishing inter-device isolation. Such lattice matching between the substrate and overlying semiconductor layers minimizes the formation of defects, such as threaded dislocations, which can decrease the production yield and operational life-time of 6.1-.ANG. family heterostructure devices.

  4. Energetic semiconductor bridge device incorporating Al/MoOx multilayer nanofilms and negative temperature coefficient thermistor chip

    NASA Astrophysics Data System (ADS)

    Zhu, Peng; Jiao, Jianshe; Shen, Ruiqi; Ye, Yinghua; Fu, Shuai; Li, Dongle

    2014-05-01

    The design, fabrication, and characterization of an energetic semiconductor bridge device are presented. The device consists of a semiconductor bridge heating element, which has been selectively coated with Al/MoOx multilayer nanofilms to enhance ignition of a conventional pyrotechnics. Integrated negative temperature coefficient thermistor chip provides protection against electromagnetic and electrostatic discharge events. The device was specifically configured to allow ease of interconnection by wire bonds and silver-filled conductive epoxy. Extensive design validation testing was performed. The device has demonstrated low, predictable firing energy and insensitivity. Al/MoOx multilayer nanofilms have no distinct influence on the electrical properties of semiconductor bridge. Nanothermite reaction provides reliable ignition by being able to ignite across a gap.

  5. Characteristics and device applications of erbium doped III-V semiconductors grown by molecular beam epitaxy

    NASA Astrophysics Data System (ADS)

    Sethi, S.; Bhattacharya, P. K.

    1996-03-01

    We have studied the properties of molecular beam epitaxially (MBE)-grown Erdoped III-V semiconductors for optoelectronic applications. Optically excited Er3+ in insulating materials exhibits optical emission chiefly around 1.54 μm, in the range of minimum loss in silica fiber. It was thought, therefore, that an electrically pumped Er-doped semiconductor laser would find great applicability in fiber-optic communication systems. Exhaustive photoluminescence (PL) characterization was conducted on several of As-based III-V semiconductors doped with Er, on bulk as well as quantum-well structures. We did not observe any Errelated PL emission at 1.54 μm for any of the materials/structures studied, a phenomenon which renders impractical the realization of an Er-doped III-V semiconductor laser. Deep level transient spectroscopy studies were performed on GaAs and AlGaAs co-doped with Er and Si to investigate the presence of any Er-related deep levels. The lack of band-edge luminescence in the GaAs:Er films led us to perform carrier-lifetime measurements by electro-optic sampling of photoconductive transients generated in these films. We discovered lifetimes in the picosecond regime, tunable by varying the Er concentration in the films. We also found the films to be highly resistive, the resistivity increasing with increasing Er-concentration. Intensive structural characterization (double-crys-tal x-ray and transmission electron microscopy) performed by us on GaAs:Er epilayers indicates the presence of high-density nanometer-sized ErAs precipitates in MBE-grown GaAs:Er. These metallic nanoprecipitates probably form internal Schottky barriers within the GaAs matrix, which give rise to Shockley-Read-Hall recombination centers, thus accounting for both the high resistivities and the ultrashort carrier lifetimes. Optoelectronic devices fabricated included novel tunable (in terms of speed and responsivity) high-speed metal-semiconductor-metal (MSM) photodiodes made with Ga

  6. The world's first high voltage GaN-on-Diamond power semiconductor devices

    NASA Astrophysics Data System (ADS)

    Baltynov, Turar; Unni, Vineet; Narayanan, E. M. Sankara

    2016-11-01

    This paper presents the detailed fabrication method and extensive electrical characterisation results of the first-ever demonstrated high voltage GaN power semiconductor devices on CVD Diamond substrate. Fabricated circular GaN-on-Diamond HEMTs with gate-to-drain drift length of 17 μm and source field plate length of 3 μm show an off-state breakdown voltage of ∼1100 V. Temperature characterisation of capacitance-voltage characteristics and on-state characteristics provides insight on the temperature dependence of key parameters such as threshold voltage, 2DEG sheet carrier concentration, specific on-state resistance, and drain saturation current in the fabricated devices.

  7. Mixed-RKDG Finite Element Methods for the 2-D Hydrodynamic Model for Semiconductor Device Simulation

    DOE PAGES

    Chen, Zhangxin; Cockburn, Bernardo; Jerome, Joseph W.; Shu, Chi-Wang

    1995-01-01

    In this paper we introduce a new method for numerically solving the equations of the hydrodynamic model for semiconductor devices in two space dimensions. The method combines a standard mixed finite element method, used to obtain directly an approximation to the electric field, with the so-called Runge-Kutta Discontinuous Galerkin (RKDG) method, originally devised for numerically solving multi-dimensional hyperbolic systems of conservation laws, which is applied here to the convective part of the equations. Numerical simulations showing the performance of the new method are displayed, and the results compared with those obtained by using Essentially Nonoscillatory (ENO) finite difference schemes. Frommore » the perspective of device modeling, these methods are robust, since they are capable of encompassing broad parameter ranges, including those for which shock formation is possible. The simulations presented here are for Gallium Arsenide at room temperature, but we have tested them much more generally with considerable success.« less

  8. Quantum-corrected drift-diffusion models for transport in semiconductor devices

    SciTech Connect

    De Falco, Carlo; Gatti, Emilio; Lacaita, Andrea L.; Sacco, Riccardo . E-mail: riccardo.sacco@mate.polimi.it

    2005-04-10

    In this paper, we propose a unified framework for Quantum-corrected drift-diffusion (QCDD) models in nanoscale semiconductor device simulation. QCDD models are presented as a suitable generalization of the classical drift-diffusion (DD) system, each particular model being identified by the constitutive relation for the quantum-correction to the electric potential. We examine two special, and relevant, examples of QCDD models; the first one is the modified DD model named Schroedinger-Poisson-drift-diffusion, and the second one is the quantum-drift-diffusion (QDD) model. For the decoupled solution of the two models, we introduce a functional iteration technique that extends the classical Gummel algorithm widely used in the iterative solution of the DD system. We discuss the finite element discretization of the various differential subsystems, with special emphasis on their stability properties, and illustrate the performance of the proposed algorithms and models on the numerical simulation of nanoscale devices in two spatial dimensions.

  9. Ultraviolet random lasing from asymmetrically contacted MgZnO metal-semiconductor-metal device

    SciTech Connect

    Morshed, Muhammad M.; Suja, Mohammad; Zuo, Zheng; Liu, Jianlin

    2014-11-24

    Nitrogen-doped Mg{sub 0.12}Zn{sub 0.88}O nanocrystalline thin film was grown on c-plane sapphire substrate. Asymmetric Ni/Au and Ti/Au Schottky contacts and symmetric Ni/Au contacts were deposited on the thin film to form metal-semiconductor-metal (MSM) laser devices. Current-voltage, photocurrent, and electroluminescence characterizations were performed. Evident random lasing with a threshold current of ∼36 mA is demonstrated only from the asymmetric MSM device. Random lasing peaks are mostly distributed between 340 and 360 nm and an output power of 15 nW is measured at 43 mA injection current. The electron affinity difference between the contact metal and Mg{sub 0.12}Zn{sub 0.88}O:N layer plays an important role for electron and hole injection and subsequent stimulated random lasing.

  10. Characterization of an oxygen plasma process for cleaning packaged semiconductor devices. Final report

    SciTech Connect

    Adams, B.E.

    1996-11-01

    The purpose of this research was to experimentally determine the operating {open_quotes}window{close_quotes} for an oxygen plasma cleaning process to be used on microelectronics components just prior to wire bonding. The process was being developed to replace one that used vapor degreasing with trichlorotrifluoroethane, an ozone-depleting substance. A Box-Behnken experimental design was used to generate data from which the oxygen plasma cleaning process could be characterized. Auger electron spectrophotometry was used to measure the contamination thickness on the dice after cleaning. An empirical equation correlating the contamination thickness on the die surface with the operating parameters of the plasma system was developed from the collected Auger data, and optimum settings for cleaning semiconductor devices were determined. Devices were also tested for undesirable changes in electrical parameters resulting from cleaning in the plasma system. An increase in leakage current occurred for bipolar transistors and diodes after exposure to the oxygen plasma. Although an increase in leakage current occurred, each device`s parameter remained well below the acceptable specification limit. Based upon the experimental results, the optimum settings for the plasma cleaning process were determined to be 200 watts of power applied for five minutes in an enclosure maintained at 0.7 torr. At these settings, all measurable contamination was removed without compromising the reliability of the devices.

  11. SEMICONDUCTOR DEVICES: Total ionizing dose effects and annealing behavior for domestic VDMOS devices

    NASA Astrophysics Data System (ADS)

    Bo, Gao; Xuefeng, Yu; Diyuan, Ren; Gang, Liu; Yiyuan, Wang; Jing, Sun; Jiangwei, Cui

    2010-04-01

    Total dose effects and annealing behavior of domestic n-channel VDMOS devices under different bias conditions were investigated. The dependences of typical electrical parameters such as threshold voltage, breakdown voltage, leakage current, and on-state resistance upon total dose were discussed. We also observed the relationships between these parameters and annealing time. The experiment results show that: the threshold voltage negatively shifts with the increasing of total dose and continues to decrease at the beginning of 100 °C annealing; the breakdown voltage under the drain bias voltage has passed through the pre-irradiation threshold voltage during annealing behaving with a “rebound" effect; there is a latent interface-trap buildup (LITB) phenomenon in the VDMOS devices; the leakage current is suppressed; and on-state resistance is almost kept constant during irradiation and annealing. Our experiment results are meaningful and important for further improvements in the design and processing.

  12. Present and Future of Semiconductor Pulsed Power Generator ˜Role of Power Semiconductor Devices in Plasma Research˜ 6.High-Speed, Large-Current Power Semiconductors for Pulse Power Generation

    NASA Astrophysics Data System (ADS)

    Takata, Ikunori

    This paper describes the operation principles and limits of power semiconductors. In addition, operation mechanisms of the new pulse power devices, SOS (Semiconductor Opening Switch) and dynistors, are explained qualitatively. The fastest operating power device is the series connection of comparatively low-voltage devices. For large-current operation, a uniformly operating pin-diode structure device is essential. An SOS is constructed from dozens of medium voltage (about 3kV) special hard-recovery diodes. This can shut off 2kA current at 10kV with in 10ns. The dynistor has n+pnp+ four layers and two electrodes. Serial-connected dynistors have the potential to replace thyratrons. These new devices can endure over 10 kA/cm2 at much higher voltage than their static breakdown values in the repetitive use more than 1011 times.

  13. 78 FR 68814 - Subzone 183B; Authorization of Production Activity; Samsung Austin Semiconductor, LLC...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-15

    ... (78 FR 40427, 7-5-2013). The FTZ Board has determined that no further review of the activity is... Foreign-Trade Zones Board Subzone 183B; Authorization of Production Activity; Samsung Austin Semiconductor, LLC (Semiconductors); Austin, Texas On June 26, 2013, Samsung Austin Semiconductor, LLC submitted...

  14. Device fabrication, characterization, and thermal neutron detection response of LiZnP and LiZnAs semiconductor devices

    NASA Astrophysics Data System (ADS)

    Montag, Benjamin W.; Ugorowski, Philip B.; Nelson, Kyle A.; Edwards, Nathaniel S.; McGregor, Douglas S.

    2016-11-01

    Nowotny-Juza compounds continue to be explored as candidates for solid-state neutron detectors. Such a device would have greater efficiency, in a compact form, than present day gas-filled 3He and 10BF3 detectors. The 6Li(n,t)4He reaction yields a total Q-value of 4.78 MeV, larger than 10B, an energy easily identified above background radiations. Hence, devices fabricated from semiconductor compounds having either natural Li (nominally 7.5% 6Li) or enriched 6Li (usually 95% 6Li) as constituent atoms may provide a material for compact high efficiency neutron detectors. Starting material was synthesized by preparing equimolar portions of Li, Zn, and As sealed under vacuum (10-6 Torr) in quartz ampoules lined with boron nitride and subsequently reacted in a compounding furnace [1]. The raw synthesized material indicated the presence high impurity levels (material and electrical property characterizations). A static vacuum sublimation in quartz was performed to help purify the synthesized material [2,3]. Bulk crystalline samples were grown from the purified material [4,5]. Samples were cut using a diamond wire saw, and processed into devices. Bulk resistivity was determined from I-V curve measurements, ranging from 106-1011 Ω cm. Devices were characterized for sensitivity to 5.48 MeV alpha particles, 337 nm laser light, and neutron sensitivity in a thermal neutron diffracted beam at the Kansas State University TRIGA Mark II nuclear reactor. Thermal neutron reaction product charge induction was measured with a LiZnP device, and the reaction product spectral response was observed.

  15. The spatial origin of current noise in semiconductor devices in the framework of semiclassical transport

    NASA Astrophysics Data System (ADS)

    Korman, C. E.; Noaman, B. A.

    2010-10-01

    A new model to semiconductor device electronic noise is presented in the framework of semiclassical transport theory. The salient feature of this model is that it connects the current noise characteristics directly to the physics of scattering of the semiclassical transport theory and makes no additional assumption regarding the nature of noise. Employing this approach, this work investigates the spatial origin of the current noise across two semiconductor structures. In this approach the terminal current noise is directly related to carrier scattering inside the device, which is accounted for in the Boltzmann transport equation (BTE), without the need to add Langevin noise terms to the calculations. Accordingly, it utilizes the well-established spherical harmonics expansion (SHE) technique to solve the BTE, and it combines analytical and numerical methods, in contrast with the Monte Carlo (MC) approach that employs ensemble averages of randomly generated events. The model leads to the solution of a time-dependent transient solution of the BTE with special initial and Ohmic boundary conditions that is solved in the frequency domain to directly compute the terminal current noise spectral density. It is also shown that with this approach the Nyquist theorem under thermal equilibrium conditions is recovered.

  16. Charge collection efficiency degradation induced by MeV ions in semiconductor devices: Model and experiment

    DOE PAGES

    Vittone, Ettore; Pastuovic, Zeljko; Breese, Mark B. H.; Lopez, Javier Garicia; Jaksic, Milko; Raisanen, Jyrki; Siegele, Rainer; Simon, Aliz; Vizkelethy, Gyorgy

    2016-02-08

    This study investigates both theoretically and experimentally the charge collection efficiency (CCE) degradation in silicon diodes induced by energetic ions. Ion Beam Induced Charge (IBIC) measurements carried out on n- and p-type silicon diodes which were previously irradiated with MeV He ions show evidence that the CCE degradation does not only depend on the mass, energy and fluence of the damaging ion, but also depends on the ion probe species and on the polarization state of the device. A general one-dimensional model is derived, which accounts for the ion-induced defect distribution, the ionization profile of the probing ion and themore » charge induction mechanism. Using the ionizing and non-ionizing energy loss profiles resulting from simulations based on the binary collision approximation and on the electrostatic/transport parameters of the diode under study as input, the model is able to accurately reproduce the experimental CCE degradation curves without introducing any phenomenological additional term or formula. Although limited to low level of damage, the model is quite general, including the displacement damage approach as a special case and can be applied to any semiconductor device. It provides a method to measure the capture coefficients of the radiation induced recombination centres. They can be considered indexes, which can contribute to assessing the relative radiation hardness of semiconductor materials.« less

  17. Charge collection efficiency degradation induced by MeV ions in semiconductor devices: Model and experiment

    NASA Astrophysics Data System (ADS)

    Vittone, E.; Pastuovic, Z.; Breese, M. B. H.; Garcia Lopez, J.; Jaksic, M.; Raisanen, J.; Siegele, R.; Simon, A.; Vizkelethy, G.

    2016-04-01

    This paper investigates both theoretically and experimentally the charge collection efficiency (CCE) degradation in silicon diodes induced by energetic ions. Ion Beam Induced Charge (IBIC) measurements carried out on n- and p-type silicon diodes which were previously irradiated with MeV He ions show evidence that the CCE degradation does not only depend on the mass, energy and fluence of the damaging ion, but also depends on the ion probe species and on the polarization state of the device. A general one-dimensional model is derived, which accounts for the ion-induced defect distribution, the ionization profile of the probing ion and the charge induction mechanism. Using the ionizing and non-ionizing energy loss profiles resulting from simulations based on the binary collision approximation and on the electrostatic/transport parameters of the diode under study as input, the model is able to accurately reproduce the experimental CCE degradation curves without introducing any phenomenological additional term or formula. Although limited to low level of damage, the model is quite general, including the displacement damage approach as a special case and can be applied to any semiconductor device. It provides a method to measure the capture coefficients of the radiation induced recombination centres. They can be considered indexes, which can contribute to assessing the relative radiation hardness of semiconductor materials.

  18. Ultrafast laser trimming for reduced device leakage in high performance OTFT semiconductors for flexible displays

    NASA Astrophysics Data System (ADS)

    Karnakis, Dimitris; Cooke, Michael D.; Chan, Y. F.; Ogier, Simon D.

    2013-03-01

    Organic semiconductors (OSC) are solution processable synthetic materials with high carrier mobility that promise to revolutionise flexible electronics manufacturing due to their low cost, lightweight and high volume low temperature printing in reel-to-reel (R2R) [1] for applications such as flexible display backplanes (Fig.1), RFID tags, and logic/memory devices. Despite several recent technological advances, organic thin film transistor (OTFT) printing is still not production-ready due to limitations mainly with printing resolution on dimensionally unstable substrates and device leakage that reduces dramatically electrical performance. OTFTs have the source-drain in ohmic contact with the OSC material to lower contact resistance. If they are unpatterned, a leakage pathway from source to drain develops which results in non-optimum on/off currents and not controllable device uniformity (Fig.2). DPSS lasers offer several key advantages for OTFT patterning including maskless, non-contact, dry patterning, scalable large area operation with precision registration, well-suited to R2R manufacturing at overall μm size resolutions. But the thermal management of laser processing is very important as the devices are very sensitive to heat and thermomechanical damage [2]. This paper discusses 343nm picosecond laser ablation trimming of 50nm thick PTAA, TIPS pentacene and other semiconductor compounds on thin 50nm thick metal gold electrodes in a top gate configuration. It is shown that with careful optimisation, a suitable process window exists resulting in clean laser structuring without damage to the underlying layers while also containing laser debris. Several order of magnitude improvements were recorded in on/off currents up to 106 with OSC mobilities of 1 cm2/Vsec, albeit at slightly higher than optimum threshold voltages which support demanding flexible display backplane applications.

  19. Metal insulator semiconductor solar cell devices based on a Cu{sub 2}O substrate utilizing h-BN as an insulating and passivating layer

    SciTech Connect

    Ergen, Onur; Gibb, Ashley; Vazquez-Mena, Oscar; Zettl, Alex; Regan, William Raymond

    2015-03-09

    We demonstrate cuprous oxide (Cu{sub 2}O) based metal insulator semiconductor Schottky (MIS-Schottky) solar cells with efficiency exceeding 3%. A unique direct growth technique is employed in the fabrication, and hexagonal boron nitride (h-BN) serves simultaneously as a passivation and insulation layer on the active Cu{sub 2}O layer. The devices are the most efficient of any Cu{sub 2}O based MIS-Schottky solar cells reported to date.

  20. Metal insulator semiconductor solar cell devices based on a Cu2O substrate utilizing h-BN as an insulating and passivating layer

    NASA Astrophysics Data System (ADS)

    Ergen, Onur; Gibb, Ashley; Vazquez-Mena, Oscar; Regan, William Raymond; Zettl, Alex

    2015-03-01

    We demonstrate cuprous oxide (Cu2O) based metal insulator semiconductor Schottky (MIS-Schottky) solar cells with efficiency exceeding 3%. A unique direct growth technique is employed in the fabrication, and hexagonal boron nitride (h-BN) serves simultaneously as a passivation and insulation layer on the active Cu2O layer. The devices are the most efficient of any Cu2O based MIS-Schottky solar cells reported to date.

  1. SEMICONDUCTOR DEVICES: Off-state avalanche breakdown induced degradation in 20 V NLDMOS devices

    NASA Astrophysics Data System (ADS)

    Shifeng, Zhang; Koubao, Ding; Yan, Han; Chenggong, Han; Jiaxian, Hu; Bin, Zhang

    2010-09-01

    Degradation behaviors of 20 V NLDMOS operated under off-state avalanche breakdown conditions are presented. A constant current pulse stressing test is applied to the device. Two different degradation mechanisms are identified by analysis of electrical data, technology computer-aided design (TCAD) simulations and charge pumping measurements. The first mechanism is attributed to positive oxide-trapped charges in the N-type drift region, and the second one is due to decreased electron mobility upon interface state formation in the drift region. Both of the mechanisms are enhanced with increasing avalanche breakdown current.

  2. Simulation and Modeling of Submicron Semiconductor Devices by a New Hydrodynamic Method.

    NASA Astrophysics Data System (ADS)

    Lin, Qi.

    Robust numerical methods for the solution of the hydrodynamic model are developed and implemented for the simulation of submicron semiconductor devices. The hydrodynamic equations are reformulated into readily solvable self-adjoint forms with the aid of newly defined HD-Slotboom state variables. A new discretization strategy is developed to resolve the rapid variation in the carrier densities and carrier temperatures. The approach also yields a coefficient matrix for each discretized hydrodynamic equation, which is guaranteed to be diagonally dominant. The hydrodynamic equations are decoupled by using a Gummel block iteration method. A fixed-point iteration technique is employed to solve the discretized equations, which guarantees that each decoupled equation converges for any starting value. Furthermore, the decoupling of equations and use of the fixed-point iteration scheme obviate the need for direct solutions of large matrix equations, and thereby eliminate the need for large memory allocations. The algorithm is inherently parallel, so it can be readily implemented on parallel machines to increase computation speed. Using these methods, several simulation packages are developed for the analysis of one-dimensional (1-D) n^+-n-n^+ devices, and square electric fields, two-dimensional (2-D) & three-dimensional (3-D) MOSFET's, and two-dimensional SOI MOSFET's. Various simulation results for these devices are presented. Some one-dimensional simulation results are compared with Monte Carlo calculations, and a good agreement is observed. Also convergence, stability, and efficiency of the methods are examined by a set of numerical experiments. The device simulators are applied to investigate the hot-electron induced degradation in submicron SOI devices and EPROM's. The impact of localized interface charge on device characteristics is studied. Some measured results are used to calibrate the process parameters in the simulators so that the simulators can predict device

  3. SEMICONDUCTOR DEVICES: A new SOI high voltage device based on E-SIMOX substrate

    NASA Astrophysics Data System (ADS)

    Lijuan, Wu; Shengdong, Hu; Bo, Zhang; Zhaoji, Li

    2010-04-01

    A new NI (n+ charge islands) high voltage device structure based on E-SIMOX (epitaxy-the separation by implantation of oxygen) substrate is proposed. It is characterized by equidistant high concentration n+-regions on the top interface of the dielectric buried layer. Inversion holes caused by the vertical electric field (EV) are located in the spacing of two neighboring n+-regions on the interface by the force from lateral electric field (EL) and the compositive operation of Coulomb's forces with the ionized donors in the undepleted n+-regions. This effectively enhances the electric field of dielectric buried layer (EI) and increases breakdown voltage (VB). An analytical model of the vertical interface electric field for the NI SOI is presented, and the analytical results are in good agreement with the 2D simulative results. EI = 568 V/μm and VB = 230 V of NI SOI are obtained by 2D simulation on a 0.375-μm-thick dielectric layer and 2-μm-thick top silicon layer. The device can be manufactured by using the standard CMOS process with addition of a mask for implanting arsenic to form NI. 2-μm silicon layer can be achieved by using epitaxy SIMOX technology (E-SIMOX).

  4. The importance of Fe interface states for ferromagnet-semiconductor based spintronic devices

    NASA Astrophysics Data System (ADS)

    Chantis, Athanasios

    2009-03-01

    I present our recent theoretical studies of the bias-controlled spin injection, detection sensitivity and tunneling anisotropic magnetoresistance in ferromagnetic-semiconductor tunnel junctions. Using first-principles electron transport methods we have shown that Fe 3d minority-spin surface (interface) states are responsible for at least two important effects for spin electronics. First, they can produce a sizable Tunneling Anisotropic Magnetoresistance in magnetic tunnel junctions with a single Fe electrode. The effect is driven by a Rashba shift of the resonant surface band when the magnetization changes direction. This can introduce a new class of spintronic devices, namely, Tunneling Magnetoresistance junctions with a single ferromagnetic electrode that can function at room temperatures. Second, in Fe/GaAs(001) magnetic tunnel junctions they produce a strong dependence of the tunneling current spin-polarization on applied electrical bias. A dramatic sign reversal within a voltage range of just a few tenths of an eV is found. This explains the observed sign reversal of spin-polarization in recent experiments of electrical spin injection in Fe/GaAs(001) and related reversal of tunneling magnetoresistcance through vertical Fe/GaAs/Fe trilayers. We also present a theoretical description of electrical spin-detection at a ferromagnet/semiconductor interface. We show that the sensitivity of the spin detector has strong bias dependence which, in the general case, is dramatically different from that of the tunneling current spin-polarization. We show that in realistic ferromagnet/semiconductor junctions this bias dependence can originate from two distinct physical mechanisms: 1) the bias dependence of tunneling current spin-polarization, which is of microscopic origin and depends on the specific properties of the interface, and 2) the macroscopic electron spin transport properties in the semiconductor. Our numerical results show that the magnitude of the voltage signal

  5. A Novel Method for Measuring the Temperature in the Active Region of Semiconductor Modules

    NASA Astrophysics Data System (ADS)

    Liu, Jing; Feng, Shi-Wei; Zhang, Guang-Chen; Zhu, Hui; Guo, Chun-Sheng; Qiao, Yan-Bin; Li, Jing-Wan

    2012-04-01

    The temperature in the active region of semiconductor modules can be measured by a vacuum system method. The test device is positioned on a vacuum test platform and heated in two ways, from the chip and from the case, to identify the required heat to establish stable temperature gradients for the two processes, respectively. A complementary relationship between the temperatures under the two heating methods is found. By injecting the total heat into the device, the resulting uniform temperature can be derived from the temperature curves of the chip and case. It is demonstrated that the temperature obtained from this vacuum system method is equivalent to the normal operating temperature of the device in the atmosphere. Further comparison of our result with that of the electrical method also shows good agreement.

  6. SEMICONDUCTOR DEVICES: A new integrated SOI power device based on self-isolation technology

    NASA Astrophysics Data System (ADS)

    Huanmei, Gao; Xiaorong, Luo; Wei, Zhang; Hao, Deng; Tianfei, Lei

    2010-08-01

    A new SOI LDMOS structure with buried n-islands (BNIs) on the top interface of the buried oxide (BOX) is presented in a p-SOI high voltage integrated circuits (p-SOI HVICs), which exhibits good self-isolation performance between the power device and low-voltage control circuits. Furthermore, both the donor ions of BNIs and holes collected between depleted n-islands not only enhance the electric field in BOX from 32 to 113 V/μm, but also modulate the lateral electric field distribution, resulting in an improvement of the breakdown voltage of the BNI SOI LDMOS. A 673 V BNI SOI LDMOS is experimentally obtained and presents an excellent self-isolation performance in a p-SOI HVIC.

  7. III-antimonide/nitride based semiconductors for optoelectronic materials and device studies : LDRD 26518 final report.

    SciTech Connect

    Kurtz, Steven Ross; Hargett, Terry W.; Serkland, Darwin Keith; Waldrip, Karen Elizabeth; Modine, Normand Arthur; Klem, John Frederick; Jones, Eric Daniel; Cich, Michael Joseph; Allerman, Andrew Alan; Peake, Gregory Merwin

    2003-12-01

    The goal of this LDRD was to investigate III-antimonide/nitride based materials for unique semiconductor properties and applications. Previous to this study, lack of basic information concerning these alloys restricted their use in semiconductor devices. Long wavelength emission on GaAs substrates is of critical importance to telecommunication applications for cost reduction and integration into microsystems. Currently InGaAsN, on a GaAs substrate, is being commercially pursued for the important 1.3 micrometer dispersion minima of silica-glass optical fiber; due, in large part, to previous research at Sandia National Laboratories. However, InGaAsN has not shown great promise for 1.55 micrometer emission which is the low-loss window of single mode optical fiber used in transatlantic fiber. Other important applications for the antimonide/nitride based materials include the base junction of an HBT to reduce the operating voltage which is important for wireless communication links, and for improving the efficiency of a multijunction solar cell. We have undertaken the first comprehensive theoretical, experimental and device study of this material with promising results. Theoretical modeling has identified GaAsSbN to be a similar or potentially superior candidate to InGaAsN for long wavelength emission on GaAs. We have confirmed these predictions by producing emission out to 1.66 micrometers and have achieved edge emitting and VCSEL electroluminescence at 1.3 micrometers. We have also done the first study of the transport properties of this material including mobility, electron/hole mass, and exciton reduced mass. This study has increased the understanding of the III-antimonide/nitride materials enough to warrant consideration for all of the target device applications.

  8. Pulsed Laser System to Simulate Effects of Cosmic Rays in Semiconductor Devices

    NASA Technical Reports Server (NTRS)

    Aveline, David C.; Adell, Philippe C.; Allen, Gregory R.; Guertin, Steven M.; McClure, Steven S.

    2011-01-01

    Spaceflight system electronic devices must survive a wide range of radiation environments with various particle types including energetic protons, electrons, gamma rays, x-rays, and heavy ions. High-energy charged particles such as heavy ions can pass straight through a semiconductor material and interact with a charge-sensitive region, generating a significant amount of charge (electron-hole pairs) along their tracks. These excess charges can damage the device, and the response can range from temporary perturbations to permanent changes in the state or performance. These phenomena are called single event effects (SEE). Before application in flight systems, electronic parts need to be qualified and tested for performance and radiation sensitivity. Typically, their susceptibility to SEE is tested by exposure to an ion beam from a particle accelerator. At such facilities, the device under test (DUT) is irradiated with large beams so there is no fine resolution to investigate particular regions of sensitivity on the parts. While it is the most reliable approach for radiation qualification, these evaluations are time consuming and costly. There is always a need for new cost-efficient strategies to complement accelerator testing: pulsed lasers provide such a solution. Pulsed laser light can be utilized to simulate heavy ion effects with the advantage of being able to localize the sensitive region of an integrated circuit. Generally, a focused laser beam of approximately picosecond pulse duration is used to generate carrier density in the semiconductor device. During irradiation, the laser pulse is absorbed by the electronic medium with a wavelength selected accordingly by the user, and the laser energy can ionize and simulate SEE as would occur in space. With a tightly focused near infrared (NIR) laser beam, the beam waist of about a micrometer can be achieved, and additional scanning techniques are able to yield submicron resolution. This feature allows mapping of all

  9. Quantum filter of spin polarized states: Metal–dielectric–ferromagnetic/semiconductor device

    SciTech Connect

    Makarov, Vladimir I.; Khmelinskii, Igor

    2014-02-01

    Highlights: • Development of a new spintronics device. • Development of quantum spin polarized filters. • Development of theory of quantum spin polarized filter. - Abstract: Recently we proposed a model for the Quantum Spin-Polarized State Filter (QSPSF). The magnetic moments are transported selectively in this model, detached from the electric charge carriers. Thus, transfer of a spin-polarized state between two conductors was predicted in a system of two levels coupled by exchange interaction. The strength of the exchange interaction between the two conductive layers depends on the thickness of the dielectric layer separating them. External magnetic fields modulate spin-polarized state transfer, due to Zeeman level shift. Therefore, a linearly growing magnetic field generates a series of current peaks in a nearby coil. Thus, our spin-state filter should contain as least three nanolayers: (1) conductive or ferromagnetic; (2) dielectric; and (3) conductive or semiconductive. The spectrum of spin-polarized states generated by the filter device consists of a series of resonance peaks. In a simple case the number of lines equals S, the total spin angular momentum of discrete states in one of the coupled nanolayers. Presently we report spin-polarized state transport in metal–dielectric–ferromagnetic (MDF) and metal–dielectric–semiconductor (MDS) three-layer sandwich devices. The exchange-resonance spectra in such devices are quite specific, differing also from spectra observed earlier in other three-layer devices. The theoretical model is used to interpret the available experimental results. A detailed ab initio analysis of the magnetic-field dependence of the output magnetic moment averaged over the surface of the device was carried out. The model predicts the resonance structure of the signal, although at its present accuracy it cannot predict the positions of the spectral peaks.

  10. Multimodal Complementary Metal-Oxide-Semiconductor Sensor Device for Imaging of Fluorescence and Electrical Potential in Deep Brain of Mouse

    NASA Astrophysics Data System (ADS)

    Tagawa, Ayato; Minami, Hiroki; Mitani, Masahiro; Noda, Toshihiko; Sasagawa, Kiyotaka; Tokuda, Takashi; Tamura, Hideki; Hatanaka, Yumiko; Ishikawa, Yasuyuki; Shiosaka, Sadao; Ohta, Jun

    2010-01-01

    We have developed a multimodal complementary metal-oxide-semiconductor (CMOS) sensor device for observing neural activities in the deep brain of a mouse. The CMOS sensor includes an image sensor, electrodes, and a light-emitting diode (LED). The image sensor was designed to be operated using only four inputs/outputs (I/Os) to reduce the number of connecting wires. The electrodes were placed on the pixel array of the sensor. Windows were opened in the electrode over the photodiodes to enable the fluorescence to be imaged using the pixels under the electrodes. An LED was mounted on the chip. The sensor chip was shaped like a shank to facilitate smooth insertion into the brain tissue. The entire device was coated with a parylene layer to make it biocompatible. The experimental results showed that the green fluorescent beads on the pixel array were successfully imaged using the LED on the chip as a light source. In a brain phantom, the change in the electrical potential was successfully sensed by the electrode, and green fluorescent beads were simultaneously imaged using the pixels under the electrode. We also demonstrated that the CMOS sensor device could successfully operate in the hippocampal area of an anesthetized mouse.

  11. Total-dose radiation effects data for semiconductor devices. 1985 Supplement. Volume 2, part B

    NASA Technical Reports Server (NTRS)

    Martin, K. E.; Gauthier, M. K.; Coss, J. R.; Dantas, A. R. V.; Price, W. E.

    1986-01-01

    Steady-state, total-dose radiation test data are provided in graphic format, for use by electronic designers and other personnel using semiconductor devices in a radiation environment. The data were generated by JPL for various NASA space programs. The document is in two volumes: Volume 1 provides data on diodes, bipolar transistors, field effect transistors, and miscellaneous semiconductor types, and Volume 2 (Parts A and B) provides data on integrated circuits. The data are presented in graphic, tabular, and/or narrative format, depending on the complexity of the integrated circuit. Most tests were done steady-state 2.5-MeV electron beam. However, some radiation exposures were made with a Cobalt-60 gamma ray source, the results of which should be regarded as only an approximate measure of the radiation damage that would be incurred by an equivalent electron dose. All data were generated in support of NASA space programs by the JPL Radiation Effects and Testing Group (514).

  12. Hydrogen-Bonded Organic Semiconductor Micro- And Nanocrystals: From Colloidal Syntheses to (Opto-)Electronic Devices

    PubMed Central

    2014-01-01

    Organic pigments such as indigos, quinacridones, and phthalocyanines are widely produced industrially as colorants for everyday products as various as cosmetics and printing inks. Herein we introduce a general procedure to transform commercially available insoluble microcrystalline pigment powders into colloidal solutions of variously sized and shaped semiconductor micro- and nanocrystals. The synthesis is based on the transformation of the pigments into soluble dyes by introducing transient protecting groups on the secondary amine moieties, followed by controlled deprotection in solution. Three deprotection methods are demonstrated: thermal cleavage, acid-catalyzed deprotection, and amine-induced deprotection. During these processes, ligands are introduced to afford colloidal stability and to provide dedicated surface functionality and for size and shape control. The resulting micro- and nanocrystals exhibit a wide range of optical absorption and photoluminescence over spectral regions from the visible to the near-infrared. Due to excellent colloidal solubility offered by the ligands, the achieved organic nanocrystals are suitable for solution processing of (opto)electronic devices. As examples, phthalocyanine nanowire transistors as well as quinacridone nanocrystal photodetectors, with photoresponsivity values by far outperforming those of vacuum deposited reference samples, are demonstrated. The high responsivity is enabled by photoinduced charge transfer between the nanocrystals and the directly attached electron-accepting vitamin B2 ligands. The semiconducting nanocrystals described here offer a cheap, nontoxic, and environmentally friendly alternative to inorganic nanocrystals as well as a new paradigm for obtaining organic semiconductor materials from commercial colorants. PMID:25253644

  13. Low Temperature Processed Complementary Metal Oxide Semiconductor (CMOS) Device by Oxidation Effect from Capping Layer

    PubMed Central

    Wang, Zhenwei; Al-Jawhari, Hala A.; Nayak, Pradipta K.; Caraveo-Frescas, J. A.; Wei, Nini; Hedhili, M. N.; Alshareef, H. N.

    2015-01-01

    In this report, both p- and n-type tin oxide thin-film transistors (TFTs) were simultaneously achieved using single-step deposition of the tin oxide channel layer. The tuning of charge carrier polarity in the tin oxide channel is achieved by selectively depositing a copper oxide capping layer on top of tin oxide, which serves as an oxygen source, providing additional oxygen to form an n-type tin dioxide phase. The oxidation process can be realized by annealing at temperature as low as 190°C in air, which is significantly lower than the temperature generally required to form tin dioxide. Based on this approach, CMOS inverters based entirely on tin oxide TFTs were fabricated. Our method provides a solution to lower the process temperature for tin dioxide phase, which facilitates the application of this transparent oxide semiconductor in emerging electronic devices field. PMID:25892711

  14. Total-dose radiation effects data for semiconductor devices. 1985 supplement. Volume 2, part A

    NASA Technical Reports Server (NTRS)

    Martin, K. E.; Gauthier, M. K.; Coss, J. R.; Dantas, A. R. V.; Price, W. E.

    1986-01-01

    Steady-state, total-dose radiation test data, are provided in graphic format for use by electronic designers and other personnel using semiconductor devices in a radiation environment. The data were generated by JPL for various NASA space programs. This volume provides data on integrated circuits. The data are presented in graphic, tabular, and/or narrative format, depending on the complexity of the integrated circuit. Most tests were done using the JPL or Boeing electron accelerator (Dynamitron) which provides a steady-state 2.5 MeV electron beam. However, some radiation exposures were made with a Cobalt-60 gamma ray source, the results of which should be regarded as only an approximate measure of the radiation damage that would be incurred by an equivalent electron dose.

  15. Heterodyne mixing of millimetre electromagnetic waves and sub-THz sound in a semiconductor device

    PubMed Central

    Heywood, Sarah L.; Glavin, Boris A.; Beardsley, Ryan P.; Akimov, Andrey V.; Carr, Michael W.; Norman, James; Norton, Philip C.; Prime, Brian; Priestley, Nigel; Kent, Anthony J.

    2016-01-01

    We demonstrate heterodyne mixing of a 94 GHz millimetre wave photonic signal, supplied by a Gunn diode oscillator, with coherent acoustic waves of frequency ~100 GHz, generated by pulsed laser excitation of a semiconductor surface. The mixing takes place in a millimetre wave Schottky diode, and the intermediate frequency electrical signal is in the 1–12 GHz range. The mixing process preserves all the spectral content in the acoustic signal that falls within the intermediate frequency bandwidth. Therefore this technique may find application in high-frequency acoustic spectroscopy measurements, exploiting the nanometre wavelength of sub-THz sound. The result also points the way to exploiting acoustoelectric effects in photonic devices working at sub-THz and THz frequencies, which could provide functionalities at these frequencies, e.g. acoustic wave filtering, that are currently in widespread use at lower (GHz) frequencies. PMID:27477841

  16. Heterodyne mixing of millimetre electromagnetic waves and sub-THz sound in a semiconductor device.

    PubMed

    Heywood, Sarah L; Glavin, Boris A; Beardsley, Ryan P; Akimov, Andrey V; Carr, Michael W; Norman, James; Norton, Philip C; Prime, Brian; Priestley, Nigel; Kent, Anthony J

    2016-08-01

    We demonstrate heterodyne mixing of a 94 GHz millimetre wave photonic signal, supplied by a Gunn diode oscillator, with coherent acoustic waves of frequency ~100 GHz, generated by pulsed laser excitation of a semiconductor surface. The mixing takes place in a millimetre wave Schottky diode, and the intermediate frequency electrical signal is in the 1-12 GHz range. The mixing process preserves all the spectral content in the acoustic signal that falls within the intermediate frequency bandwidth. Therefore this technique may find application in high-frequency acoustic spectroscopy measurements, exploiting the nanometre wavelength of sub-THz sound. The result also points the way to exploiting acoustoelectric effects in photonic devices working at sub-THz and THz frequencies, which could provide functionalities at these frequencies, e.g. acoustic wave filtering, that are currently in widespread use at lower (GHz) frequencies.

  17. Heterodyne mixing of millimetre electromagnetic waves and sub-THz sound in a semiconductor device

    NASA Astrophysics Data System (ADS)

    Heywood, Sarah L.; Glavin, Boris A.; Beardsley, Ryan P.; Akimov, Andrey V.; Carr, Michael W.; Norman, James; Norton, Philip C.; Prime, Brian; Priestley, Nigel; Kent, Anthony J.

    2016-08-01

    We demonstrate heterodyne mixing of a 94 GHz millimetre wave photonic signal, supplied by a Gunn diode oscillator, with coherent acoustic waves of frequency ~100 GHz, generated by pulsed laser excitation of a semiconductor surface. The mixing takes place in a millimetre wave Schottky diode, and the intermediate frequency electrical signal is in the 1–12 GHz range. The mixing process preserves all the spectral content in the acoustic signal that falls within the intermediate frequency bandwidth. Therefore this technique may find application in high-frequency acoustic spectroscopy measurements, exploiting the nanometre wavelength of sub-THz sound. The result also points the way to exploiting acoustoelectric effects in photonic devices working at sub-THz and THz frequencies, which could provide functionalities at these frequencies, e.g. acoustic wave filtering, that are currently in widespread use at lower (GHz) frequencies.

  18. Heterodyne mixing of millimetre electromagnetic waves and sub-THz sound in a semiconductor device.

    PubMed

    Heywood, Sarah L; Glavin, Boris A; Beardsley, Ryan P; Akimov, Andrey V; Carr, Michael W; Norman, James; Norton, Philip C; Prime, Brian; Priestley, Nigel; Kent, Anthony J

    2016-01-01

    We demonstrate heterodyne mixing of a 94 GHz millimetre wave photonic signal, supplied by a Gunn diode oscillator, with coherent acoustic waves of frequency ~100 GHz, generated by pulsed laser excitation of a semiconductor surface. The mixing takes place in a millimetre wave Schottky diode, and the intermediate frequency electrical signal is in the 1-12 GHz range. The mixing process preserves all the spectral content in the acoustic signal that falls within the intermediate frequency bandwidth. Therefore this technique may find application in high-frequency acoustic spectroscopy measurements, exploiting the nanometre wavelength of sub-THz sound. The result also points the way to exploiting acoustoelectric effects in photonic devices working at sub-THz and THz frequencies, which could provide functionalities at these frequencies, e.g. acoustic wave filtering, that are currently in widespread use at lower (GHz) frequencies. PMID:27477841

  19. Low temperature processed complementary metal oxide semiconductor (CMOS) device by oxidation effect from capping layer.

    PubMed

    Wang, Zhenwei; Al-Jawhari, Hala A; Nayak, Pradipta K; Caraveo-Frescas, J A; Wei, Nini; Hedhili, M N; Alshareef, H N

    2015-04-20

    In this report, both p- and n-type tin oxide thin-film transistors (TFTs) were simultaneously achieved using single-step deposition of the tin oxide channel layer. The tuning of charge carrier polarity in the tin oxide channel is achieved by selectively depositing a copper oxide capping layer on top of tin oxide, which serves as an oxygen source, providing additional oxygen to form an n-type tin dioxide phase. The oxidation process can be realized by annealing at temperature as low as 190 °C in air, which is significantly lower than the temperature generally required to form tin dioxide. Based on this approach, CMOS inverters based entirely on tin oxide TFTs were fabricated. Our method provides a solution to lower the process temperature for tin dioxide phase, which facilitates the application of this transparent oxide semiconductor in emerging electronic devices field.

  20. Substrate-emitting semiconductor laser with a trapezoidal active region

    SciTech Connect

    Dikareva, N V; Nekorkin, S M; Karzanova, M V; Zvonkov, B N; Aleshkin, V Ya; Dubinov, A A; Afonenko, A A

    2014-04-28

    Semiconductor lasers with a narrow (∼2°) directional pattern in the planes both parallel and perpendicular to the p–n junction are fabricated. To achieve a low radiation divergence in the p–n junction plane, the active region in this plane was designed in the form of a trapezium. The narrow directional pattern in the plane perpendicular to the p–n junction was ensured by the use of a leaky mode, through which more than 90% of laser power was coupled out. (lasers)

  1. Transmission line pulse system for avalanche characterization of high power semiconductor devices

    NASA Astrophysics Data System (ADS)

    Riccio, Michele; Ascione, Giovanni; De Falco, Giuseppe; Maresca, Luca; De Laurentis, Martina; Irace, Andrea; Breglio, Giovanni

    2013-05-01

    Because of the increasing in power density of electronic devices for medium and high power application, reliabilty of these devices is of great interest. Understanding the avalanche behaviour of a power device has become very important in these last years because it gives an indication of the maximum energy ratings which can be seen as an index of the device ruggedness. A good description of this behaviour is given by the static IV blocking characteristc. In order to avoid self heating, very relevant in high power devices, very short pulses of current have to be used, whose value can change from few milliamps up to tens of amps. The most used method to generate short pulses is the TLP (Transmission Line Pulse) test, which is based on charging the equivalent capacitance of a transmission line to high value of voltage and subsequently discharging it onto a load. This circuit let to obtain very short square pulses but it is mostly used for evaluate the ESD capability of semiconductor and, in this environment, it generates pulses of low amplitude which are not high enough to characterize the avalanche behaviour of high power devices . Advanced TLP circuit able to generate high current are usually very expensive and often suffer of distorption of the output pulse. In this article is proposed a simple, low cost circuit, based on a boosted-TLP configuration, which is capable to produce very square pulses of about one hundreds of nanosecond with amplitude up to some tens of amps. A prototype is implemented which can produce pulses up to 20A of amplitude with 200 ns of duration which can characterize power devices up to 1600V of breakdown voltage. Usage of microcontroller based logic make the circuit very flexible. Results of SPICE simulation are provided, together with experimental results. To prove the effectiveness of the circuit, the I-V blocking characteristics of two commercial devices, namely a 600V PowerMOS and a 1200V Trench-IGBT, are measured at different

  2. The Influence of the Construction of the Cooling System of Semiconductor Devices on the Watt-Hour Efficiency of DC-DC Converters

    NASA Astrophysics Data System (ADS)

    Zarębski, Janusz; Górecki, Krzysztof

    In the paper the influence of cooling conditions of semiconductor devices on the characteristics of a boost converter is considered. The form of the thermal model of semiconductor devices is proposed and some results of calculations and measurements of the characteristics of this converter are shown. The investigations were performed for the selected types of power MOSFETs operating at different cooling conditions.

  3. Development of a Handmade Conductivity Measurement Device for a Thin-Film Semiconductor and Its Application to Polypyrrole

    ERIC Educational Resources Information Center

    Seng, Set; Shinpei, Tomita; Yoshihiko, Inada; Masakazu, Kita

    2014-01-01

    The precise measurement of conductivity of a semiconductor film such as polypyrrole (Ppy) should be carried out by the four-point probe method; however, this is difficult for classroom application. This article describes the development of a new, convenient, handmade conductivity device from inexpensive materials that can measure the conductivity…

  4. Method for sputtering a PIN amorphous silicon semi-conductor device having partially crystallized P and N-layers

    DOEpatents

    Moustakas, Theodore D.; Maruska, H. Paul

    1985-07-09

    A high efficiency amorphous silicon PIN semiconductor device having partially crystallized (microcrystalline) P and N layers is constructed by the sequential sputtering of N, I and P layers and at least one semi-transparent ohmic electrode. The method of construction produces a PIN device, exhibiting enhanced electrical and optical properties, improved physical integrity, and facilitates the preparation in a singular vacuum system and vacuum pump down procedure.

  5. Analytical study of acoustically perturbed Brillouin active magnetized semiconductor plasma

    SciTech Connect

    Shukla, Arun; Jat, K. L.

    2015-07-31

    An analytical study of acoustically perturbed Brillouin active magnetized semiconductor plasma has been reported. In the present analytical investigation, the lattice displacement, acousto-optical polarization, susceptibility, acousto-optical gain constant arising due to the induced nonlinear current density and acousto-optical process are deduced in an acoustically perturbed Brillouin active magnetized semiconductor plasma using the hydrodynamical model of plasma and coupled mode scheme. The influence of wave number and magnetic field has been explored. The analysis has been applied to centrosymmetric crystal. Numerical estimates are made for n-type InSb crystal duly irradiated by a frequency doubled 10.6 µm CO{sub 2} laser. It is found that lattice displacement, susceptibility and acousto-optical gain increase linearly with incident wave number and applied dc magnetic field, while decrease with scattering angle. The gain also increases with electric amplitude of incident laser beam. Results are found to be well in agreement with available literature.

  6. Multifunctional semiconductor micro-Hall devices for magnetic, electric, and photo-detection

    SciTech Connect

    Gilbertson, A. M.; Cohen, L. F.; Sadeghi, Hatef; Lambert, C. J.; Panchal, V.; Kazakova, O.; Solin, S. A.

    2015-12-07

    We report the real-space voltage response of InSb/AlInSb micro-Hall devices to local photo-excitation, electric, and magnetic fields at room temperature using scanning probe microscopy. We show that the ultrafast generation of localised photocarriers results in conductance perturbations analogous to those produced by local electric fields. Experimental results are in good agreement with tight-binding transport calculations in the diffusive regime. The magnetic, photo, and charge sensitivity of a 2 μm wide probe are evaluated at a 10 μA bias current in the Johnson noise limit (valid at measurement frequencies > 10 kHz) to be, respectively, 500 nT/√Hz; 20 pW/√Hz (λ = 635 nm) comparable to commercial photoconductive detectors; and 0.05 e/√Hz comparable to that of single electron transistors. These results demonstrate the remarkably versatile sensing attributes of simple semiconductor micro-Hall devices that can be applied to a host of imaging and sensing applications.

  7. Multifunctional semiconductor micro-Hall devices for magnetic, electric, and photo-detection

    NASA Astrophysics Data System (ADS)

    Gilbertson, A. M.; Sadeghi, Hatef; Panchal, V.; Kazakova, O.; Lambert, C. J.; Solin, S. A.; Cohen, L. F.

    2015-12-01

    We report the real-space voltage response of InSb/AlInSb micro-Hall devices to local photo-excitation, electric, and magnetic fields at room temperature using scanning probe microscopy. We show that the ultrafast generation of localised photocarriers results in conductance perturbations analogous to those produced by local electric fields. Experimental results are in good agreement with tight-binding transport calculations in the diffusive regime. The magnetic, photo, and charge sensitivity of a 2 μm wide probe are evaluated at a 10 μA bias current in the Johnson noise limit (valid at measurement frequencies > 10 kHz) to be, respectively, 500 nT/√Hz; 20 pW/√Hz (λ = 635 nm) comparable to commercial photoconductive detectors; and 0.05 e/√Hz comparable to that of single electron transistors. These results demonstrate the remarkably versatile sensing attributes of simple semiconductor micro-Hall devices that can be applied to a host of imaging and sensing applications.

  8. Tin disulfide-an emerging layered metal dichalcogenide semiconductor: materials properties and device characteristics.

    PubMed

    Huang, Yuan; Sutter, Eli; Sadowski, Jerzy T; Cotlet, Mircea; Monti, Oliver L A; Racke, David A; Neupane, Mahesh R; Wickramaratne, Darshana; Lake, Roger K; Parkinson, Bruce A; Sutter, Peter

    2014-10-28

    Layered metal dichalcogenides have attracted significant interest as a family of single- and few-layer materials that show new physics and are of interest for device applications. Here, we report a comprehensive characterization of the properties of tin disulfide (SnS2), an emerging semiconducting metal dichalcogenide, down to the monolayer limit. Using flakes exfoliated from layered bulk crystals, we establish the characteristics of single- and few-layer SnS2 in optical and atomic force microscopy, Raman spectroscopy and transmission electron microscopy. Band structure measurements in conjunction with ab initio calculations and photoluminescence spectroscopy show that SnS2 is an indirect bandgap semiconductor over the entire thickness range from bulk to single-layer. Field effect transport in SnS2 supported by SiO2/Si suggests predominant scattering by centers at the support interface. Ultrathin transistors show on-off current ratios >10(6), as well as carrier mobilities up to 230 cm(2)/(V s), minimal hysteresis, and near-ideal subthreshold swing for devices screened by a high-k (deionized water) top gate. SnS2 transistors are efficient photodetectors but, similar to other metal dichalcogenides, show a relatively slow response to pulsed irradiation, likely due to adsorbate-induced long-lived extrinsic trap states.

  9. Growth and Characterization of III-V Semiconductors for Device Applications

    NASA Technical Reports Server (NTRS)

    Williams, Michael D.

    2000-01-01

    The research goal was to achieve a fundamental understanding of the physical processes occurring at the surfaces and interfaces of epitaxially grown InGaAs/GaAs (100) heterostructures. This will facilitate the development of quantum well devices for infrared optical applications and provide quantitative descriptions of key phenomena which impact their performance. Devices impacted include high-speed laser diodes and modulators for fiber optic communications at 1.55 micron wavelengths and intersub-band lasers for longer infrared wavelengths. The phenomenon of interest studied was the migration of indium in InGaAs structures. This work centered on the molecular beam epitaxy reactor and characterization apparatus donated to CAU by AT&T Bell Laboratories. The material characterization tool employed was secondary ion mass spectrometry. The training of graduate and undergraduate students was an integral part of this program. The graduate students received a thorough exposure to state-of-the-art techniques and equipment for semiconductor materials analysis as part of the Master''s degree requirement in physics. The undergraduates were exposed to a minority scientist who has an excellent track record in this area. They also had the opportunity to explore surface physics as a career option. The results of the scientific work was published in a refereed journal and several talks were presented professional conferences and academic seminars.

  10. George E. Pake Prize: A Few Challenges in the Evolution of Semiconductor Device/Manufacturing Technology

    NASA Astrophysics Data System (ADS)

    Doering, Robert

    In the early 1980s, the semiconductor industry faced the related challenges of ``scaling through the one-micron barrier'' and converting single-level-metal NMOS integrated circuits to multi-level-metal CMOS. Multiple advances in lithography technology and device materials/process integration led the way toward the deep-sub-micron transistors and interconnects that characterize today's electronic chips. In the 1990s, CMOS scaling advanced at an accelerated pace enabled by rapid advances in many aspects of optical lithography. However, the industry also needed to continue the progress in manufacturing on ever-larger silicon wafers to maintain economy-of-scale trends. Simultaneously, the increasing complexity and absolute-precision requirements of manufacturing compounded the necessity for new processes, tools, and control methodologies. This talk presents a personal perspective on some of the approaches that addressed the aforementioned challenges. In particular, early work on integrating silicides, lightly-doped-drain FETs, shallow recessed isolation, and double-level metal will be discussed. In addition, some pioneering efforts in deep-UV lithography and single-wafer processing will be covered. The latter will be mainly based on results from the MMST Program - a 100 M +, 5-year R&D effort, funded by DARPA, the U.S. Air Force, and Texas Instruments, that developed a wide range of new technologies for advanced semiconductor manufacturing. The major highlight of the program was the demonstration of sub-3-day cycle time for manufacturing 350-nm CMOS integrated circuits in 1993. This was principally enabled by the development of: (1) 100% single-wafer processing, including rapid-thermal processing (RTP), and (2) computer-integrated-manufacturing (CIM), including real-time, in-situ process control.

  11. Raman spectra of semiconductor nanoparticles: Disorder-activated phonons

    NASA Astrophysics Data System (ADS)

    Ingale, Alka; Rustagi, K. C.

    1998-09-01

    We present Raman spectra of four semiconductor doped glasses and a single crystal of CdS0.55Se0.45 in the range 30-800 cm-1 in the backscattering geometry. This includes the first-order Raman scattering from the disorder-activated zone-edge phonons and the LO phonons. TO phonon modes are not observed, as in bulk CdS, for the excitation well above the lowest gap. We show that the asymmetric line profile of the LO phonon structure can be understood as a composite of two phonon modes: the zone center and the zone edge phonons. Disorder-activated modes in the (30-130)-cm-1 range and the higher-order Raman spectra are also observed and found to be consistent with this assignment.

  12. Method to determine the position-dependant metal correction factor for dose-rate equivalent laser testing of semiconductor devices

    DOEpatents

    Horn, Kevin M.

    2013-07-09

    A method reconstructs the charge collection from regions beneath opaque metallization of a semiconductor device, as determined from focused laser charge collection response images, and thereby derives a dose-rate dependent correction factor for subsequent broad-area, dose-rate equivalent, laser measurements. The position- and dose-rate dependencies of the charge-collection magnitude of the device are determined empirically and can be combined with a digital reconstruction methodology to derive an accurate metal-correction factor that permits subsequent absolute dose-rate response measurements to be derived from laser measurements alone. Broad-area laser dose-rate testing can thereby be used to accurately determine the peak transient current, dose-rate response of semiconductor devices to penetrating electron, gamma- and x-ray irradiation.

  13. Laser-based irradiation apparatus and method to measure the functional dose-rate response of semiconductor devices

    DOEpatents

    Horn, Kevin M.

    2008-05-20

    A broad-beam laser irradiation apparatus can measure the parametric or functional response of a semiconductor device to exposure to dose-rate equivalent infrared laser light. Comparisons of dose-rate response from before, during, and after accelerated aging of a device, or from periodic sampling of devices from fielded operational systems can determine if aging has affected the device's overall functionality. The dependence of these changes on equivalent dose-rate pulse intensity and/or duration can be measured with the apparatus. The synchronized introduction of external electrical transients into the device under test can be used to simulate the electrical effects of the surrounding circuitry's response to a radiation exposure while exposing the device to dose-rate equivalent infrared laser light.

  14. Nonlinear current-voltage characteristics based on semiconductor nanowire networks enable a new concept in thermoelectric device optimization

    NASA Astrophysics Data System (ADS)

    Diaz Leon, Juan J.; Norris, Kate J.; Hartnett, Ryan J.; Garrett, Matthew P.; Tompa, Gary S.; Kobayashi, Nobuhiko P.

    2016-08-01

    Thermoelectric (TE) devices that produce electric power from heat are driven by a temperature gradient (Δ T = T_{{hot}} - T_{{cold}}, T hot: hot side temperature, T cold: cold side temperature) with respect to the average temperature ( T). While the resistance of TE devices changes as Δ T and/or T change, the current-voltage ( I- V) characteristics have consistently been shown to remain linear, which clips generated electric power ( P gen) within the given open-circuit voltage ( V OC) and short-circuit current ( I SC). This P gen clipping is altered when an appropriate nonlinearity is introduced to the I- V characteristics—increasing P gen. By analogy, photovoltaic cells with a large fill factor exhibit nonlinear I- V characteristics. In this paper, the concept of a unique TE device with nonlinear I- V characteristics is proposed and experimentally demonstrated. A single TE device with nonlinear I- V characteristics is fabricated by combining indium phosphide (InP) and silicon (Si) semiconductor nanowire networks. These TE devices show P gen that is more than 25 times larger than those of comparable devices with linear I- V characteristics. The plausible causes of the nonlinear I- V characteristics are discussed. The demonstrated concept suggests that there exists a new pathway to increase P gen of TE devices made of semiconductors.

  15. A globally convergent algorithm for the solution of the steady-state semiconductor device equations

    NASA Astrophysics Data System (ADS)

    Korman, Can E.; Mayergoyz, Isaak D.

    1990-08-01

    An iterative method for solving the discretized steady-state semiconductor device equations is presented. This method uses Gummel's block iteration technique to decouple the nonlinear Poisson and electron-hole current continuity equations. However, the main feature of this method is that it takes advantage of the diagonal nonlinearity of the discretized equations, and solves each equation iteratively by using the nonlinear Jacobi method. Using the fact that the diagonal nonlinearities are monotonically increasing functions, it is shown that this method has two important advantages. First, it has global convergence, i.e., convergence is guaranteed for any initial guess. Second, the solution of simultaneous algebraic equations is avoided by updating the value of the electrostatic and quasi-Fermi potentials at each mesh point by means of explicit formulae. This allows the implementation of this method on computers with small random access memories, such as personal computers, and also makes it very attractive to use on parallel processor machines. Furthermore, for serial computations, this method is generalized to the faster nonlinear successive overrelaxation method which has global convergence as well. The iterative solution of the nonlinear Poisson equation is formulated with energy- and position-dependent interface traps. It is shown that the iterative method is globally convergent for arbitrary distributions of interface traps. This is an important step in analyzing hot-electron effects in metal-oxide-silicon field-effect transistors (MOSFETs). Various numerical results on two- and three-dimensional MOSFET geometries are presented as well.

  16. Local lattice strain measurements in semiconductor devices by using convergent-beam electron diffraction

    NASA Astrophysics Data System (ADS)

    Toda, Akio; Ikarashi, Nobuyuki; Ono, Haruhiko

    2000-03-01

    We examined the lattice strain distribution around local oxidation of silicon (LOCOS) in a semiconductor device by using highly accurate (1.8×10 -4 standard deviation) convergent-beam electron diffraction (CBED) at a nanometer-scale spatial resolution (10 nm in diameter). The nanometer-scale measurement was done by reducing the elastic relaxation using a thick (about 600 nm) sample and by removing the inelastically scattered electrons by means of an electron energy filter. A highly accurate measurement was achieved through the analysis of higher-order Laue zone (HOLZ) patterns using the least-squares fitting of HOLZ line intersection distances between the observations and calculations. Our examination showed that the LOCOS structure gave singularities in strain distributions at the field edge. That is, compressive strain exists in both the vertical and horizontal directions of the substrate, and the shear strain increased there. Most notably, two-dimensional measurements revealed that the singularity of the normal strain in the horizontal direction of the substrate generated at the field edge propagated into the substrate.

  17. Quantum interference measurement of spin interactions in a bio-organic/semiconductor device structure

    DOE PAGES

    Deo, Vincent; Zhang, Yao; Soghomonian, Victoria; Heremans, Jean J.

    2015-03-30

    Quantum interference is used to measure the spin interactions between an InAs surface electron system and the iron center in the biomolecule hemin in nanometer proximity in a bio-organic/semiconductor device structure. The interference quantifies the influence of hemin on the spin decoherence properties of the surface electrons. The decoherence times of the electrons serve to characterize the biomolecule, in an electronic complement to the use of spin decoherence times in magnetic resonance. Hemin, prototypical for the heme group in hemoglobin, is used to demonstrate the method, as a representative biomolecule where the spin state of a metal ion affects biologicalmore » functions. The electronic determination of spin decoherence properties relies on the quantum correction of antilocalization, a result of quantum interference in the electron system. Spin-flip scattering is found to increase with temperature due to hemin, signifying a spin exchange between the iron center and the electrons, thus implying interactions between a biomolecule and a solid-state system in the hemin/InAs hybrid structure. The results also indicate the feasibility of artificial bioinspired materials using tunable carrier systems to mediate interactions between biological entities.« less

  18. Quantum interference measurement of spin interactions in a bio-organic/semiconductor device structure

    SciTech Connect

    Deo, Vincent; Zhang, Yao; Soghomonian, Victoria; Heremans, Jean J.

    2015-03-30

    Quantum interference is used to measure the spin interactions between an InAs surface electron system and the iron center in the biomolecule hemin in nanometer proximity in a bio-organic/semiconductor device structure. The interference quantifies the influence of hemin on the spin decoherence properties of the surface electrons. The decoherence times of the electrons serve to characterize the biomolecule, in an electronic complement to the use of spin decoherence times in magnetic resonance. Hemin, prototypical for the heme group in hemoglobin, is used to demonstrate the method, as a representative biomolecule where the spin state of a metal ion affects biological functions. The electronic determination of spin decoherence properties relies on the quantum correction of antilocalization, a result of quantum interference in the electron system. Spin-flip scattering is found to increase with temperature due to hemin, signifying a spin exchange between the iron center and the electrons, thus implying interactions between a biomolecule and a solid-state system in the hemin/InAs hybrid structure. The results also indicate the feasibility of artificial bioinspired materials using tunable carrier systems to mediate interactions between biological entities.

  19. Impact of carbon and nitrogen on gate dielectrics in metal-oxide-semiconductor devices

    NASA Astrophysics Data System (ADS)

    Choi, Minseok; Lyons, John; Janotti, Anderson; van de Walle, Chris

    2013-03-01

    Al2O3 and HfO2 are used as alternative gate oxides in CMOS technology. Promising results have been achieved with Al2O3/III-V and HfO2/Si MOS structures, which exhibit relatively low densities of interface states. However, the presence of charge traps and fixed-charge centers near the oxide/semiconductor interface still poses serious limitations in device performance. Native point defects are usually proposed as an explanation; unintentional incorporation of impurities in the gate dielectric during the deposition process has so far received less attention. Using first-principles calculations based on hybrid functionals we investigate the effects of carbon and nitrogen impurities in Al2O3 and HfO2. By analyzing the position of the impurity levels with respect to the III-V and Si band edges, we determine if these impurities can act as charge traps or sources of fixed charge. Our results show that carbon can act as a charge trap and lead to leakage current through the gate dielectric. Nitrogen can act as a source of negative fixed charge, but may be effective in alleviating the problem of charge traps and fixed charges associated with Al, Hf, and O vacancies. This work was supported by the ONR DEFINE MURI program.

  20. Enabling Earth-Abundant Pyrite (FeS2) Semiconductor Nanostructures for High Performance Photovoltaic Devices

    SciTech Connect

    Jin, Song

    2014-11-18

    This project seeks to develop nanostructures of iron pyrite, an earth-abundant semiconductor, to enable their applications in high-performance photovoltaic (PV) devices. Growth of high purity iron pyrite nanostructures (nanowires, nanorods, and nanoplates), as well as iron pyrite thin films and single crystals, has been developed and their structures characterized. These structures have been fundamentally investigated to understand the origin of the low solar energy conversion efficiency of iron pyrite and various passivation strategies and doping approaches have been explored in order to improve it. By taking advantage of the high surface-to-bulk ratio in nanostructures and effective electrolyte gating, we fully characterized both the surface inversion and bulk electrical transport properties for the first time through electrolyte-gated Hall measurements of pyrite nanoplate devices and show that pyrite is n-type in the bulk and p-type near the surface due to strong inversion, which has important consequences to using nanocrystalline pyrite for efficient solar energy conversion. Furthermore, through a comprehensive investigation on n-type iron pyrite single crystals, we found the ionization of high-density bulk deep donor states, likely resulting from bulk sulfur vacancies, creates a non-constant charge distribution and a very narrow surface space charge region that limits the total barrier height, thus satisfactorily explains the limited photovoltage and poor photoconversion efficiency of iron pyrite single crystals. These findings suggest new ideas on how to improve single crystal pyrite and nanocrystalline or polycrystalline pyrite films to enable them for high performance solar applications.

  1. The way to zeros: The future of semiconductor device and chemical mechanical polishing technologies

    NASA Astrophysics Data System (ADS)

    Tsujimura, Manabu

    2016-06-01

    For the last 60 years, the development of cutting-edge semiconductor devices has strongly emphasized scaling; the effort to scale down current CMOS devices may well achieve the target of 5 nm nodes by 2020. Planarization by chemical mechanical polishing (CMP), is one technology essential for supporting scaling. This paper summarizes the history of CMP transitions in the planarization process as well as the changing degree of planarity required, and, finally, introduces innovative technologies to meet the requirements. The use of CMP was triggered by the replacement of local oxidation of silicon (LOCOS) as the element isolation technology by shallow trench isolation (STI) in the 1980s. Then, CMP’s use expanded to improving embedability of aluminum wiring, tungsten (W) contacts, Cu wiring, and, more recently, to its adoption in high-k metal gate (HKMG) and FinFET (FF) processes. Initially, the required degree of planarity was 50 nm, but now 0 nm is required. Further, zero defects on a post-CMP wafer is now the goal, and it is possible that zero psi CMP loading pressure will be required going forward. Soon, it seems, everything will have to be “zero” and perfect. Although the process is also chemical in nature, the CMP process is actually mechanical with a load added using slurry particles several tens of nm in diameter. Zero load in the loading process, zero nm planarity with no trace of processing, and zero residual foreign material, including the very slurry particles used in the process, are all required. This article will provide an overview of how to achieve these new requirements and what technologies should be employed.

  2. Active and intelligent inhaler device development.

    PubMed

    Tobyn, Mike; Staniforth, John N; Morton, David; Harmer, Quentin; Newton, Mike E

    2004-06-11

    The dry powder inhaler, which has traditionally relied on the patient's inspiratory force to deaggregate and deliver the active agent to the target region of the lung, has been a successful delivery device for the provision of locally active agents for the treatment of conditions such as asthma and chronic obstructive pulmonary disease (COPD). However, such devices can suffer from poor delivery characteristics and/or poor reproducibility. More recently, drugs for systemic delivery and more high value compounds have been put into DPI devices. Regulatory, dosing, manufacturing and economic concerns have demanded that a more efficient and reproducible performance is achieved by these devices. Recently strategies have been put in place to produce a more efficient DPI device/formulation combination. Using one novel device as an example the paper will examine which features are important in such a device and some of the strategies required to implement these features. All of these technological advances are invisible, and may be irrelevant, to the patient. However, their inability to use an inhaler device properly has significant implications for their therapy. Use of active device mechanisms, which reduce the dependence on patient inspiratory flow, and sensible industrial design, which give the patient the right clues to use, are important determinants of performance here.

  3. Heteroepitaxial growth of 3-5 semiconductor compounds by metal-organic chemical vapor deposition for device applications

    NASA Technical Reports Server (NTRS)

    Collis, Ward J.; Abul-Fadl, Ali

    1988-01-01

    The purpose of this research is to design, install and operate a metal-organic chemical vapor deposition system which is to be used for the epitaxial growth of 3-5 semiconductor binary compounds, and ternary and quaternary alloys. The long-term goal is to utilize this vapor phase deposition in conjunction with existing current controlled liquid phase epitaxy facilities to perform hybrid growth sequences for fabricating integrated optoelectronic devices.

  4. Method for manufacturing electrical contacts for a thin-film semiconductor device

    DOEpatents

    Carlson, David E.; Dickson, Charles R.; D'Aiello, Robert V.

    1988-11-08

    A method of fabricating spaced-apart back contacts on a thin film of semiconductor material by forming strips of buffer material on top of the semiconductor material in locations corresponding to the desired dividing lines between back contacts, forming a film of metal substantially covering the semiconductor material and buffer strips, and scribing portions of the metal film overlying the buffer strips with a laser without contacting the underlying semiconductor material to separate the metal layer into a plurality of back contacts. The buffer material serves to protect the underlying semiconductor material from being damaged during the laser scribing. Back contacts and multi-cell photovoltaic modules incorporating such back contacts also are disclosed.

  5. Enhanced quality thin film Cu(In,Ga)Se[sub 2] for semiconductor device applications by vapor-phase recrystallization

    DOEpatents

    Tuttle, J.R.; Contreras, M.A.; Noufi, R.; Albin, D.S.

    1994-10-18

    Enhanced quality thin films of Cu[sub w](In,Ga[sub y])Se[sub z] for semiconductor device applications are fabricated by initially forming a Cu-rich, phase-separated compound mixture comprising Cu(In,Ga):Cu[sub x]Se on a substrate to form a large-grain precursor and then converting the excess Cu[sub x]Se to Cu(In,Ga)Se[sub 2] by exposing it to an activity of In and/or Ga, either in vapor In and/or Ga form or in solid (In,Ga)[sub y]Se[sub z]. Alternatively, the conversion can be made by sequential deposition of In and/or Ga and Se onto the phase-separated precursor. The conversion process is preferably performed in the temperature range of about 300--600 C, where the Cu(In,Ga)Se[sub 2] remains solid, while the excess Cu[sub x]Se is in a liquid flux. The characteristic of the resulting Cu[sub w](In,Ga)[sub y]Se[sub z] can be controlled by the temperature. Higher temperatures, such as 500--600 C, result in a nearly stoichiometric Cu(In,Ga)Se[sub 2], whereas lower temperatures, such as 300--400 C, result in a more Cu-poor compound, such as the Cu[sub z](In,Ga)[sub 4]Se[sub 7] phase. 7 figs.

  6. Enhanced quality thin film Cu(In,Ga)Se.sub.2 for semiconductor device applications by vapor-phase recrystallization

    DOEpatents

    Tuttle, John R.; Contreras, Miguel A.; Noufi, Rommel; Albin, David S.

    1994-01-01

    Enhanced quality thin films of Cu.sub.w (In,Ga.sub.y)Se.sub.z for semiconductor device applications are fabricated by initially forming a Cu-rich, phase-separated compound mixture comprising Cu(In,Ga):Cu.sub.x Se on a substrate to form a large-grain precursor and then converting the excess Cu.sub.x Se to Cu(In,Ga)Se.sub.2 by exposing it to an activity of In and/or Ga, either in vapor In and/or Ga form or in solid (In,Ga).sub.y Se.sub.z. Alternatively, the conversion can be made by sequential deposition of In and/or Ga and Se onto the phase-separated precursor. The conversion process is preferably performed in the temperature range of about 300.degree.-600.degree. C., where the Cu(In,Ga)Se.sub.2 remains solid, while the excess Cu.sub.x Se is in a liquid flux. The characteristic of the resulting Cu.sub.w (In,Ga).sub.y Se.sub.z can be controlled by the temperature. Higher temperatures, such as 500.degree.-600.degree. C., result in a nearly stoichiometric Cu(In,Ga)Se.sub.2, whereas lower temperatures, such as 300.degree.-400.degree. C., result in a more Cu-poor compound, such as the Cu.sub.z (In,Ga).sub.4 Se.sub.7 phase.

  7. Exploring the Electronic Landscape at Interfaces and Junctions in Semiconductor Nanowire Devices with Subsurface Local Probing of Carrier Dynamics

    NASA Astrophysics Data System (ADS)

    McGuckin, Terrence

    The solid state devices that are pervasive in our society, are based on building blocks composed of interfaces between materials and junctions that manipulate how charge carriers behave in a device. As the dimensions of these devices are reduced to the nanoscale, surfaces and interfaces play a larger role in the behavior of carriers in devices and must be thoroughly investigated to understand not only the material properties but how these materials interact. Separating the effects of these different building blocks is a challenge, as most testing methods measure the performance of the whole device. Semiconductor nanowires represent an excellent test system to explore the limits of size and novel device structures. The behavior of charge carriers in semiconductor nanowire devices under operational conditions is investigated using local probing technique electron beam induced current (EBIC). The behavior of locally excited carriers are driven by the forces of drift, from electric fields within a device at junctions, surfaces, contacts and, applied voltage bias, and diffusion. This thesis presents the results of directly measuring these effects spatially with nanometer resolution, using EBIC in Ge, Si, and complex heterostructure GaAs/AlGaAs nanowire devices. Advancements to the EBIC technique, have pushed the resolution from tens of nanometers down to 1 to 2 nanometers. Depth profiling and tuning of the interaction volume allows for the separating the signal originating from the surface and the interior of the nanowire. Radial junctions and variations in bands can now be analyzed including core/shell hetero-structures. This local carrier probing reveals a number of surprising behaviors; Most notably, directly imaging the evolution of surface traps filling with electrons causing bandbending at the surface of Ge nanowires that leads to an enhancement in the charge separation of electrons and holes, and extracting different characteristic lengths from GaAs and AlGaAs in

  8. Crystal growth of hexaferrite architecture for magnetoelectrically tunable microwave semiconductor integrated devices

    NASA Astrophysics Data System (ADS)

    Hu, Bolin

    Hexaferrites (i.e., hexagonal ferrites), discovered in 1950s, exist as any one of six crystallographic structural variants (i.e., M-, X-, Y-, W-, U-, and Z-type). Over the past six decades, the hexaferrites have received much attention owing to their important properties that lend use as permanent magnets, magnetic data storage materials, as well as components in electrical devices, particularly those operating at RF frequencies. Moreover, there has been increasing interest in hexaferrites for new fundamental and emerging applications. Among those, electronic components for mobile and wireless communications especially incorporated with semiconductor integrated circuits at microwave frequencies, electromagnetic wave absorbers for electromagnetic compatibility, random-access memory (RAM) and low observable technology, and as composite materials having low dimensions. However, of particular interest is the magnetoelectric (ME) effect discovered recently in the hexaferrites such as SrScxFe12-xO19 (SrScM), Ba2--xSrxZn 2Fe12O22 (Zn2Y), Sr4Co2Fe 36O60 (Co2U) and Sr3Co2Fe 24O41 (Co2Z), demonstrating ferroelectricity induced by the complex internal alignment of magnetic moments. Further, both Co 2Z and Co2U have revealed observable magnetoelectric effects at room temperature, representing a step toward practical applications using the ME effect. These materials hold great potential for applications, since strong magnetoelectric coupling allows switching of the FE polarization with a magnetic field (H) and vice versa. These features could lead to a new type of storage devices, such as an electric field-controlled magnetic memory. A nanoscale-driven crystal growth of magnetic hexaferrites was successfully demonstrated at low growth temperatures (25--40% lower than the temperatures required often for crystal growth). This outcome exhibits thermodynamic processes of crystal growth, allowing ease in fabrication of advanced multifunctional materials. Most importantly, the

  9. Semiconductor devices: solar cells. January 1975-May 1981 (citations from the International Information Service for the Physics and Engineering Communities Data Base). Report for Jan 75-May 81

    SciTech Connect

    Not Available

    1981-05-01

    The applications of semiconductor devices to solar cells and arrays are presented. Emphasis is placed on manufacturing processes, cell design, and performance. (Contains 235 citations fully indexed and including a title list.)

  10. A novel measuring method of clamping force for electrostatic chuck in semiconductor devices

    NASA Astrophysics Data System (ADS)

    Kesheng, Wang; Jia, Cheng; Yin, Zhong; Linhong, Ji

    2016-04-01

    Electrostatic chucks are one of the core components of semiconductor devices. As a key index of electrostatic chucks, the clamping force must be controlled within a reasonable range. Therefore, it is essential to accurately measure the clamping force. To reduce the negative factors influencing measurement precision and repeatability, this article presents a novel method to measure the clamping force and we elaborate both the principle and the key procedure. A micro-force probe component is introduced to monitor, adjust, and eliminate the gap between the wafer and the electrostatic chuck. The contact force between the ruby probe and the wafer is selected as an important parameter to characterize de-chucking, and we have found that the moment of de-chucking can be exactly judged. Moreover, this article derives the formula calibrating equivalent action area of backside gas pressure under real working conditions, which can effectively connect the backside gas pressure at the moment of de-chucking and the clamping force. The experiments were then performed on a self-designed measuring platform. The de-chucking mechanism is discussed in light of our analysis of the experimental data. Determination criteria for de-chucking point are summed up. It is found that the relationship between de-chucking pressure and applied voltage conforms well to quadratic equation. Meanwhile, the result reveals that actual de-chucking behavior is much more complicated than the description given in the classical empirical formula. Project supported by No. 02 National Science and Technology Major Project of China (No. 2011ZX02403-004).

  11. Improved interfacial and electrical properties of vanadyl-phthalocyanine metal-insulator-semiconductor devices with silicon nitride as gate insulator

    SciTech Connect

    Wang, Lijuan Song, Xiaofeng; Liu, Xin; Zhang, Long; Li, Yiping; Yan, Donghang

    2013-12-09

    We have investigated the interfacial and electrical properties of vanadyl-phthalocyanine (VOPc) metal-insulator-semiconductor devices by the measurement of capacitance and conductance. The devices have been fabricated on ordered para-sexiphenyl (p-6P) layer with silicon nitride (SiN{sub x}) as gate insulator. The VOPc/p-6P/SiN{sub x} devices have shown a negligible hysteresis, low series resistance, and high operated frequency. Bulk traps have been distinguished from interface traps by two loss peaks in conductance measurement. Trap densities and distribution of trap energy level have been obtained. The improved properties indicate that VOPc/ p-6P devices with SiN{sub x} insulator hold a great promise of application in flexible displays.

  12. Orientation and morphology of self-assembled oligothiophene semiconductors and development of hybrid nanostructures for photovoltaic devices

    NASA Astrophysics Data System (ADS)

    Tevis, Ian David

    This dissertation examines the self-assembly of electronically active small molecules for heterojunction photovoltaic devices and the synthesis of nanoscale hybrid materials with a focus on orientation and morphology. A hairpin-shaped self-assembling molecule featuring two semiconducting sexithiophene arms connected through a diamidocyclohexane linker was found to form p-type semiconducting nanowires through H-aggregation as well as J-aggregated bundles. This molecule was incorporated into heterojunction photovoltaics with phenyl-(C61/C71)-butyric acid methyl ester through spin-coating. The sexithiophene assembled during drying to form a percolating network of nanowires and fullerenes. Thermal annealing enhanced efficiencies by increasing domain sizes and organizing the fullerenes into the groves of the nanofibers to produce 0.48% efficient devices. A p-type quarterthiophene derivative was designed and synthesized to assemble through pi-pi stacking and hydrogen bonding and its assembly was explored. Solutions of the quarterthiophene drop-cast on poly(tetrafluoroethylene) dried quickly to form bundled fibers parallel to the substrate. Slower drying and higher concentrations led to the formation of rhombohedra and randomly oriented hexagonal prisms, respectively. Liquid-liquid interfacial precipitation was used with a porous aluminum oxide membrane between a solution of quarterthiophene and toluene to orient the hexagonal prisms perpendicular to the membrane. Depositing the molecule from solution onto a UV/Ozone treated transparent conducting oxide subtrated affored prisms and sheets with perpendicular pi-pi stacking was anisotropy observed by 2D-GISAXS. This perpendicular pi-pi stacking orientation and sheet formation on a planar electrode shortens charge transport distances and minimizes film defects, which could lead to improved photovoltaic devices. Interpenetrating donor and acceptor hybrid materials with perpendicular orientation for enhanced morphological

  13. Reliability study of opto-coupled semiconductor devices and Light Emitting Diodes (LED)

    NASA Technical Reports Server (NTRS)

    Maurer, R. C.; Weissflug, V. A.; Sisul, E. V.

    1977-01-01

    Opto-coupler and light emitting diode (LED) failure mechanisms and associated activation energies were determind from the results of environmental and accelerated lift tests of over 2,400 devices. The evaluation program included LED phototransistor opto-couplers from three sources, LED photoamplifier opto-couplers from a single source, and discrete infrared emitting LEDs from two sources. Environmental tests to evaluate device mechanical integrity included power cycling (10,000 cycles), temperature cycling (500 cycles) and a sequence of monitored shock, monitored vibration and constant acceleration. Multiple temperature operating life tests were conducted at ambient temperatures between 25 C and 200 C. Opto-couplers were operated in both the 'on' and 'off' states during life testing.

  14. Accumulation capacitance frequency dispersion of III-V metal-insulator-semiconductor devices due to disorder induced gap states

    SciTech Connect

    Galatage, R. V.; Zhernokletov, D. M.; Dong, H.; Brennan, B.; Hinkle, C. L.; Wallace, R. M.; Vogel, E. M.

    2014-07-07

    The origin of the anomalous frequency dispersion in accumulation capacitance of metal-insulator-semiconductor devices on InGaAs and InP substrates is investigated using modeling, electrical characterization, and chemical characterization. A comparison of the border trap model and the disorder induced gap state model for frequency dispersion is performed. The fitting of both models to experimental data indicate that the defects responsible for the measured dispersion are within approximately 0.8 nm of the surface of the crystalline semiconductor. The correlation between the spectroscopically detected bonding states at the dielectric/III-V interface, the interfacial defect density determined using capacitance-voltage, and modeled capacitance-voltage response strongly suggests that these defects are associated with the disruption of the III-V atomic bonding and not border traps associated with bonding defects within the high-k dielectric.

  15. Intravital fluorescence imaging of mouse brain using implantable semiconductor devices and epi-illumination of biological tissue

    PubMed Central

    Takehara, Hiroaki; Ohta, Yasumi; Motoyama, Mayumi; Haruta, Makito; Nagasaki, Mizuki; Takehara, Hironari; Noda, Toshihiko; Sasagawa, Kiyotaka; Tokuda, Takashi; Ohta, Jun

    2015-01-01

    The application of the fluorescence imaging method to living animals, together with the use of genetically engineered animals and synthesized photo-responsive compounds, is a powerful method for investigating brain functions. Here, we report a fluorescence imaging method for the brain surface and deep brain tissue that uses compact and mass-producible semiconductor imaging devices based on complementary metal-oxide semiconductor (CMOS) technology. An image sensor chip was designed to be inserted into brain tissue, and its size was 1500 × 450 μm. Sample illumination is also a key issue for intravital fluorescence imaging. Hence, for the uniform illumination of the imaging area, we propose a new method involving the epi-illumination of living biological tissues, and we performed investigations using optical simulations and experimental evaluation. PMID:26137364

  16. Accumulation capacitance frequency dispersion of III-V metal-insulator-semiconductor devices due to disorder induced gap states

    NASA Astrophysics Data System (ADS)

    Galatage, R. V.; Zhernokletov, D. M.; Dong, H.; Brennan, B.; Hinkle, C. L.; Wallace, R. M.; Vogel, E. M.

    2014-07-01

    The origin of the anomalous frequency dispersion in accumulation capacitance of metal-insulator-semiconductor devices on InGaAs and InP substrates is investigated using modeling, electrical characterization, and chemical characterization. A comparison of the border trap model and the disorder induced gap state model for frequency dispersion is performed. The fitting of both models to experimental data indicate that the defects responsible for the measured dispersion are within approximately 0.8 nm of the surface of the crystalline semiconductor. The correlation between the spectroscopically detected bonding states at the dielectric/III-V interface, the interfacial defect density determined using capacitance-voltage, and modeled capacitance-voltage response strongly suggests that these defects are associated with the disruption of the III-V atomic bonding and not border traps associated with bonding defects within the high-k dielectric.

  17. Tungsten polyoxometalate molecules as active nodes for dynamic carrier exchange in hybrid molecular/semiconductor capacitors

    SciTech Connect

    Balliou, A.; Douvas, A. M.; Normand, P.; Argitis, P.; Glezos, N.; Tsikritzis, D.; Kennou, S.

    2014-10-14

    In this work we study the utilization of molecular transition metal oxides known as polyoxometalates (POMs), in particular the Keggin structure anions of the formula PW₁₂O₄₀³⁻, as active nodes for potential switching and/or fast writing memory applications. The active molecules are being integrated in hybrid Metal-Insulator/POM molecules-Semiconductor capacitors, which serve as prototypes allowing investigation of critical performance characteristics towards the design of more sophisticated devices. The charging ability as well as the electronic structure of the molecular layer is probed by means of electrical characterization, namely, capacitance-voltage and current-voltage measurements, as well as transient capacitance measurements, C (t), under step voltage polarization. It is argued that the transient current peaks observed are manifestations of dynamic carrier exchange between the gate electrode and specific molecular levels, while the transient C (t) curves under conditions of molecular charging can supply information for the rate of change of the charge that is being trapped and de-trapped within the molecular layer. Structural characterization via surface and cross sectional scanning electron microscopy as well as atomic force microscopy, spectroscopic ellipsometry, UV and Fourier-transform IR spectroscopies, UPS, and XPS contribute to the extraction of accurate electronic structure characteristics and open the path for the design of new devices with on-demand tuning of their interfacial properties via the controlled preparation of the POM layer.

  18. Microchamber Device Equipped with Complementary Metal Oxide Semiconductor Optical Polarization Analyzer Chip for Micro Total Analysis System

    NASA Astrophysics Data System (ADS)

    Minakawa, Kyosuke; Yamada, Hirofumi; Sasagawa, Kiyotaka; Tokuda, Takashi; Ohta, Jun

    2009-04-01

    We fabricated a device equipped with a microchannel on a complementary metal oxide semiconductor (CMOS) sensor to observe the optical polarization rotation angle during in situ monitoring. The sensor is based on the integrated wire-grid polarization detection method. The microchannel is fabricated on a Si layer by deep reactive ion etching (DRIE). Using this device, we measured the optical rotation of chiral molecules in a microfluid. This showed that the device is applicable to in situ chiral measurement. Optical rotation angles of the linearly polarized light corresponded to different concentrations of sucrose solution. Sensor output reflecting the temporal concentration change of chiral molecules was also observed. These results clearly demonstrate that the CMOS sensor has the capability of measuring chiral molecules in situ.

  19. Capacitance-voltage studies of InP metal-oxide-semiconductor devices irradiated with 4He + ions

    NASA Astrophysics Data System (ADS)

    Tin, C. C.; Barnes, P. A.; Williams, J. R.; Patuwathavithane, C. S.; Van Staagen, P. K.

    1989-11-01

    Capacitance-voltage (C-V) measurements have been made on n-InP metal-oxide-semiconductor (MOS) devices damaged by 2-MeV 4 He+ ion bombardment. The C-V curves for samples with thin oxide layer (˜100 Å) show the presence of a depletion layer during both forward and reverse bias. This behavior is significantly different from those of normal, undamaged MOS devices. Measurements made on n-InP MOS samples with different oxide thicknesses show that the C-V curves gradually approach that of a MOS device on a p-type substrate. The anomalous behavior of the C-V curves for the irradiated samples can be explained by the presence of an n-p-n structure under the oxide layer.

  20. Group III nitride semiconductors for short wavelength light-emitting devices

    NASA Astrophysics Data System (ADS)

    Orton, J. W.; Foxon, C. T.

    1998-01-01

    The group III nitrides (AlN, GaN and InN) represent an important trio of semiconductors because of their direct band gaps which span the range 1.95-6.2 eV, including the whole of the visible region and extending well out into the ultraviolet (UV) range. They form a complete series of ternary alloys which, in principle, makes available any band gap within this range and the fact that they also generate efficient luminescence has been the main driving force for their recent technological development. High brightness visible light-emitting diodes (LEDs) are now commercially available, a development which has transformed the market for LED-based full colour displays and which has opened the way to many other applications, such as in traffic lights and efficient low voltage, flat panel white light sources. Continuously operating UV laser diodes have also been demonstrated in the laboratory, exciting tremendous interest for high-density optical storage systems, UV lithography and projection displays. In a remarkably short space of time, the nitrides have therefore caught up with and, in some ways, surpassed the wide band gap II-VI compounds (ZnCdSSe) as materials for short wavelength optoelectronic devices. The purpose of this paper is to review these developments and to provide essential background material in the form of the structural, electronic and optical properties of the nitrides, relevant to these applications. We have been guided by the fact that the devices so far available are based on the binary compound GaN (which is relatively well developed at the present time), together with the ternary alloys AlGaN and InGaN, containing modest amounts of Al or In. We therefore concentrate, to a considerable extent, on the properties of GaN, then introduce those of the alloys as appropriate, emphasizing their use in the formation of the heterostructures employed in devices. The nitrides crystallize preferentially in the hexagonal wurtzite structure and devices have so

  1. Development of Complementary Metal Oxide Semiconductor Imaging Devices for Detecting Green Fluorescent Protein in the Deep Brain of a Freely Moving Mouse

    NASA Astrophysics Data System (ADS)

    Tagawa, Ayato; Higuchi, Asako; Sugiyama, Tetsuya; Sasagawa, Kiyotaka; Tokuda, Takashi; Tamura, Hideki; Hatanaka, Yumiko; Ishikawa, Yasuyuki; Shiosaka, Sadao; Ohta, Jun

    2009-04-01

    We have developed to observe neural activities in the deep brain of a freely moving mouse with green fluorescent protein (GFP). We implanted a dedicated complementary metal oxide semiconductor (CMOS) imaging device into the hippocampus or the basal ganglion of an anesthetized mouse to confirm the effectiveness of the CMOS imaging device for the detection of GFP generated in the deep brain of the anesthetized mouse. Moreover, we conducted an experiment to demonstrate the capability of the CMOS imaging device to detect GFP in the deep brain of a freely-moving mouse. As a result of the in vivo experiments with two methods of GFP expression, we successfully detected the light intensity of GFP in the hippocampus or the basal ganglion of the anesthetized mouse. Furthermore, we demonstrated that the implanted CMOS imaging device operated well in the freely moving mouse after one week from implantation. We demonstrated the basic technology to realize the observation of neural activities in the deep brain of a freely moving mouse.

  2. Semiconductor technology program: Progress briefs

    NASA Technical Reports Server (NTRS)

    Galloway, K. F.; Scace, R. I.; Walters, E. J.

    1981-01-01

    Measurement technology for semiconductor materials, process control, and devices, is discussed. Silicon and silicon based devices are emphasized. Highlighted activities include semiinsulating GaAs characterization, an automatic scanning spectroscopic ellipsometer, linewidth measurement and coherence, bandgap narrowing effects in silicon, the evaluation of electrical linewidth uniformity, and arsenicomplanted profiles in silicon.

  3. Label-free detection of rheumatoid factor using YbYxOy electrolyte-insulator-semiconductor devices.

    PubMed

    Pan, Tung-Ming; Lin, Ting-Wei; Chen, Ching-Yi

    2015-09-01

    In this study, we investigated the effect of yttrium content on the structural properties and sensing characteristics of YbYxOy sensing membranes for electrolyte-insulator-semiconductor (EIS) sensors to detect the rheumatoid factor (RF). The YbYxOy EIS device prepared at the 60 W plasma condition exhibited a higher sensitivity of 65.77 mV/pH, a lower hysteresis voltage of ∼1 mV, and a smaller drift rate of 0.14 mV/h than did those prepared at the other conditions. We attribute this behavior to the optimal yttrium content in the YbYxOy film forming a smooth surface. Furthermore, we used a novel YbTixOy EIS biosensor to measure the RF antigen in human serum because of its rapid and label-free detection. Two different techniques were used for the immobilization of RF antibody onto the surface of an YbTixOy EIS sensor. The RF antibody was directly immobilized on the EIS surface modified with 3-aminopropyltriethoxysilane (APTES) followed by glutaraldehyde (GA). In contrast, a mixture of 1-ethyl-3-(3-dimethylamino-propyl)carbodiimide (EDC) and N-hydroxysuccinimide (NHS) solution was used to functionalize the carboxyl groups at the tail of RF antibodies. RF antibodies functionalized with the active NHS esters were covalently immobilized on the APTES-modified YbTixOy surface. The immobilized RF antibodies on the EIS that are functionalized with the EDC and NHS exhibit higher (41.11mV/pCRF) for detection of serum RF antigen in the range 10(-7) to 10(-3) M, compared to traditional antibody immobilization technique via APTES and GA linkage. The YbTixOy EIS biosensor is a promising analytical tool for RF antigen monitoring due to its good sensitivity, stability and repeatability.

  4. Active plasmonic and metamaterials and devices

    NASA Astrophysics Data System (ADS)

    Kim, Seong-Ku; Sylvain, Nathan; Benight, Stephanie J.; Kosilkin, Ilya; Bale, Denise H.; Robinson, Bruce H.; Park, Junghun; Geary, Kevin; Jen, Alex K.; Steier, William H.; Fetterman, Harold R.; Berini, Pierre; Dalton, Larry R.

    2010-08-01

    This communication focuses on the integration of organic nonlinear optical and gain materials into plasmonic and metamaterial device architectures and most specifically focuses on the integration of organic electro-optic (OEO) materials into such structures. The central focus is on structures that lead to sub-optical wavelength concentration of light (mode confinement) and the interaction of photonic and plasmonic modes. Optical loss and bandwidth limitations are serious issues with such structures and optical loss is evaluated for prototype device architectures associated with the use of silver and gold nanoparticles and membranes supporting plasmonic resonances. Electro-optic activity in organic materials requires that chromophores exhibit finite noncentrosymmetric organization. Because of material conductivity and integration issues, plasmonic and metamaterial device architectures are more challenging than conventional triple stack all-organic device architectures and electro-optic of a given OEO material may be an order of magnitude less in such structures. Because of this, we have turned to a variety of materials processing options for such integration including crystal growth, sequential synthesis/self assembly, and electric field poling of materials deposited from solution or by vapor deposition. Recent demonstration of integration of silicon photonic modulator and lithium niobate modulator structures with metallic plasmonic structures represent a severe challenge for organic electro-optic material plasmonic devices as these devices afford high bandwidth operation and attractive VμL performance. Optical loss remains a challenge for all structures.

  5. [Batteries Used in Active Implantable Medical Devices].

    PubMed

    Ma, Bozhi; Hao, Hongwei; Li, Luming

    2015-03-01

    In recent years active implantable medical devices(AIMD) are being developed rapidly. Many battery systems have been developed for different AIMD applications. These batteries have the same requirements which include high safety, reliability, energy density and long service life, discharge indication. History, present and future of batteries used in AIMD are introduced in the article. PMID:26524787

  6. Influence of material quality and process-induced defects on semiconductor device performance and yield

    NASA Technical Reports Server (NTRS)

    Porter, W. A.; Mckee, W. R.

    1974-01-01

    An overview of major causes of device yield degradation is presented. The relationships of device types to critical processes and typical defects are discussed, and the influence of the defect on device yield and performance is demonstrated. Various defect characterization techniques are described and applied. A correlation of device failure, defect type, and cause of defect is presented in tabular form with accompanying illustrations.

  7. Air-gating and chemical-gating in transistors and sensing devices made from hollow TiO2 semiconductor nanotubes.

    PubMed

    Alivov, Yahya; Funke, Hans; Nagpal, Prashant

    2015-07-24

    Rapid miniaturization of electronic devices down to the nanoscale, according to Moore's law, has led to some undesirable effects like high leakage current in transistors, which can offset additional benefits from scaling down. Development of three-dimensional transistors, by spatial extension in the third dimension, has allowed higher contact area with a gate electrode and better control over conductivity in the semiconductor channel. However, these devices do not utilize the large surface area and interfaces for new electronic functionality. Here, we demonstrate air gating and chemical gating in hollow semiconductor nanotube devices and highlight the potential for development of novel transistors that can be modulated using channel bias, gate voltage, chemical composition, and concentration. Using chemical gating, we reversibly altered the conductivity of nanoscaled semiconductor nanotubes (10-500 nm TiO2 nanotubes) by six orders of magnitude, with a tunable rectification factor (ON/OFF ratio) ranging from 1-10(6). While demonstrated air- and chemical-gating speeds were slow here (∼seconds) due to the mechanical-evacuation rate and size of our chamber, the small nanoscale volume of these hollow semiconductors can enable much higher switching speeds, limited by the rate of adsorption/desorption of molecules at semiconductor interfaces. These chemical-gating effects are completely reversible, additive between different chemical compositions, and can enable semiconductor nanoelectronic devices for 'chemical transistors', 'chemical diodes', and very high-efficiency sensing applications.

  8. Air-gating and chemical-gating in transistors and sensing devices made from hollow TiO2 semiconductor nanotubes

    NASA Astrophysics Data System (ADS)

    Alivov, Yahya; Funke, Hans; Nagpal, Prashant

    2015-07-01

    Rapid miniaturization of electronic devices down to the nanoscale, according to Moore’s law, has led to some undesirable effects like high leakage current in transistors, which can offset additional benefits from scaling down. Development of three-dimensional transistors, by spatial extension in the third dimension, has allowed higher contact area with a gate electrode and better control over conductivity in the semiconductor channel. However, these devices do not utilize the large surface area and interfaces for new electronic functionality. Here, we demonstrate air gating and chemical gating in hollow semiconductor nanotube devices and highlight the potential for development of novel transistors that can be modulated using channel bias, gate voltage, chemical composition, and concentration. Using chemical gating, we reversibly altered the conductivity of nanoscaled semiconductor nanotubes (10-500 nm TiO2 nanotubes) by six orders of magnitude, with a tunable rectification factor (ON/OFF ratio) ranging from 1-106. While demonstrated air- and chemical-gating speeds were slow here (˜seconds) due to the mechanical-evacuation rate and size of our chamber, the small nanoscale volume of these hollow semiconductors can enable much higher switching speeds, limited by the rate of adsorption/desorption of molecules at semiconductor interfaces. These chemical-gating effects are completely reversible, additive between different chemical compositions, and can enable semiconductor nanoelectronic devices for ‘chemical transistors’, ‘chemical diodes’, and very high-efficiency sensing applications.

  9. Multiphysics modeling of non-linear laser-matter interactions for optically active semiconductors

    NASA Astrophysics Data System (ADS)

    Kraczek, Brent; Kanp, Jaroslaw

    Development of photonic devices for sensors and communications devices has been significantly enhanced by computational modeling. We present a new computational method for modelling laser propagation in optically-active semiconductors within the paraxial wave approximation (PWA). Light propagation is modeled using the Streamline-upwind/Petrov-Galerkin finite element method (FEM). Material response enters through the non-linear polarization, which serves as the right-hand side of the FEM calculation. Maxwell's equations for classical light propagation within the PWA can be written solely in terms of the electric field, producing a wave equation that is a form of the advection-diffusion-reaction equations (ADREs). This allows adaptation of the computational machinery developed for solving ADREs in fluid dynamics to light-propagation modeling. The non-linear polarization is incorporated using a flexible framework to enable the use of multiple methods for carrier-carrier interactions (e.g. relaxation-time-based or Monte Carlo) to enter through the non-linear polarization, as appropriate to the material type. We demonstrate using a simple carrier-carrier model approximating the response of GaN. Supported by ARL Materials Enterprise.

  10. Semiconductor nanowire thermoelectric materials and devices, and processes for producing same

    DOEpatents

    Lagally, Max G.; Evans, Paul G.; Ritz, Clark S.

    2015-11-17

    The present invention provides nanowires and nanoribbons that are well suited for use in thermoelectric applications. The nanowires and nanoribbons are characterized by a periodic compositional longitudinal modulation. The nanowires are constructed using lithographic techniques from thin semiconductor membranes, or "nanomembranes."

  11. Semiconductor nanowire thermoelectric materials and devices, and processes for producing same

    DOEpatents

    Lagally, Max G.; Evans, Paul G.; Ritz, Clark S.

    2011-02-15

    The present invention provides nanowires and nanoribbons that are well suited for use in thermoelectric applications. The nanowires and nanoribbons are characterized by a periodic longitudinal modulation, which may be a compositional modulation or a strain-induced modulation. The nanowires are constructed using lithographic techniques from thin semiconductor membranes, or "nanomembranes."

  12. Semiconductor nanowire thermoelectric materials and devices, and processes for producing same

    DOEpatents

    Lagally, Max G; Evans, Paul G; Ritz, Clark S

    2013-09-17

    The present invention provides nanowires and nanoribbons that are well suited for use in thermoelectric applications. The nanowires and nanoribbons are characterized by a periodic compositional longitudinal modulation. The nanowires are constructed using lithographic techniques from thin semiconductor membranes, or "nanomembranes."

  13. Compound semiconductor native oxide-based technologies for optical and electrical devices grown on gallium arsenide substrates using MOCVD

    NASA Astrophysics Data System (ADS)

    Holmes, Adrian Lawrence

    1999-11-01

    The beginning of the modern microelectronics industry can be traced back to an invention made in 1947 when Bardeen and Brattain created the first semiconductor switch, called a transistor. Several other important discoveries followed; however, two of the more significant were (i) the development of the first planar process using silicon dioxide (SiO2) as a mask for diffusions into silicon by Frosch in 1955, and (ii) the subsequent integration of several transistors in tiny circuits by Kilby in 1958. Due to the superior quality of the SiO2-silicon interface, Si-based metal-oxide-semiconductor (MOS) transistors have primarily been used in integrated circuits. Until recently, compound semiconductors did not have a native oxide of sufficient quality to create similar MOS transistors. In 1990, research performed by Professor Holonyak and his group at the University of Illinois at Urbana-Champaign has led to a high-quality, stable, and insulating native oxide created from aluminum-containing compound semiconductor alloys. This study investigates native oxide films that are formed by the thermal oxidation of AlAs and InAlP epitaxial layers grown lattice-matched on GaAs substrates using metalorganic chemical vapor deposition (MOCVD). The primary goal is to evaluate how these native oxides can help form novel device structures and transistors. To qualify the material properties of these native oxide films, we have used several characterization techniques including photoluminescence, cross-sectional scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Additionally, we have performed leakage current and capacitance-voltage measurements to evaluate the electrical characteristics of the native oxide-semiconductor interface. The kinetics of the thermal oxidation process for both the surface oxidation of InAlP and lateral oxidation of AlAs are studied and contrasted. Aided by this knowledge, we have created a sealed

  14. Scattering efficiency and near field enhancement of active semiconductor plasmonic antennas at terahertz frequencies.

    PubMed

    Giannini, Vincenzo; Berrier, Audrey; Maier, Stefan A; Sánchez-Gil, José Antonio; Rivas, Jaime Gómez

    2010-02-01

    Terahertz plasmonic resonances in semiconductor (indium antimonide, InSb) dimer antennas are investigated theoretically. The antennas are formed by two rods separated by a small gap. We demonstrate that, with an appropriate choice of the shape and dimension of the semiconductor antennas, it is possible to obtain large electromagnetic field enhancement inside the gap. Unlike metallic antennas, the enhancement around the semiconductor plasmonics antenna can be easily adjusted by varying the concentration of free carriers, which can be achieved by optical or thermal excitation of carriers or electrical carrier injection. Such active plasmonic antennas are interesting structures for THz applications such as modulators and sensors.

  15. Scattering efficiency and near field enhancement of active semiconductor plasmonic antennas at terahertz frequencies.

    PubMed

    Giannini, Vincenzo; Berrier, Audrey; Maier, Stefan A; Sánchez-Gil, José Antonio; Rivas, Jaime Gómez

    2010-02-01

    Terahertz plasmonic resonances in semiconductor (indium antimonide, InSb) dimer antennas are investigated theoretically. The antennas are formed by two rods separated by a small gap. We demonstrate that, with an appropriate choice of the shape and dimension of the semiconductor antennas, it is possible to obtain large electromagnetic field enhancement inside the gap. Unlike metallic antennas, the enhancement around the semiconductor plasmonics antenna can be easily adjusted by varying the concentration of free carriers, which can be achieved by optical or thermal excitation of carriers or electrical carrier injection. Such active plasmonic antennas are interesting structures for THz applications such as modulators and sensors. PMID:20174108

  16. A comprehensive study of charge trapping in organic field-effect devices with promising semiconductors and different contact metals by displacement current measurements

    NASA Astrophysics Data System (ADS)

    Bisoyi, Sibani; Rödel, Reinhold; Zschieschang, Ute; Kang, Myeong Jin; Takimiya, Kazuo; Klauk, Hagen; Tiwari, Shree Prakash

    2016-02-01

    A systematic and comprehensive study on the charge-carrier injection and trapping behavior was performed using displacement current measurements in long-channel capacitors based on four promising small-molecule organic semiconductors (pentacene, DNTT, C10-DNTT and DPh-DNTT). In thin-film transistors, these semiconductors showed charge-carrier mobilities ranging from 1.0 to 7.8 cm2 V-1 s-1. The number of charges injected into and extracted from the semiconductor and the density of charges trapped in the device during each measurement were calculated from the displacement current characteristics and it was found that the density of trapped charges is very similar in all devices and of the order 1012 cm-2, despite the fact that the four semiconductors show significantly different charge-carrier mobilities. The choice of the contact metal (Au, Ag, Cu, Pd) was also found to have no significant effect on the trapping behavior.

  17. Synthesis Methods, Microscopy Characterization and Device Integration of Nanoscale Metal Oxide Semiconductors for Gas Sensing

    PubMed Central

    Vander Wal, Randy L.; Berger, Gordon M.; Kulis, Michael J.; Hunter, Gary W.; Xu, Jennifer C.; Evans, Laura

    2009-01-01

    A comparison is made between SnO2, ZnO, and TiO2 single-crystal nanowires and SnO2 polycrystalline nanofibers for gas sensing. Both nanostructures possess a one-dimensional morphology. Different synthesis methods are used to produce these materials: thermal evaporation-condensation (TEC), controlled oxidation, and electrospinning. Advantages and limitations of each technique are listed. Practical issues associated with harvesting, purification, and integration of these materials into sensing devices are detailed. For comparison to the nascent form, these sensing materials are surface coated with Pd and Pt nanoparticles. Gas sensing tests, with respect to H2, are conducted at ambient and elevated temperatures. Comparative normalized responses and time constants for the catalyst and noncatalyst systems provide a basis for identification of the superior metal-oxide nanostructure and catalyst combination. With temperature-dependent data, Arrhenius analyses are made to determine activation energies for the catalyst-assisted systems. PMID:22408484

  18. SEMICONDUCTOR DEVICES: Analysis of the thermo-optic effect in lateral-carrier-injection SOI ridge waveguide devices

    NASA Astrophysics Data System (ADS)

    Jiate, Zhao; Yong, Zhao; Wanjun, Wang; Yinlei, Hao; Qiang, Zhou; Jianyi, Yang; Minghua, Wang; Xiaoqing, Jiang

    2010-06-01

    The thermo-optic effect in the lateral-carrier-injection pin junction SOI ridge waveguide is analyzed according to the thermal field equation. Numerical analysis and experimental results show that the thermo-optic effect caused by carrier injection is significant in such devices, especially for small structure ones. For a device with a 1000 μm modulation length, the refractive index rise introduced by heat accounts for 1/8 of the total effect under normal working conditions. A proposal of adjusting the electrode position to cool the devices to diminish the thermal-optic effect is put forward.

  19. ZnCdMgSe as a Materials Platform for Advanced Photonic Devices: Broadband Quantum Cascade Detectors and Green Semiconductor Disk Lasers

    NASA Astrophysics Data System (ADS)

    De Jesus, Joel

    The ZnCdMgSe family of II-VI materials has unique and promising characteristics that may be useful in practical applications. For example they can be grown lattice matched to InP substrates with lattice matched bandgaps that span from 2.1 to 3.5 eV, they can be successfully doped n-type, have a large conduction band offset (CBO) with no intervalley scattering present when strained, they have lower average phonon energies, and the InP lattice constant lies in the middle of the ZnSe and CdSe binaries compounds giving room to experiment with tensile and compressive stress. However they have not been studied in detail for use in practical devices. Here we have identified two types of devices that are being currently developed that benefit from the ZnCdMgSe-based material properties. These are the intersubband (ISB) quantum cascade (QC) detectors and optically pumped semiconductor lasers that emit in the visible range. The paucity for semiconductor lasers operating in the green-orange portion of the visible spectrum can be easily overcome with the ZnCdMgSe materials system developed in our research. The non-strain limited, large CBO available allows to expand the operating wavelength of ISB devices providing shorter and longer wavelengths than the currently commercially available devices. This property can also be exploited to develop broadband room temperature operation ISB detectors. The work presented here focused first on using the ZnCdMgSe-based material properties and parameter to understand and predict the interband and intersubband transitions of its heterostructures. We did this by studying an active region of a QC device by contactless electroreflectance, photoluminescence, FTIR transmittance and correlating the measurements to the quantum well structure by transfer matrix modeling. Then we worked on optimizing the ZnCdMgSe material heterostructures quality by studying the effects of growth interruptions on their optical and optoelectronic properties of

  20. Active superconducting devices formed of thin films

    DOEpatents

    Martens, Jon S.; Beyer, James B.; Nordman, James E.; Hohenwarter, Gert K. G.

    1991-05-28

    Active superconducting devices are formed of thin films of superconductor which include a main conduction channel which has an active weak link region. The weak link region is composed of an array of links of thin film superconductor spaced from one another by voids and selected in size and thickness such that magnetic flux can propagate across the weak link region when it is superconducting. Magnetic flux applied to the weak link region will propagate across the array of links causing localized loss of superconductivity in the links and changing the effective resistance across the links. The magnetic flux can be applied from a control line formed of a superconducting film deposited coplanar with the main conduction channel and weak link region on a substrate. The devices can be formed of any type to superconductor but are particularly well suited to the high temperature superconductors since the devices can be entirely formed from coplanar films with no overlying regions. The devices can be utilized for a variety of electrical components, including switching circuits, amplifiers, oscillators and modulators, and are well suited to microwave frequency applications.

  1. Performance of an MPI-only semiconductor device simulator on a quad socket/quad core InfiniBand platform.

    SciTech Connect

    Shadid, John Nicolas; Lin, Paul Tinphone

    2009-01-01

    This preliminary study considers the scaling and performance of a finite element (FE) semiconductor device simulator on a capacity cluster with 272 compute nodes based on a homogeneous multicore node architecture utilizing 16 cores. The inter-node communication backbone for this Tri-Lab Linux Capacity Cluster (TLCC) machine is comprised of an InfiniBand interconnect. The nonuniform memory access (NUMA) nodes consist of 2.2 GHz quad socket/quad core AMD Opteron processors. The performance results for this study are obtained with a FE semiconductor device simulation code (Charon) that is based on a fully-coupled Newton-Krylov solver with domain decomposition and multilevel preconditioners. Scaling and multicore performance results are presented for large-scale problems of 100+ million unknowns on up to 4096 cores. A parallel scaling comparison is also presented with the Cray XT3/4 Red Storm capability platform. The results indicate that an MPI-only programming model for utilizing the multicore nodes is reasonably efficient on all 16 cores per compute node. However, the results also indicated that the multilevel preconditioner, which is critical for large-scale capability type simulations, scales better on the Red Storm machine than the TLCC machine.

  2. Development of an electronic device quality aluminum antimonide (AlSb) semiconductor for solar cell applications

    SciTech Connect

    Sherohman, John W; Yee, Jick Hong; Combs, III, Arthur W

    2014-11-11

    Electronic device quality Aluminum Antimonide (AlSb)-based single crystals produced by controlled atmospheric annealing are utilized in various configurations for solar cell applications. Like that of a GaAs-based solar cell devices, the AlSb-based solar cell devices as disclosed herein provides direct conversion of solar energy to electrical power.

  3. Methods of producing strain in a semiconductor waveguide and related devices

    DOEpatents

    Cox, Johathan Albert; Rakich, Peter Thomas

    2016-02-16

    Quasi-phase matched (QPM), semiconductor photonic waveguides include periodically-poled alternating first and second sections. The first sections exhibit a high degree of optical coupling (abbreviated "X.sup.2"), while the second sections have a low X.sup.2. The alternating first and second sections may comprise high-strain and low-strain sections made of different material states (such as crystalline and amorphous material states) that exhibit high and low X.sup.2 properties when formed on a particular substrate, and/or strained corrugated sections of different widths. The QPM semiconductor waveguides may be implemented as silicon-on-insulator (SOI), or germanium-on-silicon structures compatible with standard CMOS processes, or as silicon-on-sapphire (SOS) structures.

  4. The 1.7 kilogram microchip: energy and material use in the production of semiconductor devices.

    PubMed

    Williams, Eric D; Ayres, Robert U; Heller, Miriam

    2002-12-15

    The scale of environmental impacts associated with the manufacture of microchips is characterized through analysis of material and energy inputs into processes in the production chain. The total weight of secondary fossil fuel and chemical inputs to produce and use a single 2-gram 32MB DRAM chip are estimated at 1600 g and 72 g, respectively. Use of water and elemental gases (mainly N2) in the fabrication stage are 32,000 and 700 g per chip, respectively. The production chain yielding silicon wafers from quartz uses 160 times the energy required for typical silicon, indicating that purification to semiconductor grade materials is energy intensive. Due to its extremely low-entropy, organized structure, the materials intensity of a microchip is orders of magnitude higher than that of "traditional" goods. Future analysis of semiconductor and other low entropy high-tech goods needs to include the use of secondary materials, especially for purification.

  5. Methods and devices for optimizing the operation of a semiconductor optical modulator

    DOEpatents

    Zortman, William A.

    2015-07-14

    A semiconductor-based optical modulator includes a control loop to control and optimize the modulator's operation for relatively high data rates (above 1 GHz) and/or relatively high voltage levels. Both the amplitude of the modulator's driving voltage and the bias of the driving voltage may be adjusted using the control loop. Such adjustments help to optimize the operation of the modulator by reducing the number of errors present in a modulated data stream.

  6. Device modeling of perovskite solar cells based on structural similarity with thin film inorganic semiconductor solar cells

    NASA Astrophysics Data System (ADS)

    Minemoto, Takashi; Murata, Masashi

    2014-08-01

    Device modeling of CH3NH3PbI3-xCl3 perovskite-based solar cells was performed. The perovskite solar cells employ a similar structure with inorganic semiconductor solar cells, such as Cu(In,Ga)Se2, and the exciton in the perovskite is Wannier-type. We, therefore, applied one-dimensional device simulator widely used in the Cu(In,Ga)Se2 solar cells. A high open-circuit voltage of 1.0 V reported experimentally was successfully reproduced in the simulation, and also other solar cell parameters well consistent with real devices were obtained. In addition, the effect of carrier diffusion length of the absorber and interface defect densities at front and back sides and the optimum thickness of the absorber were analyzed. The results revealed that the diffusion length experimentally reported is long enough for high efficiency, and the defect density at the front interface is critical for high efficiency. Also, the optimum absorber thickness well consistent with the thickness range of real devices was derived.

  7. High precision two-dimensional strain mapping in semiconductor devices using nanobeam electron diffraction in the transmission electron microscope

    SciTech Connect

    Baumann, Frieder H.

    2014-06-30

    A classical method used to characterize the strain in modern semiconductor devices is nanobeam diffraction (NBD) in the transmission electron microscope. One challenge for this method lies in the fact that the smaller the beam becomes, the more difficult it becomes to analyze the resulting diffraction spot pattern. We show that a carefully designed fitting algorithm enables us to reduce the sampling area for the diffraction patterns on the camera chip dramatically (∼1/16) compared to traditional settings without significant loss of precision. The resulting lower magnification of the spot pattern permits the presence of an annular dark field detector, which in turn makes the recording of images for drift correction during NBD acquisition possible. Thus, the reduced sampling size allows acquisition of drift corrected NBD 2D strain maps of up to 3000 pixels while maintaining a precision of better than 0.07%. As an example, we show NBD strain maps of a modern field effect transistor (FET) device. A special filtering feature used in the analysis makes it is possible to measure strain in silicon devices even in the presence of other crystalline materials covering the probed area, which is important for the characterization of the next generation of devices (Fin-FETs).

  8. Carrier-density-wave transport and local internal electric field measurements in biased metal-oxide-semiconductor n-Si devices using contactless laser photo-carrier radiometry

    NASA Astrophysics Data System (ADS)

    Mandelis, Andreas; Pawlak, Micha; Shaughnessy, Derrick

    2004-11-01

    Laser infrared photo-carrier radiometry was used with an n-type Si metal-oxide-semiconductor (MOS) diode and with a Si-SiO2 structure with a transparent electrode and under external bias. Application of three-dimensional PCR theory yielded values of the minority carrier (hole) transport properties in the presence of the thus created local internal electric field at fixed frequencies. Furthermore, the internal electric field at fixed applied voltage was calculated. Under the combination of increased temperature and voltage, the sub-interface position of the carrier-density-wave centroid was found to depend on a trade-off between increased recombination lifetime and decreased ambipolar (conductivity) mobility. The ability of PCR to measure local internal electric fields by combining applied bias sweeps and frequency scans appears to pave the way towards the contactless reconstruction of depth profiles of these fields in active devices.

  9. Defect state passivation at III-V oxide interfaces for complementary metal–oxide–semiconductor devices

    SciTech Connect

    Robertson, J.; Guo, Y.; Lin, L.

    2015-03-21

    The paper describes the reasons for the greater difficulty in the passivation of interface defects of III–V semiconductors like GaAs. These include the more complex reconstructions of the starting surface which already possess defect configurations, the possibility of injecting As antisites into the substrate which give rise to gap states, and the need to avoid As-As bonds and As dangling bonds which give rise to gap states. The nature of likely defect configurations in terms of their electronic structure is described. The benefits of diffusion barriers and surface nitridation are discussed.

  10. Chemical vapor deposition and characterization of polysilanes polymer based thin films and their applications in compound semiconductors and silicon devices

    NASA Astrophysics Data System (ADS)

    Oulachgar, El Hassane

    As the semiconductors industry is moving toward nanodevices, there is growing need to develop new materials and thin films deposition processes which could enable strict control of the atomic composition and structure of thin film materials in order to achieve precise control on their electrical and optical properties. The accurate control of thin film characteristics will become increasingly important as the miniaturization of semiconductor devices continue. There is no doubt that chemical synthesis of new materials and their self assembly will play a major role in the design and fabrication of next generation semiconductor devices. The objective of this work is to investigate the chemical vapor deposition (CVD) process of thin film using a polymeric precursor as a source material. This process offers many advantages including low deposition cost, hazard free working environment, and most importantly the ability to customize the polymer source material through polymer synthesis and polymer functionalization. The combination between polymer synthesis and CVD process will enable the design of new generation of complex thin film materials with a wide range of improved chemical, mechanical, electrical and optical properties which cannot be easily achieved through conventional CVD processes based on gases and small molecule precursors. In this thesis we mainly focused on polysilanes polymers and more specifically poly(dimethylsilanes). The interest in these polymers is motivated by their distinctive electronic and photonic properties which are attributed to the delocalization of the sigma-electron along the Si-Si backbone chain. These characteristics make polysilane polymers very promising in a broad range of applications as a dielectric, a semiconductor and a conductor. The polymer-based CVD process could be eventually extended to other polymer source materials such as polygermanes, as well as and a variety of other inorganic and hybrid organic-inorganic polymers

  11. SEMICONDUCTOR DEVICES Design consideration of the thermal and electro stability of multi-finger HBTs based on different device structures

    NASA Astrophysics Data System (ADS)

    Yanhu, Chen; Huajun, Shen; Xinyu, Liu; Hui, Xu; Ling, Li; Huijun, Li

    2010-10-01

    The thermal and electro stability of multi-finger heterojunction bipolar transistors (HBTs) with different structures were analyzed and discussed simultaneously. The thermal stability of the devices with different layout structures was assessed by the DC-IV test and thermal resistance calculation. Their electro stability was assessed by the calculation of the stability factor K based on the S parameter of the HBT. It is found that HBTs with higher thermal stability are prone to lower electro stability. The trade-off relationship between the two types of stability was explained and discussed by using a compact K-factor analytic formula which is derived from the small signal equivalent circuit model of HBT. The electro stability of the device with a thermal ballasting resistor was also discussed, based on the analytic formula.

  12. SEMICONDUCTOR DEVICES A novel modified charge pumping method for trapped charge characterization in nanometer-scale devices

    NASA Astrophysics Data System (ADS)

    Peng, Zhu; Liyang, Pan; Haiming, Gu; Fengying, Qiao; Ning, Deng; Jun, Xu

    2010-10-01

    A new modified method based on the charge pumping technique is proposed and adopted to extract the lateral profiles of oxide charges in an advanced MOSFET. A 0.12 μm SONOS device with 50 nm threshold voltage peak is designed and utilized to demonstrate the proposed method. The trapped charge distribution with a narrow peak can be precisely characterized with this method, which shows good consistency with the measured threshold voltage.

  13. Optical and electrical characterization of high resistivity semiconductors for constant-bias microbolometer devices

    NASA Astrophysics Data System (ADS)

    Saint John, David B.

    The commercial market for uncooled infrared imaging devices has expanded in the last several decades, following the declassification of pulse-biased microbolometer-based focal plane arrays (FPAs) using vanadium oxide as the sensing material. In addition to uncooled imaging platforms based on vanadium oxide, several constant-bias microbolometer FPAs have been developed using doped hydrogenated amorphous silicon (a-Si:H) as the active sensing material. While a-Si:H and the broader Si1-xGex:H system have been studied within the context of photovoltaic (PV) devices, only recently have these materials been studied with the purpose of qualifying and optimizing them for potential use in microbolometer applications, which demand thinner films deposited onto substrates different than those used in PV. The behavior of Ge:H is of particular interest for microbolometers due to its intrinsically low resistivity without the introduction of dopants, which alter the growth behavior and frustrate any attempt to address the merits of protocrystalline a-Ge:H. This work reports the optical, microstructural, and electrical characterization and qualification of a variety of Si:H, Si1-xGex:H, and Ge:H films deposited using a plasma enhanced chemical vapor deposition (PECVD) process, including a-Ge:H films which exhibit high TCR (4-6 -%/K) and low 1/f noise at resistivities of interest for microbolometers (4000 -- 6000 O cm). Thin film deposition has been performed simultaneously with real-time optical characterization of the growth evolution dynamics, providing measurement of optical properties and surface roughness evolutions relevant to controlling the growth process for deliberate variations in film microstructure. Infrared spectroscopic ellipsometry has been used to characterize the Si-H and Ge-H absorption modes allowing assessment of the hydrogen content and local bonding behavior in thinner films than measured traditionally. This method allows IR absorption analysis of hydrogen

  14. Modeling direct band-to-band tunneling: From bulk to quantum-confined semiconductor devices

    SciTech Connect

    Carrillo-Nuñez, H.; Ziegler, A.; Luisier, M.; Schenk, A.

    2015-06-21

    A rigorous framework to study direct band-to-band tunneling (BTBT) in homo- and hetero-junction semiconductor nanodevices is introduced. An interaction Hamiltonian coupling conduction and valence bands (CVBs) is derived using a multiband envelope method. A general form of the BTBT probability is then obtained from the linear response to the “CVBs interaction” that drives the system out of equilibrium. Simple expressions in terms of the one-electron spectral function are developed to compute the BTBT current in two- and three-dimensional semiconductor structures. Additionally, a two-band envelope equation based on the Flietner model of imaginary dispersion is proposed for the same purpose. In order to characterize their accuracy and differences, both approaches are compared with full-band, atomistic quantum transport simulations of Ge, InAs, and InAs-Si Esaki diodes. As another numerical application, the BTBT current in InAs-Si nanowire tunnel field-effect transistors is computed. It is found that both approaches agree with high accuracy. The first one is considerably easier to conceive and could be implemented straightforwardly in existing quantum transport tools based on the effective mass approximation to account for BTBT in nanodevices.

  15. SEMICONDUCTOR DEVICES: An improved HCI degradation model for a VLSI MOSFET

    NASA Astrophysics Data System (ADS)

    Yi, Tang; Xinggong, Wan; Xiang, Gu; Wenyuan, Wang; Huirui, Zhang; Yuwei, Liu

    2009-12-01

    An improved hot carrier injection (HCI) degradation model was proposed based on interface trap generation and oxide charge injection theory. It was evident that the degradation behavior of electric parameters such as Idlin, Idsat, Gm and Vt fitted well with this model. Devices were prepared with 0.35 μm technology and different LDD processes. Idlin and Idsat after HCI stress were analyzed with the improved model. The effects of interface trap generation and oxide charge injection on device degradation were extracted, and the charge injection site could be obtained by this method. The work provides important information to device designers and process engineers.

  16. Development and fabrication of improved power transistor switches. [fabrication and manufacturing of semiconductor devices

    NASA Technical Reports Server (NTRS)

    Hower, P. L.; Chu, C. K.

    1976-01-01

    A new class of high-voltage power transistors has been achieved by adapting present interdigitated thyristor processing techniques to the fabrication of NPN Si transistors. Present devices are 2.3 cm in diameter. The electrical performance obtained is consistent with the predictions of an optimum design theory specifically developed for power switching transistors. The forward safe operating area of the experimental transistors shows a significant improvement over commercially available devices. The report describes device design, wafer processing, and various measurements which include dc characteristics, forward and reverse second breakdown limits, and switching times.

  17. A bio-inspired memory device based on interfacing Physarum polycephalum with an organic semiconductor

    SciTech Connect

    Romeo, Agostino; Dimonte, Alice; Tarabella, Giuseppe; D’Angelo, Pasquale E-mail: iannotta@imem.cnr.it; Erokhin, Victor; Iannotta, Salvatore E-mail: iannotta@imem.cnr.it

    2015-01-01

    The development of devices able to detect and record ion fluxes is a crucial point in order to understand the mechanisms that regulate communication and life of organisms. Here, we take advantage of the combined electronic and ionic conduction properties of a conducting polymer to develop a hybrid organic/living device with a three-terminal configuration, using the Physarum polycephalum Cell (PPC) slime mould as a living bio-electrolyte. An over-oxidation process induces a conductivity switch in the polymer, due to the ionic flux taking place at the PPC/polymer interface. This behaviour endows a current-depending memory effect to the device.

  18. Electroluminescence from metal-oxide-semiconductor devices with erbium-doped CeO{sub 2} films on silicon

    SciTech Connect

    Lv, Chunyan; Zhu, Chen; Wang, Canxing; Gao, Yuhan; Ma, Xiangyang Yang, Deren

    2015-04-06

    We report on erbium (Er)-related electroluminescence (EL) in the visible and near-infrared (NIR) from metal-oxide-semiconductor (MOS) devices with Er-doped CeO{sub 2} (CeO{sub 2}:Er) films on silicon. The onset voltage of such EL under either forward or reverse bias is smaller than 10 V. Moreover, the EL quenching can be avoidable for the CeO{sub 2}:Er-based MOS devices. Analysis on the current-voltage characteristic of the device indicates that the electron transportation at the EL-enabling voltages under either forward or reverse bias is dominated by trap-assisted tunneling mechanism. Namely, electrons in n{sup +}-Si/ITO can tunnel into the conduction band of CeO{sub 2} host via defect states at sufficiently high forward/reverse bias voltages. Then, a fraction of such electrons are accelerated by electric field to become hot electrons, which impact-excite the Er{sup 3+} ions, thus leading to characteristic emissions. It is believed that this work has laid the foundation for developing viable silicon-based emitters using CeO{sub 2}:Er films.

  19. CdSe Nanowire-Based Flexible Devices: Schottky Diodes, Metal-Semiconductor Field-Effect Transistors, and Inverters.

    PubMed

    Jin, Weifeng; Zhang, Kun; Gao, Zhiwei; Li, Yanping; Yao, Li; Wang, Yilun; Dai, Lun

    2015-06-24

    Novel CdSe nanowire (NW)-based flexible devices, including Schottky diodes, metal-semiconductor field-effect transistors (MESFETs), and inverters, have been fabricated and investigated. The turn-on voltage of a typical Schottky diode is about 0.7 V, and the rectification ratio is larger than 1 × 10(7). The threshold voltage, on/off current ratio, subthreshold swing, and peak transconductance of a typical MESFET are about -0.3 V, 4 × 10(5), 78 mV/dec, and 2.7 μS, respectively. The inverter, constructed with two MESFETs, exhibits clear inverting behavior with the gain to be about 28, 34, and 38, at the supply voltages (V(DD)) of 3, 5, and 7 V, respectively. The inverter also shows good dynamic behavior. The rising and falling times of the output signals are about 0.18 and 0.09 ms, respectively, under 1000 Hz square wave signals input. The performances of the flexible devices are stable and reliable under different bending conditions. Our work demonstrates these flexible NW-based Schottky diodes, MESFETs, and inverters are promising candidate components for future portable transparent nanoelectronic devices.

  20. Irradiate-anneal screening of total dose effects in semiconductor devices. [radiation hardening of spacecraft components of Mariner spacecraft

    NASA Technical Reports Server (NTRS)

    Stanley, A. G.; Price, W. E.

    1976-01-01

    An extensive investigation of irradiate-anneal (IRAN) screening against total dose radiation effects was carried out as part of a program to harden the Mariner Jupiter/Saturn 1977 (MJS'77) spacecraft to survive the Jupiter radiation belts. The method consists of irradiating semiconductor devices with Cobalt-60 to a suitable total dose under representative bias conditions and of separating the parts in the undesired tail of the distribution from the bulk of the parts by means of a predetermined acceptance limit. The acceptable devices are then restored close to their preirradiation condition by annealing them at an elevated temperature. IRAN was used when lot screen methods were impracticable due to lack of time, and when members of a lot showed a diversity of radiation response. The feasibility of the technique was determined by testing of a number of types of linear bipolar integrated circuits, analog switches, n-channel JFETS and bipolar transistors. Based on the results of these experiments a number of device types were selected for IRAN of flight parts in the MJS'77 spacecraft systems. The part types, screening doses, acceptance criteria, number of parts tested and rejected as well as the program steps are detailed.

  1. Materials and device design with III-V and II-VI compound-based diluted magnetic semiconductors

    NASA Astrophysics Data System (ADS)

    Katayama-Yoshida, Hiroshi; Sato, Kazunori

    2002-03-01

    Since the discovery of the carrier induced ferromagnetism in (In, Mn)As and (Ga, Mn)As, diluted magnetic semiconductors (DMS) have been of much interest from the industrial viewpoint because of their potentiality as a new functional material (spintronics). In this paper, the magnetism in DMS is investigated based on the first principles calculations, and materials and device design with the DMS is proposed toward the spintronics. The electronic structure is calculated by the Korringa-Kohn-Rostoker method combined with the coherent potential approximation based on the local spin density approximation. We calculate the electronic structure of ferromagnetic and spin-glass DMS, and total energy difference between them is calculated to estimate whether the ferromagnetic state is stable or not. It is shown that V-, Cr- and Mn-doped III-V compounds, V- and Cr-doped II-VI compounds and Fe-, Co- and Ni-doped ZnO are promising candidates for a high-Curie temperature ferromagnet. A chemical trend in the ferromagnetism is well understood based on the double exchange mechanism [1]. Based upon this material design, some prototypes of the spintronics devices, such as a spin-FET, a photo-induced-magnetic memory and a coherent-spin-infection device, are proposed. [1] K. Sato and H. Katayama-Yoshida, Jpn. J. Appl. Phys. 39 (2000) L555, 40 (2001) L334, L485 and L651.

  2. Nano-/microstructure improved photocatalytic activities of semiconductors.

    PubMed

    Zhao, Tianyi; Zhao, Yong; Jiang, Lei

    2013-10-13

    Photocatalysis has emerged as a promising technique owing to its valuable applications in environmental purification. With the demand of building effective photocatalyst materials, semiconductor investigation experienced a developing process from simple chemical modification to complicated morphology design. In this review, the general relationship between morphology structures and photocatalytic properties is mainly discussed. Various nano-/microsized structures from zero- to three-dimensional are discussed, and the photocatalytic efficiency correspon- ding to the structures is analysed. The results showed that simple structures can be easily obtained and can facilitate chemical modification, whereas one- or three-dimensional structures can provide structure-enhanced properties such as surface area increase, multiple reflections of UV light, etc. Those principles of structure-related photocatalytic properties will afford basic ideology in designing new photocatalytic materials with more effective catalytic properties.

  3. SEMICONDUCTOR DEVICES: Short channel effect in deep submicron PDSOI nMOSFETs

    NASA Astrophysics Data System (ADS)

    Jianhui, Bu; Jinshun, Bi; Limei, Song; Zhengsheng, Han

    2010-01-01

    Deep submicron partially depleted silicon on insulator (PDSOI) nMOSFETs were fabricated based on the 0.35 μm SOI process developed by the Institute of Microelectronics of the Chinese Academy of Sciences (IMECAS). Mechanisms determining short-channel effects (SCE) in PDSOI nMOSFETs are clarified based on experimental results of threshold voltage dependence upon gate length. The effects of body bias, drain bias, temperature and body contact on the SCE have been investigated. The SCE in SOI devices is found to be dependent on body bias, drain bias and body contact. Floating body devices show a more severe reverse short channel effect (RSCE) than devices with body contact structure. Devices with low body bias and high drain bias show a more obvious SCE.

  4. Glass-to-metal bonding process improves stability and performance of semiconductor devices

    NASA Technical Reports Server (NTRS)

    Trent, R. L.

    1970-01-01

    Anodic bonding of glass coverslips to photodiodes and photovoltaic devices eliminates the need for adhesive. The process requires relatively low temperatures /less than 560 degrees C/ and the metals and glass remain solid throughout the bonding process.

  5. Boron Arsenide and Boron Phosphide for High Temperature and Luminescent Devices. [semiconductor devices - crystal growth/crystal structure

    NASA Technical Reports Server (NTRS)

    Chu, T. L.

    1975-01-01

    The crystal growth of boron arsenide and boron phosphide in the form of bulk crystals and epitaxial layers on suitable substrates is discussed. The physical, chemical, and electrical properties of the crystals and epitaxial layers are examined. Bulk crystals of boron arsenide were prepared by the chemical transport technique, and their carrier concentration and Hall mobility were measured. The growth of boron arsenide crystals from high temperature solutions was attempted without success. Bulk crystals of boron phosphide were also prepared by chemical transport and solution growth techniques. Techniques required for the fabrication of boron phosphide devices such as junction shaping, diffusion, and contact formation were investigated. Alloying techniques were developed for the formation of low-resistance ohmic contacts to boron phosphide. Four types of boron phosphide devices were fabricated: (1) metal-insulator-boron phosphide structures, (2) Schottky barriers; (3) boron phosphide-silicon carbide heterojunctions; and (4) p-n homojunctions. Easily visible red electroluminescence was observed from both epitaxial and solution grown p-n junctions.

  6. Device applications and structural and optical properties of Indigo - A biodegradable, low-cost organic semiconductor

    NASA Astrophysics Data System (ADS)

    Wang, Zhengjun; Pisane, Kelly L.; Sierros, Konstantinos; Seehra, Mohindar S.; Korakakis, Dimitris

    2015-03-01

    Currently, memory devices based on organic materials are attracting great attention due to their simplicity in device structure, mechanical flexibility, potential for scalability, low-cost potential, low-power operation, and large capacity for data storage. In a recent paper from our group, Indigo-based nonvolatile organic write-once-read-many-times (WORM) memory device, consisting of a 100nm layer of indigo sandwiched between an indium tin oxide (ITO) cathode and an Al anode, has been reported. This device is found to be at its low resistance state (ON state) and can be switched to high resistance state (OFF state) by applying a positive bias with ON/OFF current ratio of the device being up to 1.02 × e6. A summary of these results along with the structural and optical properties of indigo powder will be reported. Analysis of x-ray diffraction shows a monoclinic structure with lattice parameters a(b)[c] = 0.924(0.577)[0.1222]nm and β =117° . Optical absorption shows a band edge at 1.70 eV with peak of absorption occurring at 1.90 eV. These results will be interpreted in terms of the HOMO-LUMO bands of Indigo.

  7. Bottom-up superconducting and Josephson junction devices and qubits inside a Group-IV semiconductor

    NASA Astrophysics Data System (ADS)

    Shim, Yun-Pil

    2014-03-01

    The Nb/AlOx/Nb (or Al/AlOx/Al) Josephson junction (JJ) has become ubiquitous for superconducting (SC) applications such as magnetometers, voltage standards, logic, and qubits. But heterogeneous devices such as these can pose problems, especially for low-power or quantum applications, where losses in or at the interfaces of the various materials can limit device quality dramatically. Possible solutions include better materials, weak-link junctions, symmetry protection, or 3D cavity qubits. Here we consider another alternative: atomically-precise, hole-doped SC silicon (or germanium) JJ devices and qubits made entirely out of the same crystal. Like the Si spin qubit, our super-semi JJ devices exist inside the ``vacuum'' of ultra-pure silicon, far away from any dirty interfaces. We predict the possibility of SC wires, JJs, and qubits, calculate their critical parameters, and find that most known SC qubits should be realizable. This approach could enable better devices, hybrid superconducting-spin qubit systems, and exotic SC circuits, as well as a new physical testbed for superconductivity.

  8. Single event upset (SEU) of semiconductor devices - A summary of JPL test data

    NASA Astrophysics Data System (ADS)

    Nichols, D. K.; Price, W. E.; Malone, C. J.

    1983-12-01

    The data summarized describe single event upset (bit-flips) for 60 device types having data storage elements. The data are from 15 acceleration tests with both protons and heavier ions. Tables are included summarizing the upset threshold data and listing the devices tested for heavy ion induced bit-flip and the devices tested with protons. With regard to the proton data, it is noted that the data are often limited to one proton energy, since the tests were usually motivated by the engineering requirement of comparing similar candidate devices for a system. It is noted that many of the devices exhibited no upset for the given test conditions (the maximum fluence and the maximum proton energy Ep are given for these cases). It is believed, however, that some possibility of upset usually exists because there is a slight chance that the recoil atom may receive up to 10 to 20 MeV of recoil energy (with more energy at higher Ep).

  9. Physics of Organic Semiconductors

    NASA Astrophysics Data System (ADS)

    Brütting, Wolfgang

    2004-05-01

    Organic semiconductors are of steadily growing interest as active components in electronics and optoelectronics. Due to their flexibility, low cost and ease-of-production they represent a valid alternative to conventional inorganic semiconductor technology in a number of applications, such as flat panel displays and illumination, plastic integrated circuits or solar energy conversion. Although first commercial applications of this technology are being realized nowadays, there is still the need for a deeper scientific understanding in order to achieve optimum device performance.This special issue of physica status solidi (a) tries to give an overview of our present-day knowledge of the physics behind organic semiconductor devices. Contributions from 17 international research groups cover various aspects of this field ranging from the growth of organic layers and crystals, their electronic properties at interfaces, their photophysics and electrical transport properties to the application of these materials in different devices like organic field-effect transistors, photovoltaic cells and organic light-emitting diodes.Putting together such a special issue one soon realizes that it is simply impossible to fully cover the whole area of organic semiconductors. Nevertheless, we hope that the reader will find the collection of topics in this issue useful for getting an up-to-date review of a field which is still developing very dynamically.

  10. Method for sputtering a PIN microcrystalline/amorphous silicon semiconductor device with the P and N-layers sputtered from boron and phosphorous heavily doped targets

    DOEpatents

    Moustakas, Theodore D.; Maruska, H. Paul

    1985-04-02

    A silicon PIN microcrystalline/amorphous silicon semiconductor device is constructed by the sputtering of N, and P layers of silicon from silicon doped targets and the I layer from an undoped target, and at least one semi-transparent ohmic electrode.

  11. SEMICONDUCTOR DEVICES: A high-performance enhancement-mode AlGaN/GaN HEMT

    NASA Astrophysics Data System (ADS)

    Zhihong, Feng; Shengyin, Xie; Rui, Zhou; Jiayun, Yin; Wei, Zhou; Shujun, Cai

    2010-08-01

    An enhancement-mode AlGaN/GaN HEMT with a threshold voltage of 0.35 V was fabricated by fluorine plasma treatment. The enhancement-mode device demonstrates high-performance DC characteristics with a saturation current density of 667 mA/mm at a gate bias of 4 V and a peak transconductance of 201 mS/mm at a gate bias of 0.8 V. The current-gain cut-off frequency and the maximum oscillation frequency of the enhancement-mode device with a gate length of 1 μm are 10.3 GHz and 12.5 GHz, respectively, which is comparable with the depletion-mode device. A numerical simulation supported by SIMS results was employed to give a reasonable explanation that the fluorine ions act as an acceptor trap center in the barrier layer.

  12. SEMICONDUCTOR DEVICES A compressed wide period-tunable grating working at low voltage

    NASA Astrophysics Data System (ADS)

    Xiang, Liu; Tie, Li; Anjie, Ming; Yuelin, Wang

    2010-10-01

    A MEMS compressed period-tunable grating device with a wide tuning range has been designed, fabricated and characterized. To increase the tuning range, avoid instability with tuning and improve the performance, we propose in this paper a period-tunable grating which is compressed by large-displacement comb actuators with tilted folded beams. The experimental results show that the designed grating device has a compression range of up to 144 μm within 37 V driving voltage. The period of the grating can be adjusted continuously from 16 to 14 μm with a tuning range of 12.5%. The maximum tuning range of the first-order diffraction angle is 0.34° at 632.8 nm and the reflectivity of the grating is more than 92.6% in the mid-infrared region. The grating device can be fabricated by simple processes and finds applications in mid-infrared spectrometers.

  13. SEMICONDUCTOR DEVICES Nanoscale strained-Si MOSFET physics and modeling approaches: a review

    NASA Astrophysics Data System (ADS)

    Chaudhry, Amit; Roy, J. N.; Joshi, Garima

    2010-10-01

    An attempt has been made to give a detailed review of strained silicon technology. Various device models have been studied that consider the effect of strain on the devices, and comparisons have been drawn. A review of some modeling issues in strained silicon technology has also been outlined. The review indicates that this technology is very much required in nanoscale MOSFETs due to its several potential benefits, and there is a strong need for an analytical model which describes the complete physics of the strain technology.

  14. Impact of Air Filter Material on Metal Oxide Semiconductor (MOS) Device Characteristics in HF Vapor Environment

    NASA Astrophysics Data System (ADS)

    Hsiao, Chih-Wen; Lou, Jen-Chung; Yeh, Ching-Fa; Hsieh, Chih-Ming; Lin, Shiuan-Jeng; Kusumi, Toshio

    2004-05-01

    Airborne molecular contamination (AMC) is becoming increasingly important as devices are scaled down to the nanometer generation. Optimum ultra low penetration air (ULPA) filter technology can eliminate AMC. In a cleanroom, however, the acid vapor generated from the cleaning process may degrade the ULPA filter, releasing AMC to the air and the surface of wafers, degrading the electrical characteristics of devices. This work proposes the new PTFE ULPA filter, which is resistant to acid vapor corrosion, to solve this problem. Experimental results demonstrate that the PTFE ULPA filter can effectively eliminate the AMC and provide a very clean cleanroom environment.

  15. SEMICONDUCTOR DEVICES Thermal analysis of the cavity facet for an 808 nm semiconductor laser by using near-field scanning optical microscopy

    NASA Astrophysics Data System (ADS)

    Lan, Rao; Guofeng, Song; Lianghui, Chen

    2010-10-01

    In order to analyze the thermal characteristics of the cavity facet of a semiconductor laser, a home-built near-field scanning optical microscopy (NSOM) is employed to probe the topography of the facet. By comparing the topographic images of two samples under different DC current injections, we can find that the thermal characteristic is related to its lifetime. We show that it is possible to predict the lifetime of the semiconductor laser diode with non-destructive tests.

  16. Improvement of process control using wafer geometry for enhanced manufacturability of advanced semiconductor devices

    NASA Astrophysics Data System (ADS)

    Lee, Honggoo; Lee, Jongsu; Kim, Sang Min; Lee, Changhwan; Han, Sangjun; Kim, Myoungsoo; Kwon, Wontaik; Park, Sung-Ki; Vukkadala, Pradeep; Awasthi, Amartya; Kim, J. H.; Veeraraghavan, Sathish; Choi, DongSub; Huang, Kevin; Dighe, Prasanna; Lee, Cheouljung; Byeon, Jungho; Dey, Soham; Sinha, Jaydeep

    2015-03-01

    Aggressive advancements in semiconductor technology have resulted in integrated chip (IC) manufacturing capability at sub-20nm half-pitch nodes. With this, lithography overlay error budgets are becoming increasingly stringent. The delay in EUV lithography readiness for high volume manufacturing (HVM) and the need for multiple-patterning lithography with 193i technology has further amplified the overlay issue. Thus there exists a need for technologies that can improve overlay errors in HVM. The traditional method for reducing overlay errors predominantly focused on improving lithography scanner printability performance. However, processes outside of the lithography sector known as processinduced overlay errors can contribute significantly to the total overlay at the current requirements. Monitoring and characterizing process-induced overlay has become critical for advanced node patterning. Recently a relatively new technique for overlay control that uses high-resolution wafer geometry measurements has gained significance. In this work we present the implementation of this technique in an IC fabrication environment to monitor wafer geometry changes induced across several points in the process flow, of multiple product layers with critical overlay performance requirement. Several production wafer lots were measured and analyzed on a patterned wafer geometry tool. Changes induced in wafer geometry as a result of wafer processing were related to down-stream overlay error contribution using the analytical in-plane distortion (IPD) calculation model. Through this segmentation, process steps that are major contributors to down-stream overlay were identified. Subsequent process optimization was then isolated to those process steps where maximum benefit might be realized. Root-cause for the within-wafer, wafer-to-wafer, tool-to-tool, and station-to-station variations observed were further investigated using local shape curvature changes - which is directly related to

  17. 21 CFR 890.5050 - Daily activity assist device.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Daily activity assist device. 890.5050 Section 890.5050 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5050 Daily...

  18. 21 CFR 890.5050 - Daily activity assist device.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Daily activity assist device. 890.5050 Section 890.5050 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5050 Daily...

  19. 21 CFR 890.5050 - Daily activity assist device.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Daily activity assist device. 890.5050 Section 890.5050 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5050 Daily...

  20. 21 CFR 890.5050 - Daily activity assist device.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Daily activity assist device. 890.5050 Section 890.5050 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5050 Daily...

  1. 21 CFR 890.5050 - Daily activity assist device.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Daily activity assist device. 890.5050 Section 890.5050 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5050 Daily...

  2. Influence of majority carrier bandtails on the performance of semiconductor devices

    NASA Astrophysics Data System (ADS)

    Van Mieghem, P.; Decoutere, S.; Borghs, G.; Mertens, R.

    1992-05-01

    A model for bandtailing is built into the 1-D device simulator SEDAN. The influence of bandtails on the current gain of a state-of-the-art bipolar transistor is examined. It is shown that for transistors with high emitter doping, bandtail effects decrease the current gain significantly. This reduction in current gain is more pronounced at low temperature.

  3. Total-dose radiation effects data for semiconductor devices, volume 3

    NASA Technical Reports Server (NTRS)

    Price, W. E.; Martin, K. E.; Nichols, D. K.; Gauthier, M. K.; Brown, S. F.

    1982-01-01

    Volume 3 of this three-volume set provides a detailed analysis of the data in Volumes 1 and 2, most of which was generated for the Galileo Orbiter Program in support of NASA space programs. Volume 1 includes total ionizing dose radiation test data on diodes, bipolar transistors, field effect transistors, and miscellaneous discrete solid-state devices. Volume 2 includes similar data on integrated circuits and a few large-scale integrated circuits. The data of Volumes 1 and 2 are combined in graphic format in Volume 3 to provide a comparison of radiation sensitivities of devices of a given type and different manufacturer, a comparison of multiple tests for a single data code, a comparison of multiple tests for a single lot, and a comparison of radiation sensitivities vs time (date codes). All data were generated using a steady-state 2.5-MeV electron source (Dynamitron) or a Cobalt-60 gamma ray source. The data that compose Volume 3 represent 26 different device types, 224 tests, and a total of 1040 devices. A comparison of the effects of steady-state electrons and Cobat-60 gamma rays is also presented.

  4. Total-dose radiation effects data for semiconductor devices, volume 3

    NASA Astrophysics Data System (ADS)

    Price, W. E.; Martin, K. E.; Nichols, D. K.; Gauthier, M. K.; Brown, S. F.

    1982-09-01

    Volume 3 of this three-volume set provides a detailed analysis of the data in Volumes 1 and 2, most of which was generated for the Galileo Orbiter Program in support of NASA space programs. Volume 1 includes total ionizing dose radiation test data on diodes, bipolar transistors, field effect transistors, and miscellaneous discrete solid-state devices. Volume 2 includes similar data on integrated circuits and a few large-scale integrated circuits. The data of Volumes 1 and 2 are combined in graphic format in Volume 3 to provide a comparison of radiation sensitivities of devices of a given type and different manufacturer, a comparison of multiple tests for a single data code, a comparison of multiple tests for a single lot, and a comparison of radiation sensitivities vs time (date codes). All data were generated using a steady-state 2.5-MeV electron source (Dynamitron) or a Cobalt-60 gamma ray source. The data that compose Volume 3 represent 26 different device types, 224 tests, and a total of 1040 devices. A comparison of the effects of steady-state electrons and Cobat-60 gamma rays is also presented.

  5. Semiconductor diode laser material and devices with emission in visible region of the spectrum

    NASA Technical Reports Server (NTRS)

    Ladany, I.; Kressel, H.

    1975-01-01

    Two alloy systems, (AlGa)As and (InGa)P, were studied for their properties relevant to obtaining laser diode operation in the visible region of the spectrum. (AlGa)As was prepared by liquid-phase epitaxy (LPE) and (InGa)P was prepared both by vapor-phase epitaxy and by liquid-phase epitaxy. Various schemes for LPE growth were applied to (InGa)P, one of which was found to be capable of producing device material. All the InGaP device work was done using vapor-phase epitaxy. The most successful devices were fabricated in (AlGa)As using heterojunction structures. At room temperature, the large optical cavity design yielded devices lasing in the red (7000 A). Because of the relatively high threshold due to the basic band structure limitation in this alloy, practical laser diode operation is presently limited to about 7300 A. At liquid-nitrogen temperature, practical continuous-wave operation was obtained at a wavelength of 6500 to 6600 A, with power emission in excess of 50 mW. The lowest pulsed lasing wavelength is 6280 A. At 223 K, lasing was obtained at 6770 A, but with high threshold currents. The work dealing with CW operation at room temperature was successful with practical operation having been achieved to about 7800 A.

  6. Graphene active plasmonics for terahertz device applications

    NASA Astrophysics Data System (ADS)

    Otsuji, Taiichi; Dubinov, Alexander; Ryzhii, Maxim; Boubanga Tombet, Stephane; Satou, Akira; Mitin, Vladimir; Shur, Michael S.; Ryzhii, Victor

    2015-05-01

    This paper reviews recent advances in the double-graphene-layer (DGL) active plasmonic heterostructures for the terahertz (THz) device applications. The DGL consists of a core shell in which a thin tunnel barrier layer is sandwiched by the two GLs being independently connected with the side contacts and outer gate stack layers at both sides. The DGL core shell works as a nano-capacitor, exhibiting inter-GL resonant tunneling (RT) when the band offset between the two GLs is aligned. The RT produces a strong nonlinearity with a negative differential conductance in the DGL current-voltage characteristics. The excitation of the graphene plasmons by the THz radiation resonantly modulates the tunneling currentvoltage characteristics. When the band offset is aligned to the THz photon energy, the DGL structure can mediate photonassisted RT, resulting in resonant emission or detection of the THz radiation. The cooperative double-resonant excitation with structure-sensitive graphene plasmons gives rise to various functionalities such as rectification (detection), photomixing, higher harmonic generation, and self-oscillation, in the THz device implementations.

  7. Stress-induced Effects Caused by 3D IC TSV Packaging in Advanced Semiconductor Device Performance

    SciTech Connect

    Sukharev, V.; Kteyan, A.; Choy, J.-H.; Hovsepyan, H.; Markosian, A.; Zschech, E.; Huebner, R.

    2011-11-10

    Potential challenges with managing mechanical stress and the consequent effects on device performance for advanced 3D through-silicon-via (TSV) based technologies are outlined. The paper addresses the growing need in a simulation-based design verification flow capable to analyze a design of 3D IC stacks and to determine across-die out-of-spec variations in device electrical characteristics caused by the layout and through-silicon-via (TSV)/package-induced mechanical stress. The limited characterization/measurement capabilities for 3D IC stacks and a strict ''good die'' requirement make this type of analysis critical for the achievement of an acceptable level of functional and parametric yield and reliability. The paper focuses on the development of a design-for-manufacturability (DFM) type of methodology for managing mechanical stresses during a sequence of designs of 3D TSV-based dies, stacks and packages. A set of physics-based compact models for a multi-scale simulation to assess the mechanical stress across the device layers in silicon chips stacked and packaged with the 3D TSV technology is proposed. A calibration technique based on fitting to measured stress components and electrical characteristics of the test-chip devices is presented. A strategy for generation of a simulation feeding data and respective materials characterization approach are proposed, with the goal to generate a database for multi-scale material parameters of wafer-level and package-level structures. For model validation, high-resolution strain measurements in Si channels of the test-chip devices are needed. At the nanoscale, the transmission electron microscopy (TEM) is the only technique available for sub-10 nm strain measurements so far.

  8. Screening of inorganic wide-bandgap p-type semiconductors for high performance hole transport layers in organic photovoltaic devices

    NASA Astrophysics Data System (ADS)

    Ginley, David; Zakutayev, Andriy; Garcia, Andreas; Widjonarko, Nicodemus; Ndione, Paul; Sigdel, Ajaya; Parilla, Phillip; Olson, Dana; Perkins, John; Berry, Joseph

    2011-03-01

    We will report on the development of novel inorganic hole transport layers (HTL) for organic photovoltaics (OPV). All the studied materials belong to the general class of wide-bandgap p-type oxide semiconductors. Potential candidates suitable for HTL applications include SnO, NiO, Cu2O (and related CuAlO2, CuCrO2, SrCu2O4 etc) and Co3O4 (and related ZnCo2O4, NiCo2O4, MgCo2O4 etc.). Materials have been optimized by high-throughput combinatorial approaches. The thin films were deposited by RF sputtering and pulsed laser deposition at ambient and elevated temperatures. Performance of the inorganic HTLs and that of the reference organic PEDOT:PSS HTL were compared by measuring the power conversion efficiencies and spectral responses of the P3HT/PCBM- and PCDTBT/PCBM-based OPV devices. Preliminary results indicate that Co3O4-based HTLs have performance comparable to that of our previously reported NiOs and PEDOT:PSS HTLs, leading to a power conversion efficiency of about 4 percent. The effect of composition and work function of the ternary materials on their performance in OPV devices is under investigation.

  9. Nanoscale-driven crystal growth of hexaferrite heterostructures for magnetoelectric tuning of microwave semiconductor integrated devices.

    PubMed

    Hu, Bolin; Chen, Zhaohui; Su, Zhijuan; Wang, Xian; Daigle, Andrew; Andalib, Parisa; Wolf, Jason; McHenry, Michael E; Chen, Yajie; Harris, Vincent G

    2014-11-25

    A nanoscale-driven crystal growth of magnetic hexaferrites was successfully demonstrated at low growth temperatures (25-40% lower than the temperatures required often for crystal growth). This outcome exhibits thermodynamic processes of crystal growth, allowing ease in fabrication of advanced multifunctional materials. Most importantly, the crystal growth technique is considered theoretically and experimentally to be universal and suitable for the growth of a wide range of diverse crystals. In the present experiment, the conical spin structure of Co2Y ferrite crystals was found to give rise to an intrinsic magnetoelectric effect. Our experiment reveals a remarkable increase in the conical phase transition temperature by ∼150 K for Co2Y ferrite, compared to 5-10 K of Zn2Y ferrites recently reported. The high quality Co2Y ferrite crystals, having low microwave loss and magnetoelectricity, were successfully grown on a wide bandgap semiconductor GaN. The demonstration of the nanostructure materials-based "system on a wafer" architecture is a critical milestone to next generation microwave integrated systems. It is also practical that future microwave integrated systems and their magnetic performances could be tuned by an electric field because of the magnetoelectricity of hexaferrites.

  10. Reactively-sputtered zinc semiconductor films of high conductivity for heterojunction devices

    NASA Technical Reports Server (NTRS)

    Stirn, Richard J. (Inventor)

    1986-01-01

    A high conductivity, n-doped semiconductor film is produced from zinc, or Zn and Cd, and group VI elements selected from Se, S and Te in a reactive magnetron sputtering system having a chamber with one or two targets, a substrate holder, means for heating the substrate holder, and an electric field for ionizing gases in the chamber. Zinc or a compound of Zn and Cd is placed in the position of one of the two targets and doping material in the position of the other of the two targets. Zn and Cd may be placed in separate targets while a dopant is placed in the third target. Another possibility is to place an alloy of Zn and dopant, or Zn, Cd and dopant in one target, thus using only one target. A flow of the inert gas is ionized and directed toward said targets, while a flow of a reactant gas consisting of hydrides of the group VI elements is directed toward a substrate on the holder. The targets are biased to attract negatively ionized inert gas. The desired stochiometry for high conductivity is achieved by controlling the temperature of the substrate, and partial pressures of the gases, and the target power and total pressure of the gases in the chamber.

  11. Ultrafast-laser-induced surface texturing and crystallization of semiconductors for photovoltaic devices

    NASA Astrophysics Data System (ADS)

    Nayak, Barada K.

    This dissertation discusses the development of a novel laser texturing method that enables fabrication of unique nano/micro surface structures in different material systems and their applications. The primary application described in this work is on the development of improved photovoltaic cells. The interaction of ultrafast lasers in the presence of different reactive and inert gases leads towards formation of nearly regular arrays of conical microstructures (and in some cases nanospikes atop microstructures). These textured surfaces trap the incident light very efficiently in a very broad spectrum (almost 100% over the entire solar spectrum and around 95% in the infrared spectral range of 2.5-25 mum for silicon) and the material looks pitch dark to bare eye. We thoroughly investigated the role of different gases and laser parameters on the formation of these structures and their applications. Laser texturing and crystallization can be achieved as a one step process for amorphous thin film silicon for photovoltaic application. We have also demonstrated the unique capability of low cost semiconductor laser for crystallizing thick silicon films for photovoltaic applications. Laser texturing and crystallization technique has been applied to fabricate efficient thin film solar cells. Encouraging results for cells fabricated in bulk textured silicon has also been observed. Additionally, we have demonstrated three unique applications of this texturing technology: (a) producing superhydrophobic surfaces in titanium and stainless steel; (b) fabrication of arrays of micro/nano holes in silicon; (c) growth and proliferation of stem cells in textured titanium surfaces.

  12. Gate-control efficiency and interface state density evaluated from capacitance-frequency-temperature mapping for GaN-based metal-insulator-semiconductor devices

    SciTech Connect

    Shih, Hong-An; Kudo, Masahiro; Suzuki, Toshi-kazu

    2014-11-14

    We present an analysis method for GaN-based metal-insulator-semiconductor (MIS) devices by using capacitance-frequency-temperature (C-f-T) mapping to evaluate the gate-control efficiency and the interface state density, both exhibiting correlations with the linear-region intrinsic transconductance. The effectiveness of the method was exemplified by application to AlN/AlGaN/GaN MIS devices to elucidate the properties of AlN-AlGaN interfaces depending on their formation processes. Using the C-f-T mapping, we extract the gate-bias-dependent activation energy with its derivative giving the gate-control efficiency, from which we evaluate the AlN-AlGaN interface state density through the Lehovec equivalent circuit in the DC limit. It is shown that the gate-control efficiency and the interface state density have correlations with the linear-region intrinsic transconductance, all depending on the interface formation processes. In addition, we give characterization of the AlN-AlGaN interfaces by using X-ray photoelectron spectroscopy, in relation with the results of the analysis.

  13. Low-frequency noise in AlN/AlGaN/GaN metal-insulator-semiconductor devices: A comparison with Schottky devices

    SciTech Connect

    Le, Son Phuong; Nguyen, Tuan Quy; Shih, Hong-An; Kudo, Masahiro; Suzuki, Toshi-kazu

    2014-08-07

    We have systematically investigated low-frequency noise (LFN) in AlN/AlGaN/GaN metal-insulator-semiconductor (MIS) devices, where the AlN gate insulator layer was sputtering-deposited on the AlGaN surface, in comparison with LFN in AlGaN/GaN Schottky devices. By measuring LFN in ungated two-terminal devices and heterojunction field-effect transistors (HFETs), we extracted LFN characteristics in the intrinsic gated region of the HFETs. Although there is a bias regime of the Schottky-HFETs in which LFN is dominated by the gate leakage current, LFN in the MIS-HFETs is always dominated by only the channel current. Analyzing the channel-current-dominated LFN, we obtained Hooge parameters α for the gated region as a function of the sheet electron concentration n{sub s} under the gate. In a regime of small n{sub s}, both the MIS- and Schottky-HFETs exhibit α∝n{sub s}{sup −1}. On the other hand, in a middle n{sub s} regime of the MIS-HFETs, α decreases rapidly like n{sub s}{sup −ξ} with ξ ∼ 2-3, which is not observed for the Schottky-HFETs. In addition, we observe strong increase in α∝n{sub s}{sup 3} in a large n{sub s} regime for both the MIS- and Schottky-HFETs.

  14. Heavy ion induced Single Event Phenomena (SEP) data for semiconductor devices from engineering testing

    NASA Technical Reports Server (NTRS)

    Nichols, Donald K.; Huebner, Mark A.; Price, William E.; Smith, L. S.; Coss, James R.

    1988-01-01

    The accumulation of JPL data on Single Event Phenomena (SEP), from 1979 to August 1986, is presented in full report format. It is expected that every two years a supplement report will be issued for the follow-on period. This data for 135 devices expands on the abbreviated test data presented as part of Refs. (1) and (3) by including figures of Single Event Upset (SEU) cross sections as a function of beam Linear Energy Transfer (LET) when available. It also includes some of the data complied in the JPL computer in RADATA and the SPACERAD data bank. This volume encompasses bipolar and MOS (CMOS and MHNOS) device data as two broad categories for both upsets (bit-flips) and latchup. It also includes comments on less well known phenomena, such as transient upsets and permanent damage modes.

  15. Evaluation of radiation damage to Metal-Oxide-Semiconductor (MOS) devices

    NASA Astrophysics Data System (ADS)

    1982-12-01

    The purpose of these experiments was to provide qualitative and quantitative information on the effects of various hydrogen and nitrogen annealing treatments on the radiation hardness, or resistivity to damage, of MOS capacitors. Toward this end, the following tasks were performed: Construction of capacitor TO-5 packages for device evaluation; The experimental determination of the 1 MHz capacitance-voltage bias curves for both the pre- and post-irradiated capacitors; Evaluation of the change in Flat Band Voltage (Delta V sub fb) for the pre- and post-radiation stressed devices; Compilation of all 1 MHz data for cataloging purposes and the establishment of a benchmark for the new computer automated test system; and Reported data to the Contracting Officer's Technical Representative (COTR) on a case-by-case basis, as time was of the essence.

  16. SEMICONDUCTOR DEVICES: Analysis of trigger behavior of high voltage LDMOS under TLP and VFTLP stress

    NASA Astrophysics Data System (ADS)

    Jing, Zhu; Qinsong, Qian; Weifeng, Sun; Siyang, Liu

    2010-01-01

    The physical mechanisms triggering electrostatic discharge (ESD) in high voltage LDMOS power transistors (> 160 V) under transmission line pulsing (TLP) and very fast transmission line pulsing (VFTLP) stress are investigated by TCAD simulations using a set of macroscopic physical models related to previous studies implemented in Sentaurus Device. Under VFTLP stress, it is observed that the triggering voltage of the high voltage LDMOS obviously increases, which is a unique phenomenon compared with the low voltage ESD protection devices like NMOS and SCR. The relationship between the triggering voltage increase and the parasitic capacitances is also analyzed in detail. A compact equivalent circuit schematic is presented according to the investigated phenomena. An improved structure to alleviate this effect is also proposed and confirmed by the experiments.

  17. Cathodoluminescence observation of SiO2 layers in a semiconductor device

    NASA Astrophysics Data System (ADS)

    Koyama, H.

    1980-04-01

    Dispersive cathodoluminescence images from thin films of SiO2 in a Test-Element-Group pattern of a conventional Large Scale Integrated circuit device were observed. Band A (290 nm) and band C (560 nm) of the cathodoluminescence were characteristic of a thermally grown SiO2 covered with chemically vapor-deposited (CVD) SiO2 and may be useful for the study of irradiation induced damages in SiO2. Band B (415 nm) and band D (650 nm) were intense in the surface CVD SiO2 and may provide information on process induced impurities in SiO2 layers. The spatial resolution of a cathodoluminescence image is 2 μm, and it is possible to survey SiO2 layers on a conventional LSI device with this technique.

  18. The Effects of Thermal Cycling on Gallium Nitride and Silicon Carbide Semiconductor Devices for Aerospace Use

    NASA Technical Reports Server (NTRS)

    Patterson, Richard L.; Hammoud, Ahmad

    2012-01-01

    Electronics designed for use in NASA space missions are required to work efficiently and reliably under harsh environment conditions. These Include radiation, extreme temperatures, thermal cycling, to name a few. Preliminary data obtained on new Gallium Nitride and Silicon Carbide power devices under exposure to radiation followed by long term thermal cycling are presented. This work was done in collaboration with GSFC and JPL in support of the NASA Electronic Parts and Packaging (NEPP) Program

  19. Application of the transition semiconductor semimetal in modulated nanostructures for communication as infrared optoelectronic device

    NASA Astrophysics Data System (ADS)

    El Abidi, A.; Nafidi, A.; Chaib, H.; El Kaaouachi, A.; Braigue, M.; Morghi, R.; EL Yakoubi, E. Y.; d'Astuto, M.

    2010-02-01

    We report here electronic properties of a two-dimensional modulated superlattice nanostructure. Our sample, grown by MBE, had a period d= d1+ d2 (90 layers) of d1=5.6 nm (HgTe)/ d2=3 nm (CdTe). Calculations of the specters of energy E( d2), E( k z) and E( kp), respectively, in the direction of growth and in plane of the superlattice; were performed in the envelope function formalism. The energy E ( d2, Γ, 4.2 K,), shown that for each d1/ d2, when d2 increase the gap Eg decrease to zero at the transition semiconductor to semimetal conductivity behavior and become negative accusing a semimetallic conduction. At 4.2 K, the sample exhibits p type conductivity with a Hall mobility of 8200 cm 2/Vs. This allowed us to observe the Shubnikov-de Haas effect with p=1.80×10 12 cm -2. Using the calculated effective mass (mHH*=0,297m0) of the degenerated heavy holes gas, the Fermi energy (2D) was EF=14 meV in agreement with 12 meV of thermoelectric power α. In intrinsic regime, α∼ T-3/2 and RHT3/2 indicates a gap Eg= E1- HH1=190 meV in agreement with calculated Eg ( Γ, 300 K)=178 meV. The formalism used here predicts that this sample is a narrow gap, two-dimensional modulated nanostructure and medium-infrared detector.

  20. Active terahertz metamaterials

    SciTech Connect

    Chen, Hou-tong

    2009-01-01

    We demonstrate planar terahertz metamaterial devices enabling actively controllable transmission amplitude, phase, or frequency at room temperature via carrier depletion or photoexcitation in the semiconductor substrate or in semiconductor materials incorporated into the metamaterial structure.

  1. Method for making photovoltaic devices using oxygenated semiconductor thin film layers

    SciTech Connect

    Johnson, James Neil; Albin, David Scott; Feldman-Peabody, Scott; Pavol, Mark Jeffrey; Gossman, Robert Dwayne

    2014-12-16

    A method for making a photovoltaic device is presented. The method includes steps of disposing a window layer on a substrate and disposing an absorber layer on the window layer. Disposing the window layer, the absorber layer, or both layers includes introducing a source material into a deposition zone, wherein the source material comprises oxygen and a constituent of the window layer, of the absorber layer or of both layers. The method further includes step of depositing a film that comprises the constituent and oxygen.

  2. SEMICONDUCTOR DEVICES Intrinsic stability of an HBT based on a small signal equivalent circuit model

    NASA Astrophysics Data System (ADS)

    Yanhu, Chen; Huajun, Shen; Xinyu, Liu; Huijun, Li; Hui, Xu; Ling, Li

    2010-12-01

    Intrinsic stability of the heterojunction bipolar transistor (HBT) was analyzed and discussed based on a small signal equivalent circuit model. The stability factor of the HBT device was derived based on a compact T-type small signal equivalent circuit model of the HBT. The effect of the mainly small signal model parameters of the HBT on the stability of the HBT was thoroughly examined. The discipline of parameter optimum to improve the intrinsic stability of the HBT was achieved. The theoretic analysis results of the stability were also used to explain the experimental results of the stability of the HBT and they were verified by the experimental results.

  3. SEMICONDUCTOR DEVICES: A symbolically defined InP double heterojunction bipolar transistor large-signal model

    NASA Astrophysics Data System (ADS)

    Yuxiong, Cao; Zhi, Jin; Ji, Ge; Yongbo, Su; Xinyu, Liu

    2009-12-01

    A self-built accurate and flexible large-signal model based on an analysis of the characteristics of InP double heterojunction bipolar transistors (DHBTs) is implemented as a seven-port symbolically defined device (SDD) in Agilent ADS. The model accounts for most physical phenomena including the self-heating effect, Kirk effect, soft knee effect, base collector capacitance and collector transit time. The validity and the accuracy of the large-signal model are assessed by comparing the simulation with the measurement of DC, multi-bias small signal S parameters for InP DHBTs.

  4. Damage correlations in semiconductor devices exposed to gamma and high energy swift heavy ions

    NASA Astrophysics Data System (ADS)

    Pushpa, N.; Prakash, A. P. Gnana

    2015-05-01

    NPN rf power transistors and N-channel depletion MOSFETs are irradiated by different high energy swift heavy ions and 60Co gamma radiation in the dose range of 100 krad to 100 Mrad. The damage created by different heavy ions and 60Co gamma radiation in NPN rf power transistors and N-channel depletion MOSFETs have been correlated and studied in the same dose range. The recoveries in the electrical characteristics of different swift heavy ions and 60Co gamma irradiated devices have been studied after annihilation.

  5. Recipient luminophoric mediums having narrow spectrum luminescent materials and related semiconductor light emitting devices and methods

    DOEpatents

    LeToquin, Ronan P; Tong, Tao; Glass, Robert C

    2014-12-30

    Light emitting devices include a light emitting diode ("LED") and a recipient luminophoric medium that is configured to down-convert at least some of the light emitted by the LED. In some embodiments, the recipient luminophoric medium includes a first broad-spectrum luminescent material and a narrow-spectrum luminescent material. The broad-spectrum luminescent material may down-convert radiation emitted by the LED to radiation having a peak wavelength in the red color range. The narrow-spectrum luminescent material may also down-convert radiation emitted by the LED into the cyan, green or red color range.

  6. Damage correlations in semiconductor devices exposed to gamma and high energy swift heavy ions

    SciTech Connect

    Pushpa, N.; Prakash, A. P. Gnana

    2015-05-15

    NPN rf power transistors and N-channel depletion MOSFETs are irradiated by different high energy swift heavy ions and {sup 60}Co gamma radiation in the dose range of 100 krad to 100 Mrad. The damage created by different heavy ions and {sup 60}Co gamma radiation in NPN rf power transistors and N-channel depletion MOSFETs have been correlated and studied in the same dose range. The recoveries in the electrical characteristics of different swift heavy ions and {sup 60}Co gamma irradiated devices have been studied after annihilation.

  7. Effects of Activation Energy to Transient Response of Semiconductor Gas Sensor

    NASA Astrophysics Data System (ADS)

    Fujimoto, Akira; Ohtani, Tatsuki

    The smell classifiable gas sensor will be desired for many applications such as gas detection alarms, process controls for food production and so on. We have tried to realize the sensor using transient responses of semiconductor gas sensor consisting of tin dioxide and pointed out that the sensor gave us different transient responses for kinds of gas. Results of model calculation showed the activation energy of chemical reaction on the sensor surface strongly depended on the transient response. We tried to estimate the activation energies by molecular orbital calculation with SnO2 Cluster. The results show that there is a liner relationship between the gradient of the transient responses and activation energies for carboxylic and alcoholic gases. Transient response will be predicted from activation energy in the same kind of gas and the smell discrimination by single semiconductor gas sensor will be realized by this relationship.

  8. SEMICONDUCTOR DEVICES: A process simplification scheme for fabricating CMOS polycrystalline-Si thin film transistors

    NASA Astrophysics Data System (ADS)

    Miin-Horng, Juang; Chia-Wei, Chang; Der-Chih, Shye; Chuan-Chou, Hwang; Jih-Liang, Wang; Sheng-Liang, Jang

    2010-06-01

    A process simplification scheme for fabricating CMOS poly-Si thin-film transistors (TFTs) has been proposed, which employs large-angle-tilt-implantation of dopant through a gate sidewall spacer (LATITS). By this LATITS scheme, a lightly doped drain region under the oxide spacer is formed by low-dose tilt implantation of phosphorus (or boron) dopant through the spacer, and then the n+-source/drain (n+-S/D) (or p+-S/D) region is formed via using the same photo-mask layer during CMOS integration. For both n-TFT and p-TFT devices, as compared to the sample with conventional single n+-S/D (or p+-S/D) structure, the LATITS scheme can cause an obviously smaller leakage current, due to more gradual dopant distribution and thus smaller electric field. In addition, the resultant on-state currents only show slight degradation for the LATITS scheme. As a result, by the LATITS scheme, CMOS poly-Si TFT devices with an on/off current ratio well above 8 orders may be achieved without needing extra photo-mask layers during CMOS integration.

  9. Epitaxial Growth of Icosahedral Boride Semiconductors for Novel Energy Conversion Devices

    SciTech Connect

    Edgar, J.H.

    2006-01-03

    The chemical vapor deposition and properties of the boron-rich semiconductors B12As2 and B12P2 on 6H-SiC(0001) and silicon substrates were investigated. Crystalline, stoichiometric films were deposited between 1200 C and 1500 C using two types of reactants, hydrides (B2H6 and AsH3) for B12As2 and halides (BBr3 and PBr3) for B12P2. 6H-SiC proved to be the better substrate for B12As2 heteroepitaxy, in terms of the residual impurity concentrations. Films on Si substrates suffered from high concentrations of Si (up to 4at.%); in contrast, the Si and C concentrations in the B12As2 films deposited on 6H-SiC at 1300 C were at or below the detection limits of secondary ion mass spectrometry (SIMS). The deposition temperature was significant as films deposited at 1450 C contained high residual C and Si concentrations (>1020 cm-3), probably due to the decomposition of the substrate. The hydrogen concentration in all B12As2 films was relatively high, with a minimum concentration of 3x1019 cm-3 in undoped B12As2. SIMS measurements showed that the hydrogen concentration was directly proportional to and tracked the Si concentration, reaching values as high as 3 x 1020 cm-3. The structural properties of the B12As2 films were characterized by x-ray diffraction and transmission electron microscopy. The FWHM of typical high resolution x-ray rocking curves for the (333) peaks of the B12As2 films were 800 arcsec. The films are under tensile strain due the higher coefficient of thermal expansion for B12As2 than SiC. Rotational twins were present in B12As2 films deposited on (0001) oriented 6H-SiC substrates, as revealed by cross-sectional TEM and x-ray diffraction pole figures. While the c-plane 6H-SiC has six-fold rotational symmetry, rhombohedral B12As2 has only 3-fold symmetry (along its (111) axis), thus it randomly nucleates with two different in-plane orientations. The electrical properties of undoped and silicon-doped B12As2 deposited on semi-insulating 6H-SiC substrates were

  10. Compound Semiconductor Devices for Low-Power High-Efficiency Radio Frequency Electronics

    SciTech Connect

    Baca, A.G.; Chang, P.C.; Hietala, V.M.; Sloan, L.R.

    1999-02-18

    The power consumption of Radio Frequency (RF) electronics is a significant issue for Wireless systems. Since most wireless systems are portable and thus battery operated, reductions in DC power consumption can significantly reduce the weight and/or increase the battery lifetime of the system. As transmission consumes significantly more power than reception for most Wireless applications, previous efforts have been focused on increasing the efficiency of RF power amplification. These efforts have resulted in large increases in transmit efficiencies with research-grade amplifier efficiencies approaching 100%. In this paper, they describe their efforts on reducing power consumption of reception and other small signal RF functions. Additionally, recent power efficiency measurements on InP HEMT devices for transmission are presented. This work focuses on the needs of today's typical portable Wireless systems, which operate at frequencies up to several GHz.

  11. SEMICONDUCTOR DEVICES: Analysis of a wavelength selectable cascaded DFB laser based on the transfer matrix method

    NASA Astrophysics Data System (ADS)

    Hongyun, Xie; Liang, Chen; Pei, Shen; Botao, Sun; Renqing, Wang; Ying, Xiao; Yunxia, You; Wanrong, Zhang

    2010-06-01

    A novel cascaded DFB laser, which consists of two serial gratings to provide selectable wavelengths, is presented and analyzed by the transfer matrix method. In this method, efficient facet reflectivity is derived from the transfer matrix built for each serial section and is then used to simulate the performance of the novel cascaded DFB laser through self-consistently solving the gain equation, the coupled wave equation and the current continuity equations. The simulations prove the feasibility of this kind of wavelength selectable laser and a corresponding designed device with two selectable wavelengths of 1.51 μm and 1.53 μm is realized by experiments on InP-based multiple quantum well structure.

  12. SEMICONDUCTOR DEVICES MEMS magnetic field sensor based on silicon bridge structure

    NASA Astrophysics Data System (ADS)

    Guangtao, Du; Xiangdong, Chen; Qibin, Lin; Hui, Li; Huihui, Guo

    2010-10-01

    A MEMS piezoresistive magnetic field sensor based on a silicon bridge structure has been simulated and tested. The sensor consists of a silicon sensitivity diaphragm embedded with a piezoresistive Wheatstone bridge, and a ferromagnetic magnet adhered to the sensitivity diaphragm. When the sensor is subjected to an external magnetic field, the magnetic force bends the silicon sensitivity diaphragm, producing stress and resistors change of the Wheatstone bridge and the output voltage of the sensor. Good agreement is observed between the theory and measurement behavior of the magnetic field sensor. Experimental results demonstrate that the maximum sensitivity and minimum resolution are 48 m V/T and 160 μT, respectively, making this device suitable for strong magnetic field measurement. Research results indicate that the sensor repeatability and dynamic response time are about 0.66% and 150 ms, respectively.

  13. SEMICONDUCTOR DEVICES: Design and optimization of a monolithic GalnP/GalnAs tandem solar cell

    NASA Astrophysics Data System (ADS)

    Han, Zhang; Nuofu, Chen; Yu, Wang; Zhigang, Yin; Xlngwang, Zhang; Huiwei, Shi; Yanshuo, Wang; Tianmao, Huang

    2010-08-01

    We have theoretically calculated the photovoltaic conversion efficiency of a monolithic dual-junction GaInP/GaInAs device, which can be experimentally fabricated on a binary GaAs substrate. By optimizing the bandgap combination of the considered structure, an improvement of conversion efficiency has been observed in comparison to the conventional GaInP2/GaAs system. For the suggested bandgap combination 1.83 eV/1.335 eV, our calculation indicates that the attainable efficiency can be enhanced up to 40.45% (300 suns, AM1.5d) for the optimal structure parameter (1550 nm GaInP top and 5500 nm GaInAs bottom), showing promising application prospects due to its acceptable lattice-mismatch (0.43%) to the GaAs substrate.

  14. SEMICONDUCTOR DEVICES Negative bias temperature instability induced single event transient pulse narrowing and broadening

    NASA Astrophysics Data System (ADS)

    Jianjun, Chen; Shuming, Chen; Bin, Liang; Biwei, Liu

    2010-12-01

    The effect of negative bias temperature instability (NBTI) on a single event transient (SET) has been studied in a 130 nm bulk silicon CMOS process based on 3D TCAD device simulations. The investigation shows that NBTI can result in the pulse width and amplitude of SET narrowing when the heavy ion hits the PMOS in the high-input inverter; but NBTI can result in the pulse width and amplitude of SET broadening when the heavy ion hits the NMOS in the low-input inverter. Based on this study, for the first time we propose that the impact of NBTI on a SET produced by the heavy ion hitting the NMOS has already been a significant reliability issue and should be of wide concern, and the radiation hardened design must consider the impact of NBTI on a SET.

  15. Characterization and modeling of radiation effects NASA/MSFC semiconductor devices

    NASA Technical Reports Server (NTRS)

    Kerns, D. V., Jr.; Cook, K. B., Jr.

    1978-01-01

    A literature review of the near-Earth trapped radiation of the Van Allen Belts, the radiation within the solar system resulting from the solar wind, and the cosmic radiation levels of deep space showed that a reasonable simulation of space radiation, particularly the Earth orbital environment, could be simulated in the laboratory by proton bombardment. A 3 MeV proton accelerator was used to irradiate CMOS integrated circuits fabricated from three different processes. The drain current and output voltage for three inverters was recorded as the input voltage was swept from zero to ten volts after each successive irradiation. Device parameters were extracted. Possible damage mechanisms are discussed and recommendations for improved radiation hardness are suggested.

  16. Optical wafer metrology sensors for process-robust CD and overlay control in semiconductor device manufacturing

    NASA Astrophysics Data System (ADS)

    den Boef, Arie J.

    2016-06-01

    This paper presents three optical wafer metrology sensors that are used in lithography for robustly measuring the shape and position of wafers and device patterns on these wafers. The first two sensors are a level sensor and an alignment sensor that measure, respectively, a wafer height map and a wafer position before a new pattern is printed on the wafer. The third sensor is an optical scatterometer that measures critical dimension-variations and overlay after the resist has been exposed and developed. These sensors have different optical concepts but they share the same challenge that sub-nm precision is required at high throughput on a large variety of processed wafers and in the presence of unknown wafer processing variations. It is the purpose of this paper to explain these challenges in more detail and give an overview of the various solutions that have been introduced over the years to come to process-robust optical wafer metrology.

  17. 25th anniversary article: materials for high-performance biodegradable semiconductor devices.

    PubMed

    Hwang, Suk-Won; Park, Gayoung; Cheng, Huanyu; Song, Jun-Kyul; Kang, Seung-Kyun; Yin, Lan; Kim, Jae-Hwan; Omenetto, Fiorenzo G; Huang, Yonggang; Lee, Kyung-Mi; Rogers, John A

    2014-04-01

    We review recent progress in a class of silicon-based electronics that is capable of complete, controlled dissolution when immersed in water or bio-fluids. This type of technology, referred to in a broader sense as transient electronics, has potential applications in resorbable biomedical devices, eco-friendly electronics, environmental sensors, secure hardware systems and others. New results reported here include studies of the kinetics of hydrolysis of nanomembranes of single crystalline silicon in bio-fluids and aqueous solutions at various pH levels and temperatures. Evaluations of toxicity using live animal models and test coupons of transient electronic materials provide some evidence of their biocompatibility, thereby suggesting potential for use in bioresorbable electronic implants.

  18. Semiconductor light-emitting devices having concave microstructures providing improved light extraction efficiency and method for producing same

    DOEpatents

    Tansu, Nelson; Gilchrist, James F; Ee, Yik-Khoon; Kumnorkaew, Pisist

    2013-11-19

    A conventional semiconductor LED is modified to include a microlens layer over its light-emitting surface. The LED may have an active layer including at least one quantum well layer of InGaN and GaN. The microlens layer includes a plurality of concave microstructures that cause light rays emanating from the LED to diffuse outwardly, leading to an increase in the light extraction efficiency of the LED. The concave microstructures may be arranged in a substantially uniform array, such as a close-packed hexagonal array. The microlens layer is preferably constructed of curable material, such as polydimethylsiloxane (PDMS), and is formed by soft-lithography imprinting by contacting fluid material of the microlens layer with a template bearing a monolayer of homogeneous microsphere crystals, to cause concave impressions, and then curing the material to fix the concave microstructures in the microlens layer and provide relatively uniform surface roughness.

  19. Real-time and on-site γ-ray radiation response testing system for semiconductor devices and its applications

    NASA Astrophysics Data System (ADS)

    Mu, Yifei; Zhao, Ce Zhou; Qi, Yanfei; Lam, Sang; Zhao, Chun; Lu, Qifeng; Cai, Yutao; Mitrovic, Ivona Z.; Taylor, Stephen; Chalker, Paul R.

    2016-04-01

    The construction of a turnkey real-time and on-site radiation response testing system for semiconductor devices is reported. Components of an on-site radiation response probe station, which contains a 1.11 GBq Cs137 gamma (γ)-ray source, and equipment of a real-time measurement system are described in detail for the construction of the whole system. The real-time measurement system includes a conventional capacitance-voltage (C-V) and stress module, a pulse C-V and stress module, a conventional current-voltage (I-V) and stress module, a pulse I-V and stress module, a DC on-the-fly (OTF) module and a pulse OTF module. Electrical characteristics of MOS capacitors or MOSFET devices are measured by each module integrated in the probe station under continuous γ-ray exposure and the measurement results are presented. The dose rates of different gate dielectrics are calculated by a novel calculation model based on the Cs137 γ-ray source placed in the probe station. For the sake of operators' safety, an equivalent dose rate of 70 nSv/h at a given operation distance is indicated by a dose attenuation model in the experimental environment. HfO2 thin films formed by atomic layer deposition are employed to investigate the radiation response of the high-κ material by using the conventional C-V and pulse C-V modules. The irradiation exposure of the sample is carried out with a dose rate of 0.175 rad/s and ±1 V bias in the radiation response testing system. Analysis of flat-band voltage shifts (ΔVFB) of the MOS capacitors suggests that the on-site and real-time/pulse measurements detect more serious degradation of the HfO2 thin films compared with the off-site irradiation and conventional measurement techniques.

  20. INSERTION DEVICE ACTIVITIES FOR NSLS-II.

    SciTech Connect

    TANABE,T.; HARDER, D.A.; HULBERT, S.; RAKOWSKI, G.; SKARITKA, J.

    2007-06-25

    National Synchrotron Light Source-II (NSLS-II) will be a medium energy storage ring of 3GeV electron beam energy with sub-nm.rad horizontal emittance and top-off capability at 500mA. Damping wigglers will be used not only to reduce the beam emittance but also used as broadband sources for users. Cryo-Permanent Magnet Undulators (CPMUs) are considered for hard X-ray linear device, and permanent magnet based elliptically polarized undulators (EPUs) for variable polarization devices for soft X-ray. 6T superconducting wiggler with minimal fan angle will be installed in the second phase as well as quasi-periodic EPU for VUV and possibly high-temperature superconducting undulator. R&D plans have been established to pursue the performance enhancement of the baseline devices and to design new types of insertion devices. A new insertion device development laboratory will also be established.

  1. Novel adiabatic tapered couplers for active III-V/SOI devices fabricated through transfer printing.

    PubMed

    Dhoore, Sören; Uvin, Sarah; Van Thourhout, Dries; Morthier, Geert; Roelkens, Gunther

    2016-06-13

    We present the design of two novel adiabatic tapered coupling structures that allow efficient and alignment tolerant mode conversion between a III-V membrane waveguide and a single-mode SOI waveguide in active heterogeneously integrated devices. Both proposed couplers employ a broad intermediate waveguide to facilitate highly alignment tolerant coupling. This robustness is needed to comply with the current misalignment tolerance requirements for high-throughput transfer printing. The proposed coupling structures are expected to pave the way for transfer-printing-based heterogeneous integration of active III-V devices such as semiconductor optical amplifiers (SOAs), photodetectors, electro-absorption modulators (EAMs) and single wavelength lasers on silicon photonic integrated circuits. PMID:27410317

  2. SEMICONDUCTOR DEVICES: Low-field mobility and carrier transport mechanism transition in nanoscale MOSFETs

    NASA Astrophysics Data System (ADS)

    Hongwei, Liu; Runsheng, Wang; Ru, Huang; Xing, Zhang

    2010-04-01

    This paper extends the flux scattering method to study the carrier transport property in nanoscale MOSFETs with special emphasis on the low-field mobility and the transport mechanism transition. A unified analytical expression for the low-field mobility is proposed, which covers the entire regime from drift-diffusion transport to quasi-ballistic transport in 1-D, 2-D and 3-D MOSFETs. Two key parameters, namely the long-channel low-field mobility (μ0) and the low-field mean free path (λ0), are obtained from the experimental data, and the transport mechanism transition in MOSFETs is further discussed both experimentally and theoretically. Our work shows that λ0 is available to characterize the inherent transition of the carrier transport mechanism rather than the low-field mobility. The mobility reduces in the MOSFET with the shrinking of the channel length; however, λ0 is nearly a constant, and λ0 can be used as the “entry criterion" to determine whether the device begins to operate under quasi-ballistic transport to some extent.

  3. SEMICONDUCTOR DEVICES Physical effect on transition from blocking to conducting state of barrier-type thyristor

    NASA Astrophysics Data System (ADS)

    Hairong, Li; Siyuan, Li

    2010-12-01

    The transition of the barrier-type thyristor (BTH) from blocking to conducting-state occurs between two entirely contrary physical states with great disparity in nature. The physical effects and mechanisms of the transition are studied in depth. The features of the transition snapback point are analyzed in detail. The transition snapback point has duality and is just the position where the barrier is flattened. It has a significant influence on the capture cross-section of the hole and high-level hole lifetime, resulting in the device entering into deep base conductance modulation. The physical nature of the negative differential resistance segment I-V characteristics is studied. It is testified by using experimental data that the deep conductance modulation is the basic feature and the linchpin of the transition process. The conditions and physical mechanisms of conductance modulation are investigated. The related physical subjects, including the flattening of the channel barrier, the buildup of the double injection, the formation of the plasma, the realization of the high-level injection, the elimination of the gate junction depletion region, the deep conductance modulation, and the increase in the hole's lifetime are all discussed in this paper.

  4. Method of making compound semiconductor films and making related electronic devices

    DOEpatents

    Basol, Bulent M.; Kapur, Vijay K.; Halani, Arvind T.; Leidholm, Craig R.; Roe, Robert A.

    1999-01-01

    A method of forming a compound film includes the steps of preparing a source material, depositing the source material on a base to form a precursor film, and heating the precursor film in a suitable atmosphere to form a film. The source material includes Group IB-IIIA alloy-containing particles having at least one Group IB-IIIA alloy phase, with Group IB-IIIA alloys constituting greater than about 50 molar percent of the Group IB elements and greater than about 50 molar percent of the Group IIIA elements in the source material. The film, then, includes a Group IB-IIIA-VIA compound. The molar ratio of Group IB to Group IIIA elements in the source material may be greater than about 0.80 and less than about 1.0, or substantially greater than 1.0, in which case this ratio in the compound film may be reduced to greater than about 0.80 and less than about 1.0. The source material may be prepared as an ink from particles in powder form. The alloy phase may include a dopant. Compound films including a Group IIB-IVA-VA compound or a Group IB-VA-VIA compound may be substituted using appropriate substitutions in the method. The method, also, is applicable to fabrication of solar cells and other electronic devices.

  5. Detection of ferromagnetic domain wall pinning and depinning with a semiconductor device

    SciTech Connect

    Malec, Chris E.; Bennett, Brian R.; Johnson, Mark B.

    2015-12-21

    We demonstrate the detection of a ferromagnetic domain wall using a nanoscale Hall cross. A narrow permalloy wire is defined lithographically on top of a Hall cross fabricated from an InAs quantum well. The width of the Hall cross (500 nm–1 μm) is similar to the width of the ferromagnetic wire (200–500 nm), and a geometric pinning site is fabricated in the ferromagnetic wire to trap a domain wall within the area of the Hall cross. The devices provide a signal that is often the same order of magnitude as the offset Hall voltage when a domain wall is located above the Hall cross, and may be useful for memory applications. Different geometries for the Hall cross and ferromagnetic wire are tested, and radiofrequency pulses are sent into the wire to demonstrate current driven domain wall motion. Further changes to the Hall bar geometry with respect to the wire geometry are investigated by numerical computation. A large gain in signal is seen for Hall bars only slightly wider than the ferromagnetic wires as compared to those twice as wide, as well as a larger sensitivity to the exact position of the domain wall with respect to the center of the Hall cross.

  6. Semiconductor ohmic contact

    NASA Technical Reports Server (NTRS)

    Hawrylo, Frank Zygmunt (Inventor); Kressel, Henry (Inventor)

    1977-01-01

    A semiconductor device has one surface of P type conductivity material having a wide energy bandgap and a large crystal lattice parameter. Applied to the P type surface of the semiconductor device is a degenerate region of semiconductor material, preferably a group III-V semiconductor material, having a narrower energy bandgap. The degenerate region is doped with tin to increase the crystal lattice of the region to more closely approximate the crystal lattice of the one surface of the semiconductor device. The degenerate region is compensatingly doped with a P type conductivity modifier. An electrical contact is applied to one surface of the degenerate region forming an ohmic contact with the semiconductor device.

  7. Biosynthesis and Antimicrobial Activity of Semiconductor Nanoparticles against Oral Pathogens

    PubMed Central

    Malarkodi, C.; Rajeshkumar, S.; Paulkumar, K.; Vanaja, M.; Gnanajobitha, G.; Annadurai, G.

    2014-01-01

    Dental care is an essential phenomenon in human health. Oral pathogens can cause severe break which may show the way to serious issues in human disease like blood circulation and coronary disease. In the current study, we demonstrated the synthesis and antimicrobial activity of cadmium sulphide and zinc sulphide nanoparticles against oral pathogens. The process for the synthesis of cadmium sulphide (CdS) and zinc sulphide (ZnS) nanoparticles is fast, novel, and ecofriendly. Formation of cadmium sulphide (CdS) and zinc sulphide (ZnS) nanoparticles was confirmed by surface plasmon spectra using UV-Vis spectrophotometer. The morphology of crystalline phase of nanoparticles was determined from transmission electron microscopy (TEM) and X-ray diffraction (XRD) spectra. The average size of cadmium sulphide (CdS) and zinc sulphide (ZnS) nanoparticles was in the range of 10 nm to 25 nm and 65 nm, respectively, and the observed morphology was spherical. The results indicated that the proteins, which contain amine groups, played a reducing and controlling responsibility during the formation of cadmium sulphide (CdS) and zinc sulphide (ZnS) nanoparticles in the colloidal solution. The antimicrobial activity was assessed against oral pathogens such as Streptococcus sp. Staphylococcus sp. Lactobacillus sp., and Candida albicans and these results confirmed that the sulphide nanoparticles are exhibiting good bactericidal activity. PMID:24860280

  8. Oxide-based method of making compound semiconductor films and making related electronic devices

    DOEpatents

    Kapur, Vijay K.; Basol, Bulent M.; Leidholm, Craig R.; Roe, Robert A.

    2000-01-01

    A method for forming a compound film includes the steps of preparing a source material, depositing the source material on a base and forming a preparatory film from the source material, heating the preparatory film in a suitable atmosphere to form a precursor film, and providing suitable material to said precursor film to form the compound film. The source material includes oxide-containing particles including Group IB and IIIA elements. The precursor film includes non-oxide Group IB and IIIA elements. The compound film includes a Group IB-IIIA-VIA compound. The oxides may constitute greater than about 95 molar percent of the Group IB elements and greater than about 95 molar percent of the Group IIIA elements in the source material. Similarly, non-oxides may constitute greater than about 95 molar percent of the Group IB elements and greater than about 95 molar percent of the Group IIIA elements in the precursor film. The molar ratio of Group IB to Group IIIA elements in the source material may be greater than about 0.6 and less than about 1.0, or substantially greater that 1.0, in which case this ratio in the compound film may be reduced to greater than about 0.6 and less than about 1.0. The source material may be prepared as an ink from particles in powder form. The oxide-containing particles may include a dopant, as may the compound film. Compound films including a Group IIB-IVA-VA compound may be substituted using appropriate substitutions in the method. The method, also, is applicable to fabrication of solar cells and other electronic devices.

  9. Cognitive Inference Device for Activity Supervision in the Elderly

    PubMed Central

    2014-01-01

    Human activity, life span, and quality of life are enhanced by innovations in science and technology. Aging individual needs to take advantage of these developments to lead a self-regulated life. However, maintaining a self-regulated life at old age involves a high degree of risk, and the elderly often fail at this goal. Thus, the objective of our study is to investigate the feasibility of implementing a cognitive inference device (CI-device) for effective activity supervision in the elderly. To frame the CI-device, we propose a device design framework along with an inference algorithm and implement the designs through an artificial neural model with different configurations, mapping the CI-device's functions to minimise the device's prediction error. An analysis and discussion are then provided to validate the feasibility of CI-device implementation for activity supervision in the elderly. PMID:25405211

  10. Study of damage formation and annealing of implanted III-nitride semiconductors for optoelectronic devices

    NASA Astrophysics Data System (ADS)

    Faye, D. Nd.; Fialho, M.; Magalhães, S.; Alves, E.; Ben Sedrine, N.; Rodrigues, J.; Correia, M. R.; Monteiro, T.; Boćkowski, M.; Hoffmann, V.; Weyers, M.; Lorenz, K.

    2016-07-01

    An n-GaN/n-AlGaN/p-GaN light emitting diode (LED) structure was implanted with Eu ions. High temperature high pressure annealing at 1400 °C efficiently decreases implantation damage and optically activates the Eu ions. However, the electrical properties of the p-n junction deteriorate possibly due to the formation of conducting paths along dislocations during the extreme annealing conditions.

  11. Surface properties and photocatalytic activity of KTaO3, CdS, MoS2 semiconductors and their binary and ternary semiconductor composites.

    PubMed

    Bajorowicz, Beata; Cybula, Anna; Winiarski, Michał J; Klimczuk, Tomasz; Zaleska, Adriana

    2014-09-24

    Single semiconductors such as KTaO3, CdS MoS2 or their precursor solutions were combined to form novel binary and ternary semiconductor nanocomposites by the calcination or by the hydro/solvothermal mixed solutions methods, respectively. The aim of this work was to study the influence of preparation method as well as type and amount of the composite components on the surface properties and photocatalytic activity of the new semiconducting photoactive materials. We presented different binary and ternary combinations of the above semiconductors for phenol and toluene photocatalytic degradation and characterized by X-ray powder diffraction (XRD), UV-Vis diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) specific surface area and porosity. The results showed that loading MoS2 onto CdS as well as loading CdS onto KTaO3 significantly enhanced absorption properties as compared with single semiconductors. The highest photocatalytic activity in phenol degradation reaction under both UV-Vis and visible light irradiation and very good stability in toluene removal was observed for ternary hybrid obtained by calcination of KTaO3, CdS, MoS2 powders at the 10:5:1 molar ratio. Enhanced photoactivity could be related to the two-photon excitation in KTaO3-CdS-MoS2 composite under UV-Vis and/or to additional presence of CdMoO4 working as co-catalyst.

  12. Recrystallization method to selenization of thin-film Cu(In,Ga)Se.sub.2 for semiconductor device applications

    DOEpatents

    Albin, David S.; Carapella, Jeffrey J.; Tuttle, John R.; Contreras, Miguel A.; Gabor, Andrew M.; Noufi, Rommel; Tennant, Andrew L.

    1995-07-25

    A process for fabricating slightly Cu-poor thin-films of Cu(In,Ga)Se.sub.2 on a substrate for semiconductor device applications includes the steps of forming initially a slightly Cu-rich, phase separated, mixture of Cu(In,Ga)Se.sub.2 :Cu.sub.x Se on the substrate in solid form followed by exposure of the Cu(In,Ga)Se.sub.2 :Cu.sub.x Se solid mixture to an overpressure of Se vapor and (In,Ga) vapor for deposition on the Cu(In,Ga)Se.sub.2 :Cu.sub.x Se solid mixture while simultaneously increasing the temperature of the solid mixture toward a recrystallization temperature (about 550.degree. C.) at which Cu(In,Ga)Se.sub.2 is solid and Cu.sub.x Se is liquid. The (In,Ga) flux is terminated while the Se overpressure flux and the recrystallization temperature are maintained to recrystallize the Cu.sub.x Se with the (In, Ga) that was deposited during the temperature transition and with the Se vapor to form the thin-film of slightly Cu-poor Cu.sub.x (In,Ga).sub.y Se.sub.z. The initial Cu-rich, phase separated large grain mixture of Cu(In,Ga)Se.sub.2 :Cu.sub.x Se can be made by sequentially depositing or co-depositing the metal precursors, Cu and (In, Ga), on the substrate at room temperature, ramping up the thin-film temperature in the presence of Se overpressure to a moderate anneal temperature (about 450.degree. C.) and holding that temperature and the Se overpressure for an annealing period. A nonselenizing, low temperature anneal at about 100.degree. C. can also be used to homogenize the precursors on the substrates before the selenizing, moderate temperature anneal.

  13. Strain mapping with nm-scale resolution for the silicon-on-insulator generation of semiconductor devices by advanced electron microscopy

    SciTech Connect

    Cooper, David; Denneulin, Thibaud; Barnes, Jean-Paul; Hartmann, Jean-Michel; Hutin, Louis; Le Royer, Cyrille; Beche, Armand; Rouviere, Jean-Luc

    2012-12-15

    Strain engineering in the conduction channel is a cost effective method of boosting the performance in state-of-the-art semiconductor devices. However, given the small dimensions of these devices, it is difficult to quantitatively measure the strain with the required spatial resolution. Three different transmission electron microscopy techniques, high-angle annular dark field scanning transmission electron microscopy, dark field electron holography, and nanobeam electron diffraction have been applied to measure the strain in simple bulk and SOI calibration specimens. These techniques are then applied to different gate length SiGe SOI pFET devices in order to measure the strain in the conduction channel. For these devices, improved spatial resolution is required, and strain maps with spatial resolutions as good as 1 nm have been achieved. Finally, we discuss the relative advantages and disadvantages of using these three different techniques when used for strain measurement.

  14. Activated-Carbon Sorbent With Integral Heat-Transfer Device

    NASA Technical Reports Server (NTRS)

    Jones, Jack A.; Yavrouian, Andre

    1996-01-01

    Prototype adsorption device used, for example, in adsorption heat pump, to store natural gas to power automobile, or to separate components of fluid mixtures. Device includes activated carbon held together by binder and molded into finned heat-transfer device providing rapid heating or cooling to enable rapid adsorption or desorption of fluids. Concepts of design and fabrication of device equally valid for such other highly thermally conductive devices as copper-finned tubes, and for such other high-surface-area sorbents as zeolites or silicates.

  15. Monolithic integrated high-T.sub.c superconductor-semiconductor structure

    NASA Technical Reports Server (NTRS)

    Burns, Michael J. (Inventor); de la Houssaye, Paul R. (Inventor); Garcia, Graham A. (Inventor); Russell, Stephen D. (Inventor); Clayton, Stanley R. (Inventor); Barfknecht, Andrew T. (Inventor)

    2000-01-01

    A method for the fabrication of active semiconductor and high-temperature superconducting device of the same substrate to form a monolithically integrated semiconductor-superconductor (MISS) structure is disclosed. A common insulating substrate, preferably sapphire or yttria-stabilized zirconia, is used for deposition of semiconductor and high-temperature superconductor substructures. Both substructures are capable of operation at a common temperature of at least 77 K. The separate semiconductor and superconductive regions may be electrically interconnected by normal metals, refractory metal silicides, or superconductors. Circuits and devices formed in the resulting MISS structures display operating characteristics which are equivalent to those of circuits and devices prepared on separate substrates.

  16. Method for making a monolithic integrated high-T.sub.c superconductor-semiconductor structure

    NASA Technical Reports Server (NTRS)

    Burns, Michael J. (Inventor); de la Houssaye, Paul R. (Inventor); Garcia, Graham A. (Inventor); Russell, Stephen D. (Inventor); Clayton, Stanley R. (Inventor); Barfknecht, Andrew T. (Inventor)

    2000-01-01

    A method for the fabrication of active semiconductor and high-temperature perconducting devices on the same substrate to form a monolithically integrated semiconductor-superconductor (MISS) structure is disclosed. A common insulating substrate, preferably sapphire or yttria-stabilized zirconia, is used for deposition of semiconductor and high-temperature superconductor substructures. Both substructures are capable of operation at a common temperature of at least 77 K. The separate semiconductor and superconductive regions may be electrically interconnected by normal metals, refractory metal silicides, or superconductors. Circuits and devices formed in the resulting MISS structures display operating characteristics which are equivalent to those of circuits and devices prepared on separate substrates.

  17. A splitting scheme based on the space-time CE/SE method for solving multi-dimensional hydrodynamical models of semiconductor devices

    NASA Astrophysics Data System (ADS)

    Nisar, Ubaid Ahmed; Ashraf, Waqas; Qamar, Shamsul

    2016-08-01

    Numerical solutions of the hydrodynamical model of semiconductor devices are presented in one and two-space dimension. The model describes the charge transport in semiconductor devices. Mathematically, the models can be written as a convection-diffusion type system with a right hand side describing the relaxation effects and interaction with a self consistent electric field. The proposed numerical scheme is a splitting scheme based on the conservation element and solution element (CE/SE) method for hyperbolic step, and a semi-implicit scheme for the relaxation step. The numerical results of the suggested scheme are compared with the splitting scheme based on Nessyahu-Tadmor (NT) central scheme for convection step and the same semi-implicit scheme for the relaxation step. The effects of various parameters such as low field mobility, device length, lattice temperature and voltages for one-space dimensional hydrodynamic model are explored to further validate the generic applicability of the CE/SE method for the current model equations. A two dimensional simulation is also performed by CE/SE method for a MESFET device, producing results in good agreement with those obtained by NT-central scheme.

  18. Microwave annealing, a low-thermal-budget process for dopant activation in phosphorus-implanted MOSFET devices

    NASA Astrophysics Data System (ADS)

    Lim, Cheol-Min; Cho, Won-Ju

    2016-09-01

    In this work, we investigated a low-thermal-budget dopant activation process based on microwave annealing (MWA) of phosphorus ions implanted by plasma doping and compared the proposed technique with the conventional furnace annealing and the rapid thermal annealing processes. We fabricated p-n junction diodes and metal-oxide-semiconductor field-effect transistors (MOSFETs) on silicon and silicon-on-insulator substrates, respectively, in order to examine the dopant activation resulting from MWA. The investigated low-thermal-budget MWA technique proved effective for implanted dopant atom activation and diffusion suppression. In addition, a good interface property between the gate oxide and the silicon channel was achieved. Thus, low-thermal-budget MWA is a promising and effective method for the fabrication of highly-integrated semiconductor devices.

  19. SEMICONDUCTOR DEVICES: Dose-rate effects of p-channel metal oxide semiconductor field-effect transistors at various biasing conditions

    NASA Astrophysics Data System (ADS)

    Bo, Lan; Qi, Guo; Jing, Sun; Jiangwei, Cui; Maoshun, Li; Rui, Chen; Wuxiong, Fei; Yun, Zhao

    2010-05-01

    The total-dose response and annealing effect of p-channel metal oxide semiconductor field-effect transistors (PMOSFETs) were investigated at various dose rates and biasing conditions. The results show that the shift of threshold voltage is more obvious when the dose rate is decreased. Under the various dose rates and biasing conditions, some have exhibited a time-dependent effect and others showed enhanced low-dose-rate sensitivity (ELDRS). Finally, using the subthreshold-separating method, the threshold-voltage shift is separated into shifts due to interface states and oxide-trapped charges, and the underlying mechanisms of the observed effects are discussed. It has been indicated that the ELDRS effect results from the different quantities of the interface states generated at high and low dose rates.

  20. Activity Coefficients of Electrons and Holes in Degenerate Semiconductors with Nonuniform Composition

    NASA Astrophysics Data System (ADS)

    Chang, Kow-Ming; Yeh, Ta-Hsun; Wang, Shih-Wei; Lee, Chi-Hung

    1994-03-01

    A new simple, general and rigorous analytic expression for the equilibrium activity coefficients of electrons and holes in degenerate semiconductors with nonuniform composition is presented. These activity coefficients are functions of the carrier degeneracy (Fermi-Dirac statistics), the band gap, the electron affinity and the density of states which vary with position. The calculation of carrier activity coefficients requires the selection of chemical potential and electrostatic potential references. The choice of these reference states is addressed. The relationships between purely thermodynamic quantities and parameters of the band theory are also presented. Emphasis is also placed on formulating an equation in a simple, Boltzmann-like form in which the nonideal behavior is described by two parameters, the effective band-gap shrinkage, ΔE g, and the effective asymmetry factor, A. In this form the working equations for the carrier densities and activity coefficients are convenient for use in computer-aided analysis and design. The approach presented here allows convenient treatment of nonuniform degenerate semiconductors in a manner that is consistent with thermodynamics as well as with the Poisson-Boltzmann equation for the electrostatic potential.

  1. Investigation of p-side contact layers for II-VI compound semiconductor optical devices fabricated on InP substrates by MBE

    NASA Astrophysics Data System (ADS)

    Takamatsu, Shingo; Nomura, Ichirou; Shiraishi, Tomohiro; Kishino, Katsumi

    2015-09-01

    N-doped p-type ZnTe and ZnSeTe contact layers were investigated to evaluate which is more suitable for use in II-VI compound semiconductor optical devices on InP substrates. Contact resistances (Rc) between the contact layers and several electrode materials (Pd/Pt/Au, Pd/Au, and Au) were measured by the circular transmission line model (c-TLM) method using p-n diode samples grown on InP substrates by molecular beam epitaxy (MBE). The lowest Rc (6.5×10-5 Ω cm2) was obtained in the case of the ZnTe contact and Pd/Pt/Au electrode combination, which proves that the combination is suitable for obtaining low Rc. Yellow light-emitting diode devices with a ZnTe and ZnSeTe p-contact layer were fabricated by MBE to investigate the effect of different contact layers. The devices were characterized under direct current injections at room temperature. Yellow emission at around 600 nm was observed for each device. Higher emission intensity and lower slope resistance were obtained for the device with the ZnTe contact layer and Pd/Pt/Au electrode compared with other devices. These device performances are ascribed to the low Rc of the ZnTe contact and Pd/Pt/Au electrode combination.

  2. Production of 35S for a Liquid Semiconductor Betavoltaic

    SciTech Connect

    Meier, David E.; Garnov, A. Y.; Robertson, J. D.; Kwon, J. W.; Wacharasindhu, T.

    2009-10-01

    The specific energy density from radioactive decay is five to six orders of magnitude greater than the specific energy density in conventional chemical battery and fuel cell technologies. We are currently investigating the use of liquid semiconductor based betavoltaics as a way to directly convert the energy of radioactive decay into electrical power and potentially avoid the radiation damage that occurs in solid state semiconductor devices due to non-ionizing energy loss. Sulfur-35 was selected as the isotope for the liquid semiconductor demonstrations because it can be produced in high specific activity and it is chemically compatible with known liquid semiconductor media.

  3. Passive and active sol-gel materials and devices

    NASA Astrophysics Data System (ADS)

    Andrews, Mark P.; Najafi, S. Iraj

    1997-07-01

    This paper examines sol-gel materials for photonics in terms of partnerships with other material contenders for processing optical devices. The discussion in four sections identifies semiconductors, amorphous and crystalline inorganic dielectrics, and amorphous and crystalline organic dielectrics as strategic agents in the rapidly evolving area of materials and devices for data communications and telecommunications. With Zyss, we trace the hierarchical lineage that connects molecular hybridization (chemical functionality), through supramolecular hybridization (collective properties and responses), to functional hybridization (device and system level constructs). These three concepts thread their way through discussions of the roles sol-gel glasses might be anticipated to assume in a photonics marketplace. We assign a special place to glass integrated optics and show how high temperature consolidated sol-gel derived glasses fit into competitive glass fabrication technologies. Low temperature hybrid sol-gel glasses that combine attractive features of organic polymers and inorganic glasses are considered by drawing on examples of our own new processes for fabricating couplers, power splitters, waveguides and gratings by combining chemical synthesis and sol-gel processing with simple photomask techniques.

  4. 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.

  5. 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.

  6. Correlation of Photocatalytic Activity with Band Structure of Low-dimensional Semiconductor Nanostructures

    NASA Astrophysics Data System (ADS)

    Meng, Fanke

    Photocatalytic hydrogen generation by water splitting is a promising technique to produce clean and renewable solar fuel. The development of effective semiconductor photocatalysts to obtain efficient photocatalytic activity is the key objective. However, two critical reasons prevent wide applications of semiconductor photocatalysts: low light usage efficiency and high rates of charge recombination. In this dissertation, several low-dimensional semiconductors were synthesized with hydrothermal, hydrolysis, and chemical impregnation methods. The band structures of the low-dimensional semiconductor materials were engineered to overcome the above mentioned two shortcomings. In addition, the correlation between the photocatalytic activity of the low-dimensional semiconductor materials and their band structures were studied. First, we studied the effect of oxygen vacancies on the photocatalytic activity of one-dimensional anatase TiO2 nanobelts. Given that the oxygen vacancy plays a significant role in band structure and photocatalytic performance of semiconductors, oxygen vacancies were introduced into the anatase TiO2 nanobelts during reduction in H2 at high temperature. The oxygen vacancies of the TiO2 nanobelts boosted visible-light-responsive photocatalytic activity but weakened ultraviolet-light-responsive photocatalytic activity. As oxygen vacancies are commonly introduced by dopants, these results give insight into why doping is not always beneficial to the overall photocatalytic performance despite increases in absorption. Second, we improved the photocatalytic performance of two-dimensional lanthanum titanate (La2Ti2 O7) nanosheets, which are widely studied as an efficient photocatalyst due to the unique layered crystal structure. Nitrogen was doped into the La2Ti2O7 nanosheets and then Pt nanoparticles were loaded onto the La2Ti2O7 nanosheets. Doping nitrogen narrowed the band gap of the La2Ti 2O7 nanosheets by introducing a continuum of states by the valence

  7. Active resonant subwavelength grating devices for high speed spectroscopic sensing

    NASA Astrophysics Data System (ADS)

    Gin, A. V.; Kemme, S. A.; Boye, R. R.; Peters, D. W.; Ihlefeld, J. F.; Briggs, R. D.; Wendt, J. R.; Marshall, L. H.; Carter, T. R.; Samora, S.

    2009-02-01

    In this paper, we describe progress towards a multi-color spectrometer and radiometer based upon an active resonant subwavelength grating (RSG). This active RSG component acts as a tunable high-speed optical filter that allows device miniaturization and ruggedization not realizable using current sensors with conventional bulk optics. Furthermore, the geometrical characteristics of the device allow for inherently high speed operation. Because of the small critical dimensions of the RSG devices, the fabrication of these sensors can prove challenging. However, we utilize the state-of-the-art capabilities at Sandia National Laboratories to realize these subwavelength grating devices. This work also leverages previous work on passive RSG devices with greater than 98% efficiency and ~1nm FWHM. Rigorous coupled wave analysis has been utilized to design RSG devices with PLZT, PMN-PT and BaTiO3 electrooptic thin films on sapphire substrates. The simulated interdigitated electrode configuration achieves field strengths around 3×107 V/m. This translates to an increase in the refractive index of 0.05 with a 40V bias potential resulting in a 90% contrast of the modulated optical signal. We have fabricated several active RSG devices on selected electro-optic materials and we discuss the latest experimental results on these devices with variable electrostatic bias and a tunable wavelength source around 1.5μm. Finally, we present the proposed data acquisition hardware and system integration plans.

  8. Measurement techniques for high-power semiconductor materials and devices. Annual report, October 1, 1980-December 31, 1981. [For calculating excess-carrier lifetime in silicon

    SciTech Connect

    Thurber, W R; Phillips, W E; Larrabee, R D

    1982-08-01

    This annual report describes results of NBS research directed toward the development of measurement methods for semiconductor materials and devices which will lead to more effective use of high-power semiconductor devices in applications for energy generation, transmission, conversion, and conservation. Emphasis is on the development of measurement methods for power-device-grade silicon. Major accomplishments during this reporting period were : (1) characterizing by deep level transient spectroscopy (DLTS) the energy levels in silicon power rectifier diodes, (2) writing of a computer program to predict lifetime-related parameters using as input the measured properties of the deep energy levels, (3) developing a novel method to detect nonexponential transients using a conventional double-boxcar DLTS system, (4) analyzing transient capacitance measurements to extend the techniques to nonexponential decays, (5) using a platinum resistance thermometer to calibrate temperature sensing diodes to obtain the precision needed for careful isothermal capacitance measurements, and (6) utilizing trap changing time as a technique to resolve overlapping DLTS peaks in sulfur-doped silicon.

  9. Mechanism of electronic-excitation transfer in organic light-emitting devices based on semiconductor quantum dots

    SciTech Connect

    Vitukhnovskii, A. G. Vashchenko, A. A.; Lebedev, V. S.; Vasiliev, R. B.; Brunkov, P. N.; Bychkovskii, D. N.

    2013-07-15

    The results of an experimental study of organic light-emitting diodes (LEDs) with luminescent layers based on two types of CdSe/CdS semiconductor quantum dots (QDs) with an average CdSe core diameter of 3 and 5 nm and a characteristic CdS shell thickness of 0.5 nm are presented. The dependences of the LED efficiency on the QD concentration are determined. The experimental data are used to determine the mechanism of electronic-excitation transfer from the organic matrix to the semiconductor QDs. Ways of optimizing the design of the LEDs in order to improve their efficiency are suggested on this basis.

  10. Test Standard Revision Update: JESD57, "Procedures for the Measurement of Single-Event Effects in Semiconductor Devices from Heavy-Ion Irradiation"

    NASA Technical Reports Server (NTRS)

    Lauenstein, Jean-Marie

    2015-01-01

    The JEDEC JESD57 test standard, Procedures for the Measurement of Single-Event Effects in Semiconductor Devices from Heavy-Ion Irradiation, is undergoing its first revision since 1996. In this talk, we place this test standard into context with other relevant radiation test standards to show its importance for single-event effect radiation testing for space applications. We show the range of industry, government, and end-user party involvement in the revision. Finally, we highlight some of the key changes being made and discuss the trade-space in which setting standards must be made to be both useful and broadly adopted.

  11. Longevity improvement of optically activated, high gain GaAs photoconductive semiconductor switches

    SciTech Connect

    MAR,ALAN; LOUBRIEL,GUILLERMO M.; ZUTAVERN,FRED J.; O'MALLEY,MARTIN W.; HELGESON,WESLEY D.; BROWN,DARWIN JAMES; HJALMARSON,HAROLD P.; BACA,ALBERT G.

    2000-03-02

    The longevity of high gain GaAs photoconductive semiconductor switches (PCSS) has been extended to over 100 million pulses at 23A, and over 100 pulses at 1kA. This is achieved by improving the ohmic contacts by doping the semi-insulating GaAs underneath the metal, and by achieving a more uniform distribution of contact wear across the entire switch by distributing the trigger light to form multiple filaments. This paper will compare various approaches to doping the contacts, including ion implantation, thermal diffusion, and epitaxial growth. The device characterization also includes examination of the filament behavior using open-shutter, infra-red imaging during high gain switching. These techniques provide information on the filament carrier densities as well as the influence that the different contact structures and trigger light distributions have on the distribution of the current in the devices. This information is guiding the continuing refinement of contact structures and geometries for further improvements in switch longevity.

  12. Microscopic studies of the fate of charges in organic semiconductors: Scanning Kelvin probe measurements of charge trapping, transport, and electric fields in p- and n-type devices

    NASA Astrophysics Data System (ADS)

    Smieska, Louisa Marion

    Organic semiconductors could have wide-ranging applications in lightweight, efficient electronic circuits. However, several fundamental questions regarding organic electronic device behavior have not yet been fully addressed, including the nature of chemical charge traps, and robust models for injection and transport. Many studies focus on engineering devices through bulk transport measurements, but it is not always possible to infer the microscopic behavior leading to the observed measurements. In this thesis, we present scanning-probe microscope studies of organic semiconductor devices in an effort to connect local properties with local device behavior. First, we study the chemistry of charge trapping in pentacene transistors. Working devices are doped with known pentacene impurities and the extent of charge trap formation is mapped across the transistor channel. Trap-clearing spectroscopy is employed to measure an excitation of the pentacene charge trap species, enabling identification of the degradationrelated chemical trap in pentacene. Second, we examine transport and trapping in peryelene diimide (PDI) transistors. Local mobilities are extracted from surface potential profiles across a transistor channel, and charge injection kinetics are found to be highly sensitive to electrode cleanliness. Trap-clearing spectra generally resemble PDI absorption spectra, but one derivative yields evidence indicating variation in trap-clearing mechanisms for different surface chemistries. Trap formation rates are measured and found to be independent of surface chemistry, contradicting a proposed silanol trapping mechanism. Finally, we develop a variation of scanning Kelvin probe microscopy that enables measurement of electric fields through a position modulation. This method avoids taking a numeric derivative of potential, which can introduce high-frequency noise into the electric field signal. Preliminary data is presented, and the theoretical basis for electric field

  13. Development of novel active transport membrande devices

    SciTech Connect

    Laciak, D.V.

    1994-11-01

    Air Products has undertaken a research program to fabricate and evaluate gas separation membranes based upon promising ``active-transport`` (AT) materials recently developed in our laboratories. Active Transport materials are ionic polymers and molten salts which undergo reversible interaction or reaction with ammonia and carbon dioxide. The materials are useful for separating these gases from mixtures with hydrogen. Moreover, AT membranes have the unique property of possessing high permeability towards ammnonia and carbon dioxide but low permeability towards hydrogen and can thus be used to permeate these components from a gas stream while retaining hydrogen at high pressure.

  14. Reliability Assessment and Activation Energy Study of Au and Pd-Coated Cu Wires Post High Temperature Aging in Nanoscale Semiconductor Packaging.

    PubMed

    Gan, C L; Hashim, U

    2013-06-01

    Wearout reliability and high temperature storage life (HTSL) activation energy of Au and Pd-coated Cu (PdCu) ball bonds are useful technical information for Cu wire deployment in nanoscale semiconductor device packaging. This paper discusses the influence of wire type on the wearout reliability performance of Au and PdCu wire used in fine pitch BGA package after HTSL stress at various aging temperatures. Failure analysis has been conducted to identify the failure mechanism after HTSL wearout conditions for Au and PdCu ball bonds. Apparent activation energies (Eaa) of both wire types are investigated after HTSL test at 150 °C, 175 °C and 200 °C aging temperatures. Arrhenius plot has been plotted for each ball bond types and the calculated Eaa of PdCu ball bond is 0.85 eV and 1.10 eV for Au ball bond in 110 nm semiconductor device. Obviously Au ball bond is identified with faster IMC formation rate with IMC Kirkendall voiding while PdCu wire exhibits equivalent wearout and or better wearout reliability margin compare to conventional Au wirebond. Lognormal plots have been established and its mean to failure (t50) have been discussed in this paper.

  15. Use of vacuum tubes in test instrumentation for measuring characteristics of fast high-voltage semiconductor devices

    NASA Technical Reports Server (NTRS)

    Berning, D.

    1981-01-01

    Circuits are described that permit measurement of fast events occurring in power semiconductors. These circuits were developed for the dynamic characterization of transistors used in inductive-load switching applications. Fast voltage clamping using vacuum diodes is discussed, and reference is made to a unique circuit that was built for performing nondestructive, reverse-bias, second-breakdown tests on transistors.

  16. Semiconductor devices for optical communications in 1 micron band of wavelength. [gallium indium arsenide phosphide lasers and diodes

    NASA Technical Reports Server (NTRS)

    Suematsu, Y.; Iga, K.

    1980-01-01

    Crystal growth and the characteristics of semiconductor lasers and diodes for the long wavelength band used in optical communications are examined. It is concluded that to utilize the advantages of this band, it is necessary to have a large scale multiple wavelength communication, along with optical cumulative circuits and optical exchangers.

  17. Geometric investigation of a gaming active device

    NASA Astrophysics Data System (ADS)

    Menna, Fabio; Remondino, Fabio; Battisti, Roberto; Nocerino, Erica

    2011-07-01

    3D imaging systems are widely available and used for surveying, modeling and entertainment applications, but clear statements regarding their characteristics, performances and limitations are still missing. The VDI/VDE and the ASTME57 committees are trying to set some standards but the commercial market is not reacting properly. Since many new users are approaching these 3D recording methodologies, clear statements and information clarifying if a package or system satisfies certain requirements before investing are fundamental for those users who are not really familiar with these technologies. Recently small and portable consumer-grade active sensors came on the market, like TOF rangeimaging cameras or low-cost triangulation-based range sensor. A quite interesting active system was produced by PrimeSense and launched on the market thanks to the Microsoft Xbox project with the name of Kinect. The article reports the geometric investigation of the Kinect active sensors, considering its measurement performances, the accuracy of the retrieved range data and the possibility to use it for 3D modeling application.

  18. The role of ultra-thin SiO2 layers in metal-insulator-semiconductor (MIS) photoelectrochemical devices (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Esposito, Daniel V.

    2015-08-01

    Solid-state junctions based on a metal-insulator-semiconductor (MIS) architecture are of great interest for a number of optoelectronic applications such as photovoltaics, photoelectrochemical cells, and photodetection. One major advantage of the MIS junction compared to the closely related metal-semiconductor junction, or Schottky junction, is that the thin insulating layer (1-3 nm thick) that separates the metal and semiconductor can significantly reduce the density of undesirable interfacial mid-gap states. The reduction in mid-gap states helps "un-pin" the junction, allowing for significantly higher built-in-voltages to be achieved. A second major advantage of the MIS junction is that the thin insulating layer can also protect the underlying semiconductor from corrosion in an electrochemical environment, making the MIS architecture well-suited for application in (photo)electrochemical applications. In this presentation, discontinuous Si-based MIS junctions immersed in electrolyte are explored for use as i.) photoelectrodes for solar-water splitting in photoelectrochemical cells (PECs) and ii.) position-sensitive photodetectors. The development and optimization of MIS photoelectrodes for both of these applications relies heavily on understanding how processing of the thin SiO2 layer impacts the properties of nano- and micro-scale MIS junctions, as well as the interactions of the insulating layer with the electrolyte. In this work, we systematically explore the effects of insulator thickness, synthesis method, and chemical treatment on the photoelectrochemical and electrochemical properties of these MIS devices. It is shown that electrolyte-induced inversion plays a critical role in determining the charge carrier dynamics within the MIS photoelectrodes for both applications.

  19. CMOS Imaging Device for Optical Imaging of Biological Activities

    NASA Astrophysics Data System (ADS)

    Shishido, Sanshiro; Oguro, Yasuhiro; Noda, Toshihiko; Sasagawa, Kiyotaka; Tokuda, Takashi; Ohta, Jun

    In this paper, we propose a CMOS image sensor device placed on the brain surface or cerebral sulcus (Fig. 1). The device has a photo detector array where a single optical detector is usually used. The proposed imaging device enables the analysis which reflects a surface blood pattern in the observed area. It is also possible to improve effective sensitivity by image processing and to simplify the measurement system by the CMOS sensor device with on-chip light source. We describe the design details and characterization of proposed device. We also demonstrate detection of hemoglobin oxygenation level with external light source, imaging capability of biological activities, and image processing for sensitivity improvement is also realized.

  20. Stretchable semiconductor elements and stretchable electrical circuits

    DOEpatents

    Rogers, John A.; Khang, Dahl-Young; Menard, Etienne

    2009-07-07

    The invention provides methods and devices for fabricating printable semiconductor elements and assembling printable semiconductor elements onto substrate surfaces. Methods, devices and device components of the present invention are capable of generating a wide range of flexible electronic and optoelectronic devices and arrays of devices on substrates comprising polymeric materials. The present invention also provides stretchable semiconductor structures and stretchable electronic devices capable of good performance in stretched configurations.

  1. Low-background instrumental neutron activation analysis of silicon semiconductor materials

    SciTech Connect

    Smith, A.R.; McDonald, R.J.; Manini, H.; Hurley, D.L.; Norman, E.B.; Vella, M.C.; Odom, R.W.

    1996-01-01

    Samples of silicon wafers, some implanted with zinc, some with memory circuits fabricated on them, and some with oxide coatings were activated with neutrons and analyzed for trace element impurities with low-background germanium gamma-ray spectrometers. Results are presented for these samples as well as for a reference material. Because the silicon matrix activation is so small, reduced spectrometer system background permits the detection of significantly lower impurity concentrations than would otherwise be possible. For the highest efficiency and lowest background system, limits on the lowest levels of trace element concentrations have been measured for wafer sized (1 to 10 g) samples and inferred for bulk sized (365 g) samples. For wafer-sized samples, part-per-trillion detection capabilities are demonstrated for a variety of elemental contaminants important in semiconductor fabrication.

  2. Synthesis Methods, Microscopy Characterization and Device Integration of Nanoscale Metal Oxide Semiconductors for Gas Sensing in Aerospace Applications

    NASA Technical Reports Server (NTRS)

    VanderWal, Randy L.; Berger, Gordon M.; Kulis, Michael J.; Hunter, Gary W.; Xu, Jennifer C.; Evans, Laura J.

    2009-01-01

    A comparison is made between SnO2, ZnO, and TiO2 single-crystal nanowires and SnO2 polycrystalline nanofibers for gas sensing. Both nanostructures possess a one-dimensional morphology. Different synthesis methods are used to produce these materials: thermal evaporation-condensation (TEC), controlled oxidation, and electrospinning. Advantages and limitations of each technique are listed. Practical issues associated with harvesting, purification, and integration of these materials into sensing devices are detailed. For comparison to the nascent form, these sensing materials are surface coated with Pd and Pt nanoparticles. Gas sensing tests, with respect to H2, are conducted at ambient and elevated temperatures. Comparative normalized responses and time constants for the catalyst and noncatalyst systems provide a basis for identification of the superior metal-oxide nanostructure and catalyst combination. With temperature-dependent data, Arrhenius analyses are made to determine an activation energy for the catalyst-assisted systems.

  3. Efficient charge transfer and field-induced tunneling transport in hybrid composite device of organic semiconductor and cadmium telluride quantum dots

    SciTech Connect

    Varade, Vaibhav Jagtap, Amardeep M.; Koteswara Rao, K. S. R.; Ramesh, K. P.; Menon, R.; Anjaneyulu, P.

    2015-06-07

    Temperature and photo-dependent current–voltage characteristics are investigated in thin film devices of a hybrid-composite comprising of organic semiconductor poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) and cadmium telluride quantum dots (CdTe QDs). A detailed study of the charge injection mechanism in ITO/PEDOT:PSS-CdTe QDs/Al device exhibits a transition from direct tunneling to Fowler–Nordheim tunneling with increasing electric field due to formation of high barrier at the QD interface. In addition, the hybrid-composite exhibits a huge photoluminescence quenching compared to aboriginal CdTe QDs and high increment in photoconductivity (∼ 400%), which is attributed to the charge transfer phenomena. The effective barrier height (Φ{sub B} ≈ 0.68 eV) is estimated from the transition voltage and the possible origin of its variation with temperature and photo-illumination is discussed.

  4. Reproducible bipolar resistive switching in entire nitride AlN/n-GaN metal-insulator-semiconductor device and its mechanism

    SciTech Connect

    Chen, Yiren; Song, Hang E-mail: lidb@ciomp.ac.cn; Jiang, Hong; Li, Zhiming; Zhang, Zhiwei; Sun, Xiaojuan; Li, Dabing E-mail: lidb@ciomp.ac.cn; Miao, Guoqing

    2014-11-10

    Reproducible bipolar resistive switching characteristics are demonstrated in entire nitride AlN/n-GaN metal-insulator-semiconductor devices. The mechanism involved confirms to trap-controlled space charge limited current theory and can be attributed to the nitrogen vacancies of AlN serving as electron traps that form/rupture electron transport channel by trapping/detrapping electrons. This study will lead to the development of in-situ growth of group-III nitrides by metal-organic chemical vapor deposition as a candidate for next-generation nonvolatile memory device. Moreover, it will be benefit to structure monolithic integrated one-transistor-one-resistor memory with nitride high electron mobility transistors.

  5. Special Issue featuring invited articles arising from UK Semiconductors 2012

    NASA Astrophysics Data System (ADS)

    Clarke, Edmund; Wada, Osamu

    2013-07-01

    Semiconductor research has formed the basis of many technological advances over the past 50 years, and the field is still highly active, as new material systems and device concepts are developed to address new applications or operating conditions. In addition to the development of traditional semiconductor devices, the wealth of experience with these materials also allows their use as an ideal environment for testing new physics, leading to new classes of devices exploiting quantum mechanical effects that can also benefit from the advantages of existing semiconductor technology in scalability, compactness and ease of mass production. This special issue features papers arising from the UK Semiconductors 2012 Conference, held at the University of Sheffield. The annual conference covers all aspects of semiconductor research, from crystal growth, through investigations of the physics of semiconductor structures to realization of semiconductor devices and their application in emerging technologies. The 2012 conference featured over 150 presentations, including plenary sessions on interband cascade lasers for the 3-6 µm spectral band, efficient single photon sources based on InAs quantum dots embedded in GaAs photonic nanowires, nitride-based quantum dot visible lasers and single photon sources, and engineering of organic light-emitting diodes. The seven papers collected here highlight current research advances, taken from across the scope of the conference. The papers feature growth of novel nitride-antimonide material systems for mid-infrared sources and detectors, use of semiconductor nanostructures for charge-based memory and visible lasers, optimization of device structures either to reduce losses in solar cells or achieve low noise amplification in transistors, design considerations for surface-emitting lasers incorporating photonic crystals and an assessment of laser power convertors for power transfer. The editors of this special issue and the conference

  6. Improving the catalytic activity of semiconductor nanocrystals through selective domain etching.

    PubMed

    Khon, Elena; Lambright, Kelly; Khnayzer, Rony S; Moroz, Pavel; Perera, Dimuthu; Butaeva, Evgeniia; Lambright, Scott; Castellano, Felix N; Zamkov, Mikhail

    2013-05-01

    Colloidal chemistry offers an assortment of synthetic tools for tuning the shape of semiconductor nanocrystals. While many nanocrystal architectures can be obtained directly via colloidal growth, other nanoparticle morphologies require alternative processing strategies. Here, we show that chemical etching of colloidal nanoparticles can facilitate the realization of nanocrystal shapes that are topologically inaccessible by hot-injection techniques alone. The present methodology is demonstrated by synthesizing a two-component CdSe/CdS nanoparticle dimer, constructed in a way that both CdSe and CdS semiconductor domains are exposed to the external environment. This structural morphology is highly desirable for catalytic applications as it enables both reductive and oxidative reactions to occur simultaneously on dissimilar nanoparticle surfaces. Hydrogen production tests confirmed the improved catalytic activity of CdSe/CdS dimers, which was enhanced 3-4 times upon etching treatment. We expect that the demonstrated application of etching to shaping of colloidal heteronanocrystals can become a common methodology in the synthesis of charge-separating nanocrystals, leading to advanced nanoparticles architectures for applications in areas of photocatalysis, photovoltaics, and light detection.

  7. Microwave photonic bandgap devices with active plasma elements

    NASA Astrophysics Data System (ADS)

    Wang, Benjamin; Colon Quinones, Roberto; Biggs, David; Underwood, Thomas; Lucca Fabris, Andrea; Cappelli, Mark; Stanford Plasma Physics Laboratory Team

    2015-09-01

    A 3-D alumina rod based microwave photonic crystal device with integrated gaseous plasma elements is designed and characterized. Modulation of the plasma density of the active plasma elements is shown to allow for high fidelity modulation of the output signal of the photonic crystal device. Finite difference time domain (FDTD) simulations of the device are presented, and the functional effects of the plasma electron density, plasma collision frequency, and plasma dimensions are studied. Experimental characterization of the transmission of the device shows active tunability through adjustments of plasma parameters, including discharge current and plasma size. Additional photonic crystal structures with integrated plasma elements are explored. Sponsored by the AFSOR MURI and DOD NDSEG.

  8. Valorization of GaN based metal-organic chemical vapor deposition dust a semiconductor power device industry waste through mechanochemical oxidation and leaching: A sustainable green process.

    PubMed

    Swain, Basudev; Mishra, Chinmayee; Lee, Chan Gi; Park, Kyung-Soo; Lee, Kun-Jae

    2015-07-01

    Dust generated during metal organic vapor deposition (MOCVD) process of GaN based semiconductor power device industry contains significant amounts of gallium and indium. These semiconductor power device industry wastes contain gallium as GaN and Ga0.97N0.9O0.09 is a concern for the environment which can add value through recycling. In the present study, this waste is recycled through mechanochemical oxidation and leaching. For quantitative recovery of gallium, two different mechanochemical oxidation leaching process flow sheets are proposed. In one process, first the Ga0.97N0.9O0.09 of the MOCVD dust is leached at the optimum condition. Subsequently, the leach residue is mechanochemically treated, followed by oxidative annealing and finally re-leached. In the second process, the MOCVD waste dust is mechanochemically treated, followed by oxidative annealing and finally leached. Both of these treatment processes are competitive with each other, appropriate for gallium leaching and treatment of the waste MOCVD dust. Without mechanochemical oxidation, 40.11 and 1.86 w/w% of gallium and Indium are leached using 4M HCl, 100°C and pulp density of 100 kg/m(3,) respectively. After mechanochemical oxidation, both these processes achieved 90 w/w% of gallium and 1.86 w/w% of indium leaching at their optimum condition.

  9. Semiconductor bridge (SCB) detonator

    DOEpatents

    Bickes, Jr., Robert W.; Grubelich, Mark C.

    1999-01-01

    The present invention is a low-energy detonator for high-density secondary-explosive materials initiated by a semiconductor bridge igniter that comprises a pair of electrically conductive lands connected by a semiconductor bridge. The semiconductor bridge is in operational or direct contact with the explosive material, whereby current flowing through the semiconductor bridge causes initiation of the explosive material. Header wires connected to the electrically-conductive lands and electrical feed-throughs of the header posts of explosive devices, are substantially coaxial to the direction of current flow through the SCB, i.e., substantially coaxial to the SCB length.

  10. Semiconductor bridge (SCB) detonator

    DOEpatents

    Bickes, R.W. Jr.; Grubelich, M.C.

    1999-01-19

    The present invention is a low-energy detonator for high-density secondary-explosive materials initiated by a semiconductor bridge (SCB) igniter that comprises a pair of electrically conductive lands connected by a semiconductor bridge. The semiconductor bridge is in operational or direct contact with the explosive material, whereby current flowing through the semiconductor bridge causes initiation of the explosive material. Header wires connected to the electrically-conductive lands and electrical feed-throughs of the header posts of explosive devices, are substantially coaxial to the direction of current flow through the SCB, i.e., substantially coaxial to the SCB length. 3 figs.

  11. Rhombohedral cubic semiconductor materials on trigonal substrate with single crystal properties and devices based on such materials

    NASA Technical Reports Server (NTRS)

    Park, Yeonjoon (Inventor); Choi, Sang Hyouk (Inventor); King, Glen C. (Inventor); Elliott, James R. (Inventor)

    2012-01-01

    Growth conditions are developed, based on a temperature-dependent alignment model, to enable formation of cubic group IV, group II-V and group II-VI crystals in the [111] orientation on the basal (0001) plane of trigonal crystal substrates, controlled such that the volume percentage of primary twin crystal is reduced from about 40% to about 0.3%, compared to the majority single crystal. The control of stacking faults in this and other embodiments can yield single crystalline semiconductors based on these materials that are substantially without defects, or improved thermoelectric materials with twinned crystals for phonon scattering while maintaining electrical integrity. These methods can selectively yield a cubic-on-trigonal epitaxial semiconductor material in which the cubic layer is substantially either directly aligned, or 60 degrees-rotated from, the underlying trigonal material.

  12. Doped Contacts for High-Longevity Optically Activated, High Gain GaAs Photoconductive Semiconductor Switches

    SciTech Connect

    MAR,ALAN; LOUBRIEL,GUILLERMO M.; ZUTAVERN,FRED J.; O'MALLEY,MARTIN W.; HELGESON,WESLEY D.; BROWN,DARWIN JAMES; HJALMARSON,HAROLD P.; BACA,ALBERT G.; THORNTON,R.L.; DONALDSON,R.D.

    1999-12-17

    The longevity of high gain GaAs photoconductive semiconductor switches (PCSS) has been extended to over 100 million pulses. This was achieved by improving the ohmic contacts through the incorporation of a doped layer that is very effective in the suppression of filament formation, alleviating current crowding. Damage-free operation is now possible with virtually infinite expected lifetime at much higher current levels than before. The inherent damage-free current capacity of the bulk GaAs itself depends on the thickness of the doped layers and is at least 100A for a dopant diffusion depth of 4pm. The contact metal has a different damage mechanism and the threshold for damage ({approx}40A) is not further improved beyond a dopant diffusion depth of about 2{micro}m. In a diffusion-doped contact switch, the switching performance is not degraded when contact metal erosion occurs, unlike a switch with conventional contacts. This paper will compare thermal diffusion and epitaxial growth as approaches to doping the contacts. These techniques will be contrasted in terms of the fabrication issues and device characteristics.

  13. Doped Contacts for High-Longevity Optically Activated, High Gain GaAs Photoconductive Semiconductor Switches

    SciTech Connect

    Baca, A.G.; Brown, D.J.; Donaldson, R.D.; Helgeson, W.D.; Hjalmarson, H.P.; Loubriel, G.M.; Mar, A.; O'Malley, M.W.; Thornton, R.L.; Zutavern, F.J.

    1999-08-05

    The longevity of high gain GaAs photoconductive semiconductor switches (PCSS) has been extended to over 50 million pulses. This was achieved by improving the ohmic contacts through the incorporation of a doped layer beneath the PCSS contacts which is very effective in the suppression of filament formation and alleviating current crowding to improve the longevity of PCSS. Virtually indefinite, damage-free operation is now possible at much higher current levels than before. The inherent damage-free current capacity of the switch depends on the thickness of the doped layers and is at least 100A for a dopant diffusion depth of 4pm. The contact metal has a different damage mechanism and the threshold for damage ({approximately}40A) is not further improved beyond a dopant diffusion depth of about 2{micro}m. In a diffusion-doped contact switch, the switching performance is not degraded when contact metal erosion occurs. This paper will compare thermal diffusion and epitaxial growth as approaches to doping the contacts. These techniques will be contrasted in terms of the fabrication issues and device characteristics.

  14. One dimensional semiconductor nanostructures: An effective active-material for terahertz detection

    SciTech Connect

    Vitiello, Miriam S. Viti, Leonardo; Ercolani, Daniele; Sorba, Lucia; Coquillat, Dominique; Knap, Wojciech

    2015-02-01

    One-dimensional (1D) nanostructure devices are at the frontline of studies on future electronics, although issues like massive parallelization, doping control, surface effects, and compatibility with silicon industrial requirements are still open challenges. The recent progresses in atomic to nanometer scale control of materials morphology, size, and composition including the growth of axial, radial, and branched nanowire (NW)-based heterostructures make the NW an ideal building block for implementing rectifying diodes or detectors that could be well operated into the Terahertz (THz), thanks to their typical achievable attofarad-order capacitance. Here, we report on our recent progresses in the development of 1D InAs or InAs/InSb NW-based field effect transistors exploiting novel morphologies and/or material combinations effective for addressing the goal of a semiconductor plasma-wave THz detector array technology. Through a critical review of material-related parameters (NW doping concentration, geometry, and/or material choice) and antenna-related issues, here we underline the crucial aspects that can affect detection performance across the THz frequency region.

  15. Optimization of Vertical Double-Diffused Metal-Oxide Semiconductor (VDMOS) Power Transistor Structure for Use in High Frequencies and Medical Devices.

    PubMed

    Farhadi, Rozita; Farhadi, Bita

    2014-01-01

    Power transistors, such as the vertical, double-diffused, metal-oxide semiconductor (VDMOS), are used extensively in the amplifier circuits of medical devices. The aim of this research was to construct a VDMOS power transistor with an optimized structure to enhance the operation of medical devices. First, boron was implanted in silicon by implanting unclamped inductive switching (UIS) and a Faraday shield. The Faraday shield was implanted in order to replace the gate-field parasitic capacitor on the entry part of the device. Also, implanting the UIS was used in order to decrease the effect of parasitic bipolar junction transistor (BJT) of the VDMOS power transistor. The research tool used in this study was Silvaco software. By decreasing the transistor entry resistance in the optimized VDMOS structure, power losses and noise at the entry of the transistor were decreased, and, by increasing the breakdown voltage, the lifetime of the VDMOS transistor lifetime was increased, which resulted in increasing drain flow and decreasing Ron. This consequently resulted in enhancing the operation of high-frequency medical devices that use transistors, such as Radio Frequency (RF) and electrocardiograph machines.

  16. GaAs metal-oxide-semiconductor based non-volatile flash memory devices with InAs quantum dots as charge storage nodes

    SciTech Connect

    Islam, Sk Masiul Chowdhury, Sisir; Sarkar, Krishnendu; Nagabhushan, B.; Banerji, P.; Chakraborty, S.

    2015-06-24

    Ultra-thin InP passivated GaAs metal-oxide-semiconductor based non-volatile flash memory devices were fabricated using InAs quantum dots (QDs) as charge storing elements by metal organic chemical vapor deposition technique to study the efficacy of the QDs as charge storage elements. The grown QDs were embedded between two high-k dielectric such as HfO{sub 2} and ZrO{sub 2}, which were used for tunneling and control oxide layers, respectively. The size and density of the QDs were found to be 5 nm and 1.8×10{sup 11} cm{sup −2}, respectively. The device with a structure Metal/ZrO{sub 2}/InAs QDs/HfO{sub 2}/GaAs/Metal shows maximum memory window equivalent to 6.87 V. The device also exhibits low leakage current density of the order of 10{sup −6} A/cm{sup 2} and reasonably good charge retention characteristics. The low value of leakage current in the fabricated memory device is attributed to the Coulomb blockade effect influenced by quantum confinement as well as reduction of interface trap states by ultra-thin InP passivation on GaAs prior to HfO{sub 2} deposition.

  17. Technology breakthroughs in high performance metal-oxide-semiconductor devices for ultra-high density, low power non-volatile memory applications

    NASA Astrophysics Data System (ADS)

    Hong, Augustin Jinwoo

    Non-volatile memory devices have attracted much attention because data can be retained without power consumption more than a decade. Therefore, non-volatile memory devices are essential to mobile electronic applications. Among state of the art non-volatile memory devices, NAND flash memory has earned the highest attention because of its ultra-high scalability and therefore its ultra-high storage capacity. However, human desire as well as market competition requires not only larger storage capacity but also lower power consumption for longer battery life time. One way to meet this human desire and extend the benefits of NAND flash memory is finding out new materials for storage layer inside the flash memory, which is called floating gate in the state of the art flash memory device. In this dissertation, we study new materials for the floating gate that can lower down the power consumption and increase the storage capacity at the same time. To this end, we employ various materials such as metal nanodot, metal thin film and graphene incorporating complementary-metal-oxide-semiconductor (CMOS) compatible processes. Experimental results show excellent memory effects at relatively low operating voltages. Detailed physics and analysis on experimental results are discussed. These new materials for data storage can be promising candidates for future non-volatile memory application beyond the state of the art flash technologies.

  18. A Novel Step-Doping Fully-Depleted Silicon-on-Insulator Metal-Oxide-Semiconductor Field-Effect Transistor for Reliable Deep Sub-micron Devices

    NASA Astrophysics Data System (ADS)

    Elahipanah, Hossein; Orouji, Ali A.

    2009-11-01

    For first time, we report a novel deep sub-micron fully-depleted silicon-on-insulator metal-oxide-semiconductor field-effect-transistor (FD SOI MOSFET) where the channel layer consists of two sections with a step doping (SD) region in order to increase performance and reliability of the device. This new structure that called SD FD SOI structure (SDFD-SOI MOSFET), were used for reaching suitable threshold voltage upon device scaling and reliability improvement. We demonstrate that the electric field was modified in the channel and common peak near the source junction have been reduced in the SDFD-SOI structure. The device demonstrates large enhancements in performance areas such as current drive capability, output resistance, hot-carrier reliability and threshold voltage roll-off. It was found that the device performance is very much dependent upon the SD region parameters. Simulation results show that the proposed structure improved on/off current ratio, and saturated output characteristics compared with conventional SOI structure (C-SOI MOSFET). Also, it was shown that substrate current of SDFD-SOI MOSFET is much lower than the C-SOI MOSFET which presented the lower hot-carrier degradation in proposed MOSFET. Results show that the most short-channel problems in very large scale integrated circuits (VLSI) could be solved and the proposed SDFD-SOI MOSFETs can work very well in deep sub-micron and nanoscale regime.

  19. Optimization of Vertical Double-Diffused Metal-Oxide Semiconductor (VDMOS) Power Transistor Structure for Use in High Frequencies and Medical Devices.

    PubMed

    Farhadi, Rozita; Farhadi, Bita

    2014-01-01

    Power transistors, such as the vertical, double-diffused, metal-oxide semiconductor (VDMOS), are used extensively in the amplifier circuits of medical devices. The aim of this research was to construct a VDMOS power transistor with an optimized structure to enhance the operation of medical devices. First, boron was implanted in silicon by implanting unclamped inductive switching (UIS) and a Faraday shield. The Faraday shield was implanted in order to replace the gate-field parasitic capacitor on the entry part of the device. Also, implanting the UIS was used in order to decrease the effect of parasitic bipolar junction transistor (BJT) of the VDMOS power transistor. The research tool used in this study was Silvaco software. By decreasing the transistor entry resistance in the optimized VDMOS structure, power losses and noise at the entry of the transistor were decreased, and, by increasing the breakdown voltage, the lifetime of the VDMOS transistor lifetime was increased, which resulted in increasing drain flow and decreasing Ron. This consequently resulted in enhancing the operation of high-frequency medical devices that use transistors, such as Radio Frequency (RF) and electrocardiograph machines. PMID:25763152

  20. Micro- and Nanostructured Materials for Active Devices and Molecular Electronics

    SciTech Connect

    Martin, Peter M.; Graff, Gordon L.; Gross, Mark E.; Burrows, Paul E.; Bennett, Wendy D.; Mast, Eric S.; Hall, Michael G.; Bonham, Charles C.; Zumhoff, Mac R.; Williford, Rick E.

    2003-10-01

    Traditional single layer barrier coatings are not adequate in preventing degradation of the performance of organic molecular electronic and other active devices. Most advanced devices used in display technology now consist of micro and nanostructured small molecule, polymer and inorganic coatings with thin high reactive group 1A metals. This includes organic electronics such as organic light emitting devices (OLED). The lifetimes of these devices rapidly degrades when they are exposed to atmospheric oxygen and water vapor. Thin film photovoltaics and batteries are also susceptible to degradation by moisture and oxygen. Using in-line coating techniques we apply a composite nanostructured inorganic/polymer thin film barrier that restricts moisture and oxygen permeation to undetectable levels using conventional permeation test equipment. We describe permeation mechanisms for this encapsulation coating and flat panel display and other device applications. Permeation through the multilayer barrier coating is defect and pore limited and can be described by Knudsen diffusion involving a long and tortuous path. Device lifetime is also enhanced by the long lag times required to reach the steady state flux regime. Permeation rates in the range of 10-6 cc,g/m2/d have been achieved and OLED device lifetimes. The structure is robust, yet flexible. The resulting device performance and lifetimes will also be described. The barrier film can be capped with a thin film of transparent conductive oxide yielding an engineered nanostructured device for next generation, rugged, lightweight or flexible displays. This enables, for the first time, thin film encapsulation of emissive organic displays.

  1. Brain activity during stepping: a novel MRI-compatible device.

    PubMed

    Hollnagel, Christoph; Brügger, Mike; Vallery, Heike; Wolf, Peter; Dietz, Volker; Kollias, Spyros; Riener, Robert

    2011-09-30

    Little is known about the impact of supraspinal centers on the control of human locomotion. Analyzing brain activity can help to clarify their impact and to improve the effects of locomotor training. A fMRI-compatible pneumatic robotic device is presented that can generate freely programmable, highly repetitive periodic active and passive leg movements comprised by hip, knee, and ankle joint displacements. Forces of up to 400N can be applied to each foot while the subject is lying in a supine position. Magnetic interference of the device with the magnetic field of the scanner is measurable, but does not affect the image quality as obtained by a usual image analysis procedure. In a first experiment, brain activity of one healthy subject was acquired during nine different gait-like movement conditions. Brain activity in the somatosensory and motor function related areas increased more when the subject actively moved the legs than when the legs were passively moved by the device. In almost all conditions, mean head motion could be limited to 2mm within the duration of one fMRI scan by a specifically developed head and trunk fixation system. Based on these results, it is concluded that our device will significantly contribute to a better understanding of human locomotor control and related therapeutic effects in spinal cord injured and stroke patients, and thereby, to improve training approaches. PMID:21827788

  2. Effect of NO annealing on charge traps in oxide insulator and transition layer for 4H-SiC metal–oxide–semiconductor devices

    NASA Astrophysics Data System (ADS)

    Jia, Yifan; Lv, Hongliang; Niu, Yingxi; Li, Ling; Song, Qingwen; Tang, Xiaoyan; Li, Chengzhan; Zhao, Yanli; Xiao, Li; Wang, Liangyong; Tang, Guangming; Zhang, Yimen; Zhang, Yuming

    2016-09-01

    The effect of nitric oxide (NO) annealing on charge traps in the oxide insulator and transition layer in n-type 4H–SiC metal–oxide–semiconductor (MOS) devices has been investigated using the time-dependent bias stress (TDBS), capacitance–voltage (C–V), and secondary ion mass spectroscopy (SIMS). It is revealed that two main categories of charge traps, near interface oxide traps (Nniot) and oxide traps (Not), have different responses to the TDBS and C–V characteristics in NO-annealed and Ar-annealed samples. The Nniot are mainly responsible for the hysteresis occurring in the bidirectional C–V characteristics, which are very close to the semiconductor interface and can readily exchange charges with the inner semiconductor. However, Not is mainly responsible for the TDBS induced C–V shifts. Electrons tunneling into the Not are hardly released quickly when suffering TDBS, resulting in the problem of the threshold voltage stability. Compared with the Ar-annealed sample, Nniot can be significantly suppressed by the NO annealing, but there is little improvement of Not. SIMS results demonstrate that the Nniot are distributed within the transition layer, which correlated with the existence of the excess silicon. During the NO annealing process, the excess Si atoms incorporate into nitrogen in the transition layer, allowing better relaxation of the interface strain and effectively reducing the width of the transition layer and the density of Nniot. Project supported by the National Natural Science Foundation of China (Grant Nos. 61404098 and 61274079), the Doctoral Fund of Ministry of Education of China (Grant No. 20130203120017), the National Key Basic Research Program of China (Grant No. 2015CB759600), the National Grid Science & Technology Project, China (Grant No. SGRI-WD-71-14-018), and the Key Specific Project in the National Science & Technology Program, China (Grant Nos. 2013ZX02305002-002 and 2015CB759600).

  3. Effect of NO annealing on charge traps in oxide insulator and transition layer for 4H-SiC metal-oxide-semiconductor devices

    NASA Astrophysics Data System (ADS)

    Jia, Yifan; Lv, Hongliang; Niu, Yingxi; Li, Ling; Song, Qingwen; Tang, Xiaoyan; Li, Chengzhan; Zhao, Yanli; Xiao, Li; Wang, Liangyong; Tang, Guangming; Zhang, Yimen; Zhang, Yuming

    2016-09-01

    The effect of nitric oxide (NO) annealing on charge traps in the oxide insulator and transition layer in n-type 4H-SiC metal-oxide-semiconductor (MOS) devices has been investigated using the time-dependent bias stress (TDBS), capacitance-voltage (C-V), and secondary ion mass spectroscopy (SIMS). It is revealed that two main categories of charge traps, near interface oxide traps (Nniot) and oxide traps (Not), have different responses to the TDBS and C-V characteristics in NO-annealed and Ar-annealed samples. The Nniot are mainly responsible for the hysteresis occurring in the bidirectional C-V characteristics, which are very close to the semiconductor interface and can readily exchange charges with the inner semiconductor. However, Not is mainly responsible for the TDBS induced C-V shifts. Electrons tunneling into the Not are hardly released quickly when suffering TDBS, resulting in the problem of the threshold voltage stability. Compared with the Ar-annealed sample, Nniot can be significantly suppressed by the NO annealing, but there is little improvement of Not. SIMS results demonstrate that the Nniot are distributed within the transition layer, which correlated with the existence of the excess silicon. During the NO annealing process, the excess Si atoms incorporate into nitrogen in the transition layer, allowing better relaxation of the interface strain and effectively reducing the width of the transition layer and the density of Nniot. Project supported by the National Natural Science Foundation of China (Grant Nos. 61404098 and 61274079), the Doctoral Fund of Ministry of Education of China (Grant No. 20130203120017), the National Key Basic Research Program of China (Grant No. 2015CB759600), the National Grid Science & Technology Project, China (Grant No. SGRI-WD-71-14-018), and the Key Specific Project in the National Science & Technology Program, China (Grant Nos. 2013ZX02305002-002 and 2015CB759600).

  4. Laser-based irradiation apparatus and methods for monitoring the dose-rate response of semiconductor devices

    DOEpatents

    Horn, Kevin M.

    2006-03-28

    A scanned, pulsed, focused laser irradiation apparatus can measure and image the photocurrent collection resulting from a dose-rate equivalent exposure to infrared laser light across an entire silicon die. Comparisons of dose-rate response images or time-delay images from before, during, and after accelerated aging of a device, or from periodic sampling of devices from fielded operational systems allows precise identification of those specific age-affected circuit structures within a device that merit further quantitative analysis with targeted materials or electrical testing techniques. Another embodiment of the invention comprises a broad-beam, dose rate-equivalent exposure apparatus. The broad-beam laser irradiation apparatus can determine if aging has affected the device's overall functionality. This embodiment can be combined with the synchronized introduction of external electrical transients into a device under test to simulate the electrical effects of the surrounding circuitry's response to a radiation exposure.

  5. EDITORIAL The 23rd Nordic Semiconductor Meeting The 23rd Nordic Semiconductor Meeting

    NASA Astrophysics Data System (ADS)

    Ólafsson, Sveinn; Sveinbjörnsson, Einar

    2010-12-01

    A Nordic Semiconductor Meeting is held every other year with the venue rotating amongst the Nordic countries of Denmark, Finland, Iceland, Norway and Sweden. The focus of these meetings remains 'original research and science being carried out on semiconductor materials, devices and systems'. Reports on industrial activity have usually featured. The topics have ranged from fundamental research on point defects in a semiconductor to system architecture of semiconductor electronic devices. Proceedings from these events are regularly published as a topical issue of Physica Scripta. All of the papers in this topical issue have undergone critical peer review and we wish to thank the reviewers and the authors for their cooperation, which has been instrumental in meeting the high scientific standards and quality of the series. This meeting of the 23rd Nordic Semiconductor community, NSM 2009, was held at Háskólatorg at the campus of the University of Iceland, Reykjavik, Iceland, 14-17 June 2009. Support was provided by the University of Iceland. Almost 50 participants presented a broad range of topics covering semiconductor materials and devices as well as related material science interests. The conference provided a forum for Nordic and international scientists to present and discuss new results and ideas concerning the fundamentals and applications of semiconductor materials. The meeting aim was to advance the progress of Nordic science and thus aid in future worldwide technological advances concerning technology, education, energy and the environment. Topics Theory and fundamental physics of semiconductors Emerging semiconductor technologies (for example III-V integration on Si, novel Si devices, graphene) Energy and semiconductors Optical phenomena and optical devices MEMS and sensors Program 14 June Registration 13:00-17:00 15 June Meeting program 09:30-17:00 and Poster Session I 16 June Meeting program 09:30-17:00 and Poster Session II 17 June Excursion and dinner

  6. Photo-catalytic Activities of Plant Hormones on Semiconductor Nanoparticles by Laser-Activated Electron Tunneling and Emitting

    NASA Astrophysics Data System (ADS)

    Tang, Xuemei; Huang, Lulu; Zhang, Wenyang; Jiang, Ruowei; Zhong, Hongying

    2015-03-01

    Understanding of the dynamic process of laser-induced ultrafast electron tunneling is still very limited. It has been thought that the photo-catalytic reaction of adsorbents on the surface is either dependent on the number of resultant electron-hole pairs where excess energy is lost to the lattice through coupling with phonon modes, or dependent on irradiation photon wavelength. We used UV (355 nm) laser pulses to excite electrons from the valence band to the conduction band of titanium dioxide (TiO2), zinc oxide (ZnO) and bismuth cobalt zinc oxide (Bi2O3)0.07(CoO)0.03(ZnO)0.9 semiconductor nanoparticles with different photo catalytic properties. Photoelectrons are extracted, accelerated in a static electric field and eventually captured by charge deficient atoms of adsorbed organic molecules. A time-of-flight mass spectrometer was used to detect negative molecules and fragment ions generated by un-paired electron directed bond cleavages. We show that the probability of electron tunneling is determined by the strength of the static electric field and intrinsic electron mobility of semiconductors. Photo-catalytic dissociation or polymerization reactions of adsorbents are highly dependent on the kinetic energy of tunneling electrons as well as the strength of laser influx. By using this approach, photo-activities of phytohormones have been investigated.

  7. Photo-catalytic Activities of Plant Hormones on Semiconductor Nanoparticles by Laser-Activated Electron Tunneling and Emitting

    PubMed Central

    Tang, Xuemei; Huang, Lulu; Zhang, Wenyang; Jiang, Ruowei; Zhong, Hongying

    2015-01-01

    Understanding of the dynamic process of laser-induced ultrafast electron tunneling is still very limited. It has been thought that the photo-catalytic reaction of adsorbents on the surface is either dependent on the number of resultant electron-hole pairs where excess energy is lost to the lattice through coupling with phonon modes, or dependent on irradiation photon wavelength. We used UV (355 nm) laser pulses to excite electrons from the valence band to the conduction band of titanium dioxide (TiO2), zinc oxide (ZnO) and bismuth cobalt zinc oxide (Bi2O3)0.07(CoO)0.03(ZnO)0.9 semiconductor nanoparticles with different photo catalytic properties. Photoelectrons are extracted, accelerated in a static electric field and eventually captured by charge deficient atoms of adsorbed organic molecules. A time-of-flight mass spectrometer was used to detect negative molecules and fragment ions generated by un-paired electron directed bond cleavages. We show that the probability of electron tunneling is determined by the strength of the static electric field and intrinsic electron mobility of semiconductors. Photo-catalytic dissociation or polymerization reactions of adsorbents are highly dependent on the kinetic energy of tunneling electrons as well as the strength of laser influx. By using this approach, photo-activities of phytohormones have been investigated. PMID:25749635

  8. Photo-catalytic activities of plant hormones on semiconductor nanoparticles by laser-activated electron tunneling and emitting.

    PubMed

    Tang, Xuemei; Huang, Lulu; Zhang, Wenyang; Jiang, Ruowei; Zhong, Hongying

    2015-01-01

    Understanding of the dynamic process of laser-induced ultrafast electron tunneling is still very limited. It has been thought that the photo-catalytic reaction of adsorbents on the surface is either dependent on the number of resultant electron-hole pairs where excess energy is lost to the lattice through coupling with phonon modes, or dependent on irradiation photon wavelength. We used UV (355 nm) laser pulses to excite electrons from the valence band to the conduction band of titanium dioxide (TiO₂), zinc oxide (ZnO) and bismuth cobalt zinc oxide (Bi₂O₃)₀.₀₇(CoO)₀.₀₃(ZnO)₀.₉ semiconductor nanoparticles with different photo catalytic properties. Photoelectrons are extracted, accelerated in a static electric field and eventually captured by charge deficient atoms of adsorbed organic molecules. A time-of-flight mass spectrometer was used to detect negative molecules and fragment ions generated by un-paired electron directed bond cleavages. We show that the probability of electron tunneling is determined by the strength of the static electric field and intrinsic electron mobility of semiconductors. Photo-catalytic dissociation or polymerization reactions of adsorbents are highly dependent on the kinetic energy of tunneling electrons as well as the strength of laser influx. By using this approach, photo-activities of phytohormones have been investigated.

  9. New developments in power semiconductors

    NASA Technical Reports Server (NTRS)

    Sundberg, G. R.

    1983-01-01

    This paper represents an overview of some recent power semiconductor developments and spotlights new technologies that may have significant impact for aircraft electric secondary power. Primary emphasis will be on NASA-Lewis-supported developments in transistors, diodes, a new family of semiconductors, and solid-state remote power controllers. Several semiconductor companies that are moving into the power arena with devices rated at 400 V and 50 A and above are listed, with a brief look at a few devices.

  10. Stripline mount for semiconductor lasers

    SciTech Connect

    Dietrich, N.R.; Holbrook, W.R.; Johnson, A.F. Jr.; Zacharias, A.

    1988-08-02

    An arrangement for coupling a semiconductor optical device to a signal source, is described, the arrangement comprising a stripline transmission path having a predetermined characteristic impedance Z/sub 0/; and resistance means connected in series with the stripline transmission path, chosen to provide impedance matching between the stripline transmission path and an associated semiconductor optical device.

  11. Positive bias temperature instability in p-type metal-oxide-semiconductor devices with HfSiON/SiO{sub 2} gate dielectrics

    SciTech Connect

    Samanta, Piyas; Huang, Heng-Sheng; Chen, Shuang-Yuan; Liu, Chuan-Hsi; Cheng, Li-Wei

    2014-02-21

    We present a detailed investigation on positive-bias temperature stress (PBTS) induced degradation of nitrided hafnium silicate (HfSiON)/SiO{sub 2} gate stack in n{sup +}-poly crystalline silicon (polySi) gate p-type metal-oxide-semiconductor (pMOS) devices. The measurement results indicate that gate dielectric degradation is a composite effect of electron trapping in as-fabricated as well as newly generated neutral traps, resulting a significant amount of stress-induced leakage current and generation of surface states at the Si/SiO{sub 2} interface. Although, a significant amount of interface states are created during PBTS, the threshold voltage (V{sub T}) instability of the HfSiON based pMOS devices is primarily caused by electron trapping and detrapping. It is also shown that PBTS creates both acceptor- and donor-like interface traps via different depassivation mechanisms of the Si{sub 3} ≡ SiH bonds at the Si/SiO{sub 2} interface in pMOS devices. However, the number of donor-like interface traps ΔN{sub it}{sup D} is significantly greater than that of acceptor-like interface traps ΔN{sup A}{sub it}, resulting the PBTS induced net interface traps as donor-like.

  12. Thermophotovoltaic energy conversion device

    DOEpatents

    Charache, Greg W.; Baldasaro, Paul F.; Egley, James L.

    1998-01-01

    A thermophotovoltaic device and a method for making the thermophotovoltaic device. The device includes an n-type semiconductor material substrate having top and bottom surfaces, a tunnel junction formed on the top surface of the substrate, a region of active layers formed on top of the tunnel junction and a back surface reflector (BSR). The tunnel junction includes a layer of heavily doped n-type semiconductor material that is formed on the top surface of the substrate and a layer of heavily doped p-type semiconductor material formed on the n-type layer. An optional pseudomorphic layer can be formed between the n-type and p-type layers. A region of active layers is formed on top of the tunnel junction. This region includes a base layer of p-type semiconductor material and an emitter layer of n-type semiconductor material. An optional front surface window layer can be formed on top of the emitter layer. An optional interference filter can be formed on top of the emitter layer or the front surface window layer when it is used.

  13. Thermophotovoltaic energy conversion device

    DOEpatents

    Charache, G.W.; Baldasaro, P.F.; Egley, J.L.

    1998-05-19

    A thermophotovoltaic device and a method for making the thermophotovoltaic device are disclosed. The device includes an n-type semiconductor material substrate having top and bottom surfaces, a tunnel junction formed on the top surface of the substrate, a region of active layers formed on top of the tunnel junction and a back surface reflector (BSR). The tunnel junction includes a layer of heavily doped n-type semiconductor material that is formed on the top surface of the substrate and a layer of heavily doped p-type semiconductor material formed on the n-type layer. An optional pseudomorphic layer can be formed between the n-type and p-type layers. A region of active layers is formed on top of the tunnel junction. This region includes a base layer of p-type semiconductor material and an emitter layer of n-type semiconductor material. An optional front surface window layer can be formed on top of the emitter layer. An optional interference filter can be formed on top of the emitter layer or the front surface window layer when it is used. 1 fig.

  14. SEMICONDUCTOR DEVICES Structure optimization of a uni-traveling-carrier photodiode with introduction of a hydro-dynamic model

    NASA Astrophysics Data System (ADS)

    Guoyu, Li; Yejin, Zhang; Xiaojian, Li; Lilin, Tian

    2010-10-01

    Characteristics of a uni-traveling-carrier photodiode (UTC-PD) are investigated. A hydro-dynamic model is introduced which takes into account the electrons' velocity overshoot in the depletion region, which is a more accurate high speed device than using the normal drift—diffuse model. Based on previous results, two modified UTC-PDs are presented, and an optimized device is obtained, the bandwidth of which is more than twice that of the original.

  15. Rapid growth of thin and flexible organic semiconductor single crystal Anthracene by solution growth technique for device fabrication

    NASA Astrophysics Data System (ADS)

    Thirupugalmani, K.; Shanmugam, G.; Kannan, V.; Brahadeeswaran, S.

    2015-03-01

    Growth of thin and flexible organic semiconductor crystal Anthracene (AN) has been achieved in a very short duration. This simple, yet an effective approach was serendipitously found to yield high quality crystal with typical dimensions of 22×23×0.15-0.50 mm3 within a duration of about 30 min whereas a conventional method could take about 7-10 days to achieve similar dimensions. Further, these crystals were seen swirling and settling down slowly at the bottom of the growth flask. These factors were favorably utilized to place the Anthracene crystals firmly on prefabricated flexible substrates when they were kept in different heights within the solutions. This systematic approach also facilitated the fabrication of organic field effect transistor (OFET) and the results obtained were encouraging.

  16. Charge-flow structures as polymeric early-warning fire alarm devices. M.S. Thesis; [metal oxide semiconductors

    NASA Technical Reports Server (NTRS)

    Sechen, C. M.; Senturia, S. D.

    1977-01-01

    The charge-flow transistor (CFT) and its applications for fire detection and gas sensing were investigated. The utility of various thin film polymers as possible sensing materials was determined. One polymer, PAPA, showed promise as a relative humidity sensor; two others, PFI and PSB, were found to be particularly suitable for fire detection. The behavior of the charge-flow capacitor, which is basically a parallel-plate capacitor with a polymer-filled gap in the metallic tip electrode, was successfully modeled as an RC transmission line. Prototype charge-flow transistors were fabricated and tested. The effective threshold voltage of this metal oxide semiconductor was found to be dependent on whether surface or bulk conduction in the thin film was dominant. Fire tests with a PFI-coated CFT indicate good sensitivity to smouldering fires.

  17. Application of the transition semiconductor to semimetal in type II nanostructure superlattice for mid-infrared optoelectronic devices

    NASA Astrophysics Data System (ADS)

    Boutramine, Abderrazak; Nafidi, Abdelhakim; Barkissy, Driss; Hannour, Abdelkrim; Elanique, Abdellatif; Gouti, Thami El

    2016-04-01

    The present work is devoted to the study of band structure and band gap in symmetric InAs (d 1 = 25 Å)/GaSb (d 2 = 25 Å) type II superlattice. Our calculations were performed in the envelope function formalism with the valence band offset Λ = 570 meV. We discussed the semiconductor to semimetal transition and the evolutions of the fundamental band gap, E g (Γ), as a function of d 1, Λ and the temperature. This study suggests that a wide range of wavelength can be reached by adjusting d 1. In addition, E g (Γ, T) decreases from 288.7 to 230 meV in the range of 4.2-300 K, corresponding to the cutoff wavelength ranging from 4.3 to 5.4 µm. These latter results explain the recent experimental ones realized by C. Cervera et al. for our Λ = 588 meV.

  18. Rare earth ion implantation and optical activation in nitride semiconductors for multicolor emission

    NASA Astrophysics Data System (ADS)

    Ruterana, Pierre; Chauvat, Marie-Pierre; Lorenz, Katharina

    2015-04-01

    In order to understand the behavior of nitride semiconductors when submitted to ion implantation, we have used 300 keV europium at fluences from 1012 to above 1017 ions cm-2. Subsequently, Rutherford backscattering (RBS), x-ray diffraction (XRD), and transmission electron microscopy (TEM) were used to investigate the evolution of damage. The optical properties were investigated prior to and after annealing. It was found that the behavior of the three compounds (AlN, GaN InN) under ion implantation is rather different: whereas InN breaks down at very low fluences (˜1012 ions cm-2), the damage formation mechanisms are similar in AlN and GaN. In both compounds, extended defects such as stacking faults play a critical role. However, they exhibit different stability, as a consequence, GaN transforms to nanocrystalline state from the surface at a fluence of around 2.5 × 1015 ions cm-2, whereas AlN undergoes a chemical amorphization starting at the projected range (Rp), when implanted to extremely high Eu fluences >1017 ionscm-2. As for the optical activation, the formation of highly stable extended defects in these compounds constitutes a real challenge for the annealing of heavily doped layers, and it was noticed that for a substantial optical activation, the implantation fluences should be kept low (<1015 Eu at cm-2).

  19. SEMICONDUCTOR DEVICES Density-controllable nonvolatile memory devices having metal nanocrystals through chemical synthesis and assembled by spin-coating technique

    NASA Astrophysics Data System (ADS)

    Guangli, Wang; Yubin, Chen; Yi, Shi; Lin, Pu; Lijia, Pan; Rong, Zhang; Youdou, Zheng

    2010-12-01

    A novel two-step method is employed, for the first time, to fabricate nonvolatile memory devices that have metal nanocrystals. First, size-averaged Au nanocrystals are synthesized chemically; second, they are assembled into memory devices by a spin-coating technique at room temperature. This attractive approach makes it possible to tailor the diameter and control the density of nanocrystals individually. In addition, processes at room temperature prevent Au diffusion, which is a main concern for the application of metal nanocrystal-based memory. The experimental results, both the morphology characterization and the electrical measurements, reveal that there is an optimum density of nanocrystal monolayer to balance between long data retention and a large hysteresis memory window. At the same time, density-controllable devices could also feed the preferential emphasis on either memory window or retention time. All these facts confirm the advantages and novelty of our two-step method.

  20. Overview of the recent activities of the RD50 collaboration on radiation hardening of semiconductor detectors for the sLHC

    NASA Astrophysics Data System (ADS)

    Casse, Gianluigi

    2009-01-01

    The RD50 collaboration has been exploring the development of radiation hard semiconductor devices for very high-luminosity colliders since 2002. The target fluence to qualify detectors set by the anticipated dose for the innermost tracking layers of the future upgrade of the CERN large hadron collider (LHC) is 10 16 1 MeV neutron equivalent (n eq) cm -2. This is about an order of magnitude higher than the maximum dose for the most exposed silicon detectors in the current machine. RD50 investigates the radiation hardening of silicon sensors from many angles: improvement of the intrinsic tolerance of the substrate material, optimisation of the readout geometry and study of novel design of detectors. A review of some of the recent activities within RD50 is here presented.