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Sample records for hf-based high-k gate

  1. Electronic structure characterization of La incorporated Hf-based high-k gate dielectrics by NEXAFS.

    PubMed

    Yamamoto, Takashi; Ogawa, Singo; Kunisu, Masahiro; Tsuji, Junichi; Kita, Koji; Saeki, Masayuki; Oku, Yudai; Arimura, Hiroaki; Kitano, Naomu; Hosoi, Takuji; Shimura, Takayoshi; Watanabe, Heiji

    2011-04-01

    The electronic structures of lanthunum (La) incorporated hafnium (Hf)-based oxides (HfLaO) and their silicate (HfLaSiO) films were investigated by the Near Edge X-ray Absorption Fine Structure (NEXAFS) technique. The oxygen (O) K-edge spectra, which reflected the hybridized Hf 5d state with the O 2p orbital, were found to reveal features of the unoccupied state of the metal oxides, as well as the conduction-band edge. We also found that, while La incorporation into the Hf-based oxides simply changed the features of the conduction-band structure, subsequent thermal annealing of the La-incorporated films led to a conduction-band edge shift due to an interface silicate reaction and/or local bond rearrangement depending on the La concentration and annealing temperature. The impact of La incorporation into the Hf-based high-k materials on the electronic structure is discussed by taking into account the intrinsic nature of these metal oxides.

  2. Thermal response of Ru electrodes in contact with SiO2 and Hf-based high-k gate dielectrics

    NASA Astrophysics Data System (ADS)

    Wen, H.-C.; Lysaght, P.; Alshareef, H. N.; Huffman, C.; Harris, H. R.; Choi, K.; Senzaki, Y.; Luan, H.; Majhi, P.; Lee, B. H.; Campin, M. J.; Foran, B.; Lian, G. D.; Kwong, D.-L.

    2005-08-01

    A systematic experimental evaluation of the thermal stability of Ru metal gate electrodes in direct contact with SiO2 and Hf-based dielectric layers was performed and correlated with electrical device measurements. The distinctly different interfacial reactions in the Ru /SiO2, Ru /HfO2, and Ru /HfSiOx film systems were observed through cross-sectional high-resolution transmission electron microscopy, high angle annular dark field scanning transmission electron microscopy with electron-energy-loss spectra, and energy dispersive x-ray spectra analysis. Ru interacted with SiO2, but remained stable on HfO2 at 1000°C. The onset of Ru /SiO2 interfacial interactions is identified via silicon substrate pitting possibly from Ru diffusion into the dielectric in samples exposed to a 900°C/10-s anneal. The dependence of capacitor device degradation with decreasing SiO2 thickness suggests Ru diffuses through SiO2, followed by an abrupt, rapid, nonuniform interaction of ruthenium silicide as Ru contacts the Si substrate. Local interdiffusion detected on Ru /HfSiOx samples may be due to phase separation of HfSiOx into HfO2 grains within a SiO2 matrix, suggesting that SiO2 provides a diffusion pathway for Ru. Detailed evidence consistent with a dual reaction mechanism for the Ru /SiO2 system at 1000°C is presented.

  3. Interface engineering and chemistry of Hf-based high-k dielectrics on III-V substrates

    NASA Astrophysics Data System (ADS)

    He, Gang; Chen, Xiaoshuang; Sun, Zhaoqi

    2013-03-01

    Recently, III-V materials have been extensively studied as potential candidates for post-Si complementary metal-oxide-semiconductor (CMOS) channel materials. The main obstacle to implement III-V compound semiconductors for CMOS applications is the lack of high quality and thermodynamically stable insulators with low interface trap densities. Due to their excellent thermal stability and relatively high dielectric constants, Hf-based high-k gate dielectrics have been recently highlighted as the most promising high-k dielectrics for III-V-based devices. This paper provides an overview of interface engineering and chemistry of Hf-based high-k dielectrics on III-V substrates. We begin with a survey of methods developed for generating Hf-based high-k gate dielectrics. To address the impact of these hafnium based materials, their interfaces with GaAs as well as a variety of semiconductors are discussed. After that, the integration issues are highlighted, including the development of high-k deposition without Fermi level pinning, surface passivation and interface state, and integration of novel device structure with Si technology. Finally, we conclude this review with the perspectives and outlook on the future developments in this area. This review explores the possible influences of research breakthroughs of Hf-based gate dielectrics on the current and future applications for nano-MOSFET devices.

  4. SEMICONDUCTOR TECHNOLOGY: Wet etching characteristics of a HfSiON high-k dielectric in HF-based solutions

    NASA Astrophysics Data System (ADS)

    Yongliang, Li; Qiuxia, Xu

    2010-03-01

    The wet etching properties of a HfSiON high-k dielectric in HF-based solutions are investigated. HF-based solutions are the most promising wet chemistries for the removal of HfSiON, and etch selectivity of HF-based solutions can be improved by the addition of an acid and/or an alcohol to the HF solution. Due to densification during annealing, the etch rate of HfSiON annealed at 900 °C for 30 s is significantly reduced compared with as-deposited HfSiON in HF-based solutions. After the HfSiON film has been completely removed by HF-based solutions, it is not possible to etch the interfacial layer and the etched surface does not have a hydrophobic nature, since N diffuses to the interface layer or Si substrate formation of Si-N bonds that dissolves very slowly in HF-based solutions. Existing Si-N bonds at the interface between the new high-k dielectric deposit and the Si substrate may degrade the carrier mobility due to Coulomb scattering. In addition, we show that N2 plasma treatment before wet etching is not very effective in increasing the wet etch rate for a thin HfSiON film in our case.

  5. High-k metal-gate PMOS FinFET threshold voltage tuning with aluminum implantation

    NASA Astrophysics Data System (ADS)

    Rao, K. V.; Ngai, T.; Hobbs, C.; Rodgers, M.; Vivekanand, S.; Chavva, V.; Khaja, F.; Henry, T.; Shim, K. H.; Kirsch, P.; Jammy, R.

    2012-11-01

    In this work, we report the use of Aluminum ion implantation to modulate the threshold voltage for Hf-based high-k /TiN metal gate PMOS FinFETs on SOI. A positive 170mV VFB shift with 0.8Å reduction in CETinv was achieved by implanting Aluminum at shallow tilt angle into TiN on the sidewalls of FinFETs. The Al was thermally driven during the SD activation anneal to form dipoles in the high-k dielectric to tune the PMOS Vt, resulting in 8% performance improvement in PMOS Ion/Ioff, without degrading short channel effects. These results demonstrate key progress towards realizing multi-Vt FinFET device architectures for 20nm node and beyond. Remote interfacial layer scavenging of oxygen induced by the metal gate dopants has an added advantage of improving the CET, without impacting short channel behavior.

  6. Improvement of metal gate/high-k dielectric CMOSFETs characteristics by atomic layer etching of high-k gate dielectric

    NASA Astrophysics Data System (ADS)

    Min, K. S.; Park, C.; Kang, C. Y.; Park, C. S.; Park, B. J.; Kim, Y. W.; Lee, B. H.; Lee, Jack C.; Bersuker, G.; Kirsch, P.; Jammy, R.; Yeom, G. Y.

    2013-04-01

    Atomic layer etching (ALE) has been applied to the high-k dielectric patterning in complementary metal-oxide-semiconductor field effect transistors (CMOSFETs), and its electrical characteristics were compared with those etched by conventional etching such as wet etching (WE) or reactive ion etching (RIE). The CMOSFET etched by the ALE showed the improvement of the off-state leakage current (Ioff), which was mainly attributed to the decreased perimeter component of the gate leakage current (IG) particularly, at the low field region. The better electrical characteristics are due to the low trap density at the edge of gate oxides in the S/D region of CMOSFETs.

  7. On-current limitation of high-k gate insulator MOSFETs

    NASA Astrophysics Data System (ADS)

    Shih, Chun-Hsing; Wang, Jhong-Sheng; Chien, Nguyen Dang; Shia, Ruei-Kai

    2012-12-01

    This work explores the limitation of high-k gate insulator on improving the driving currents of MOSFET devices. The use of high-k gate dielectric prevents from the gate tunneling current to have an acceptable equivalent oxide thickness (EOT) in scaled MOSFETs. However, the effectiveness of continued EOT reduction in strengthening gate control is limited strongly by the non-scalability of the quantum effect of inversion layer thickness. Both classical and quantum-mechanical approaches of inversion layer thickness are presented to study the effective gate capacitances and associated on-state drain currents. The enhancements of drain current and gate capacitance generated by high-k gate dielectrics are gradually saturated when a higher permittivity dielectric is applied.

  8. Plasma etching of Hf-based high-k thin films. Part I. Effect of complex ions and radicals on the surface reactions

    SciTech Connect

    Martin, Ryan M.; Chang, Jane P.

    2009-03-15

    The effect of ion and radical compositions in BCl{sub 3}/Cl{sub 2} plasmas was assessed in this work with a focus on the formation of etch products in patterning hafnium aluminate, a potential high-k gate oxide material. The plasma composition became increasingly more complex as the percentage of boron trichloride was increased, which led to the formation of a significant amount of boron-containing species including B{sup +}, BCl{sup +}, BCl{sub 2}{sup +}, BCl{sub 3}{sup +}, B{sub 2}Cl{sub 3}{sup +}, and B{sub 2}OCl{sub 3}{sup +} in the plasma. The BCl{sub 2}{sup +} ions were found to be the dominant species in BCl{sub 3} containing plasmas at most conditions; however, increasing the pressure or decreasing the power led to an increase in the formation of higher mass ions. Several compositions of Hf{sub 1-x}Al{sub x}O{sub y} thin films ranging from pure HfO{sub 2} to pure Al{sub 2}O{sub 3} were etched in BCl{sub 3}/Cl{sub 2} plasmas as functions of ion energy and plasma composition. The etch product distributions were measured and the dominant metal-containing etch products were HfCl{sub x} and AlCl{sub x} in a Cl{sub 2} plasma and HfCl{sub x}, HfBOCl{sub 4}, and Al{sub x}Cl{sub y} in a BCl{sub 3} plasma, and their concentrations increased with increasing ion energy. Oxygen was detected removed in the form of ClO in Cl{sub 2} and as trichloroboroxin ((BOCl){sub 3}) in BCl{sub 3}. Both the etch rate and the etch product formation are enhanced in BCl{sub 3}/Cl{sub 2} plasmas, as compared to those in Cl{sub 2} plasmas, due to the change in the composition and reactivity of the dominant ions and radicals.

  9. 28nm FDSOI high-K metal gate CD variability investigation

    NASA Astrophysics Data System (ADS)

    Desvoivres, L.; Gouraud, P.; Le Gratiet, B.; Bouyssou, R.; Ranica, R.; Gallon, C.; Thomas, I.

    2014-03-01

    Planar Fully-Depleted (FD) Silicon On Insulator (SOI) MOSFET technology has already demonstrated large performance boost vs bulk at 28nm node (>30%) and is very competitive for incoming mobile & multimedia products thanks to design porting from bulk. Indeed, FDSOI is very attractive for low power applications due to its low sub threshold slope (~60mV/dec), better short channel effect (SCE) control and reduced junction capacitance. 28nm FDSOI devices highly depend on gate CD morphology because electrical effective gate length is driven by metal gate CD. High-k metal gate etching is therefore a key point to achieve these requirements. Gate profiles and metal gate CD control are mandatory and variability has to be minimized across the wafer (WiW), wafer to wafer and lot to lot. In this paper, we will focus on metal gate CD variability investigation. Once polysilicon gate profiles are frozen, metal gate profiles adjustment is achieved, based on scatterometry metal gate profiles measurements, TEM analysis and electrical results. Thanks to this methodology, a metal gate etching process has been tuned on 300mm industrial platform etcher. This work was performed at ST Crolles 300 facility in collaboration between STMicroelectronics & CEA/LETI.

  10. A new analytical threshold voltage model for symmetrical double-gate MOSFETs with high- k gate dielectrics

    NASA Astrophysics Data System (ADS)

    Chiang, T. K.; Chen, M. L.

    2007-03-01

    Based on the fully two-dimensional (2D) Poisson's solution in both silicon film and insulator layer, a compact and analytical threshold voltage model, which accounts for the fringing field effect of the short channel symmetrical double-gate (SDG) MOSFETs, has been developed. Exploiting the new model, a concerned analysis combining FIBL-enhanced short-channel effects and high- k gate dielectrics assess their overall impact on SDG MOSFET's scaling. It is found that for the same equivalent oxide thickness, the gate insulator with high- k dielectric constant which keeps a great characteristic length allows less design space than SiO 2 to sustain the same FIBL induced threshold voltage degradation.

  11. Inorganic oxide core, polymer shell nanocomposite as a high K gate dielectric for flexible electronics applications.

    PubMed

    Maliakal, Ashok; Katz, Howard; Cotts, Pat M; Subramoney, Shekhar; Mirau, Peter

    2005-10-26

    Organic/inorganic core shell nanoparticles have been synthesized using high K TiO(2) as the core nanoparticle, and polystyrene as the shell. This material is easy to process and forms transparent continuous thin films, which exhibit a dielectric constant enhancement of over 3 times that of bulk polystyrene. This new dielectric material has been incorporated into capacitors and thin film transistors (TFTs). Mobilities approaching 0.2 cm(2)/V.s have been measured for pentacene TFTs incorporating the new TiO(2) polystyrene nanostructured gate dielectric, indicating good surface properties for pentacene film growth. This novel strategy for generating high K flexible gate dielectrics will be of value in improving organic and flexible electronic device performance.

  12. Investigation of High-k Dielectrics and Metal Gate Electrodes for Non-volatile Memory Applications

    NASA Astrophysics Data System (ADS)

    Jayanti, Srikant

    Due to the increasing demand of non-volatile flash memories in the portable electronics, the device structures need to be scaled down drastically. However, the scalability of traditional floating gate structures beyond 20 nm NAND flash technology node is uncertain. In this regard, the use of metal gates and high-k dielectrics as the gate and interpoly dielectrics respectively, seem to be promising substitutes in order to continue the flash scaling beyond 20nm. Furthermore, research of novel memory structures to overcome the scaling challenges need to be explored. Through this work, the use of high-k dielectrics as IPDs in a memory structure has been studied. For this purpose, IPD process optimization and barrier engineering were explored to determine and improve the memory performance. Specifically, the concept of high-k / low-k barrier engineering was studied in corroboration with simulations. In addition, a novel memory structure comprising a continuous metal floating gate was investigated in combination with high-k blocking oxides. Integration of thin metal FGs and high-k dielectrics into a dual floating gate memory structure to result in both volatile and non-volatile modes of operation has been demonstrated, for plausible application in future unified memory architectures. The electrical characterization was performed on simple MIS/MIM and memory capacitors, fabricated through CMOS compatible processes. Various analytical characterization techniques were done to gain more insight into the material behavior of the layers in the device structure. In the first part of this study, interfacial engineering was investigated by exploring La2O3 as SiO2 scavenging layer. Through the silicate formation, the consumption of low-k SiO2 was controlled and resulted in a significant improvement in dielectric leakage. The performance improvement was also gauged through memory capacitors. In the second part of the study, a novel memory structure consisting of continuous metal FG

  13. Impact of nitrogen depth profiles on the electrical properties of crystalline high-K gate dielectrics

    NASA Astrophysics Data System (ADS)

    Huang, Jhih-Jie; Tsai, Yi-Jen; Tsai, Meng-Chen; Huang, Li-Tien; Lee, Min-Hung; Chen, Miin-Jang

    2015-01-01

    The electrical characteristics of crystalline ZrO2 gate dielectrics with different nitrogen depth profiles were investigated, which were treated by the in-situ atomic layer doping of nitrogen and post-deposition nitridation processes, respectively, using remote NH3 plasma at a low treatment temperature of 250 °C. The crystalline ZrO2 gate dielectric of the tetragonal/cubic phase was formed by post-metallization annealing (PMA) at a low temperature of 450 °C, resulting in an increase of the dielectric constant. As compared with the in-situ atomic layer doping of nitrogen, the post-deposition nitrogen process leads to a lower capacitance equivalent thickness of 1.13 nm with a low leakage current density of 1.35 × 10-5 A/cm2. The enhanced capacitance density caused by the post-deposition nitrogen treatment may be ascribed to the high nitrogen concentration at the top surface of gate dielectric, giving rise to the suppression of oxygen diffusion from the ambient toward the interface and so a thinner interfacial layer. The result reveals that the nitrogen incorporation at the top surface of gate oxide is favorable to the scaling of crystalline high-K gate dielectrics.

  14. Analysis of high-k spacer on symmetric underlap DG-MOSFET with Gate Stack architecture

    NASA Astrophysics Data System (ADS)

    Das, Rahul; Chakraborty, Shramana; Dasgupta, Arpan; Dutta, Arka; Kundu, Atanu; Sarkar, Chandan K.

    2016-09-01

    This paper shows the systematic study of underlap double gate (U-DG) NMOSFETs with Gate Stack (GS) under the influence of high-k spacers. In highly scaled devices, underlap is used at the Source and Drain side so as to reduce the short channel effects (SCE's), however, it significantly reduces the on current due to the increased channel resistance. To overcome these drawbacks, the use of high-k spacers is projected as one of the remedies. In this paper, the analog performance of the devices is studied on the basis of parameters like transconductance (gm), transconductance generation factor (gm/Id) and intrinsic gain (gmro). The RF performance is analyzed on the merits of intrinsic capacitance (Cgd, Cgs), resistance (Rgd, Rgs), transport delay (τm), inductance (Lsd), cutoff frequency (fT), and the maximum frequency of oscillation (fmax). The circuit performance of the devices are studied by implementing the device as the driver MOSFET in a Single Stage Common Source Amplifier. The Gain Bandwidth Product (GBW) has been analyzed from the frequency response of the circuit.

  15. Investigation of high-k yttrium copper titanate thin films as alternative gate dielectrics

    NASA Astrophysics Data System (ADS)

    Grazia Monteduro, Anna; Ameer, Zoobia; Rizzato, Silvia; Martino, Maurizio; Caricato, Anna Paola; Tasco, Vittorianna; Chaitanya Lekshmi, Indira; Hazarika, Abhijit; Choudhury, Debraj; Sarma, D. D.; Maruccio, Giuseppe

    2016-10-01

    Nearly amorphous high-k yttrium copper titanate thin films deposited by laser ablation were investigated in both metal-oxide-semiconductor (MOS) and metal-insulator-metal (MIM) junctions in order to assess the potentialities of this material as a gate oxide. The trend of dielectric parameters with film deposition shows a wide tunability for the dielectric constant and AC conductivity, with a remarkably high dielectric constant value of up to 95 for the thick films and conductivity as low as 6  ×  10-10 S cm-1 for the thin films deposited at high oxygen pressure. The AC conductivity analysis points out a decrease in the conductivity, indicating the formation of a blocking interface layer, probably due to partial oxidation of the thin films during cool-down in an oxygen atmosphere. Topography and surface potential characterizations highlight differences in the thin film microstructure as a function of the deposition conditions; these differences seem to affect their electrical properties.

  16. Impact of Physical Vapor Deposition-Based In situ Fabrication Method on Metal/High-k Gate Stacks

    NASA Astrophysics Data System (ADS)

    Watanabe, Heiji; Horie, Shinya; Minami, Takashi; Kitano, Naomu; Kosuda, Motomu; Shimura, Takayoshi; Yasutake, Kiyoshi

    2007-04-01

    We proposed an in situ method for fabricating metal/high-k gate stacks. High-quality Hf silicate gate dielectrics were formed by utilizing a solid phase interface reaction (SPIR) between a metal Hf layer and an SiO2 underlayer, and TiN electrodes were continuously grown on the gate dielectrics using a low-damage sputtering system without exposure to air. We investigated the optimum SPIR conditions for TiN/HfSiO gate stacks, such as the thicknesses of the metal Hf and oxide underlayers, in situ annealing temperature, and oxygen pressure. The results indicate that the in situ method can be used to precisely control the SPIR to form silicate films and improve the electrical properties at metal/high-k interfaces. We demonstrated that the scaling of equivalent oxide thickness (EOT) was achieved and that the carbon impurity content at the gate stacks was successfully reduced by in situ silicate formation and continuous electrode deposition. As a consequence, we obtained excellent EOT versus gate leakage characteristics and succeeded in improving the hysteresis of capacitance-voltage curves for the TiN/HfSiO gate stacks.

  17. Implementation of nanoscale circuits using dual metal gate engineered nanowire MOSFET with high-k dielectrics for low power applications

    NASA Astrophysics Data System (ADS)

    Charles Pravin, J.; Nirmal, D.; Prajoon, P.; Ajayan, J.

    2016-09-01

    This work covers the impact of dual metal gate engineered Junctionless MOSFET with various high-k dielectric in Nanoscale circuits for low power applications. Due to gate engineering in junctionless MOSFET, graded potential is obtained and results in higher electron velocity of about 31% for HfO2 than SiO2 in the channel region, which in turn improves the carrier transport efficiency. The simulation is done using sentaurus TCAD, ON current, OFF current, ION/IOFF ratio, DIBL, gain, transconductance and transconductance generation factor parameters are analysed. When using HfO2, DIBL shows a reduction of 61.5% over SiO2. The transconductance and transconductance generation factor shows an improvement of 44% and 35% respectively. The gain and output resistance also shows considerable improvement with high-k dielectrics. Using this device, inverter circuit is implemented with different high-k dielectric material and delay have been decreased by 4% with HfO2 when compared to SiO2. In addition, a significant reduction in power dissipation of the inverter circuit is obtained with high-k dielectric Dual Metal Surround Gate Junctionless Transistor than SiO2 based device. From the analysis, it is found that HfO2 will be a better alternative for the future nanoscale device.

  18. A high-k ferroelectric relaxor terpolymer as a gate dielectric for orgnaic thin film transistors

    SciTech Connect

    Wu, Shan; Shao, Ming; Burlingame, Quinn; Chen, Xiangzhong; Lin, Minren; Xiao, Kai; Zhang, Qiming

    2013-01-01

    Poly(vinylidenefluoride-trifluoroethylene-chlorofluoroethylene) (P(VDF-TrFE-CFE)) is a ferroelectric terpolymer relaxor with a static dielectric constant of 50, which was developed using defect modification to eliminate remnant polarization in the normal ferroelectric PVDF. In this work, this solution processable terpolymer was used as the gate insulator in bottom gated organic thin-film transistors with a pentacene semiconductor layer. Due to the high dielectric constant of P(VDF-TrFE- CFE), a large capacitive coupling between the gate and channel can be achieved which causes a high charge concentration at the interface of the semiconductor and dielectric layers. In this device, an on/ off ratio of 104 and a low minimum operation gate voltage (5-10 V) were attained

  19. A new 28 nm high-k metal gate CMOS logic one-time programmable memory cell

    NASA Astrophysics Data System (ADS)

    Hsiao, Woan Yun; Mei, Chin Yu; Chao Shen, Wen; Der Chih, Yue; King, Ya-Chin; Lin, Chrong Jung

    2014-01-01

    This work presents a high density high-k metal gate (HKMG) one-time programmable (OTP) cell. Without additional processes and steps, this OTP cell is fully compatible to 28 nm HKMG CMOS process. The OTP cell adopts high-k dielectric breakdown as programming mechanism to obtain more than 105 times of on/off read window. Moreover, it features low power and fast program speed by 4.5 V program voltage in 100 µs. In addition to the ultrasmall cell area of 0.0425 µm2, the superior performance of disturb immunities and data retention further support the new logic OTP cell to be a very promising solution in advanced logic non-volatile memory (NVM) applications.

  20. Effect of high-k and vacuum dielectrics as gate stack on a junctionless cylindrical surrounding gate (JL-CSG) MOSFET

    NASA Astrophysics Data System (ADS)

    Sharma, Aniruddh; Jain, Arushi; Pratap, Yogesh; Gupta, R. S.

    2016-09-01

    In this paper, the impact of asymmetric gate stack architecture using a combination of vacuum and high-k dielectrics on a junctionless cylindrical surrounding gate (JL-CSG) MOSFET has been investigated. A comparative evaluation of short channel effects (SCEs) for various device structures has also been carried out with figure of merit (FOM) metrics such as electric field, electron temperature, drain current (Ids), and drain induced barrier lowering (DIBL). A two-dimensional analytical model has been developed for the asymmetric architecture using Poisson's equation in cylindrical coordinates assuming a parabolic potential profile. It is observed that the asymmetric gate stack device demonstrates effectiveness in suppressing hot carrier degradation and short channel effects along with improving the current drivability of the device as compared to the other device configurations. The analytical results have been verified with the simulated data obtained from ATLAS 3-D device simulator.

  1. Combining a multi deposition multi annealing technique with a scavenging (Ti) to improve the high-k/metal gate stack performance for a gate-last process

    NASA Astrophysics Data System (ADS)

    ShuXiang, Zhang; Hong, Yang; Bo, Tang; Zhaoyun, Tang; Yefeng, Xu; Jing, Xu; Jiang, Yan

    2014-10-01

    ALD HfO2 films fabricated by a novel multi deposition multi annealing (MDMA) technique are investigated, we have included samples both with and without a Ti scavenging layer. As compared to the reference gate stack treated by conventional one-time deposition and annealing (D&A), devices receiving MDMA show a significant reduction in leakage current. Meanwhile, EOT growth is effectively controlled by the Ti scavenging layer. This improvement strongly correlates with the cycle number of D&A (while keeping the total annealing time and total dielectrics thickness the same). Transmission electron microscope and energy-dispersive X-ray spectroscopy analysis suggests that oxygen incorporation into both the high-k film and the interfacial layer is likely to be responsible for the improvement of the device. This novel MDMA is promising for the development of gate stack technology in a gate last integration scheme.

  2. Band Offsets of a Ruthenium Gate on Ultrathin High-k Oxide Films on Silicon

    SciTech Connect

    Rangan, S.; Bersch, W; Bartynski, R; Garfunkel, E; Vescovo, E

    2009-01-01

    Valence-band and conduction-band edges of ultrathin oxides and their shifts upon sequential metallization with ruthenium have been measured using synchrotron-radiation-excited x-ray, ultraviolet, and inverse photoemissions. From these techniques, the offsets between the valence-band and conduction-band edges of the oxides, and the ruthenium metal gate Fermi edge have been directly measured. In addition the core levels of the oxides and the ruthenium have been characterized. Upon deposition, Ru remains metallic and no chemical alteration of the underlying oxide gates, or interfacial SiO{sub 2} in the case of the high-? thin films, can be detected. However a clear shift of the band edges is measured for all samples due to the creation of an interface dipole at the ruthenium-oxide interface. Using the energy gap, the electron affinity of the oxides, and the ruthenium work function that have been directly measured on these samples, the experimental band offsets are compared to those predicted by the induced gap states model.

  3. Cross-linking high-k fluoropolymer gate dielectrics enhances the charge mobility in rubrene field effect transistors

    NASA Astrophysics Data System (ADS)

    Adhikari, Jwala; Gadinski, Matthew; Wang, Qing; Gomez, Enrique

    2015-03-01

    Polymer dielectrics are promising materials where the chemical flexibility enables gate insulators with desired properties. For example, polar groups can be introduced to enhance the dielectric constant, although fluctuations in chain conformations at the semiconductor-dielectric interface can introduce energetic disorder and limit charge mobilities in thin-film transistors. Here, we demonstrate a photopatternable high-K fluoropolymer, poly(vinylidene fluoride-bromotrifluoroethylene) P(VDF-BTFE), with a dielectric constant between 8 and 11. The bromotrifluoroethylene moiety enables photo-crosslinking and stabilization of gate insulator films while also significantly enhancing the population of trans torsional conformations of the chains. Using rubrene single crystals as the active layer, charge mobilities exceeding 10 cm2/Vs are achieved in thin film transistors with cross-linked P(VDF-BTFE) gate dielectrics. We hypothesize that crosslinking reduces energetic disorder at the dielectric-semiconductor interface by suppressing segmental motion and controlling chain conformations of P(VDF-BTFE), thereby leading to approximately a three-fold enhancement in the charge mobility of rubrene thin-film transistors over devices incorporating uncross-linked dielectrics or silicon oxide. Center for Flexible Electronic, Penn State; The Dow Chemical Company.

  4. The understanding on the evolution of stress-induced gate leakage in high-k dielectric metal-oxide-field-effect transistor by random-telegraph-noise measurement

    NASA Astrophysics Data System (ADS)

    Hsieh, E. R.; Chung, Steve S.

    2015-12-01

    The evolution of gate-current leakage path has been observed and depicted by RTN signals on metal-oxide-silicon field effect transistor with high-k gate dielectric. An experimental method based on gate-current random telegraph noise (Ig-RTN) technique was developed to observe the formation of gate-leakage path for the device under certain electrical stress, such as Bias Temperature Instability. The results show that the evolution of gate-current path consists of three stages. In the beginning, only direct-tunnelling gate current and discrete traps inducing Ig-RTN are observed; in the middle stage, interaction between traps and the percolation paths presents a multi-level gate-current variation, and finally two different patterns of the hard or soft breakdown path can be identified. These observations provide us a better understanding of the gate-leakage and its impact on the device reliability.

  5. Comprehensive study and design of scaled metal/high-k/Ge gate stacks with ultrathin aluminum oxide interlayers

    NASA Astrophysics Data System (ADS)

    Asahara, Ryohei; Hideshima, Iori; Oka, Hiroshi; Minoura, Yuya; Ogawa, Shingo; Yoshigoe, Akitaka; Teraoka, Yuden; Hosoi, Takuji; Shimura, Takayoshi; Watanabe, Heiji

    2015-06-01

    Advanced metal/high-k/Ge gate stacks with a sub-nm equivalent oxide thickness (EOT) and improved interface properties were demonstrated by controlling interface reactions using ultrathin aluminum oxide (AlOx) interlayers. A step-by-step in situ procedure by deposition of AlOx and hafnium oxide (HfOx) layers on Ge and subsequent plasma oxidation was conducted to fabricate Pt/HfO2/AlOx/GeOx/Ge stacked structures. Comprehensive study by means of physical and electrical characterizations revealed distinct impacts of AlOx interlayers, plasma oxidation, and metal electrodes serving as capping layers on EOT scaling, improved interface quality, and thermal stability of the stacks. Aggressive EOT scaling down to 0.56 nm and very low interface state density of 2.4 × 1011 cm-2eV-1 with a sub-nm EOT and sufficient thermal stability were achieved by systematic process optimization.

  6. Low Temperature Deposition of High-k/Metal Gate Stacks on High-Sn Content (Si)GeSn-Alloys.

    PubMed

    Schulte-Braucks, C; von den Driesch, N; Glass, S; Tiedemann, A T; Breuer, U; Besmehn, A; Hartmann, J-M; Ikonic, Z; Zhao, Q T; Mantl, S; Buca, D

    2016-05-25

    (Si)GeSn is an emerging group IV alloy system offering new exciting properties, with great potential for low power electronics due to the fundamental direct band gap and prospects as high mobility material. In this Article, we present a systematic study of HfO2/TaN high-k/metal gate stacks on (Si)GeSn ternary alloys and low temperature processes for large scale integration of Sn based alloys. Our investigations indicate that SiGeSn ternaries show enhanced thermal stability compared to GeSn binaries, allowing the use of the existing Si technology. Despite the multielemental interface and large Sn content of up to 14 atom %, the HfO2/(Si)GeSn capacitors show small frequency dispersion and stretch-out. The formed TaN/HfO2/(Si)GeSn capacitors present a low leakage current of 2 × 10(-8) A/cm(2) at -1 V and a high breakdown field of ∼8 MV/cm. For large Sn content SiGeSn/GeSn direct band gap heterostructures, process temperatures below 350 °C are required for integration. We developed an atomic vapor deposition process for TaN metal gate on HfO2 high-k dielectric and validated it by resistivity as well as temperature and frequency dependent capacitance-voltage measurements of capacitors on SiGeSn and GeSn. The densities of interface traps are deduced to be in the low 10(12) cm(-2) eV(-1) range and do not depend on the Sn-concentration. The new processes developed here are compatible with (Si)GeSn integration in large scale applications. PMID:27149260

  7. Understanding the Structure of High-K Gate Oxides - Oral Presentation

    SciTech Connect

    Miranda, Andre

    2015-08-25

    Hafnium Oxide (HfO2) amorphous thin films are being used as gate oxides in transistors because of their high dielectric constant (κ) over Silicon Dioxide. The present study looks to find the atomic structure of HfO2 thin films which hasn’t been done with the technique of this study. In this study, two HfO2 samples were studied. One sample was made with thermal atomic layer deposition (ALD) on top of a Chromium and Gold layer on a silicon wafer. The second sample was made with plasma ALD on top of a Chromium and Gold layer on a Silicon wafer. Both films were deposited at a thickness of 50nm. To obtain atomic structure information, Grazing Incidence X-ray diffraction (GIXRD) was carried out on the HfO2 samples. Because of this, absorption, footprint, polarization, and dead time corrections were applied to the scattering intensity data collected. The scattering curves displayed a difference in structure between the ALD processes. The plasma ALD sample showed the broad peak characteristic of an amorphous structure whereas the thermal ALD sample showed an amorphous structure with characteristics of crystalline materials. This appears to suggest that the thermal process results in a mostly amorphous material with crystallites within. Further, the scattering intensity data was used to calculate a pair distribution function (PDF) to show more atomic structure. The PDF showed atom distances in the plasma ALD sample had structure up to 10 Å, while the thermal ALD sample showed the same structure below 10 Å. This structure that shows up below 10 Å matches the bond distances of HfO2 published in literature. The PDF for the thermal ALD sample also showed peaks up to 20 Å, suggesting repeating atomic spacing outside the HfO2 molecule in the sample. This appears to suggest that there is some crystalline structure within the thermal ALD sample.

  8. Temperature- and voltage-dependent trap generation model in high-k metal gate MOS device with percolation simulation

    NASA Astrophysics Data System (ADS)

    Xu, Hao; Yang, Hong; Wang, Yan-Rong; Wang, Wen-Wu; Luo, Wei-Chun; Qi, Lu-Wei; Li, Jun-Feng; Zhao, Chao; Chen, Da-Peng; Ye, Tian-Chun

    2016-08-01

    High-k metal gate stacks are being used to suppress the gate leakage due to tunneling for sub-45 nm technology nodes. The reliability of thin dielectric films becomes a limitation to device manufacturing, especially to the breakdown characteristic. In this work, a breakdown simulator based on a percolation model and the kinetic Monte Carlo method is set up, and the intrinsic relation between time to breakdown and trap generation rate R is studied by TDDB simulation. It is found that all degradation factors, such as trap generation rate time exponent m, Weibull slope β and percolation factor s, each could be expressed as a function of trap density time exponent α. Based on the percolation relation and power law lifetime projection, a temperature related trap generation model is proposed. The validity of this model is confirmed by comparing with experiment results. For other device and material conditions, the percolation relation provides a new way to study the relationship between trap generation and lifetime projection. Project supported by the National High Technology Research and Development Program of China (Grant No. SS2015AA010601), the National Natural Science Foundation of China (Grant Nos. 61176091 and 61306129), and the Opening Project of Key Laboratory of Microelectronics Devices & Integrated Technology, Institute of MicroElectronics of Chinese Academy of Sciences.

  9. Temperature- and voltage-dependent trap generation model in high-k metal gate MOS device with percolation simulation

    NASA Astrophysics Data System (ADS)

    Xu, Hao; Yang, Hong; Wang, Yan-Rong; Wang, Wen-Wu; Luo, Wei-Chun; Qi, Lu-Wei; Li, Jun-Feng; Zhao, Chao; Chen, Da-Peng; Ye, Tian-Chun

    2016-08-01

    High-k metal gate stacks are being used to suppress the gate leakage due to tunneling for sub-45 nm technology nodes. The reliability of thin dielectric films becomes a limitation to device manufacturing, especially to the breakdown characteristic. In this work, a breakdown simulator based on a percolation model and the kinetic Monte Carlo method is set up, and the intrinsic relation between time to breakdown and trap generation rate R is studied by TDDB simulation. It is found that all degradation factors, such as trap generation rate time exponent m, Weibull slope β and percolation factor s, each could be expressed as a function of trap density time exponent α. Based on the percolation relation and power law lifetime projection, a temperature related trap generation model is proposed. The validity of this model is confirmed by comparing with experiment results. For other device and material conditions, the percolation relation provides a new way to study the relationship between trap generation and lifetime projection. Project supported by the National High Technology Research and Development Program of China (Grant No. SS2015AA010601), the National Natural Science Foundation of China (Grant Nos. 61176091 and 61306129), and the Opening Project of Key Laboratory of Microelectronics Devices & Integrated Technology, Institute of MicroElectronics of Chinese Academy of Sciences.

  10. Sensing with Advanced Computing Technology: Fin Field-Effect Transistors with High-k Gate Stack on Bulk Silicon.

    PubMed

    Rigante, Sara; Scarbolo, Paolo; Wipf, Mathias; Stoop, Ralph L; Bedner, Kristine; Buitrago, Elizabeth; Bazigos, Antonios; Bouvet, Didier; Calame, Michel; Schönenberger, Christian; Ionescu, Adrian M

    2015-05-26

    Field-effect transistors (FETs) form an established technology for sensing applications. However, recent advancements and use of high-performance multigate metal-oxide semiconductor FETs (double-gate, FinFET, trigate, gate-all-around) in computing technology, instead of bulk MOSFETs, raise new opportunities and questions about the most suitable device architectures for sensing integrated circuits. In this work, we propose pH and ion sensors exploiting FinFETs fabricated on bulk silicon by a fully CMOS compatible approach, as an alternative to the widely investigated silicon nanowires on silicon-on-insulator substrates. We also provide an analytical insight of the concept of sensitivity for the electronic integration of sensors. N-channel fully depleted FinFETs with critical dimensions on the order of 20 nm and HfO2 as a high-k gate insulator have been developed and characterized, showing excellent electrical properties, subthreshold swing, SS ∼ 70 mV/dec, and on-to-off current ratio, Ion/Ioff ∼ 10(6), at room temperature. The same FinFET architecture is validated as a highly sensitive, stable, and reproducible pH sensor. An intrinsic sensitivity close to the Nernst limit, S = 57 mV/pH, is achieved. The pH response in terms of output current reaches Sout = 60%. Long-term measurements have been performed over 4.5 days with a resulting drift in time δVth/δt = 0.10 mV/h. Finally, we show the capability to reproduce experimental data with an extended three-dimensional commercial finite element analysis simulator, in both dry and wet environments, which is useful for future advanced sensor design and optimization.

  11. Sensing with Advanced Computing Technology: Fin Field-Effect Transistors with High-k Gate Stack on Bulk Silicon.

    PubMed

    Rigante, Sara; Scarbolo, Paolo; Wipf, Mathias; Stoop, Ralph L; Bedner, Kristine; Buitrago, Elizabeth; Bazigos, Antonios; Bouvet, Didier; Calame, Michel; Schönenberger, Christian; Ionescu, Adrian M

    2015-05-26

    Field-effect transistors (FETs) form an established technology for sensing applications. However, recent advancements and use of high-performance multigate metal-oxide semiconductor FETs (double-gate, FinFET, trigate, gate-all-around) in computing technology, instead of bulk MOSFETs, raise new opportunities and questions about the most suitable device architectures for sensing integrated circuits. In this work, we propose pH and ion sensors exploiting FinFETs fabricated on bulk silicon by a fully CMOS compatible approach, as an alternative to the widely investigated silicon nanowires on silicon-on-insulator substrates. We also provide an analytical insight of the concept of sensitivity for the electronic integration of sensors. N-channel fully depleted FinFETs with critical dimensions on the order of 20 nm and HfO2 as a high-k gate insulator have been developed and characterized, showing excellent electrical properties, subthreshold swing, SS ∼ 70 mV/dec, and on-to-off current ratio, Ion/Ioff ∼ 10(6), at room temperature. The same FinFET architecture is validated as a highly sensitive, stable, and reproducible pH sensor. An intrinsic sensitivity close to the Nernst limit, S = 57 mV/pH, is achieved. The pH response in terms of output current reaches Sout = 60%. Long-term measurements have been performed over 4.5 days with a resulting drift in time δVth/δt = 0.10 mV/h. Finally, we show the capability to reproduce experimental data with an extended three-dimensional commercial finite element analysis simulator, in both dry and wet environments, which is useful for future advanced sensor design and optimization. PMID:25817336

  12. Comprehensive study and design of scaled metal/high-k/Ge gate stacks with ultrathin aluminum oxide interlayers

    SciTech Connect

    Asahara, Ryohei; Hideshima, Iori; Oka, Hiroshi; Minoura, Yuya; Hosoi, Takuji Shimura, Takayoshi; Watanabe, Heiji; Ogawa, Shingo; Yoshigoe, Akitaka; Teraoka, Yuden

    2015-06-08

    Advanced metal/high-k/Ge gate stacks with a sub-nm equivalent oxide thickness (EOT) and improved interface properties were demonstrated by controlling interface reactions using ultrathin aluminum oxide (AlO{sub x}) interlayers. A step-by-step in situ procedure by deposition of AlO{sub x} and hafnium oxide (HfO{sub x}) layers on Ge and subsequent plasma oxidation was conducted to fabricate Pt/HfO{sub 2}/AlO{sub x}/GeO{sub x}/Ge stacked structures. Comprehensive study by means of physical and electrical characterizations revealed distinct impacts of AlO{sub x} interlayers, plasma oxidation, and metal electrodes serving as capping layers on EOT scaling, improved interface quality, and thermal stability of the stacks. Aggressive EOT scaling down to 0.56 nm and very low interface state density of 2.4 × 10{sup 11 }cm{sup −2}eV{sup −1} with a sub-nm EOT and sufficient thermal stability were achieved by systematic process optimization.

  13. Effect of atomic-arrangement matching on La2O3/Ge heterostructures for epitaxial high-k-gate-stacks

    NASA Astrophysics Data System (ADS)

    Kanashima, T.; Nohira, H.; Zenitaka, M.; Kajihara, Y.; Yamada, S.; Hamaya, K.

    2015-12-01

    We demonstrate a high-quality La2O3 layer on germanium (Ge) as an epitaxial high-k-gate-insulator, where there is an atomic-arrangement matching condition between La2O3(001) and Ge(111). Structural analyses reveal that (001)-oriented La2O3 layers were grown epitaxially only when we used Ge(111) despite low growth temperatures less than 300 °C. The permittivity (k) of the La2O3 layer is roughly estimated to be ˜19 from capacitance-voltage (C-V) analyses in Au/La2O3/Ge structures after post-metallization-annealing treatments, although the C-V curve indicates the presence of carrier traps near the interface. By using X-ray photoelectron spectroscopy analyses, we find that only Ge-O-La bonds are formed at the interface, and the thickness of the equivalent interfacial Ge oxide layer is much smaller than that of GeO2 monolayer. We discuss a model of the interfacial structure between La2O3 and Ge(111) and comment on the C-V characteristics.

  14. Mechanisms of temperature dependence of threshold voltage in high-k/metal gate transistors with different TiN thicknesses

    NASA Astrophysics Data System (ADS)

    Nishida, Yukio; Yokoyama, Shin

    2016-04-01

    The change in temperature coefficient of the threshold voltage (=dVth/dT) for poly-Si/TiN/high-k gate insulator metal-oxide-semiconductor field-effect transistors (MOSFETs) was systematically investigated with respect to various TiN thicknesses for both n- and p-channel MOSFETs. With increasing TiN thickness, dVth/dT shifts towards negative values for both n- and p-MOSFETs. A mechanism that changes dVth/dT, depending on TiN thickness is proposed. The main origins are the work function of TiN (ΦTiN) and its temperature coefficient (dΦTiN/dT). These are revealed to change when decreasing the thickness of the TiN layer, because the crystallinity of the TiN layer is degraded for thinner films, which was confirmed by ultraviolet photoelectron spectroscopy (UPS), transmission electron microscopy (TEM) and X-ray diffraction (XRD).

  15. Rubrene single crystal field-effect transistor with epitaxial BaTiO{sub 3} high-k gate insulator

    SciTech Connect

    Hiroshiba, Nobuya; Kumashiro, Ryotaro; Tanigaki, Katsumi; Takenobu, Taishi; Iwasa, Yoshihiro; Kotani, Kenta; Kawayama, Iwao; Tonouchi, Masayoshi

    2006-10-09

    High quality BaTiO{sub 3} thin-film epitaxially grown on a Nb-doped SrTiO{sub 3} (BTO/Nb-STO) substrate by a laser ablation technique is employed as a high-k gate insulator for a field-effect transistor of a rubrene single crystal in order to search for the possibility of high carrier accumulation. The high dielectric constant {epsilon} of 280 esu for the prepared BaTiO{sub 3} thin-film accumulates 0.1 holes/rubrene-molecule, which is 2.5 times as high as the maximum carrier number of 0.04 holes/rubrene-molecule attained in the case of SiO{sub 2}. This is the highest carrier number so far obtained in organic field-effect transistors (FETs). Other important parameters of rubrene single crystal FETs on BTO/Nb-STO are described in comparison with those on SiO{sub 2}/doped-Si.

  16. Multi-technique Approach for the Evaluation of the Crystalline Phase of Ultrathin High-k Gate Oxide Films

    NASA Astrophysics Data System (ADS)

    Bersch, E.; LaRose, J. D.; Wells, I.; Consiglio, S.; Clark, R. D.; Leusink, G. J.; Matyi, R. J.; Diebold, A. C.

    2011-11-01

    In order to continue scaling metal oxide semiconductor field effect transistors (MOSFETs) with HfO2 gate oxides, efforts are being made to further improve the deposited high-k film properties. Recently, a process whereby an HfO2 film is deposited through a series of depositions and anneals (so-called DADA process) has been shown to result in films that give rise to MOS capacitors (MOSCAPs) which are electrically scaled compared to MOSCAPs with HfO2 films that only received post deposition anneals (PDA) or no anneals. We have measured as-deposited, DADA and PDA HfO2 films using four measurement techniques, all of which are non-destructive and capable of being used for in-line processing, to evaluate their crystallinity and crystalline phases. Grazing incidence in-plane X-ray diffraction was used to determine the crystalline phases of the HfO2 films. We observed the crystalline phases of these films to be process dependent. Additionally, X-ray and UV photoelectron spectroscopy were used to show the presence of crystallinity in the films. As a fourth technique, spectroscopic ellipsometry was used to determine if the crystalline phases were monoclinic. The combination of techniques was useful in that XPS and UPS were able to confirm the amorphous nature of a 30 cycle DADA film, as measured by GIIXRD, and GIIXRD was able to help us interpret the SE data as being an indication of the monoclinic phase of HfO2.

  17. Attainment of dual-band edge work function by using a single metal gate and single high-k dielectric via ion implantation for HP CMOS device

    NASA Astrophysics Data System (ADS)

    Xu, Qiuxia; Xu, G.; Zhou, H.; Zhu, H.; Liu, J.; Wang, Y.; Li, J.; Xiang, J.; Liang, Q.; Wu, H.; Zhong, J.; Xu, M.; Xu, W.; Ma, X.; Wang, X.; Tong, X.; Chen, D.; Yan, J.; Zhao, C.; Ye, T.

    2016-01-01

    Attainment of dual band-edge effective work functions by using a single metal gate and single high k gate dielectric via P/BF2 implantation into a TiN metal gate for HP HKMG CMOS device applications are investigated under a gate-last process flow for the first time. The flat band voltage (VFB) modulations of about -750 mV/570 mV for N-/P-type MOS device with P/BF2 implanted TiN/HfO2/ILSiO2 gate stack are obtained respectively in the experiment range. Suitable low threshold voltages of CMOSFETs are gotten while simultaneously shrinking the EOT. The effects of P/BF2 ion implantation energy, dose and TiN gate thickness on the properties of implanted TiN/HfO2/ILSiO2 gate stack are studied, the possible mechanisms are discussed. This technique has been successfully integrated into the fabrications of aggressively scaled HP HKMG CMOSFETs and 32 CMOS frequency dividers under a gate-last process flow.

  18. Improved n-channel Ge gate stack performance using HfAlO high-k dielectric for various Al concentrations

    NASA Astrophysics Data System (ADS)

    Kothari, Shraddha; Joishi, Chandan; Ghosh, Sayantan; Biswas, Dipankar; Vaidya, Dhirendra; Ganguly, Swaroop; Lodha, Saurabh

    2016-07-01

    We demonstrate improved Ge n-channel gate stack performance versus HfO2 using HfAlO high-k dielectric for a wide (1.5–33%) range of Al% and post-high-k-deposition annealing (PDA) at 400 °C. Addition of Al to HfO2 is shown to mitigate degradation of the GeO2/Ge interface during PDA. HfAlO stacks with an equivalent oxide thickness (EOT) of 8 nm and large Al% exhibit improved transistor mobility (1.8 times higher) and midgap D it (2 times lower), whereas thin (1.9 nm) EOT HfAlO stacks show reduced gate leakage J g (by 10 times) and D it (by 1.5 times) and 1.6 times higher mobility for Al% as low as 1.5% at matched EOT.

  19. Extremely scaled high-k/In₀.₅₃Ga₀.₄₇As gate stacks with low leakage and low interface trap densities

    SciTech Connect

    Chobpattana, Varistha; Mikheev, Evgeny; Zhang, Jack Y.; Mates, Thomas E.; Stemmer, Susanne

    2014-09-28

    Highly scaled gate dielectric stacks with low leakage and low interface trap densities are required for complementary metal-oxide-semiconductor technology with III-V semiconductor channels. Here, we show that a novel pre-deposition technique, consisting of alternating cycles of nitrogen plasma and tetrakis(dimethylamino)titanium, allows for HfO₂ and ZrO₂ gate stacks with extremely high accumulation capacitance densities of more than 5 μF/cm₂ at 1 MHz, low leakage current, low frequency dispersion, and low midgap interface trap densities (10¹²cm⁻²eV⁻¹range). Using x-ray photoelectron spectroscopy, we show that the interface contains TiO₂ and small quantities of In₂O₃, but no detectable Ga- or As-oxides, or As-As bonding. The results allow for insights into the microscopic mechanisms that control leakage and frequency dispersion in high-k/III-V gate stacks.

  20. Reliability investigation of high-k/metal gate in nMOSFETs by three-dimensional kinetic Monte-Carlo simulation with multiple trap interactions

    NASA Astrophysics Data System (ADS)

    Li, Yun; Jiang, Hai; Lun, Zhiyuan; Wang, Yijiao; Huang, Peng; Hao, Hao; Du, Gang; Zhang, Xing; Liu, Xiaoyan

    2016-04-01

    Degradation behaviors in the high-k/metal gate stacks of nMOSFETs are investigated by three-dimensional (3D) kinetic Monte-Carlo (KMC) simulation with multiple trap coupling. Novel microscopic mechanisms are simultaneously considered in a compound system: (1) trapping/detrapping from/to substrate/gate; (2) trapping/detrapping to other traps; (3) trap generation and recombination. Interacting traps can contribute to random telegraph noise (RTN), bias temperature instability (BTI), and trap-assisted tunneling (TAT). Simulation results show that trap interaction induces higher probability and greater complexity in trapping/detrapping processes and greatly affects the characteristics of RTN and BTI. Different types of trap distribution cause largely different behaviors of RTN, BTI, and TAT. TAT currents caused by multiple trap coupling are sensitive to the gate voltage. Moreover, trap generation and recombination have great effects on the degradation of HfO2-based nMOSFETs under a large stress.

  1. Study of Hf-Ti-O Thin Film as High- k Gate Dielectric and Application for ETSOI MOSFETs

    NASA Astrophysics Data System (ADS)

    Chen, Xiaoqiang; Zhao, Hongbin; Xiong, Yuhua; Wei, Feng; Du, Jun; Tang, Zhaoyun; Tang, Bo; Yan, Jiang

    2016-08-01

    This work focused on the metal-oxide-semiconductor (MOS) capacitor and extremely thin silicon-on-insulator (ETSOI) p-type MOS field-effect transistor ( pMOSFET) with laminated hafnium and titanium oxide (Hf-Ti-O) thin films as gate dielectric. The electrical behavior of the MOS capacitor shows that the capacitor with Hf-Ti-O gate dielectric has high performance with low equivalent oxide thickness (EOT, ~0.77 nm), small hysteresis (Δ V fb, ~4 mV), and gate current density of 0.33 A/cm2 at V g = V fb - 1 V. The dominant conduction mechanism of the Hf-Ti-O thin film (25°C to 125°C) was Schottky emission at lower gate voltage (-0.8 V to -0.2 V) and Fowler-Nordheim (F-N) tunneling at higher gate voltage (<-0.8 V). An ETSOI pMOSFET with 25 nm gate length ( L g) also exhibited good electrical properties with switch ratio of 3.2 × 104, appropriate threshold voltage of -0.16 V, maximum transconductance ( G max) of 2.63 mS, drain-induced barrier lowering of 53 mV/V, and subthreshold swing of 65 mV/dec.

  2. Optimization of high-k and gate metal workfunction for improved analog and intermodulation performance of Gate Stack (GS)-GEWE-SiNW MOSFET

    NASA Astrophysics Data System (ADS)

    Gupta, Neha; Chaujar, Rishu

    2016-09-01

    This work optimizes the gate engineering scheme (both gate stack and gate metal workfunction engineering) of Stacked Gate (SG) Gate Electrode Workfunction Engineered (GEWE)-Silicon Nanowire MOSFET at 300 K for improved analog and intermodulation performance. This has been done by evaluating and analyzing the metrics such as Switching Ratio, Subthreshold Swing (SS), Device Efficiency, channel and output resistance, VIP3, IIP3, 1-dB Compression Point, IMD3, HD2 and HD3. Simulation results exhibit that HfO2 as a gate stack exhibit high linearity at a comparatively low gate bias of 0.56 V with higher IIP3 (6.21 dBm) and low IMD3 (9.6 dBm). Further, the characteristics/performance is modulated by adjusting the workfunction difference of metal gate. This study demonstrates that SiNW MOSFET modeled with HfO2 as a gate stack over SiO2 interfacial layer, and gate metal workfunction difference (ΔW) of 4.4 eV can be considered as a promising potential for low power switching component in ICs and Linear RF amplifiers.

  3. High-k gate dielectric GaAs MOS device with LaON as interlayer and NH3-plasma surface pretreatment

    NASA Astrophysics Data System (ADS)

    Liu, Chao-Wen; Xu, Jing-Ping; Liu, Lu; Lu, Han-Han

    2015-12-01

    High-k gate dielectric HfTiON GaAs metal-oxide-semiconductor (MOS) capacitors with LaON as interfacial passivation layer (IPL) and NH3- or N2-plasma surface pretreatment are fabricated, and their interfacial and electrical properties are investigated and compared with their counterparts that have neither LaON IPL nor surface treatment. It is found that good interface quality and excellent electrical properties can be achieved for a NH3-plasma pretreated GaAs MOS device with a stacked gate dielectric of HfTiON/LaON. These improvements should be ascribed to the fact that the NH3-plasma can provide H atoms and NH radicals that can effectively remove defective Ga/As oxides. In addition, LaON IPL can further block oxygen atoms from being in-diffused, and Ga and As atoms from being out-diffused from the substrate to the high-k dielectric. This greatly suppresses the formation of Ga/As native oxides and gives rise to an excellent high-k/GaAs interface. Project supported by the National Natural Science Foundation of China (Grant Nos. 61176100 and 61274112).

  4. Low voltage and high ON/OFF ratio field-effect transistors based on CVD MoS2 and ultra high-k gate dielectric PZT

    NASA Astrophysics Data System (ADS)

    Zhou, Changjian; Wang, Xinsheng; Raju, Salahuddin; Lin, Ziyuan; Villaroman, Daniel; Huang, Baoling; Chan, Helen Lai-Wa; Chan, Mansun; Chai, Yang

    2015-05-01

    MoS2 and other atomic-level thick layered materials have been shown to have a high potential for outperforming Si transistors at the scaling limit. In this work, we demonstrate a MoS2 transistor with a low voltage and high ON/OFF ratio. A record small equivalent oxide thickness of ~1.1 nm has been obtained by using ultra high-k gate dielectric Pb(Zr0.52Ti0.48)O3. The low threshold voltage (<0.5 V) is comparable to that of the liquid/gel gated MoS2 transistor. The small sub-threshold swing of 85.9 mV dec-1, the high ON/OFF ratio of ~108 and the negligible hysteresis ensure a high performance of the MoS2 transistor operating at 1 V. The extracted field-effect mobility of 1-10 cm2 V-1 s-1 suggests a high crystalline quality of the CVD-grown MoS2 flakes. The combination of the two-dimensional layered semiconductor and the ultra high-k dielectric may enable the development of low-power electronic applications.MoS2 and other atomic-level thick layered materials have been shown to have a high potential for outperforming Si transistors at the scaling limit. In this work, we demonstrate a MoS2 transistor with a low voltage and high ON/OFF ratio. A record small equivalent oxide thickness of ~1.1 nm has been obtained by using ultra high-k gate dielectric Pb(Zr0.52Ti0.48)O3. The low threshold voltage (<0.5 V) is comparable to that of the liquid/gel gated MoS2 transistor. The small sub-threshold swing of 85.9 mV dec-1, the high ON/OFF ratio of ~108 and the negligible hysteresis ensure a high performance of the MoS2 transistor operating at 1 V. The extracted field-effect mobility of 1-10 cm2 V-1 s-1 suggests a high crystalline quality of the CVD-grown MoS2 flakes. The combination of the two-dimensional layered semiconductor and the ultra high-k dielectric may enable the development of low-power electronic applications. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr01072a

  5. Electric field-induced transport modulation in VO2 FETs with high-k oxide/organic parylene-C hybrid gate dielectric

    NASA Astrophysics Data System (ADS)

    Wei, Tingting; Kanki, Teruo; Fujiwara, Kohei; Chikanari, Masashi; Tanaka, Hidekazu

    2016-02-01

    We report on the observation of reversible and immediate resistance switching by high-k oxide Ta2O5/organic parylene-C hybrid dielectric-gated VO2 thin films. Resistance change ratios at various temperatures in the insulating regime were demonstrated to occur in the vicinity of phase transition temperature. We also found an asymmetric hole-electron carrier modulation related to the suppression of phase transition temperature. The results in this research provide a possibility for clarifying the origin of metal-insulator transition in VO2 through the electrostatic field-induced transport modulation.

  6. Investigation of low-frequency noise of 28-nm technology process of high-k/metal gate p-MOSFETs with fluorine incorporation

    NASA Astrophysics Data System (ADS)

    Kao, Tsung-Hsien; Chang, Shoou-Jinn; Fang, Yean-Kuen; Huang, Po-Chin; Wang, Bo-Chin; Wu, Chung-Yi; Wu, San-Lein

    2016-01-01

    In this study, the properties of dielectric traps by the impact of Fluorine (F) implantation on 1/f noise and the random telegraph noise (RTN) of high-k/metal gate (HK/MG) p-type metal-oxide-semiconductor field-effect transistors (pMOSFETs) were investigated. The incorporation of F has been identified as an effective method to passivate oxygen vacancies, defect sites, and reduce the gate leakage current in pMOSFETs. Compared with a control device, the F-implanted HK/MG devices show that the trap positions were closer to the SiO2 interfacial layer (IL)/Si channel. Furthermore, we found that F implantation could result in a smaller tunneling attenuation length (λ) and smaller slow oxide interface trap density (Nt).

  7. Influence of multi-deposition multi-annealing on time-dependent dielectric breakdown characteristics of PMOS with high-k/metal gate last process

    NASA Astrophysics Data System (ADS)

    Wang, Yan-Rong; Yang, Hong; Xu, Hao; Wang, Xiao-Lei; Luo, Wei-Chun; Qi, Lu-Wei; Zhang, Shu-Xiang; Wang, Wen-Wu; Yan, Jiang; Zhu, Hui-Long; Zhao, Chao; Chen, Da-Peng; Ye, Tian-Chun

    2015-11-01

    A multi-deposition multi-annealing technique (MDMA) is introduced into the process of high-k/metal gate MOSFET for the gate last process to effectively reduce the gate leakage and improve the device’s performance. In this paper, we systematically investigate the electrical parameters and the time-dependent dielectric breakdown (TDDB) characteristics of positive channel metal oxide semiconductor (PMOS) under different MDMA process conditions, including the deposition/annealing (D&A) cycles, the D&A time, and the total annealing time. The results show that the increases of the number of D&A cycles (from 1 to 2) and D&A time (from 15 s to 30 s) can contribute to the results that the gate leakage current decreases by about one order of magnitude and that the time to fail (TTF) at 63.2% increases by about several times. However, too many D&A cycles (such as 4 cycles) make the equivalent oxide thickness (EOT) increase by about 1 Å and the TTF of PMOS worsen. Moreover, different D&A times and numbers of D&A cycles induce different breakdown mechanisms. Project supported by the National High Technology Research and Development Program of China (Grant No. SS2015AA010601) and the National Natural Science Foundation of China (Grant Nos. 61176091 and 61306129).

  8. An effective work-function tuning method of nMOSCAP with high-k/metal gate by TiN/TaN double-layer stack thickness

    NASA Astrophysics Data System (ADS)

    Xueli, Ma; Hong, Yang; Wenwu, Wang; Huaxiang, Yin; Huilong, Zhu; Chao, Zhao; Dapeng, Chen; Tianchun, Ye

    2014-09-01

    We evaluated the TiN/TaN/TiAl triple-layer to modulate the effective work function (EWF) of a metal gate stack for the n-type metal-oxide-semiconductor (NMOS) devices application by varying the TiN/TaN thickness. In this paper, the effective work function of EWF ranges from 4.22 to 4.56 eV with different thicknesses of TiN and TaN. The thinner TiN and/or thinner in situ TaN capping, the closer to conduction band of silicon the EWF is, which is appropriate for 2-D planar NMOS. Mid-gap work function behavior is observed with thicker TiN, thicker in situ TaN capping, indicating a strong potential candidate of metal gate material for replacement gate processed three-dimensional devices such as FIN shaped field effect transistors. The physical understandings of the sensitivity of EWF to TiN and TaN thickness are proposed. The thicker TiN prevents the Al diffusion then induces the EWF to shift to mid-gap. However, the TaN plays a different role in effective work function tuning from TiN, due to the Ta—O dipoles formed at the interface between the metal gate and the high-k layer.

  9. Electric Field-induced Resistance Switching in VO2 Channels using Hybrid Gate Dielectric of High- k Ta2O5/Organic material Parylene-C

    NASA Astrophysics Data System (ADS)

    Wei, Tingting; Kanki, Teruo; Fujiwara, Kohei; Chikanari, Masashi; Tanaka, Hidekazu

    Electrostatic approach utilizing field-effect transistor (FET) with correlated electron materials provides an avenue to realize the novel devices (Mott-transistor) and to clarify condensed matter physics. In this study, we have prepared Mott-transistors using vanadium dioxide (VO2) channels and employed hybrid gate dielectric consisted of high- k material Ta2O5 and organic polymer parylene-C to trigger carrier transport modulation in VO2. Obvious resistance modulations were observed in insulating regime through time-dependent resistance measurement at varied square-shaped gate bias (VG) . Contrasting to the hysteretic response in electric double layer transistor (EDLT), an abrupt resistance switching in less than of 2-second-interval enables us to attribute such immediate modulation to pure electrostatic effect. Moreover, the maximum of resistance change was identified to appear around phase transition temperature (TMI) , which confirmed the disordered heterogeneous regime at TMI. Taking advantage of systematic modulation using VO2-based devices, we demonstrated the pronounced shifts of TMI by gate bias. Another fascinating behavior on asymmetric drop in TMI by hole-electron carrier doping was observed.

  10. 25 GHz embedded-gate graphene transistors with high-k dielectrics on extremely flexible plastic sheets.

    PubMed

    Lee, Jongho; Ha, Tae-Jun; Li, Huifeng; Parrish, Kristen N; Holt, Milo; Dodabalapur, Ananth; Ruoff, Rodney S; Akinwande, Deji

    2013-09-24

    Despite the widespread interest in graphene electronics over the past decade, high-performance graphene field-effect transistors (GFETs) on flexible substrates have been rarely achieved, even though this atomic sheet is widely understood to have greater prospects for flexible electronic systems. In this article, we report detailed studies on the electrical and mechanical properties of vapor synthesized high-quality monolayer graphene integrated onto flexible polyimide substrates. Flexible graphene transistors with high-k dielectric afforded intrinsic gain, maximum carrier mobilities of 3900 cm(2)/V·s, and importantly, 25 GHz cutoff frequency, which is more than a factor of 2.5 times higher than prior results. Mechanical studies reveal robust transistor performance under repeated bending, down to 0.7 mm bending radius, whose tensile strain is a factor of 2-5 times higher than in prior studies. In addition, integration of functional coatings such as highly hydrophobic fluoropolymers combined with the self-passivation properties of the polyimide substrate provides water-resistant protection without compromising flexibility, which is an important advancement for the realization of future robust flexible systems based on graphene.

  11. Deposition, stabilization and characterization of zirconium oxide and hafnium oxide thin films for high k gate dielectrics

    NASA Astrophysics Data System (ADS)

    Gao, Yong

    As the MOS devices continue to scale down in feature size, the gate oxide thickness is approaching the nanometer node. High leakage current densities caused by tunneling is becoming a serious problem. Replacing silicon oxide with a high kappa material as the gate dielectrics is becoming very critical. In recent years, research has been focused on a few promising candidates, such as ZrO2, HfO2, Al2O3, Ta 2O5, and some silicates. However, unary metal oxides tend to crystallize at relatively low temperatures (less than 700°C). Crystallized films usually have a very small grain size and high leakage current due to the grain boundaries. The alternatives are high kappa oxides which are single crystal or amorphous. Silicates remain amorphous at high temperatures, but have some problems such as phase separation, interface reaction, and lower kappa value. In this work, we addressed the crystallization problems of zirconium oxide and hafnium oxide thin films. Both of these two thin films were deposited by DC reactive magnetron sputtering so that very dense films were deposited with little damage. A specially designed system was set up in order to have good control of the deposition process. The crystallization behavior of as-deposited amorphous ZrO2 and HfO2 films was studied. It was found that the films tended to have higher crystallization temperature when the films were thinner than a critical thickness of approximately 5 nm. However, it was still well below 900°C. The crystallization temperature was significantly increased by sandwiching the high kappa oxide layer between two silica layers. Ultra thin HfO2 films of 5nm thickness remained amorphous up to 900°C. This is the highest crystallization temperature which has been reported. The mechanisms for this effect are proposed. Electrical properties of these high kappa dielectric films were also studied. It was found that ultra thin amorphous HfO2 and ZrO 2 films had superior electrical properties to crystalline films

  12. Novel High-Performance Analog Devices for Advanced Low-Power High-k Metal Gate Complementary Metal-Oxide-Semiconductor Technology

    NASA Astrophysics Data System (ADS)

    Han, Jin-Ping; Shimizu, Takashi; Pan, Li-Hong; Voelker, Moritz; Bernicot, Christophe; Arnaud, Franck; Mocuta, Anda; Stahrenberg, Knut; Azuma, Atsushi; Eller, Manfred; Yang, Guoyong; Jaeger, Daniel; Zhuang, Haoren; Miyashita, Katsura; Stein, Kenneth; Nair, Deleep; Hoo Park, Jae; Kohler, Sabrina; Hamaguchi, Masafumi; Li, Weipeng; Kim, Kisang; Chanemougame, Daniel; Kim, Nam Sung; Uchimura, Sadaharu; Tsutsui, Gen; Wiedholz, Christian; Miyake, Shinich; van Meer, Hans; Liang, Jewel; Ostermayr, Martin; Lian, Jenny; Celik, Muhsin; Donaton, Ricardo; Barla, Kathy; Na, MyungHee; Goto, Yoshiro; Sherony, Melanie; Johnson, Frank S.; Wachnik, Richard; Sudijono, John; Kaste, Ed; Sampson, Ron; Ku, Ja-Hum; Steegen, An; Neumueller, Walter

    2011-04-01

    High performance analog (HPA) devices in high-k metal gate (HKMG) scheme with innovative halo engineering have been successfully demonstrated to produce superior analog and digital performance for low power applications. HPA device was processed “freely” with no extra mask, no extra litho, and no extra process step. This paper details a comprehensive study of the analog and digital characteristics of these HPA devices in comparison with analog control (conventional digital devices with matched geometry). Analog properties such as output voltage gain (also called self-gain), trans-conductance Gm, conductance Gds, Gm/Id, mismatching (MM) behavior, flicker noise (1/f noise) and current linearity have clearly reflected the advantage of HPA devices over analog control, while DC performance (e.g., Ion-Ioff, Ioff-Vtsat, DIBL, Cjswg) and reliability (HCI) have also shown the comparability of HPA devices over control.

  13. Series resistance effect on time zero dielectrics breakdown characteristics of MOSCAP with ultra-thin EOT high-k/metal gate stacks

    NASA Astrophysics Data System (ADS)

    Hao, Xu; Hong, Yang; Yanrong, Wang; Wenwu, Wang; Guangxing, Wan; Shangqing, Ren; Weichun, Luo; Luwei, Qi; Chao, Zhao; Dapeng, Chen; Xinyu, Liu; Tianchun, Ye

    2016-05-01

    The time zero dielectric breakdown characteristics of MOSCAP with ultra-thin EOT high-k metal gate stacks are studied. The TZDB results show an abnormal area dependence due to the series resistance effect. The series resistance components extracted from the Fowler–Nordheim tunneling relation are attributed to the spreading resistance due to the asymmetry electrodes. Based on a series model to eliminate the series resistance effect, an area acceleration dependence is obtained by correcting the TZDB results. The area dependence follows Poisson area scaling rules, which indicates that the mechanism of TZDB is the same as TDDB and could be considered as a trap generation process. Project supported by the National High Technology Research and Development Program (863 Program) of China (No. SS2015AA010601), the National Natural Science Foundation of China (Nos. 61176091, 61306129), and the Opening Project of the Key Laboratory of Microelectronics Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences.

  14. Trap properties of high-k/metal gate pMOSFETs with aluminum ion implantation by random telegraph noise and 1/f noise measurements

    NASA Astrophysics Data System (ADS)

    Kao, Tsung-Hsien; Wu, San-Lein; Tsai, Kai-Shiang; Fang, Yean-Kuen; Lai, Chien-Ming; Hsu, Chia-Wei; Chen, Yi-Wen; Cheng, Osbert; Chang, Shoou-Jinn

    2014-01-01

    In this study, the impact of aluminum ion implantation on 1/f noise characteristics and random telegraph noise (RTN) in high-k/metal gate (HK/MG) p-type metal-oxide-semiconductor field-effect transistors (pMOSFETs) was investigated. Aluminum ion implantation (Al I/I) into TiN/HfO2/SiO2 was implemented to tune an effective work function (EWF) in pMOSFETs without EOT increase complicated processes. RTN and 1/f results revealed that regardless of the implanted dose, HK/MG devices with Al I/I exhibit lower slow oxide trap densities than the control devices, which are responsible for the reduced trap position (xt) from the SiO2 interfacial layer (IL)/Si interface. For the HK/MG devices with different implanted doses, no significant differences in trap properties were observed.

  15. Effects of Gate Stack Structural and Process Defectivity on High-k Dielectric Dependence of NBTI Reliability in 32 nm Technology Node PMOSFETs

    PubMed Central

    Hussin, H.; Soin, N.; Bukhori, M. F.; Wan Muhamad Hatta, S.; Abdul Wahab, Y.

    2014-01-01

    We present a simulation study on negative bias temperature instability (NBTI) induced hole trapping in E′ center defects, which leads to depassivation of interface trap precursor in different geometrical structures of high-k PMOSFET gate stacks using the two-stage NBTI model. The resulting degradation is characterized based on the time evolution of the interface and hole trap densities, as well as the resulting threshold voltage shift. By varying the physical thicknesses of the interface silicon dioxide (SiO2) and hafnium oxide (HfO2) layers, we investigate how the variation in thickness affects hole trapping/detrapping at different stress temperatures. The results suggest that the degradations are highly dependent on the physical gate stack parameters for a given stress voltage and temperature. The degradation is more pronounced by 5% when the thicknesses of HfO2 are increased but is reduced by 11% when the SiO2 interface layer thickness is increased during lower stress voltage. However, at higher stress voltage, greater degradation is observed for a thicker SiO2 interface layer. In addition, the existence of different stress temperatures at which the degradation behavior differs implies that the hole trapping/detrapping event is thermally activated. PMID:25221784

  16. Interface Engineering for the Enhancement of Carrier Transport in Black Phosphorus Transistor with Ultra-Thin High-k Gate Dielectric.

    PubMed

    Ling, Zhi-Peng; Zhu, Jun-Tao; Liu, Xinke; Ang, Kah-Wee

    2016-01-01

    Black phosphorus (BP) is the most stable allotrope of phosphorus which exhibits strong in-plane anisotropic charge transport. Discovering its interface properties between BP and high-k gate dielectric is fundamentally important for enhancing the carrier mobility and electrostatics control. Here, we investigate the impact of interface engineering on the transport properties of BP transistors with an ultra-thin hafnium-dioxide (HfO2) gate dielectric of ~3.4 nm. A high hole mobility of ~536 cm(2)V(-1)s(-1) coupled with a near ideal subthreshold swing (SS) of ~66 mV/dec were simultaneously achieved at room temperature by improving the BP/HfO2 interface quality through thermal treatment. This is attributed to the passivation of phosphorus dangling bonds by hafnium (Hf) adatoms which produces a more chemically stable interface, as evidenced by the significant reduction in interface states density. Additionally, we found that an excessively high thermal treatment temperature (beyond 200 °C) could detrimentally modify the BP crystal structure, which results in channel resistance and mobility degradation due to charge-impurities scattering and lattice displacement. This study contributes to an insight for the development of high performance BP-based transistors through interface engineering. PMID:27222074

  17. Interface Engineering for the Enhancement of Carrier Transport in Black Phosphorus Transistor with Ultra-Thin High-k Gate Dielectric

    PubMed Central

    Ling, Zhi-Peng; Zhu, Jun-Tao; Liu, Xinke; Ang, Kah-Wee

    2016-01-01

    Black phosphorus (BP) is the most stable allotrope of phosphorus which exhibits strong in-plane anisotropic charge transport. Discovering its interface properties between BP and high-k gate dielectric is fundamentally important for enhancing the carrier mobility and electrostatics control. Here, we investigate the impact of interface engineering on the transport properties of BP transistors with an ultra-thin hafnium-dioxide (HfO2) gate dielectric of ~3.4 nm. A high hole mobility of ~536 cm2V−1s−1 coupled with a near ideal subthreshold swing (SS) of ~66 mV/dec were simultaneously achieved at room temperature by improving the BP/HfO2 interface quality through thermal treatment. This is attributed to the passivation of phosphorus dangling bonds by hafnium (Hf) adatoms which produces a more chemically stable interface, as evidenced by the significant reduction in interface states density. Additionally, we found that an excessively high thermal treatment temperature (beyond 200 °C) could detrimentally modify the BP crystal structure, which results in channel resistance and mobility degradation due to charge-impurities scattering and lattice displacement. This study contributes to an insight for the development of high performance BP-based transistors through interface engineering. PMID:27222074

  18. Interface Engineering for the Enhancement of Carrier Transport in Black Phosphorus Transistor with Ultra-Thin High-k Gate Dielectric

    NASA Astrophysics Data System (ADS)

    Ling, Zhi-Peng; Zhu, Jun-Tao; Liu, Xinke; Ang, Kah-Wee

    2016-05-01

    Black phosphorus (BP) is the most stable allotrope of phosphorus which exhibits strong in-plane anisotropic charge transport. Discovering its interface properties between BP and high-k gate dielectric is fundamentally important for enhancing the carrier mobility and electrostatics control. Here, we investigate the impact of interface engineering on the transport properties of BP transistors with an ultra-thin hafnium-dioxide (HfO2) gate dielectric of ~3.4 nm. A high hole mobility of ~536 cm2V‑1s‑1 coupled with a near ideal subthreshold swing (SS) of ~66 mV/dec were simultaneously achieved at room temperature by improving the BP/HfO2 interface quality through thermal treatment. This is attributed to the passivation of phosphorus dangling bonds by hafnium (Hf) adatoms which produces a more chemically stable interface, as evidenced by the significant reduction in interface states density. Additionally, we found that an excessively high thermal treatment temperature (beyond 200 °C) could detrimentally modify the BP crystal structure, which results in channel resistance and mobility degradation due to charge-impurities scattering and lattice displacement. This study contributes to an insight for the development of high performance BP-based transistors through interface engineering.

  19. Electron-electron scattering-induced channel hot electron injection in nanoscale n-channel metal-oxide-semiconductor field-effect-transistors with high-k/metal gate stacks

    SciTech Connect

    Tsai, Jyun-Yu; Liu, Kuan-Ju; Lu, Ying-Hsin; Liu, Xi-Wen; Chang, Ting-Chang; Chen, Ching-En; Ho, Szu-Han; Tseng, Tseung-Yuen; Cheng, Osbert; Huang, Cheng-Tung; Lu, Ching-Sen

    2014-10-06

    This work investigates electron-electron scattering (EES)-induced channel hot electron (CHE) injection in nanoscale n-channel metal-oxide-semiconductor field-effect-transistors (n-MOSFETs) with high-k/metal gate stacks. Many groups have proposed new models (i.e., single-particle and multiple-particle process) to well explain the hot carrier degradation in nanoscale devices and all mechanisms focused on Si-H bond dissociation at the Si/SiO{sub 2} interface. However, for high-k dielectric devices, experiment results show that the channel hot carrier trapping in the pre-existing high-k bulk defects is the main degradation mechanism. Therefore, we propose a model of EES-induced CHE injection to illustrate the trapping-dominant mechanism in nanoscale n-MOSFETs with high-k/metal gate stacks.

  20. Improved thermal stability and electrical properties of atomic layer deposited HfO{sub 2}/AlN high-k gate dielectric stacks on GaAs

    SciTech Connect

    Cao, Yan-Qiang; Li, Xin; Zhu, Lin; Cao, Zheng-Yi; Wu, Di; Li, Ai-Dong

    2015-01-15

    The thermal stability and electrical properties of atomic layer deposited HfO{sub 2}/AlN high-k gate dielectric stacks on GaAs were investigated. Compared to HfO{sub 2}/Al{sub 2}O{sub 3} gate dielectric, significant improvements in interfacial quality as well as electrical characteristics after postdeposition annealing are confirmed by constructing HfO{sub 2}/AlN dielectric stacks. The chemical states were carefully explored by the x-ray photoelectron spectroscopy, which indicates the AlN layers effectively prevent from the formation of defective native oxides at elevated temperatures. In addition, it is found that NH{sub 3} plasma during AlN plasma-enhanced atomic layer deposition also has the self-cleaning effect as Al(CH{sub 3}){sub 3} in removing native oxides. The passivating AlN layers suppress the formation of interfacial oxide and trap charge, leading to the decrease of capacitance equivalent thickness after annealing. Moreover, HfO{sub 2}/AlN/GaAs sample has a much lower leakage current density of 2.23 × 10{sup −4} A/cm{sup 2} than HfO{sub 2}/Al{sub 2}O{sub 3}/GaAs sample of 2.58 × 10{sup −2} A/cm{sup 2}. For the HfO{sub 2}/AlN/GaAs sample annealed at 500 °C, it has a lowest interface trap density value of 2.11 × 10{sup 11} eV{sup −1} cm{sup −2}. These results indicate that adopting HfO{sub 2}/AlN dielectric stacks may be a promising approach for the realization of high quality GaAs-based transistor devices.

  1. Characterization of ALD Beryllium Oxide as a Potential High- k Gate Dielectric for Low-Leakage AlGaN/GaN MOSHEMTs

    NASA Astrophysics Data System (ADS)

    Johnson, Derek W.; Yum, Jung Hwan; Hudnall, Todd W.; Mushinski, Ryan M.; Bielawski, Christopher W.; Roberts, John C.; Wang, Wei-E.; Banerjee, Sanjay K.; Harris, H. Rusty

    2014-01-01

    The chemical and electrical characteristics of atomic layer deposited (ALD) beryllium oxide (BeO) on GaN were studied via x-ray photoelectron spectroscopy, current-voltage, and capacitance-voltage measurements and compared with those of ALD Al2O3 and HfO2 on GaN. Radiofrequency (RF) and power electronics based on AlGaN/GaN high-electron-mobility transistors are maturing rapidly, but leakage current reduction and interface defect ( D it) minimization remain heavily researched. BeO has received recent attention as a high- k gate dielectric due to its large band gap (10.6 eV) and thermal stability on InGaAs and Si, but little is known about its performance on GaN. Unintentionally doped GaN was cleaned in dilute aqueous HCl immediately prior to BeO deposition (using diethylberyllium and H2O precursors). Formation of an interfacial layer was observed in as-deposited samples, similar to the layer formed during ALD HfO2 deposition on GaN. Postdeposition anneal (PDA) at 700°C and 900°C had little effect on the observed BeO binding state, confirming the strength of the bond, but led to increased Ga oxide formation, indicating the presence of unincorporated oxygen in the dielectric. Despite the interfacial layer, gate leakage current of 1.1 × 10-7 A/cm2 was realized, confirming the potential of ALD BeO for use in low-leakage AlGaN/GaN metal-oxide-semiconductor high-electron-mobility transistors.

  2. Effect of atomic-arrangement matching on La{sub 2}O{sub 3}/Ge heterostructures for epitaxial high-k-gate-stacks

    SciTech Connect

    Kanashima, T. Zenitaka, M.; Kajihara, Y.; Yamada, S.; Hamaya, K.; Nohira, H.

    2015-12-14

    We demonstrate a high-quality La{sub 2}O{sub 3} layer on germanium (Ge) as an epitaxial high-k-gate-insulator, where there is an atomic-arrangement matching condition between La{sub 2}O{sub 3}(001) and Ge(111). Structural analyses reveal that (001)-oriented La{sub 2}O{sub 3} layers were grown epitaxially only when we used Ge(111) despite low growth temperatures less than 300 °C. The permittivity (k) of the La{sub 2}O{sub 3} layer is roughly estimated to be ∼19 from capacitance-voltage (C-V) analyses in Au/La{sub 2}O{sub 3}/Ge structures after post-metallization-annealing treatments, although the C-V curve indicates the presence of carrier traps near the interface. By using X-ray photoelectron spectroscopy analyses, we find that only Ge–O–La bonds are formed at the interface, and the thickness of the equivalent interfacial Ge oxide layer is much smaller than that of GeO{sub 2} monolayer. We discuss a model of the interfacial structure between La{sub 2}O{sub 3} and Ge(111) and comment on the C-V characteristics.

  3. Schottky source/drain germanium-based metal-oxide-semiconductor field-effect transistors with self-aligned NiGe/Ge junction and aggressively scaled high-k gate stack

    NASA Astrophysics Data System (ADS)

    Hosoi, Takuji; Minoura, Yuya; Asahara, Ryohei; Oka, Hiroshi; Shimura, Takayoshi; Watanabe, Heiji

    2015-12-01

    Schottky source/drain (S/D) Ge-based metal-oxide-semiconductor field-effect transistors (MOSFETs) were fabricated by combining high permittivity (high-k) gate stacks with ultrathin AlOx interlayers and Fermi level depinning process by means of phosphorous ion implantation into NiGe/Ge contacts. Improved thermal stability of the metal/high-k/Ge stacks enabled self-aligned integration scheme for Schottky S/D complementary MOS applications. Significantly reduced parasitic resistance and aggressively scaled high-k gate stacks with sub-1-nm equivalent oxide thickness were demonstrated for both p- and n-channel Schottky Ge-FETs with the proposed combined technology.

  4. Process optimizations to recessed e-SiGe source/drain for performance enhancement in 22 nm all-last high-k/metal-gate pMOSFETs

    NASA Astrophysics Data System (ADS)

    Qin, Changliang; Wang, Guilei; Hong, Peizhen; Liu, Jinbiao; Yin, Huaxiang; Yin, Haizhou; Ma, Xiaolong; Cui, Hushan; Lu, Yihong; Meng, Lingkuan; Xiang, Jinjuan; Zhong, Huicai; Zhu, Huilong; Xu, Qiuxia; Li, Junfeng; Yan, Jian; Zhao, Chao; Radamson, Henry H.

    2016-09-01

    In this paper, the technology of recessed embedded SiGe (e-SiGe) source/drain (S/D) module is optimized for the performance enhancement in 22 nm all-last high-k/metal-gate (HK/MG) pMOSFETs. Different Si recess-etch techniques were applied in S/D regions to increase the strain in the channel and subsequently, improve the performance of transistors. A new recess-etch method consists of a two-step etch method is proposed. This process is an initial anisotropic etch for the formation of shallow trench followed by a final isotropic etch. By introducing the definition of the upper edge distance (D) between the recessed S/D region and the channel region, the process advantage of the new approach is clearly presented. It decreases the value of D than those by conventional one-step isotropic or anisotropic etch of Si. Therefore, the series resistance is reduced and the channel strain is increased, which confirmed by the simulation results. The physical reason of D reducing is analyzed in brief. Applying this recess design, the implant conditions for S/D extension (SDE) are also optimized by using a two-step implantation of BF2 in SiGe layers. The overlap space between doping junction and channel region has great effect on the device's performance. The designed implantation profile decreases the overlap space while keeps a shallow junction depth for a controllable short channel effect. The channel resistance as well as the transfer ID-VG curves varying with different process conditions are demonstrated. It shows the drive current of the device with the optimized SDE implant condition and Si recess-etch process is obviously improved. The change trend of on-off current distributions extracted from a series of devices confirmed the conclusions. This study provides a useful guideline for developing high performance strained PMOS SiGe technology.

  5. Trap state passivation improved hot-carrier instability by zirconium-doping in hafnium oxide in a nanoscale n-metal-oxide semiconductor-field effect transistors with high-k/metal gate

    NASA Astrophysics Data System (ADS)

    Liu, Hsi-Wen; Chang, Ting-Chang; Tsai, Jyun-Yu; Chen, Ching-En; Liu, Kuan-Ju; Lu, Ying-Hsin; Lin, Chien-Yu; Tseng, Tseung-Yuen; Cheng, Osbert; Huang, Cheng-Tung; Ye, Yi-Han

    2016-04-01

    This work investigates the effect on hot carrier degradation (HCD) of doping zirconium into the hafnium oxide high-k layer in the nanoscale high-k/metal gate n-channel metal-oxide-semiconductor field-effect-transistors. Previous n-metal-oxide semiconductor-field effect transistor studies demonstrated that zirconium-doped hafnium oxide reduces charge trapping and improves positive bias temperature instability. In this work, a clear reduction in HCD is observed with zirconium-doped hafnium oxide because channel hot electron (CHE) trapping in pre-existing high-k bulk defects is the main degradation mechanism. However, this reduced HCD became ineffective at ultra-low temperature, since CHE traps in the deeper bulk defects at ultra-low temperature, while zirconium-doping only passivates shallow bulk defects.

  6. Electrical properties of Ge metal-oxide-semiconductor capacitors with high-k La2O3 gate dielectric incorporated by N or/and Ti

    NASA Astrophysics Data System (ADS)

    Huoxi, Xu; Jingping, Xu

    2016-06-01

    LaON, LaTiO and LaTiON films are deposited as gate dielectrics by incorporating N or/and Ti into La2O3 using the sputtering method to fabricate Ge MOS capacitors, and the electrical properties of the devices are carefully examined. LaON/Ge capacitors exhibit the best interface quality, gate leakage property and device reliability, but a smaller k value (14.9). LaTiO/Ge capacitors exhibit a higher k value (22.7), but a deteriorated interface quality, gate leakage property and device reliability. LaTiON/Ge capacitors exhibit the highest k value (24.6), and a relatively better interface quality (3.1 × 1011 eV-1 cm-2), gate leakage property (3.6 × 10-3 A/cm2 at V g = 1 V + V fb) and device reliability. Therefore, LaTiON is more suitable for high performance Ge MOS devices as a gate dielectric than LaON and LaTiO materials. Project supported by the National Natural Science Foundation of China (No. 61274112), the Natural Science Foundation of Hubei Province (No. 2011CDB165), and the Scientific Research Program of Huanggang Normal University (No. 2012028803).

  7. Investigation of trap properties in high-k/metal gate p-type metal-oxide-semiconductor field-effect-transistors with aluminum ion implantation using random telegraph noise analysis

    SciTech Connect

    Kao, Tsung-Hsien; Chang, Shoou-Jinn Fang, Yean-Kuen; Huang, Po-Chin; Wu, Chung-Yi; Wu, San-Lein

    2014-08-11

    In this study, the impact of aluminum ion implantation (Al I/I) on random telegraph noise (RTN) in high-k/metal gate (HK/MG) p-type metal-oxide-semiconductor field-effect-transistors (pMOSFETs) was investigated. The trap parameters of HK/MG pMOSFETs with Al I/I, such as trap energy level, capture time and emission time, activation energies for capture and emission, and trap location in the gate dielectric, were determined. The configuration coordinate diagram was also established. It was observed that the implanted Al could fill defects and form a thin Al{sub 2}O{sub 3} layer and thus increase the tunneling barrier height for holes. It was also observed that the trap position in the Al I/I samples was lower due to the Al I/I-induced dipole at the HfO{sub 2}/SiO{sub 2} interface.

  8. The role of ZrN capping layer deposited on ultra-thin high-k Zr-doped yttrium oxide for metal-gate metal-insulator-semiconductor applications

    NASA Astrophysics Data System (ADS)

    Juan, Pi-Chun; Mong, Fan-Chen; Huang, Jen-Hung

    2013-08-01

    Metal-gate MIS structures with and without ZrN capping layer on high-k Y2O3:Zr/Y2O3 stack were fabricated. The binding energies and depth profiles were investigated by x-ray photoelectron spectroscopy (XPS). The x-ray diffraction (XRD) patterns were compared. It is found that Ti out-diffusion into Zr-based high-k dielectric becomes lesser with the insertion of ZrN capping layer. The electrical properties of current-voltage (I-V) and capacitance-voltage (C-V) characteristics were measured in the postannealing temperature range of 550-850 °C. According to the defect reaction model, Zr cation vacancies are associated with the concentration of Ti ion by a transition from +3 to +2 states. The amount of Zr cation vacancies is quantified and equal to a half of Ti substitution amount at Zr site. The reduction in cation vacancies at high temperatures can well explain the decrease in ΔVFB for samples with ZrN layer. In contrast, an excess of Ti outdiffusion will produce the interstitial defects in high-k films without ZrN capping.

  9. In situ atomic layer nitridation on the top and down regions of the amorphous and crystalline high-K gate dielectrics

    NASA Astrophysics Data System (ADS)

    Tsai, Meng-Chen; Lee, Min-Hung; Kuo, Chin-Lung; Lin, Hsin-Chih; Chen, Miin-Jang

    2016-11-01

    Amorphous and crystalline ZrO2 gate dielectrics treated with in situ atomic layer nitridation on the top and down regions (top and down nitridation, abbreviated as TN and DN) were investigated. In a comparison between the as-deposited amorphous DN and TN samples, the DN sample has a lower leakage current density (Jg) of ∼7 × 10-4 A/cm2 with a similar capacitance equivalent thickness (CET) of ∼1.53 nm, attributed to the formation of SiOxNy in the interfacial layer (IL). The post-metallization annealing (PMA) leads to the transformation of ZrO2 from the amorphous to the crystalline tetragonal/cubic phase, resulting in an increment of the dielectric constant. The PMA-treated TN sample exhibits a lower CET of 1.22 nm along with a similar Jg of ∼1.4 × 10-5 A/cm2 as compared with the PMA-treated DN sample, which can be ascribed to the suppression of IL regrowth. The result reveals that the nitrogen engineering in the top and down regions has a significant impact on the electrical characteristics of amorphous and crystalline ZrO2 gate dielectrics, and the nitrogen incorporation at the top of crystalline ZrO2 is an effective approach to scale the CET and Jg, as well as to improve the reliability.

  10. Modeling and estimation of process-induced stress in the nanowire field-effect-transistors (NW-FETs) on Insulator-on-Silicon substrates with high-k gate-dielectrics

    NASA Astrophysics Data System (ADS)

    Chatterjee, Sulagna; Chattopadhyay, Sanatan

    2016-10-01

    An analytical model including the simultaneous impact of lattice and thermo-elastic constant mismatch-induced stress in nanowires on Insulator-on-Silicon substrate is developed. It is used to calibrate the finite-element based software, ANSYS, which is subsequently employed to estimate process-induced stress in the sequential steps of NW-FET fabrication. The model considers crystal structures and orientations for both the nanowires and substrates. In-plane stress components along nanowire-axis are estimated for different radii and fractions of insertion. Nature of longitudinal stress is observed to change when inserted fraction of nanowires is changed. Effect of various high-k gate-dielectrics is also investigated. A longitudinal tensile stress of 2.4 GPa and compressive stress of 1.89 GPa have been obtained for NW-FETs with 1/4th and 3/4th insertions with La2O3 and TiO2 as the gate-dielectrics, respectively. Therefore, it is possible to achieve comparable values of electron and hole mobility in NW-FETs by judiciously choosing gate-dielectrics and fractional insertion of the nanowires.

  11. Plasma surface interactions in nanoscale processing: Preservation of low-k integrity and high-k gate-stack etching with silicon selectivity

    NASA Astrophysics Data System (ADS)

    Shoeb, Juline

    Plasma-surface interactions are very important in the fabrication of the nm-sized features of integrated circuits. Plasma processes are employed to produce high-resolution patterns in many of the thin layers of silicon integrated circuits and to remove masking layers while maintaining high selectivity. Integrated plasma processes consisting of sequential steps such as etch, clean and surface modification, are used in semiconductor industries. The surface in contact with the process plasma is exposed to the fluxes of neutrals, ions, molecules, electrons and photons. Modeling of surface reaction mechanisms requires the determination of the characterizations of fluxes (e.g. composition, magnitude, energy and angle) and development of the reaction mechanisms of the processes such as adsorption, reflection, bond breaking and etch product evolution, while reproducing the experimental results. When modeling the reaction mechanism for an entirely new material, the experimental data is often fragmentary. Therefore, fundamental principles such as bond energies and volatility of the etch products must be considered to develop the mechanism. In this thesis, results from a computational investigation of porous low-k SiCOH etching in fluorocarbon plasmas, damage during cleaning of CFx polymer etch residue in Ar/O2 and He/H2 plasmas, NH3 plasma pore sealing and low-k degradation due to water uptake, will be discussed. The plasma etching of HfO2 gate-stacks is also computationally investigated with an emphasis on the selectivity between HfO2 and Si.

  12. Study on Preparation of High-k Organic-Inorganic Thin Film for Organic-Inorganic Thin Film Transistor Gate Dielectric Application

    NASA Astrophysics Data System (ADS)

    Lee, Wen-Hsi; Liu, Chao-Te; Lee, Ying-Chieh

    2012-06-01

    A simple solution-based deposition technique combined with spin-coating is a plausible way to prepare ultra-thin organic-inorganic nanocomposite films. In this study, we describe the spin-coating deposition of a colloidal nanoparticle suspension to obtain an ultra-thin organic-inorganic composite film as a gate insulator for organic thin film transistor (O-TFT) application. To obtain a homogenous organic-inorganic composite film, well-dispersed TiO2 nanoparticles in γ-butyrolactone and polyimide are important; therefore, several dispersants were assessed on the basis of the measurement of the rheological behavior of slurries. The thickness of the organic-inorganic composite film is mainly determined by the speed of spin-coating and viscosity of slurries. An approximately 4000-Å-thick nanocomposite film with homogeneous distribution of TiO2 nanoparticles in polyimide and low roughness was obtained after curing at 200 °C, resulting in a low leakage current density of the nano-composite film, when less than 2 vol % TiO2 nanoparticles were well dispersed in polyimide slurry. The dielectric constant of the organic-inorganic nanocomposite increases with increasing TiO2 content in polyimide, being situated in the range between 4 and 5.

  13. Impact of the TiN barrier layer on the positive bias temperature instabilities of high-k/metal-gate field effect transistors

    NASA Astrophysics Data System (ADS)

    Huang, Da-Cheng; Gong, Jeng; Huang, Chih-Fang; Chung, Steve S.

    2015-04-01

    This study examined the impact of positive bias temperature instability (PBTI) on n-channel metal-oxide-semiconductor field-effect transistor (n-MOSFET) with TiN barrier layer sandwiched between metal gate electrode and HfO2 dielectric. The experimental results clearly demonstrate that the diffusion mechanism of oxygen and nitrogen as a result of the post metallization treatment was the root cause of the PBTI. In this mechanism, the oxygen during the post metallization annealing (PMA) was diffused into TiN layer and replaced the nitrogen in the TiN layer. Subsequently, these replaced nitrogens were diffused into the HfO2, from which these replaced nitrogen atoms were used to passivate the defects in the HfO2. Results show that by increasing the thickness of TiN barrier layer, the driving current and the PBTI of n-MOSFET can be greatly improved. The larger the thickness of the TiN layer is, the better the PBTI reliability becomes.

  14. Investigation of trap properties of Hf0.83Zr0.17O2 high-k gate stack p-type MOSFETs by low-frequency (1/f) noise and random telegraph noise analyses

    NASA Astrophysics Data System (ADS)

    Tsai, Shih-Chang; Wu, San-Lein; Huang, Po-Chin; Wang, Bo-Chin; Tsai, Kai-Shiang; Kao, Tsung-Hsien; Yang, Chih-Wei; Chen, Cheng-Guo; Cheng, Osbert; Fang, Yean-Kuen; Chang, Shoou-Jinn; Chen, Jone-Fang

    2014-08-01

    In this study, the trap properties of composite Hf0.83Zr0.17O2 high-k gate stack p-type MOSFETs (pMOSFETs) were investigated by simultaneous low-frequency (1/f) noise and random telegraph noise measurements. Compared with pure ZrO2 pMOSFETs, the interface property and drive current of Hf0.83Zr0.17O2 pMOSFETs were both improved, and the depth of the effective centroid of the fixed charges was close to the insulator/semiconductor interface. This result indicated that the trapping behavior of hole capture from a ZrO2 film can be suppressed by mixing the film with a HfO2 film. Consequently, comparable oxide trap densities and trapping depths between Hf0.83Zr0.17O2 and HfO2 pMOSFETs can be seen. In addition, it was found that the unified model can appropriately interpret the 1/f noise mechanism in Hf0.83Zr0.17O2 pMOSFETs.

  15. Study on influences of TiN capping layer on time-dependent dielectric breakdown characteristic of ultra-thin EOT high-k metal gate NMOSFET with kMC TDDB simulations

    NASA Astrophysics Data System (ADS)

    Xu, Hao; Yang, Hong; Luo, Wei-Chun; Xu, Ye-Feng; Wang, Yan-Rong; Tang, Bo; Wang, Wen-Wu; Qi, Lu-Wei; Li, Jun-Feng; Yan, Jiang; Zhu, Hui-Long; Zhao, Chao; Chen, Da-Peng; Ye, Tian-Chun

    2016-08-01

    The thickness effect of the TiN capping layer on the time dependent dielectric breakdown (TDDB) characteristic of ultra-thin EOT high-k metal gate NMOSFET is investigated in this paper. Based on experimental results, it is found that the device with a thicker TiN layer has a more promising reliability characteristic than that with a thinner TiN layer. From the charge pumping measurement and secondary ion mass spectroscopy (SIMS) analysis, it is indicated that the sample with the thicker TiN layer introduces more Cl passivation at the IL/Si interface and exhibits a lower interface trap density. In addition, the influences of interface and bulk trap density ratio N it/N ot are studied by TDDB simulations through combining percolation theory and the kinetic Monte Carlo (kMC) method. The lifetime reduction and Weibull slope lowering are explained by interface trap effects for TiN capping layers with different thicknesses. Project supported by the National High Technology Research and Development Program of China (Grant No. SS2015AA010601), the National Natural Science Foundation of China (Grant Nos. 61176091 and 61306129), and the Opening Project of Key Laboratory of Microelectronics Devices & Integrated Technology, Institute of MicroElectronics of Chinese Academy of Sciences.

  16. Study on influences of TiN capping layer on time-dependent dielectric breakdown characteristic of ultra-thin EOT high-k metal gate NMOSFET with kMC TDDB simulations

    NASA Astrophysics Data System (ADS)

    Xu, Hao; Yang, Hong; Luo, Wei-Chun; Xu, Ye-Feng; Wang, Yan-Rong; Tang, Bo; Wang, Wen-Wu; Qi, Lu-Wei; Li, Jun-Feng; Yan, Jiang; Zhu, Hui-Long; Zhao, Chao; Chen, Da-Peng; Ye, Tian-Chun

    2016-08-01

    The thickness effect of the TiN capping layer on the time dependent dielectric breakdown (TDDB) characteristic of ultra-thin EOT high-k metal gate NMOSFET is investigated in this paper. Based on experimental results, it is found that the device with a thicker TiN layer has a more promising reliability characteristic than that with a thinner TiN layer. From the charge pumping measurement and secondary ion mass spectroscopy (SIMS) analysis, it is indicated that the sample with the thicker TiN layer introduces more Cl passivation at the IL/Si interface and exhibits a lower interface trap density. In addition, the influences of interface and bulk trap density ratio N it/N ot are studied by TDDB simulations through combining percolation theory and the kinetic Monte Carlo (kMC) method. The lifetime reduction and Weibull slope lowering are explained by interface trap effects for TiN capping layers with different thicknesses. Project supported by the National High Technology Research and Development Program of China (Grant No. SS2015AA010601), the National Natural Science Foundation of China (Grant Nos. 61176091 and 61306129), and the Opening Project of Key Laboratory of Microelectronics Devices & Integrated Technology, Institute of MicroElectronics of Chinese Academy of Sciences.

  17. Plasma etching of Hf-based high-k thin films. Part II. Ion-enhanced surface reaction mechanisms

    SciTech Connect

    Martin, Ryan M.; Blom, Hans-Olof; Chang, Jane P.

    2009-03-15

    The mechanism for ion-enhanced chemical etching of hafnium aluminate thin films in Cl{sub 2}/BCl{sub 3} plasmas was investigated in this work, specifically how the film composition, ion energy, and plasma chemistry determine their etch rates. Several compositions of Hf{sub 1-x}Al{sub x}O{sub y} thin films ranging from pure HfO{sub 2} to pure Al{sub 2}O{sub 3} were etched in BCl{sub 3}/Cl{sub 2} plasmas and their etch rates were found to scale with {radical}(E{sub ion}) in both Cl{sub 2} and BCl{sub 3} plasmas. In Cl{sub 2} plasmas, a transition point was observed around 50 eV, where the etch rate was significantly enhanced while the linear dependence to {radical}(E{sub ion}) was maintained, corresponding to a change in the removal of fully chlorinated to less chlorinated reaction products. In BCl{sub 3} plasma, deposition dominates at ion energies below 50 eV, while etching occurs above that energy with an etch rate of three to seven times that in Cl{sub 2}. The faster etch rate in BCl{sub 3} was attributed to a change in the dominant ion from Cl{sub 2}{sup +} in Cl{sub 2} plasma to BCl{sub 2}{sup +} in BCl{sub 3}, which facilitated the formation of more volatile etch products and their removal. The surface chlorination (0-3 at. %) was enhanced with increasing ion energy while the amount of boron on the surface increases with decreasing ion energy, highlighting the effect of different plasma chemistries on the etch rates, etch product formation, and surface termination.

  18. Plasma etching of Hf-based high-k thin films. Part III. Modeling the reaction mechanisms

    SciTech Connect

    Martin, Ryan M.; Chang, Jane P.

    2009-03-15

    A generalized etch rate model was formulated to describe metal oxide etching in complex plasma chemistries, based on the understanding gained from detailed plasma characterization and experimental investigation into the metal oxide etching mechanisms. Using a surface site balance-based approach, the correct etch rate dependencies on neutral-to-ion flux ratio, ion energy, competing deposition and etching reaction pathways, and film properties were successfully incorporated into the model. The applicability of the model was assessed by fitting to experimental etch rate data in both Cl{sub 2} and BCl{sub 3} chemistries. Plasma gas phase analysis as well as etch and deposition rate measurements were used to calculate initial values and appropriate ranges for model parameter variation. Physically meaningful parameter values were extracted from the modeling fitting to the experimental data, thereby demonstrating the applicability of this model in assessing the plasma etching of other complex materials systems.

  19. CROSS-DISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY: Growth Related Carrier Mobility Enhancement of Pentacene Thin-Film Transistors with High-k Oxide Gate Dielectric

    NASA Astrophysics Data System (ADS)

    Yu, Ai-Fang; Qi, Qiong; Jiang, Peng; Jiang, Chao

    2009-07-01

    Carrier mobility enhancement from 0.09 to 0.59 cm2/Vs is achieved for pentacene-based thin-film transistors (TFTs) by modifying the HfO2 gate dielectric with a polystyrene (PS) thin film. The improvement of the transistor's performance is found to be strongly related to the initial film morphologies of pentacene on the dielectrics. In contrast to the three-dimensional island-like growth mode on the HfO2 surface, the Stranski-Krastanov growth mode on the smooth and nonpolar PS/HfO2 surface is believed to be the origin of the excellent carrier mobility of the TFTs. A large well-connected first monolayer with fewer boundaries is formed via the Stranski-Krastanov growth mode, which facilitates a charge transport parallel to the substrate and promotes higher carrier mobility.

  20. The interface between silicon and a high-k oxide.

    PubMed

    Först, Clemens J; Ashman, Christopher R; Schwarz, Karlheinz; Blöchl, Peter E

    2004-01-01

    The ability of the semiconductor industry to continue scaling microelectronic devices to ever smaller dimensions (a trend known as Moore's Law) is limited by quantum mechanical effects: as the thickness of conventional silicon dioxide (SiO(2)) gate insulators is reduced to just a few atomic layers, electrons can tunnel directly through the films. Continued device scaling will therefore probably require the replacement of the insulator with high-dielectric-constant (high-k) oxides, to increase its thickness, thus preventing tunnelling currents while retaining the electronic properties of an ultrathin SiO(2) film. Ultimately, such insulators will require an atomically defined interface with silicon without an interfacial SiO(2) layer for optimal performance. Following the first reports of epitaxial growth of AO and ABO(3) compounds on silicon, the formation of an atomically abrupt crystalline interface between strontium titanate and silicon was demonstrated. However, the atomic structure proposed for this interface is questionable because it requires silicon atoms that have coordinations rarely found elsewhere in nature. Here we describe first-principles calculations of the formation of the interface between silicon and strontium titanate and its atomic structure. Our study shows that atomic control of the interfacial structure by altering the chemical environment can dramatically improve the electronic properties of the interface to meet technological requirements. The interface structure and its chemistry may provide guidance for the selection process of other high-k gate oxides and for controlling their growth.

  1. Dielectric relaxation of high-k oxides

    PubMed Central

    2013-01-01

    Frequency dispersion of high-k dielectrics was observed and classified into two parts: extrinsic cause and intrinsic cause. Frequency dependence of dielectric constant (dielectric relaxation), that is the intrinsic frequency dispersion, could not be characterized before considering the effects of extrinsic frequency dispersion. Several mathematical models were discussed to describe the dielectric relaxation of high-k dielectrics. For the physical mechanism, dielectric relaxation was found to be related to the degree of polarization, which depended on the structure of the high-k material. It was attributed to the enhancement of the correlations among polar nanodomain. The effect of grain size for the high-k materials' structure mainly originated from higher surface stress in smaller grain due to its higher concentration of grain boundary. PMID:24180696

  2. Assessment of technological and geometrical device parameters by low-frequency noise investigation in SOI omega-gate nanowire NMOS FETs

    NASA Astrophysics Data System (ADS)

    Koyama, M.; Cassé, M.; Barraud, S.; Ghibaudo, G.; Iwai, H.; Faynot, O.; Reimbold, G.

    2015-06-01

    A study of the gate oxide/channel interface quality in ultra-scaled SOI omega-gate nanowire NMOS FETs with cross-section as small as 10 nm × 10 nm is experimentally presented by low-frequency noise measurements. The noise study has been efficiently applied for the characterization of various technological parameters, including strained channel, additional hydrogen anneal, or channel orientation difference. A method for rigorous contribution assessment of the two oxide/channel interfaces (top surface vs. side-walls) is also demonstrated. Quality of the interface is slightly altered among the 4-types of technological parameters and the structural variety down to nanowire. However, an excellent quality of Hf-based high-k/metal gate stack is observed and sustained in all the devices. In particular, efficient tensile strain stressor is demonstrated with high enhancement of the NMOS FET performance and preserved 1/f noise performance fulfilling the requirement for future CMOS logic node stated in the international technology roadmap for semiconductors.

  3. Memory functions of nanocrystalline cadmium selenide embedded ZrHfO high-k dielectric stack

    SciTech Connect

    Lin, Chi-Chou; Kuo, Yue

    2014-02-28

    Metal-oxide-semiconductor capacitors made of the nanocrystalline cadmium selenide nc-CdSe embedded Zr-doped HfO{sub 2} high-k stack on the p-type silicon wafer have been fabricated and studied for their charge trapping, detrapping, and retention characteristics. Both holes and electrons can be trapped to the nanocrystal-embedded dielectric stack depending on the polarity of the applied gate voltage. With the same magnitude of applied gate voltage, the sample can trap more holes than electrons. A small amount of holes are loosely trapped at the nc-CdSe/high-k interface and the remaining holes are strongly trapped to the bulk nanocrystalline CdSe site. Charges trapped to the nanocrystals caused the Coulomb blockade effect in the leakage current vs. voltage curve, which is not observed in the control sample. The addition of the nanocrystals to the dielectric film changed the defect density and the physical thickness, which are reflected on the leakage current and the breakdown voltage. More than half of the originally trapped holes can be retained in the embedded nanocrystals for more than 10 yr. The nanocrystalline CdSe embedded high-k stack is a useful gate dielectric for this nonvolatile memory device.

  4. HF-based etching processes for improving laser damage resistance of fused silica optical surfaces

    SciTech Connect

    Suratwala, T I; Miller, P E; Bude, J D; Steele, R A; Shen, N; Monticelli, M V; Feit, M D; Laurence, T A; Norton, M A; Carr, C W; Wong, L L

    2010-02-23

    The effect of various HF-based etching processes on the laser damage resistance of scratched fused silica surfaces has been investigated. Conventionally polished and subsequently scratched fused silica plates were treated by submerging in various HF-based etchants (HF or NH{sub 4}F:HF at various ratios and concentrations) under different process conditions (e.g., agitation frequencies, etch times, rinse conditions, and environmental cleanliness). Subsequently, the laser damage resistance (at 351 or 355 nm) of the treated surface was measured. The laser damage resistance was found to be strongly process dependent and scaled inversely with scratch width. The etching process was optimized to remove or prevent the presence of identified precursors (chemical impurities, fracture surfaces, and silica-based redeposit) known to lead to laser damage initiation. The redeposit precursor was reduced (and hence the damage threshold was increased) by: (1) increasing the SiF{sub 6}{sup 2-} solubility through reduction in the NH4F concentration and impurity cation impurities, and (2) improving the mass transport of reaction product (SiF{sub 6}{sup 2-}) (using high frequency ultrasonic agitation and excessive spray rinsing) away from the etched surface. A 2D finite element crack-etching and rinsing mass transport model (incorporating diffusion and advection) was used to predict reaction product concentration. The predictions are consistent with the experimentally observed process trends. The laser damage thresholds also increased with etched amount (up to {approx}30 {micro}m), which has been attributed to: (1) etching through lateral cracks where there is poor acid penetration, and (2) increasing the crack opening resulting in increased mass transport rates. With the optimized etch process, laser damage resistance increased dramatically; the average threshold fluence for damage initiation for 30 {micro}m wide scratches increased from 7 to 41 J/cm{sup 2}, and the statistical

  5. Metallorganic chemical vapor deposition and atomic layer deposition approaches for the growth of hafnium-based thin films from dialkylamide precursors for advanced CMOS gate stack applications

    NASA Astrophysics Data System (ADS)

    Consiglio, Steven P.

    To continue the rapid progress of the semiconductor industry as described by Moore's Law, the feasibility of new material systems for front end of the line (FEOL) process technologies needs to be investigated, since the currently employed polysilicon/SiO2-based transistor system is reaching its fundamental scaling limits. Revolutionary breakthroughs in complementary-metal-oxide-semiconductor (CMOS) technology were recently announced by Intel Corporation and International Business Machines Corporation (IBM), with both organizations revealing significant progress in the implementation of hafnium-based high-k dielectrics along with metal gates. This announcement was heralded by Gordon Moore as "...the biggest change in transistor technology since the introduction of polysilicon gate MOS transistors in the late 1960s." Accordingly, the study described herein focuses on the growth of Hf-based dielectrics and Hf-based metal gates using chemical vapor-based deposition methods, specifically metallorganic chemical vapor deposition (MOCVD) and atomic layer deposition (ALD). A family of Hf source complexes that has received much attention recently due to their desirable properties for implementation in wafer scale manufacturing is the Hf dialkylamide precursors. These precursors are room temperature liquids and possess sufficient volatility and desirable decomposition characteristics for both MOCVD and ALD processing. Another benefit of using these sources is the existence of chemically compatible Si dialkylamide sources as co-precursors for use in Hf silicate growth. The first part of this study investigates properties of MOCVD-deposited HfO2 and HfSixOy using dimethylamido Hf and Si precursor sources using a customized MOCVD reactor. The second part of this study involves a study of wet and dry surface pre-treatments for ALD growth of HfO2 using tetrakis(ethylmethylamido)hafnium in a wafer scale manufacturing environment. The third part of this study is an investigation of

  6. High-K MISFET channel mobility from magnetoresistance

    NASA Astrophysics Data System (ADS)

    Bate, R. T.

    2005-03-01

    Carrier trapping in the gate insulator or at the interface with the silicon can depress the effective channel mobility of high-K MISFETs below the drift mobility. This reduction in effective mobility can be distinguished from true mobility reduction due to carrier scattering by using the Hall effect to measure the channel carrier density [1]. However, channel Hall measurements have traditionally required nonstandard multidrain devices, which must be included in the test chip design. We propose measuring the reduction in drain current of conventional transistors by a magnetic field to determine the Hall coefficient. This method, which requires no multidrain devices, could become a routine diagnostic procedure. It is based on a theorem concerning the magnetoresistance of a rectangular plate with perfectly conducting end contacts [2], which has apparently not been tested experimentally, at least on MOSFET's. The validity of the method can be determined by comparison with channel carrier density determined in other ways, including split capacitance on MOSFETS, conventional Hall effect, and Corbino magnetoresistance on MISFETs. Progress toward these goals is described. [1] N.S Saks and A.K Agarwal, Appl. Phys. Letters 77 (20), 3281 -- 3283 (2000); R. T. Bate and W. P. Kirk, Bull. Am. Phys, Soc. March, 2004, Abstract S6.011 [2] H. H. Jenson and H. Smith, J. Phys. C: Solid State, 5, 2867-2880, (1972)

  7. Oxygen vacancy defect engineering using atomic layer deposited HfAlOx in multi-layered gate stack

    NASA Astrophysics Data System (ADS)

    Bhuyian, M. N.; Sengupta, R.; Vurikiti, P.; Misra, D.

    2016-05-01

    This work evaluates the defects in high quality atomic layer deposited (ALD) HfAlOx with extremely low Al (<3% Al/(Al + Hf)) incorporation in the Hf based high-k dielectrics. The defect activation energy estimated by the high temperature current voltage measurement shows that the charged oxygen vacancies, V+/V2+, are the primary source of defects in these dielectrics. When Al is added in HfO2, the V+ type defects with a defect activation energy of Ea ˜ 0.2 eV modify to V2+ type to Ea ˜ 0.1 eV with reference to the Si conduction band. When devices were stressed in the gate injection mode for 1000 s, more V+ type defects are generated and Ea reverts back to ˜0.2 eV. Since Al has a less number of valence electrons than do Hf, the change in the co-ordination number due to Al incorporation seems to contribute to the defect level modifications. Additionally, the stress induced leakage current behavior observed at 20 °C and at 125 °C demonstrates that the addition of Al in HfO2 contributed to suppressed trap generation process. This further supports the defect engineering model as reduced flat-band voltage shifts were observed at 20 °C and at 125 °C.

  8. Multilayer filter design with high K materials

    NASA Astrophysics Data System (ADS)

    Curtis, Nathaniel, II

    A novel approach to filter design is presented. A high-K multilayer coupled line filter is designed for optimal performance within a dielectric resonator of rectangular cross section. The multilayer filter is shown to have a performance comparable to its planar counterpart as well as the Lange coupler while maintaining the design advantages that come with the multilayer approach to filter design such as increased flexibility in managing parameter constraints. The performance of the rectangular cross sectioned resonator in terms of modal response and resonant frequency has been evaluated through mathematical derivation and simulation. The reader will find the step by step process to designing the resonant structure as well as a MATLAB script that will graphically display the effect changing various parameters may have on resonator size to assist in the design analysis. The resonator has been designed to provide a finite package in terms of space and performance so that it may house the multilayer filter on a printed circuit board for ease of system implementation. The proposed design with analysis will prove useful for all multilayer coupled line filter types that may take advantage of the uniform environment provided by the finite packaging of the dielectric resonator. As with any microwave system, considerable effort must be put forth to maintain signal integrity throughout the delivery process from the signal input to reception at the output. As a result a large amount of effort and research has gone into answering the question of how to efficiently feed both a dielectric resonator filter of rectangular cross section as well as a coupled line filter that would be embedded within the resonators confines. Several methods for feeding have been explored and reported on. Of the feeding methods reported on the most feasible design includes a unique microstrip delivery to the embedded multilayer filter as pictured here.* *Please refer to dissertation for diagram.

  9. Indium diffusion through high-k dielectrics in high-k/InP stacks

    SciTech Connect

    Dong, H.; Cabrera, W.; Santosh KC,; Brennan, B.; Qin, X.; McDonnell, S.; Hinkle, C. L.; Cho, K.; Chabal, Y. J.; Galatage, R. V.; Zhernokletov, D.; Wallace, R. M.

    2013-08-05

    Evidence of indium diffusion through high-k dielectric (Al{sub 2}O{sub 3} and HfO{sub 2}) films grown on InP (100) by atomic layer deposition is observed by angle resolved X-ray photoelectron spectroscopy and low energy ion scattering spectroscopy. The analysis establishes that In-out diffusion occurs and results in the formation of a PO{sub x} rich interface.

  10. Gate dielectric scaling in MOSFETs device

    NASA Astrophysics Data System (ADS)

    Jing, K. Hui; Arshad, M. K. Md.; Huda, A. R. N.; Ruslinda, A. R.; Gopinath, Subash C. B.; M. Nuzaihan M., N.; Ayub, R. M.; Fathil, M. F. M.; Othman, Noraini; Hashim, U.

    2016-07-01

    Metal-Oxide-Semiconductor Field Effect Transistor (MOSFET) is a basic type of transistor to be used as a switch since 1959. Since then, the successful of MOSFET is due to good properties between silicon and silicon dioxide. The reduction of silicon oxide thickness provide further enhancement in device performance. At 90 and 65 nm technology nodes, the gate oxide could not be scaled anymore due to the direct tunneling effect resulting significant increase of leakage current. At 45 nm the high-k + metal gate has been introduced. Recently, the ferroelectric effect material is introduced which significantly reduce the gate leakage current. This paper review the evolution of gate dielectric scaling from the era of silicon dioxide to high-k + metal gate and ferroelectric effect material.

  11. Hard magnetic property enhancement of Co{sub 7}Hf-based ribbons by boron doping

    SciTech Connect

    Chang, H. W.; Liao, M. C.; Shih, C. W.; Chang, W. C.; Yang, C. C.; Hsiao, C. H.; Ouyang, H.

    2014-11-10

    Hard magnetic property enhancement of melt spun Co{sub 88}Hf{sub 12} ribbons by boron doping is demonstrated. B-doping could not only remarkably enhance the magnetic properties from energy product ((BH){sub max}) of 2.6 MGOe and intrinsic coercivity ({sub i}H{sub c}) of 1.5 kOe for B-free Co{sub 88}Hf{sub 12} ribbons to (BH){sub max} = 7.7 MGOe and {sub i}H{sub c} = 3.1 kOe for Co{sub 85}Hf{sub 12}B{sub 3} ribbons but also improve the Curie temperature (T{sub C}) of 7:1 phase. The (BH){sub max} value achieved in Co{sub 85}Hf{sub 12}B{sub 3} ribbons is the highest in Co-Hf alloy ribbons ever reported, which is about 15% higher than that of Co{sub 11}Hf{sub 2}B ribbons spun at 16 m/s [M. A. McGuire, O. Rios, N. J. Ghimire, and M. Koehler, Appl. Phys. Lett. 101, 202401 (2012)]. The structural analysis confirms that B enters the orthorhombic Co{sub 7}Hf (7:1) crystal structure as interstitial atoms, forming Co{sub 7}HfB{sub x}, in the as-spun state. Yet B may diffuse out from the 7:1 phase after post-annealing, leading to the reduction of Curie temperature and the magnetic properties. The uniformly refined microstructure with B-doping results in high remanence (B{sub r}) and improves the squareness of demagnetization curve. The formation of interstitial-atom-modified Co{sub 7}HfB{sub x} phase and the microstructure refinement are the main reasons to give rise to the enhancement of hard magnetic properties in the B-containing Co{sub 7}Hf-based ribbons.

  12. High-k shallow traps observed by charge pumping with varying discharging times

    SciTech Connect

    Ho, Szu-Han; Chen, Ching-En; Tseng, Tseung-Yuen; Chang, Ting-Chang; Lu, Ying-Hsin; Lo, Wen-Hung; Tsai, Jyun-Yu; Liu, Kuan-Ju; Wang, Bin-Wei; Cao, Xi-Xin; Chen, Hua-Mao; Cheng, Osbert; Huang, Cheng-Tung; Chen, Tsai-Fu

    2013-11-07

    In this paper, we investigate the influence of falling time and base level time on high-k bulk shallow traps measured by charge pumping technique in n-channel metal-oxide-semiconductor field-effect transistors with HfO{sub 2}/metal gate stacks. N{sub T}-V{sub high} {sub level} characteristic curves with different duty ratios indicate that the electron detrapping time dominates the value of N{sub T} for extra contribution of I{sub cp} traps. N{sub T} is the number of traps, and I{sub cp} is charge pumping current. By fitting discharge formula at different temperatures, the results show that extra contribution of I{sub cp} traps at high voltage are in fact high-k bulk shallow traps. This is also verified through a comparison of different interlayer thicknesses and different Ti{sub x}N{sub 1−x} metal gate concentrations. Next, N{sub T}-V{sub high} {sub level} characteristic curves with different falling times (t{sub falling} {sub time}) and base level times (t{sub base} {sub level}) show that extra contribution of I{sub cp} traps decrease with an increase in t{sub falling} {sub time}. By fitting discharge formula for different t{sub falling} {sub time}, the results show that electrons trapped in high-k bulk shallow traps first discharge to the channel and then to source and drain during t{sub falling} {sub time}. This current cannot be measured by the charge pumping technique. Subsequent measurements of N{sub T} by charge pumping technique at t{sub base} {sub level} reveal a remainder of electrons trapped in high-k bulk shallow traps.

  13. 20. DETAIL VIEW OF NONSUBMERSIBLE TAINTER GATE, SHOWING GATE, GATE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    20. DETAIL VIEW OF NONSUBMERSIBLE TAINTER GATE, SHOWING GATE, GATE ARM, TRUNNION PIN, PIER AND GATE GAUGE, LOOKING WEST - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 10, Guttenberg, Clayton County, IA

  14. 17. DETAIL VIEW OF TAINTER GATE, SHOWING GATE, GATE ARM, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    17. DETAIL VIEW OF TAINTER GATE, SHOWING GATE, GATE ARM, PIER, TRUNNION PIN AND GATE GAUGE, LOOKING NORTHEAST - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 6, Trempealeau, Trempealeau County, WI

  15. 17. DETAIL VIEW OF TAINTER GATE, SHOWING GATES, GATE ARMS, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    17. DETAIL VIEW OF TAINTER GATE, SHOWING GATES, GATE ARMS, PIERS, GATE CHAINS AND SWITCHES, AND BRIDGE GIRDERS, LOOKING SOUTHWEST - Upper Mississippi River 9-Foot Channel Project, Lock & Dam No. 5, Minneiska, Winona County, MN

  16. 18. DETAIL VIEW OF TAINTER GATE, SHOWING GATES, GATE ARMS, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    18. DETAIL VIEW OF TAINTER GATE, SHOWING GATES, GATE ARMS, PIERS, GATE CHAINS AND SWITCHES, AND BRIDGE GIRDERS, LOOKING NORTHWEST - Upper Mississippi River 9-Foot Channel Project, Lock & Dam No. 5, Minneiska, Winona County, MN

  17. 20. DETAIL VIEW OF SUBMERSIBLE GATE, SHOWING GATE ARMS, GATE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    20. DETAIL VIEW OF SUBMERSIBLE GATE, SHOWING GATE ARMS, GATE PIERS, TRUNNION PIN AND GATE GAUGE, LOOKING NORTHEAST - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 8, On Mississippi River near Houston County, MN, Genoa, Vernon County, WI

  18. 21. DETAIL VIEW OF SUBMERSIBLE TAINTER GATE, SHOWING GATE, GATE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    21. DETAIL VIEW OF SUBMERSIBLE TAINTER GATE, SHOWING GATE, GATE ARM, TRUNNION PIN, PIER AND GATE GAUGE, LOOKING EAST - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 10, Guttenberg, Clayton County, IA

  19. 17. DETAIL VIEW OF NONSUBMERSIBLE TAINTER GATE, SHOWING GATES, GATE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    17. DETAIL VIEW OF NON-SUBMERSIBLE TAINTER GATE, SHOWING GATES, GATE ARMS, PIERS AND DAM BRIDGE, WITH ROLLER GATE HEADHOUSE IN BACKGROUND, LOOKING SOUTHEAST - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 9, Lynxville, Crawford County, WI

  20. Structural and optical properties of germanium nanostructures on Si(100) and embedded in high-k oxides

    PubMed Central

    2011-01-01

    The structural and optical properties of Ge quantum dots (QDs) grown on Si(001) for mid-infrared photodetector and Ge nanocrystals embedded in oxide matrices for floating gate memory devices are presented. The infrared photoluminescence (PL) signal from Ge islands has been studied at a low temperature. The temperature- and bias-dependent photocurrent spectra of a capped Si/SiGe/Si(001) QDs infrared photodetector device are presented. The properties of Ge nanocrystals of different size and density embedded in high-k matrices grown using radio frequency magnetron sputtering have been studied. Transmission electron micrographs have revealed the formation of isolated spherical Ge nanocrystals in high-k oxide matrix of sizes ranging from 4 to 18 nm. Embedded nanocrystals in high band gap oxides have been found to act as discrete trapping sites for exchanging charge carriers with the conduction channel by direct tunneling that is desired for applications in floating gate memory devices. PMID:21711749

  1. Ultimate Backside Sample Preparation For Ultra Thin High-k/Metal Gate Stack Characterization

    NASA Astrophysics Data System (ADS)

    Py, M.; Veillerot, M.; Martinez, E.; Fabbri, J. M.; Boujamaa, R.; Barnes, J. P.; Bertin, F.

    2011-11-01

    Backside sample preparation is a well known method to help circumvent undesired effects and artifacts in the analysis of a sample or device structure. However it remains challenging in the case of thin layers analysis since only a fraction of the original sample must remain while removing all of the substrate and maintaining a smooth and flat surface suitable for analysis. Here we present a method adapted to the preparation of ultra thin layers grown on pure Si substrates. It consists in a mechanical polishing up to a few remaining microns, followed by a dedicated wet etch. This method can be operated in a routine fashion and yields an extremely flat and smooth surface, without any remaining Si from substrate. It therefore allows precise analysis of the layers of interests with various characterization techniques.

  2. Effects of Titanium Layer Oxygen Scavenging on the High-k/InGaAs Interface.

    PubMed

    Winter, Roy; Shekhter, Pini; Tang, Kechao; Floreano, Luca; Verdini, Alberto; McIntyre, Paul C; Eizenberg, Moshe

    2016-07-01

    One of the main challenges in the path to incorporating InGaAs based metal-oxide-semiconductor structures in nanoelectronics is the passivation of high-k/InGaAs interfaces. Here, the oxygen scavenging effect of thin Ti layers on high-k/InGaAs gate stacks was studied. Electrical measurements and synchrotron X-ray photoelectron spectroscopy measurements, with in situ metal deposition, were used. Oxygen removal from the InGaAs native oxide surface layer remotely through interposed Al2O3 and HfO2 layers observed. Synchrotron X-ray photoelectron spectroscopy has revealed a decrease in the intensity of InOx features relative to In in InGaAs after Ti deposition. The signal ratio decreases further after annealing. In addition, Ti 2p spectra clearly show oxidation of the thin Ti layer in the ultrahigh vacuum XPS environment. Using capacitance-voltage and conductance-voltage measurements, Pt/Ti/Al2O3/InGaAs and Pt/Al2O3/InGaAs capacitors were characterized both before and after annealing. It was found that the remote oxygen scavenging from the oxide/semiconductor interface using a thin Ti layer can influence the density of interface traps in the high-k/InGaAs interface. PMID:27282201

  3. Effect of thin gate dielectrics and gate materials on simulated device characteristics of 3D double gate JNT

    NASA Astrophysics Data System (ADS)

    Baidya, A.; Krishnan, V.; Baishya, S.; Lenka, T. R.

    2015-01-01

    In this paper a novel Silicon based three dimensional (3D) double-gate Junctionless Nanowire Transistor (JNT) of 20 nm gate length is proposed. The device characteristics such as gate characteristics and drain characteristics are studied with the help of Sentaurus TCAD by using different gate materials such as Al, Ti, n+ Polysilicon, Au and using different ultra thin gate dielectrics such as SiO2, Si3N4 and HfO2. The effect of various work functions and dielectrics on the threshold voltage of the JNT is also analysed. From the TCAD simulation results it is observed that high-K material (HfO2) as gate dielectric shows better drain characteristics with respect to others. The JNT with Al as gate material gives better current characteristics with respect to others. It is also analysed that under flat-band condition the driving of drain current does not directly depend on the gate-oxide capacitance but depends upon the channel doping concentrations. Thus by choosing the proper gate material and gate dielectric combinations, the desired device characteristics could be obtained for JNT.

  4. 16. DETAIL VIEW OF SUBMERSIBLE TAINTER GATE, SHOWING GATE, GATE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    16. DETAIL VIEW OF SUBMERSIBLE TAINTER GATE, SHOWING GATE, GATE ARM, TRUNNION PIN AND PIER, LOOKING NORTHEAST - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 8, On Mississippi River near Houston County, MN, Genoa, Vernon County, WI

  5. 18. DETAIL VIEW OF NONSUBMERSIBLE TAINTER GATE, SHOWING GATES, GATE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    18. DETAIL VIEW OF NON-SUBMERSIBLE TAINTER GATE, SHOWING GATES, GATE ARMS, PIERS AND DAM BRIDGE, LOOKING SOUTHEAST - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 9, Lynxville, Crawford County, WI

  6. High-K isomers: some of the questions

    NASA Astrophysics Data System (ADS)

    Walker, P. M.

    2016-09-01

    High-K isomers exemplify the coexistence of individual-particle and collective motion in atomic nuclei. Here, the topic is briefly outlined, and some open questions are discussed. These include violations of the K quantum number; the high-spin limit to K isomerism; the fission stability of K isomers; possibilities for manipulation and control of K-isomer decay rates; and access to K isomers in neutron-rich nuclei.

  7. The work function engineering and thermal stability of novel metal gate electrodes for advanced CMOS devices

    NASA Astrophysics Data System (ADS)

    Zhao, Penghui

    The continuous scaling of Complementary Metal Oxide Semiconductor (CMOS) integrated circuits requires the replacement of the conventional poly-silicon gate electrode and silicon dioxide gate dielectric with metal gate electrodes and high-agate dielectrics, respectively. The most critical requirements for alternative metal gates are proper work function and good thermal stability. This dissertation has focused on the effective work function and thermal stability of molybdenum-based metal gates (Mo, MoN, and MoSiN) and fully silicided (FUSI) NiSi metal gates. Capacitance-Voltage (C-V) and Current-Voltage (I-V) measurements of MOS capacitors were performed to investigate the electrical properties of molybdenum-based metal gates. Four-point probe resistivity measurements, Rutherford Backscattering Spectroscopy (RBS), X-ray Photoelectron Spectroscopy (XPS), High Resolution Transmission Electron Microscopy (HR-TEM), Electron Nanodiffraction analysis, X-ray Diffraction (XRD) and backside Secondary Ion Mass Spectroscopy (SIMS) methods were performed as well, to characterize the thermal stability of metal gate electrodes. The effective work function and thermal stability of molybdenum-based metal gates (Mo, MoN and MoSiN) on both SiO2 and Hf-based high-kappadielectrics have been evaluated systematically. The effects of silicon and nitrogen concentrations on the work function and thermal stability are discussed. The effective work function of molybdenum nitrides on both SiO2 and Hf-based high-kappadielectrics can be tuned to ˜4.4-4.5 eV, however, the thermal budgets should be less than 900°C 10 sec due to nitrogen loss and the phase transformation behavior of molybdenum nitrides. Silicon incorporation in the Mo-N system can improve the film thermal stability and diffusion barrier properties at the interface of metal gates/dielectrics due to the presence of Si-N bonds. By optimizing the film composition, the work function of MoSiN gates on SiO2 can be tuned for fully

  8. A hetero-dielectric stack gate SOI-TFET with back gate and its application as a digital inverter

    NASA Astrophysics Data System (ADS)

    Mitra, Suman Kr.; Goswami, Rupam; Bhowmick, Brinda

    2016-04-01

    A Silicon based two dimensional (2D) hetero-dielectric stack gate SOI Tunneling Field Effect Transistor (SOI-TFET) with back-gate is proposed. Simulation results show that the proposed structure can be scaled down without affecting Subthreshold Swing unlike conventional TFETs with SiO2 as gate dielectric. On state of the device is independent of back-gate voltage unlike MOSFETs. The effects of gate lengths, lengths of high-k dielectric in lower stack (L) and back-gate voltages on the threshold voltage, Ion/Ioff and Subthreshold Swing (SS) of the SOI-TFET are analyzed. Capacitance components CGG, CGD, CGS are also observed and device shows good performance as an inverter. The fall time, overshoot and undershoot are not above 27 fs, 1.712% and 0.77% respectively considering mixed mode device and circuit simulation of capacitive loaded inverter.

  9. FLOW GATING

    DOEpatents

    Poppelbaum, W.J.

    1962-12-01

    BS>This invention is a fast gating system for eiectronic flipflop circuits. Diodes connect the output of one circuit to the input of another, and the voltage supply for the receiving flip-flop has two alternate levels. When the supply is at its upper level, no current can flow through the diodes, but when the supply is at its lower level, current can flow to set the receiving flip- flop to the same state as that of the circuit to which it is connected. (AEC)

  10. High-K multi-quasiparticle states in 254No

    NASA Astrophysics Data System (ADS)

    Clark, R. M.; Gregorich, K. E.; Berryman, J. S.; Ali, M. N.; Allmond, J. M.; Beausang, C. W.; Cromaz, M.; Deleplanque, M. A.; Dragojević, I.; Dvorak, J.; Ellison, P. A.; Fallon, P.; Garcia, M. A.; Gates, J. M.; Gros, S.; Jeppesen, H. B.; Kaji, D.; Lee, I. Y.; Macchiavelli, A. O.; Morimoto, K.; Nitsche, H.; Paschalis, S.; Petri, M.; Stavsetra, L.; Stephens, F. S.; Watanabe, H.; Wiedeking, M.

    2010-06-01

    We report results from an experiment on the decay of the high-K isomers in 254No. We have been able to establish the decay from the known high-lying four-quasiparticle isomer, which we assign as a K=16 state at an excitation energy of Ex=2.928(3) MeV. The decay of this state passes through a rotational band based on a previously unobserved state at Ex=2.012(2) MeV, which we suggest is based on a two-quasineutron configuration with K=10. This state in turn decays to a rotational band based on the known K=8 isomer, which we infer must also have a two quasineutron configuration. We are able to assign many new gamma-rays associated with the decay of the K=8 isomer, including the identification of a highly K-forbidden ΔK=8 E1 transition to the ground-state band. These results provide valuable new information on the orbitals close to the Fermi surface, pairing correlations, deformation and rotational response, and K-conservation in nuclei of the deformed trans-fermium region.

  11. Modelling and extraction procedure for gate insulator and fringing gate capacitance components of an MIS structure

    NASA Astrophysics Data System (ADS)

    Tinoco, J. C.; Martinez-Lopez, A. G.; Lezama, G.; Mendoza-Barrera, C.; Cerdeira, A.; Estrada, M.

    2016-07-01

    CMOS technology has been guided by the continuous reduction of MOS transistors used to fabricate integrated circuits. Additionally, the use of high-k dielectrics as well as a metal gate electrode have promoted the development of nanometric MOS transistors. Under this scenario, the proper modelling of the gate capacitance, with the aim of adequately evaluating the dielectric film thickness, becomes challenging for nanometric metal-insulator-semiconductor (MIS) structures due to the presence of extrinsic fringing capacitance components which affect the total gate capacitance. In this contribution, a complete intrinsic-extrinsic model for gate capacitance under accumulation of an MIS structure, together with an extraction procedure in order to independently determine the different capacitance components, is presented. ATLAS finite element simulation has been used to validate the proposed methodology.

  12. Modelling and extraction procedure for gate insulator and fringing gate capacitance components of an MIS structure

    NASA Astrophysics Data System (ADS)

    Tinoco, J. C.; Martinez-Lopez, A. G.; Lezama, G.; Mendoza-Barrera, C.; Cerdeira, A.; Estrada, M.

    2016-07-01

    CMOS technology has been guided by the continuous reduction of MOS transistors used to fabricate integrated circuits. Additionally, the use of high-k dielectrics as well as a metal gate electrode have promoted the development of nanometric MOS transistors. Under this scenario, the proper modelling of the gate capacitance, with the aim of adequately evaluating the dielectric film thickness, becomes challenging for nanometric metal-insulator-semiconductor (MIS) structures due to the presence of extrinsic fringing capacitance components which affect the total gate capacitance. In this contribution, a complete intrinsic–extrinsic model for gate capacitance under accumulation of an MIS structure, together with an extraction procedure in order to independently determine the different capacitance components, is presented. ATLAS finite element simulation has been used to validate the proposed methodology.

  13. Swift ion irradiation effect on high-k ZrO2- and Al2O3-based MOS devices

    NASA Astrophysics Data System (ADS)

    Rao, Ashwath; Chaurasia, Priyanka; Singh, B. R.

    2016-03-01

    This paper describes the heavy ion-induced effects on the electrical characteristics of reactively sputtered ZrO2 and Al2O3 high-k gate oxides deposited in argon plus nitrogen containing plasma. Radiation-induced degradation of sputtered high-k dielectric ZrO2/Si and Al2O3/Si interface was studied using 45 MeV Li3+ ions. The devices were irradiated with Li3+ ions at various fluences ranging from 5 × 109 to 5 × 1012 ions/cm2. Capacitance-voltage and current-voltage characteristics were used for electrical characterization. Shift in flat band voltage towards negative value was observed in devices after exposure to ion radiation. Post-deposition annealing effect on the electrical behavior of high-k/Si interface was also investigated. The annealed devices showed better electrical and reliability characteristics. Different device parameters such as flat band voltage, leakage current, interface defect density and oxide-trapped charge have been extracted.The surface morphology and roughness values for films deposited in nitrogen containing plasma before and after ion radiation are extracted from Atomic Force Microscopy.

  14. Evolutionary search for new high-k dielectric materials: methodology and applications to hafnia-based oxides.

    PubMed

    Zeng, Qingfeng; Oganov, Artem R; Lyakhov, Andriy O; Xie, Congwei; Zhang, Xiaodong; Zhang, Jin; Zhu, Qiang; Wei, Bingqing; Grigorenko, Ilya; Zhang, Litong; Cheng, Laifei

    2014-02-01

    High-k dielectric materials are important as gate oxides in microelectronics and as potential dielectrics for capacitors. In order to enable computational discovery of novel high-k dielectric materials, we propose a fitness model (energy storage density) that includes the dielectric constant, bandgap, and intrinsic breakdown field. This model, used as a fitness function in conjunction with first-principles calculations and the global optimization evolutionary algorithm USPEX, efficiently leads to practically important results. We found a number of high-fitness structures of SiO2 and HfO2, some of which correspond to known phases and some of which are new. The results allow us to propose characteristics (genes) common to high-fitness structures--these are the coordination polyhedra and their degree of distortion. Our variable-composition searches in the HfO2-SiO2 system uncovered several high-fitness states. This hybrid algorithm opens up a new avenue for discovering novel high-k dielectrics with both fixed and variable compositions, and will speed up the process of materials discovery.

  15. Design of a recessed-gate GaN-based MOSFET using a dual gate dielectric for high-power applications

    NASA Astrophysics Data System (ADS)

    Yoon, Young Jun; Kang, Hee-Sung; Seo, Jae Hwa; Kim, Young-Jo; Bae, Jin-Hyuk; Lee, Jung-Hee; Kang, In Man; Cho, Seongjae; Cho, Eou-Sik

    2014-11-01

    We have investigated gallium-nitride (GaN)-based metal-oxide-semiconductor field-effect transistors (MOSFETs) having a recessed-gate structure for high-power applications. Recessed-gate GaN-based MOSFETs have been designed with a dual high- k dielectric structure to overcome low current drivability. Compared to recessed-gate GaN-based MOSFETs having a single gate dielectric with the same oxide thickness, recessed-gate GaN-based MOSFETs having a dual high- k dielectric composed of Al2O3 and HfO2 have achieved a high drain current ( I D ) and transconductance ( g m ) due to the high dielectric constant of HfO2. Also, because the dual high- k dielectric forms a high electron density in the channel layer with outstanding gate control capability, low channel resistances ( R ch ) have obtained. In addition, we have studied the effect of the length between the gate and the drain ( L gd ) on the on-resistance ( R on ) to minimize the R on that is associated with power consumption and switching performance. Also, the electric field distribution of a device having a dual high- k dielectric has been examined with a field plate structure for high drive voltage. The proposed device was confirmed to be a remarkable candidate for switching devices in high-power applications.

  16. Mechanical Design of the NSTX High-k Scattering Diagnostic

    SciTech Connect

    Feder, R.; Mazzucato, E.; Munsat, T.; Park, H,; Smith, D. R.; Ellis, R.; Labik, G.; Priniski, C.

    2005-09-26

    The NSTX High-k Scattering Diagnostic measures small-scale density fluctuations by the heterodyne detection of waves scattered from a millimeter wave probe beam at 280 GHz and {lambda}=1.07 mm. To enable this measurement, major alterations were made to the NSTX vacuum vessel and Neutral Beam armor. Close collaboration between the PPPL physics and engineering staff resulted in a flexible system with steerable launch and detection optics that can position the scattering volume either near the magnetic axis ({rho} {approx} .1) or near the edge ({rho} {approx} .8). 150 feet of carefully aligned corrugated waveguide was installed for injection of the probe beam and collection of the scattered signal in to the detection electronics.

  17. High-k Dielectric Nanosheets for Two-Dimensional material Electronics

    NASA Astrophysics Data System (ADS)

    Hao, Yufeng; Cui, Xu; Yin, Jun; Lee, Gwan-Hyoung; Arefe, Ghidewon; Osada, Minoru; Sasaki, Takayoshi; Hone, James

    2015-03-01

    Two-dimensional (2D) materials, such as graphene, hexagonal boron nitride (hBN), transition metal dichalcogenides, have shown great potential in nano-electronics because of their unique and superior physical properties. Among them, hBN has been known as an alternative dielectric that is atomically flat and free of trapped charges, which drastically enhance the mobility of graphene or MoS2. However, low dielectric constant (k ~ 3.5) of hBN limits its use in transistors as gate lengths are scaled down to tens of nanometers. Here we demonstrate high performance graphene and MoS2 field effect transistors by using ultrathin Ca2NaNb4O13 nanosheet as a dielectric and mechanically stacking 2D materials. We developed a facile transfer strategy to build 2D materials devices based on the Ca2NaNb4O13 nanosheets. We measured and found that the oxide nanosheet has high dielectric strength, along with high dielectric constant at thickness of a few tens of nanometer. Therefore, multiple-stacked heterostructure of 2D materials shows high mobility at small operating voltage. This study shows possibility of high-k dielectric nanosheets for 2D electronics.

  18. The energy-band alignment at molybdenum disulphide and high-k dielectrics interfaces

    SciTech Connect

    Tao, Junguang; Chai, J. W.; Zhang, Z.; Pan, J. S.; Wang, S. J.

    2014-06-09

    Energy-band alignments for molybdenum disulphide (MoS{sub 2}) films on high-k dielectric oxides have been studied using photoemission spectroscopy. The valence band offset (VBO) at monolayer MoS{sub 2}/Al{sub 2}O{sub 3} (ZrO{sub 2}) interface was measured to be 3.31 eV (2.76 eV), while the conduction-band offset (CBO) was 3.56 eV (1.22 eV). For bulk MoS{sub 2}/Al{sub 2}O{sub 3} interface, both VBO and CBO increase by ∼0.3 eV, due to the upwards shift of Mo 4d{sub z{sup 2}} band. The symmetric change of VBO and CBO implies Fermi level pinning by interfacial states. Our finding ensures the practical application of both p-type and n-type MoS{sub 2} based complementary metal-oxide semiconductor and other transistor devices using Al{sub 2}O{sub 3} and ZrO{sub 2} as gate materials.

  19. Scatterometry measurement for gate ADI and AEI critical dimension of 28-nm metal gate technology

    NASA Astrophysics Data System (ADS)

    Huang, Yu-Hao; Chen, Howard; Shen, Kyle; Chen, H. H.; Yu, Chun Chi; Liao, J. H.; Zhang, Xiafang; Teo, Russell; Xu, Zhi-Qing; Yoo, Sungchul; Lin, Ching-Hung; Cheng, Chao-Yu; Lin, Jason

    2011-03-01

    This paper discusses the scatterometry-based metrology measurement of 28nm high k metal gate after-develop inspection (ADI) and after-etch inspection (AEI) layer structures. For these structures, the critical measurement parameters include side wall angle (SWA) and critical dimension (CD). For production process control of these structures, a metrology tool must utilize a non-destructive measurement technique, and have high sensitivity, precision and throughput. Spectroscopic critical dimension (SCD) metrology tools have been implemented in production for process control of traditional poly gate structures. For today's complex metal gate devices, extended SCD technologies are required. KLA-Tencor's new SpectraShape 8810 uses multi-azimuth angles and multi-channel optics to produce the high sensitivity and precision required for measurement of critical parameters on metal gate structures. Data from process of record (POR), focus-exposure matrix (FEM) and design of experiment (DOE) wafers are presented showing the performance of this new SCD tool on metal gate ADI and AEI process structures. Metal gate AEI scatterometry measurement results are also compared to transmission electron microscopy (TEM) reference measurements. These data suggest that the SpectraShape 8810 has the required sensitivity and precision to serve as a production process monitor for 28nm and beyond complex metal gate structures.

  20. Contactless analysis of electric dipoles at high-k/SiO2 interfaces by surface-charge-switched electron spectroscopy

    NASA Astrophysics Data System (ADS)

    Toyoda, S.; Fukuda, K.; Itoh, E.; Sugaya, H.; Morita, M.; Nakata, A.; Uchimoto, Y.; Matsubara, E.

    2016-05-01

    The continuous development of silicon devices has been supported by fundamental understanding of the two interfaces that predict the device properties: high-dielectric oxide (high-k)/SiO2 and SiO2/Si. In the absence of metal electrode fabrication, it is challenging to use spectroscopic approaches to deduce the electric dipoles in these interfaces for the prediction of electrical characteristics such as the leakage current and threshold voltage. Here, we propose a method to analyze the permanent dipole at the high-k/SiO2 interface by surface-charge-switched electron spectroscopy (SuCSES). An electron flood gun was used to switch the electrical polarity at the insulating surface to extract the interface-dipole contribution from the macroscopic dielectric polarization in the high-k/SiO2/Si stack structure. TaO3- nanosheet (TaNS) crystallites, which are a family of high-k tantalate materials deposited on the SiO2/Si substrates, were annealed to prepare a nanoscale model interface. The properties of this interface were examined as a function of annealing temperature across the crystalline-to-amorphous transition. Macroscopic dielectric polarization of the TaNS/SiO2/Si gate stack was found to exhibit a gradual decay that depended upon the quantum tunneling processes of induced carriers at the SiO2/Si interface. Additionally, the dipole at the high-k/thin-SiO2 interface abruptly changed by ˜0.4 eV before and after annealing at 400 °C, which may be the result of a decrease in conduction-band offsets at the high-k/Si interface. Thus, SuCSES can aid in determining the inherent valence-band offsets in dielectric interfaces by using X-ray photoelectron spectroscopy with high accuracy and precision. Furthermore, SuCSES can determine whether dielectric polarization, including the interfacial dipole, affects the experimental value of the band offsets.

  1. High-k lithium phosphorous oxynitride thin films

    NASA Astrophysics Data System (ADS)

    Fu, Zheng-Wen; Liu, Wen-Yuan; Li, Chi-Lin; Qin, Qi-Zong; Yao, Yin; Lu, Fang

    2003-12-01

    Lithium phosphorous oxynitride (Lipon) thin films have been fabricated onto n-Si substrate at room temperature by nitrogen plasma-assisted deposition of electron-beam reactive evaporated Li3PO4. The capacitance-voltage (C-V) and I-V characteristics of Al/Lipon/Si capacitors were measured. The accumulation, depletion, and inversion phenomena in the C-V curves of the as-deposited Lipon thin film could be clearly observed. The isothermal transient ionic current of Al/Lipon/Al as a function of time during voltage stepping from 0 to 3 V exhibits a large current response due to dipole orientation. The dielectric constant of Lipon thin films is found to be 16.6, and the leakage current density at an applied electric field of 5 kV/cm is about 6.0×10-7 A/cm2. These results suggest that lithium phosphorous oxynitride thin films are high-k materials. The incorporation of N into amorphous of Li3PO4 could significantly increase the dielectric constant of Lipon thin films.

  2. 49 CFR 234.255 - Gate arm and gate mechanism.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Gate arm and gate mechanism. 234.255 Section 234....255 Gate arm and gate mechanism. (a) Each gate arm and gate mechanism shall be inspected at least once each month. (b) Gate arm movement shall be observed for proper operation at least once each month....

  3. 49 CFR 234.255 - Gate arm and gate mechanism.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Gate arm and gate mechanism. 234.255 Section 234... Maintenance, Inspection, and Testing Inspections and Tests § 234.255 Gate arm and gate mechanism. (a) Each gate arm and gate mechanism shall be inspected at least once each month. (b) Gate arm movement shall...

  4. 49 CFR 234.255 - Gate arm and gate mechanism.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ....255 Gate arm and gate mechanism. (a) Each gate arm and gate mechanism shall be inspected at least once each month. (b) Gate arm movement shall be observed for proper operation at least once each month. (c... 49 Transportation 4 2014-10-01 2014-10-01 false Gate arm and gate mechanism. 234.255 Section...

  5. 49 CFR 234.255 - Gate arm and gate mechanism.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Gate arm and gate mechanism. 234.255 Section 234... Maintenance, Inspection, and Testing Inspections and Tests § 234.255 Gate arm and gate mechanism. (a) Each gate arm and gate mechanism shall be inspected at least once each month. (b) Gate arm movement shall...

  6. 49 CFR 234.255 - Gate arm and gate mechanism.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ....255 Gate arm and gate mechanism. (a) Each gate arm and gate mechanism shall be inspected at least once each month. (b) Gate arm movement shall be observed for proper operation at least once each month. (c... 49 Transportation 4 2013-10-01 2013-10-01 false Gate arm and gate mechanism. 234.255 Section...

  7. Low-voltage Organic Thin Film Transistors (OTFTs) with Solution-processed High-k Dielectric cum Interface Engineering

    NASA Astrophysics Data System (ADS)

    Su, Yaorong

    Although impressive progress has been made in improving the performance of organic thin film transistors (OTFTs), the high operation voltage resulting from the low gate areal capacitance of traditional SiO 2 remains a severe limitation that hinders OTFTs' development in practical applications. In this regard, developing new materials with high- k characteristics at low cost is of great scientific and technological importance in the area of both academia and industry. In this thesis, we first describe a simple solution-based method to fabricate a high-k bilayer Al2Oy/TiOx (ATO) dielectric system at low temperature. Then the dielectric properties of the ATO are characterized and discussed in detail. Furthermore, by employing the high-k ATO as gate dielectric, low-voltage copper phthalocyanine (CuPc) based OTFTs are successfully developed. Interestingly, the obtained low-voltage CuPc TFT exhibits outstanding electrical performance, which is even higher than the device fabricated on traditional low-k SiO2. The above results seem to be contradictory to the reported results due to the fact that high-k usually shows adverse effect on the device performance. This abnormal phenomenon is then studied in detail. Characterization on the initial growth shows that the CuPc molecules assemble in a "rod-like" nano crystal with interconnected network on ATO, which probably promotes the charge carrier transport, whereas, they form isolated small islands with amorphous structure on SiO2. In addition, a better metal/organic contact is observed on ATO, which benefits the charge carrier injection. Our studies suggest that the low-temperature, solution-processed high-k ATO is a promising candidate for fabrication of high-performance, low-voltage OTFTs. Furthermore, it is well known that the properties of the dielectric/semiconductor and electrode/semiconductor interfaces are crucial in controlling the electrical properties of OTFTs. Hence, investigation the effects of interfaces

  8. 6. DETAIL VIEW OF ENTRANCE GATES, SHOWING IRON GATE, STONE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. DETAIL VIEW OF ENTRANCE GATES, SHOWING IRON GATE, STONE WORK, AND GATE STOP FROM SOUTHEAST OF NORTHWEST ELEMENTS. - William Enston Home, Entrance Gate, 900 King Street, Charleston, Charleston County, SC

  9. 21. DETAIL VIEW OF SUBMERSIBLE TAINTER GATE, SHOWING GATE ARM, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    21. DETAIL VIEW OF SUBMERSIBLE TAINTER GATE, SHOWING GATE ARM, GATE PIER, TRUNNION PIN AND GATE GAUGE, LOOKING SOUTHEAST - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 9, Lynxville, Crawford County, WI

  10. Atomic Layer Deposition of Zirconium-Based High-k Metal Gate Oxide: Effect of Si Containing Zr Precursor.

    PubMed

    Cho, Jun Hee; Lee, Sang-Ick; Kim, Jong Hyun; Yim, Sang Jun; Shin, Hyung Soo; Han, Mi Jeong; Chae, Won Mook; Lee, Sung Duck; Ahn, Chi Young; Kim, Myong-Woon

    2015-01-01

    Zirconium based thin film have been deposited by atomic layer deposition (ALD) process using Zr and Si containing Zr precursor with ozone as oxidant. We have pursued a means to control composition by varying Zr and Si containing precursor by cycle frequency. The molar ratio of Si to Zr in the Zr based films was 0.2, 0.25, 0.33, and 0.5. Addition of Si containing Zr precursor on Zirconium based thin films was effective for the decrease of the roughness, while an increase of density. XPS analysis indicated that the addition of Si containing Zr precursors in the Zr based film formed the silicate structure. The XRD analysis of the all ZrO2-SiO2 mixed films annealed at 600 degrees C for 5 min indicated the presence of amorphous. However, the ZrO2 film showed diffraction peaks at 2θ = 30.6 degrees due to the presence of the Tetragonal ZrO2. The incorporation of Si into ZrO2 films helps stabilize an amorphous structure during deposition and annealing. The Zr based thin film (Si/Zr = 0.25) exhibited that the leakage current density was 6.2 x 10(-7) A/cm2 at a bias of - 1.5 V. PMID:26328365

  11. Gaussian beam incident on the one-dimensional diffraction gratings with the high-K metal gate stack structures.

    PubMed

    Kuo, Hung-Fei; Frederick

    2014-04-01

    Optical scatterometry has attracted extensive interest in extracting the geometric shape information of nanolithography patterns because of the trend of shrinking device size and complicated stack structure. RCWA is the numerical algorithm implemented in the current scatterometry tool to calculate the diffraction efficiency. However, the known weakness for the RCWA method is the analysis of metallic gratings illuminated by the TM wave. This research applies the FDTD method using the Gaussian beam excitation source to analyze the diffraction efficiency of HKMG gratings for the use in the optical scatterometry and verifies the numerical diffraction efficiency discrepancy between the Gaussian beam and plane wave excitation methods. The numerical study is carried out with the line/space nanolithography patterns on the HKMG process stacks at 45 nm node technology. The nanolithography patterns are modeled as 1-D surface relief gratings. The 0th order diffraction efficiency is analyzed as a function of CDs, SWAs, incident angles and pitches of the gratings. The study presents the impact of the polarizations of the incident waves on the diffraction efficiency. In addition, this research investigates the phase of the 0th diffraction order as a function of the SWAs and illustrates the corresponding SWA parameter effect on the phase distribution. This research suggests the minimum beam radius to converge the numerical diffraction efficiency using Gaussian beam excitation to it using the plan wave.

  12. Atomic Layer Deposition of Zirconium-Based High-k Metal Gate Oxide: Effect of Si Containing Zr Precursor.

    PubMed

    Cho, Jun Hee; Lee, Sang-Ick; Kim, Jong Hyun; Yim, Sang Jun; Shin, Hyung Soo; Han, Mi Jeong; Chae, Won Mook; Lee, Sung Duck; Ahn, Chi Young; Kim, Myong-Woon

    2015-01-01

    Zirconium based thin film have been deposited by atomic layer deposition (ALD) process using Zr and Si containing Zr precursor with ozone as oxidant. We have pursued a means to control composition by varying Zr and Si containing precursor by cycle frequency. The molar ratio of Si to Zr in the Zr based films was 0.2, 0.25, 0.33, and 0.5. Addition of Si containing Zr precursor on Zirconium based thin films was effective for the decrease of the roughness, while an increase of density. XPS analysis indicated that the addition of Si containing Zr precursors in the Zr based film formed the silicate structure. The XRD analysis of the all ZrO2-SiO2 mixed films annealed at 600 degrees C for 5 min indicated the presence of amorphous. However, the ZrO2 film showed diffraction peaks at 2θ = 30.6 degrees due to the presence of the Tetragonal ZrO2. The incorporation of Si into ZrO2 films helps stabilize an amorphous structure during deposition and annealing. The Zr based thin film (Si/Zr = 0.25) exhibited that the leakage current density was 6.2 x 10(-7) A/cm2 at a bias of - 1.5 V.

  13. Parallelizable adiabatic gate teleportation

    NASA Astrophysics Data System (ADS)

    Nakago, Kosuke; Hajdušek, Michal; Nakayama, Shojun; Murao, Mio

    2015-12-01

    To investigate how a temporally ordered gate sequence can be parallelized in adiabatic implementations of quantum computation, we modify adiabatic gate teleportation, a model of quantum computation proposed by Bacon and Flammia [Phys. Rev. Lett. 103, 120504 (2009), 10.1103/PhysRevLett.103.120504], to a form deterministically simulating parallelized gate teleportation, which is achievable only by postselection. We introduce a twisted Heisenberg-type interaction Hamiltonian, a Heisenberg-type spin interaction where the coordinates of the second qubit are twisted according to a unitary gate. We develop parallelizable adiabatic gate teleportation (PAGT) where a sequence of unitary gates is performed in a single step of the adiabatic process. In PAGT, numeric calculations suggest the necessary time for the adiabatic evolution implementing a sequence of L unitary gates increases at most as O (L5) . However, we show that it has the interesting property that it can map the temporal order of gates to the spatial order of interactions specified by the final Hamiltonian. Using this property, we present a controlled-PAGT scheme to manipulate the order of gates by a control qubit. In the controlled-PAGT scheme, two differently ordered sequential unitary gates F G and G F are coherently performed depending on the state of a control qubit by simultaneously applying the twisted Heisenberg-type interaction Hamiltonians implementing unitary gates F and G . We investigate why the twisted Heisenberg-type interaction Hamiltonian allows PAGT. We show that the twisted Heisenberg-type interaction Hamiltonian has an ability to perform a transposed unitary gate by just modifying the space ordering of the final Hamiltonian implementing a unitary gate in adiabatic gate teleportation. The dynamics generated by the time-reversed Hamiltonian represented by the transposed unitary gate enables deterministic simulation of a postselected event of parallelized gate teleportation in adiabatic

  14. Quantum gate decomposition algorithms.

    SciTech Connect

    Slepoy, Alexander

    2006-07-01

    Quantum computing algorithms can be conveniently expressed in a format of a quantum logical circuits. Such circuits consist of sequential coupled operations, termed ''quantum gates'', or quantum analogs of bits called qubits. We review a recently proposed method [1] for constructing general ''quantum gates'' operating on an qubits, as composed of a sequence of generic elementary ''gates''.

  15. Gated strip proportional detector

    DOEpatents

    Morris, Christopher L.; Idzorek, George C.; Atencio, Leroy G.

    1987-01-01

    A gated strip proportional detector includes a gas tight chamber which encloses a solid ground plane, a wire anode plane, a wire gating plane, and a multiconductor cathode plane. The anode plane amplifies the amount of charge deposited in the chamber by a factor of up to 10.sup.6. The gating plane allows only charge within a narrow strip to reach the cathode. The cathode plane collects the charge allowed to pass through the gating plane on a set of conductors perpendicular to the open-gated region. By scanning the open-gated region across the chamber and reading out the charge collected on the cathode conductors after a suitable integration time for each location of the gate, a two-dimensional image of the intensity of the ionizing radiation incident on the detector can be made.

  16. Gated strip proportional detector

    DOEpatents

    Morris, C.L.; Idzorek, G.C.; Atencio, L.G.

    1985-02-19

    A gated strip proportional detector includes a gas tight chamber which encloses a solid ground plane, a wire anode plane, a wire gating plane, and a multiconductor cathode plane. The anode plane amplifies the amount of charge deposited in the chamber by a factor of up to 10/sup 6/. The gating plane allows only charge within a narrow strip to reach the cathode. The cathode plane collects the charge allowed to pass through the gating plane on a set of conductors perpendicular to the open-gated region. By scanning the open-gated region across the chamber and reading out the charge collected on the cathode conductors after a suitable integration time for each location of the gate, a two-dimensional image of the intensity of the ionizing radiation incident on the detector can be made.

  17. Four-Quasiparticle High-K States in Neutron-Deficient Lead and Polonium Nuclei

    NASA Astrophysics Data System (ADS)

    Shi, Yue; Xu, Furong

    2012-06-01

    Configuration-constrained potential energy surface calculations have been performed to investigate four-quasiparticle high-K configurations in neutron-deficient lead and polonium isotopes. A good agreement between the calculations and the experimental data has been found for the excitation energy of the observed Kπ = 19- state in 188Pb. Several lowly excited high-K states are predicted, and the large oblate deformation and low energy indicate high-K isomerism in these nuclei.

  18. 15. DETAIL VIEW OF SUBMERSIBLE TAINTER GATE, SHOWING GATES AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. DETAIL VIEW OF SUBMERSIBLE TAINTER GATE, SHOWING GATES AND GATE ARMS, PIERS AND DAM BRIDGE, LOOKING NORTHEAST - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 8, On Mississippi River near Houston County, MN, Genoa, Vernon County, WI

  19. 4. DETAIL VIEW OF TAINTER GATE PIER AND TAINTER GATE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. DETAIL VIEW OF TAINTER GATE PIER AND TAINTER GATE NO. 7 AND NON-SUBMERSIBLE TAINTER GATES, LOOKING WEST (UPSTREAM) - Upper Mississippi River 9-Foot Channel Project, Lock & Dam 26R, Alton, Madison County, IL

  20. 19. DETAIL VIEW OF SUBMERSIBLE TAINTER GATE, SHOWING GATE ARM, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    19. DETAIL VIEW OF SUBMERSIBLE TAINTER GATE, SHOWING GATE ARM, PIER, TRUNNION PIN AND GATE GAUGE, LOOKING NORTH - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 8, On Mississippi River near Houston County, MN, Genoa, Vernon County, WI

  1. 5. DETAIL VIEW OF DAM, SHOWING TAINTER GATES, GATE PIERS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. DETAIL VIEW OF DAM, SHOWING TAINTER GATES, GATE PIERS AND DAN BRIDGE, WITH ROLLER GATE HEADHOUSES AND LOCKS IN BACKGROUND, LOOKING NORTHEAST, UPSTREAM - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 4, Alma, Buffalo County, WI

  2. Sliding-gate valve

    DOEpatents

    Usnick, George B.; Ward, Gene T.; Blair, Henry O.; Roberts, James W.; Warner, Terry N.

    1979-01-01

    This invention is a novel valve of the slidable-gate type. The valve is designed especially for long-term use with highly abrasive slurries. The sealing surfaces of the gate are shielded by the valve seats when the valve is fully open or closed, and the gate-to-seat clearance is swept with an inflowing purge gas while the gate is in transit. A preferred form of the valve includes an annular valve body containing an annular seat assembly defining a flow channel. The seat assembly comprises a first seat ring which is slidably and sealably mounted in the body, and a second seat ring which is tightly fitted in the body. These rings cooperatively define an annular gap which, together with passages in the valve body, forms a guideway extending normal to the channel. A plate-type gate is mounted for reciprocation in the guideway between positions where a portion of the plate closes the channel and where a circular aperture in the gate is in register with the channel. The valve casing includes opposed chambers which extend outwardly from the body along the axis of the guideway to accommodate the end portions of the gate. The chambers are sealed from atmosphere; when the gate is in transit, purge gas is admitted to the chambers and flows inwardly through the gate-to-seat-ring, clearance, minimizing buildup of process solids therein. A shaft reciprocated by an external actuator extends into one of the sealed chambers through a shaft seal and is coupled to an end of the gate. Means are provided for adjusting the clearance between the first seat ring and the gate while the valve is in service.

  3. High K+-Induced Relaxation by Nitric Oxide in Human Gastric Fundus

    PubMed Central

    Kim, Dae Hoon; Choi, Woong; Sung, Rohyun; Kim, Hun Sik; Kim, Heon; Yoo, Ra Young; Park, Seon-Mee; Yun, Sei Jin; Song, Young-Jin; Xu, Wen-Xie; Lee, Sang Jin

    2012-01-01

    This study was designed to elucidate high K+-induced relaxation in the human gastric fundus. Circular smooth muscle from the human gastric fundus greater curvature showed stretch-dependent high K+ (50 mM)-induced contractions. However, longitudinal smooth muscle produced stretch-dependent high K+-induced relaxation. We investigated several relaxation mechanisms to understand the reason for the discrepancy. Protein kinase inhibitors such as KT 5823 (1 µM) and KT 5720 (1 µM) which block protein kinases (PKG and PKA) had no effect on high K+-induced relaxation. K+ channel blockers except 4-aminopyridine (4-AP), a voltage-dependent K+ channel (KV) blocker, did not affect high K+-induced relaxation. However, N(G)-nitro-L-arginine and 1H-(1,2,4)oxadiazolo (4,3-A)quinoxalin-1-one, an inhibitors of soluble guanylate cyclase (sGC) and 4-AP inhibited relaxation and reversed relaxation to contraction. High K+-induced relaxation of the human gastric fundus was observed only in the longitudinal muscles from the greater curvature. These data suggest that the longitudinal muscle of the human gastric fundus greater curvature produced high K+-induced relaxation that was activated by the nitric oxide/sGC pathway through a KV channel-dependent mechanism. PMID:23118553

  4. Adiabatically implementing quantum gates

    SciTech Connect

    Sun, Jie; Lu, Songfeng Liu, Fang

    2014-06-14

    We show that, through the approach of quantum adiabatic evolution, all of the usual quantum gates can be implemented efficiently, yielding running time of order O(1). This may be considered as a useful alternative to the standard quantum computing approach, which involves quantum gates transforming quantum states during the computing process.

  5. Gates Speaks to Librarians.

    ERIC Educational Resources Information Center

    St. Lifer, Evan

    1997-01-01

    In an interview, Microsoft CEO Bill Gates answers questions about the Gates Library Foundation; Libraries Online; tax-support for libraries; comparisons to Andrew Carnegie; charges of "buying" the library market; Internet filters, policies, and government censorship; the future of the World Wide Web and the role of librarians in its future.(PEN)

  6. Optical NAND gate

    DOEpatents

    Skogen, Erik J.; Raring, James; Tauke-Pedretti, Anna

    2011-08-09

    An optical NAND gate is formed from two pair of optical waveguide devices on a substrate, with each pair of the optical waveguide devices consisting of an electroabsorption modulator and a photodetector. One pair of the optical waveguide devices is electrically connected in parallel to operate as an optical AND gate; and the other pair of the optical waveguide devices is connected in series to operate as an optical NOT gate (i.e. an optical inverter). The optical NAND gate utilizes two digital optical inputs and a continuous light input to provide a NAND function output. The optical NAND gate can be formed from III-V compound semiconductor layers which are epitaxially deposited on a III-V compound semiconductor substrate, and operates at a wavelength in the range of 0.8-2.0 .mu.m.

  7. Probing the mechanical properties of high-k dielectric nano-films by Brillouin light scattering study

    NASA Astrophysics Data System (ADS)

    Zizka, Jonathan; Bielefeld, Jeffrey; King, Sean; Sooryakumar, R.

    2014-03-01

    As microelectronic transistors scale to smaller dimensions, device functionality suffers from current leakage. This problem can be overcome by using thicker gate materials with a high dielectric constant. SiO2 has been the material of choice, but becomes unsuitable due to its relatively low dielectric constant (k = 3.9). Alternate materials, such as BN:H (k = 5.7) and HfO2 (k = 25) are promising choices to replace SiO2 to achieve the desired performance while preserving ultra-thin thickness (<10 nm). Despite these promising features, one concern of including these materials, are their mechanical and thermal properties that could degrade device functionality. There is thus a growing need for non-destructive techniques to evaluate the mechanical properties of such laminar structures since traditional methods like nano-indentation are not effective at these dimensions. We report on Brillioun light scattering studies to determine the individual elastic constants and, thus the mechanical properties of BN:H and HfO2 high-k films with thicknesses as low as 24 nm. Young's modulus (E) and Poisson's ratio (ν) were determined by measuring the frequency dispersion of confined and traveling transverse and longitudinal acoustic waves as well as their associated light scattering intensities.

  8. Observation of Work Functions, Metallicity, Band Bending, Interfacial Dipoles by EUPS for Characterizing High-k/Metal Interfaces

    SciTech Connect

    Tomie, Toshihisa; Ishitsuka, Tomoaki; Ootsuka, Teruhisa; Ota, Hiroyuki

    2011-11-10

    EUPS (EUV excited photoelectron spectroscopy) is a novel photoelectron spectroscopy technique, in which a sample is excited with 4.86 nm (255 eV), 3-ns pulse EUV light emitted from a laser-produced plasma and the resulting electron spectrum is analyzed with a time-of-flight (TOF) analyzer. EUPS gives information of the topmost atoms because the escape depth of photo-electrons excited by 4.86 nm light is only 0.5 nm. EUPS can evaluate band-bending because the peak density of the excitation light on the sample is extremely high, so that bent electronic bands in semiconductors can be flattened. Secondary electron spectra, from which the vacuum level of the material surface can be determined, are obtained very quickly owing to the use of a TOF analyzer, The metal gate related issues are one of the most challenging topics facing CMOS technology. This paper demonstrates EUPS as a powerful method for characterizing high-k/metal interfaces by showing data from direct observations of interfacial dipoles.

  9. Hole mobility modulation of solution-processed nickel oxide thin-film transistor based on high-k dielectric

    NASA Astrophysics Data System (ADS)

    Liu, Ao; Liu, Guoxia; Zhu, Huihui; Shin, Byoungchul; Fortunato, Elvira; Martins, Rodrigo; Shan, Fukai

    2016-06-01

    Solution-processed p-type oxide semiconductors have recently attracted increasing interests for the applications in low-cost optoelectronic devices and low-power consumption complementary metal-oxide-semiconductor circuits. In this work, p-type nickel oxide (NiOx) thin films were prepared using low-temperature solution process and integrated as the channel layer in thin-film transistors (TFTs). The electrical properties of NiOx TFTs, together with the characteristics of NiOx thin films, were systematically investigated as a function of annealing temperature. By introducing aqueous high-k aluminum oxide (Al2O3) gate dielectric, the electrical performance of NiOx TFT was improved significantly compared with those based on SiO2 dielectric. Particularly, the hole mobility was found to be 60 times enhancement, quantitatively from 0.07 to 4.4 cm2/V s, which is mainly beneficial from the high areal capacitance of the Al2O3 dielectric and high-quality NiOx/Al2O3 interface. This simple solution-based method for producing p-type oxide TFTs is promising for next-generation oxide-based electronic applications.

  10. 18. DETAIL VIEW OF NONSUBMERSIBLE TAINTER GATE, SHOWING GATE AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    18. DETAIL VIEW OF NON-SUBMERSIBLE TAINTER GATE, SHOWING GATE AND GATE ARMS, GATE PIER AND DAM BRIDGE, LOOKING NORTHEAST - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 8, On Mississippi River near Houston County, MN, Genoa, Vernon County, WI

  11. 17. DETAIL VIEW OF NONSUBMERSIBLE TAINTER GATE, SHOWING GATE AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    17. DETAIL VIEW OF NON-SUBMERSIBLE TAINTER GATE, SHOWING GATE AND GATE ARM, GATE PIER AND DAM BRIDGE, LOOKING SOUTHEAST - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 8, On Mississippi River near Houston County, MN, Genoa, Vernon County, WI

  12. Optical XOR gate

    DOEpatents

    Vawter, G. Allen

    2013-11-12

    An optical XOR gate is formed as a photonic integrated circuit (PIC) from two sets of optical waveguide devices on a substrate, with each set of the optical waveguide devices including an electroabsorption modulator electrically connected in series with a waveguide photodetector. The optical XOR gate utilizes two digital optical inputs to generate an XOR function digital optical output. The optical XOR gate can be formed from III-V compound semiconductor layers which are epitaxially deposited on a III-V compound semiconductor substrate, and operates at a wavelength in the range of 0.8-2.0 .mu.m.

  13. Optical NOR gate

    DOEpatents

    Skogen, Erik J.; Tauke-Pedretti, Anna

    2011-09-06

    An optical NOR gate is formed from two pair of optical waveguide devices on a substrate, with each pair of the optical waveguide devices consisting of an electroabsorption modulator electrically connected in series with a waveguide photodetector. The optical NOR gate utilizes two digital optical inputs and a continuous light input to provide a NOR function digital optical output. The optical NOR gate can be formed from III-V compound semiconductor layers which are epitaxially deposited on a III-V compound semiconductor substrate, and operates at a wavelength in the range of 0.8-2.0 .mu.m.

  14. Yttrium scandate thin film as alternative high-permittivity dielectric for germanium gate stack formation

    SciTech Connect

    Lu, Cimang Lee, Choong Hyun; Nishimura, Tomonori; Toriumi, Akira

    2015-08-17

    We investigated yttrium scandate (YScO{sub 3}) as an alternative high-permittivity (k) dielectric thin film for Ge gate stack formation. Significant enhancement of k-value is reported in YScO{sub 3} comparing to both of its binary compounds, Y{sub 2}O{sub 3} and Sc{sub 2}O{sub 3}, without any cost of interface properties. It suggests a feasible approach to a design of promising high-k dielectrics for Ge gate stack, namely, the formation of high-k ternary oxide out of two medium-k binary oxides. Aggressive scaling of equivalent oxide thickness (EOT) with promising interface properties is presented by using YScO{sub 3} as high-k dielectric and yttrium-doped GeO{sub 2} (Y-GeO{sub 2}) as interfacial layer, for a demonstration of high-k gate stack on Ge. In addition, we demonstrate Ge n-MOSFET performance showing the peak electron mobility over 1000 cm{sup 2}/V s in sub-nm EOT region by YScO{sub 3}/Y-GeO{sub 2}/Ge gate stack.

  15. Optimal simulation of Deutsch gates and the Fredkin gate

    NASA Astrophysics Data System (ADS)

    Yu, Nengkun; Ying, Mingsheng

    2015-03-01

    In this paper, we study the optimal simulation of the three-qubit unitary using two-qubit gates. First, we completely characterize the two-qubit gate cost of simulating the Deutsch gate (controlled-controlled gate) by generalizing our result on the two-qubit cost of the Toffoli gate. The function of any Deutsch gate is simply a three-qubit controlled-unitary gate and can be intuitively explained as follows: The gate outputs the states of the two control qubits directly, and applies the given one-qubit unitary u on the target qubit only if both the states of the control qubits are |1 > . Previously, it was only known that five two-qubit gates are sufficient for implementing such a gate [Sleator and Weinfurter, Phys. Rev. Lett. 74, 4087 (1995), 10.1103/PhysRevLett.74.4087]. We show that if the determinant of u is 1, four two-qubit gates are optimal. Otherwise, five two-qubit gates are required. For the Fredkin gate (the controlled-swap gate), we prove that five two-qubit gates are necessary and sufficient, which settles the open problem introduced in Smolin and DiVincenzo [Phys. Rev. A 53, 2855 (1996), 10.1103/PhysRevA.53.2855].

  16. Study of strained-Si p-channel MOSFETs with HfO2 gate dielectric

    NASA Astrophysics Data System (ADS)

    Pradhan, Diana; Das, Sanghamitra; Dash, Tara Prasanna

    2016-10-01

    In this work, the transconductance of strained-Si p-MOSFETs with high-K dielectric (HfO2) as gate oxide, has been presented through simulation using the TCAD tool Silvaco-ATLAS. The results have been compared with a SiO2/strained-Si p-MOSFET device. Peak transconductance enhancement factors of 2.97 and 2.73 has been obtained for strained-Si p-MOSFETs in comparison to bulk Si channel p-MOSFETs with SiO2 and high-K dielectric respectively. This behavior is in good agreement with the reported experimental results. The transconductance of the strained-Si device at low temperatures has also been simulated. As expected, the mobility and hence the transconductance increases at lower temperatures due to reduced phonon scattering. However, the enhancements with high-K gate dielectric is less as compared to that with SiO2.

  17. The human respiratory gate

    NASA Technical Reports Server (NTRS)

    Eckberg, Dwain L.

    2003-01-01

    Respiratory activity phasically alters membrane potentials of preganglionic vagal and sympathetic motoneurones and continuously modulates their responsiveness to stimulatory inputs. The most obvious manifestation of this 'respiratory gating' is respiratory sinus arrhythmia, the rhythmic fluctuations of electrocardiographic R-R intervals observed in healthy resting humans. Phasic autonomic motoneurone firing, reflecting the throughput of the system, depends importantly on the intensity of stimulatory inputs, such that when levels of stimulation are low (as with high arterial pressure and sympathetic activity, or low arterial pressure and vagal activity), respiratory fluctuations of sympathetic or vagal firing are also low. The respiratory gate has a finite capacity, and high levels of stimulation override the ability of respiration to gate autonomic responsiveness. Autonomic throughput also depends importantly on other factors, including especially, the frequency of breathing, the rate at which the gate opens and closes. Respiratory sinus arrhythmia is small at rapid, and large at slow breathing rates. The strong correlation between systolic pressure and R-R intervals at respiratory frequencies reflects the influence of respiration on these two measures, rather than arterial baroreflex physiology. A wide range of evidence suggests that respiratory activity gates the timing of autonomic motoneurone firing, but does not influence its tonic level. I propose that the most enduring significance of respiratory gating is its use as a precisely controlled experimental tool to tease out and better understand otherwise inaccessible human autonomic neurophysiological mechanisms.

  18. Advanced insulated gate bipolar transistor gate drive

    DOEpatents

    Short, James Evans; West, Shawn Michael; Fabean, Robert J.

    2009-08-04

    A gate drive for an insulated gate bipolar transistor (IGBT) includes a control and protection module coupled to a collector terminal of the IGBT, an optical communications module coupled to the control and protection module, a power supply module coupled to the control and protection module and an output power stage module with inputs coupled to the power supply module and the control and protection module, and outputs coupled to a gate terminal and an emitter terminal of the IGBT. The optical communications module is configured to send control signals to the control and protection module. The power supply module is configured to distribute inputted power to the control and protection module. The control and protection module outputs on/off, soft turn-off and/or soft turn-on signals to the output power stage module, which, in turn, supplies a current based on the signal(s) from the control and protection module for charging or discharging an input capacitance of the IGBT.

  19. High-k (k=30) amorphous hafnium oxide films from high rate room temperature deposition

    SciTech Connect

    Li, Flora M.; Bayer, Bernhard C.; Hofmann, Stephan; Milne, William I.; Flewitt, Andrew J.; Dutson, James D.; Wakeham, Steve J.; Thwaites, Mike J.

    2011-06-20

    Amorphous hafnium oxide (HfO{sub x}) is deposited by sputtering while achieving a very high k{approx}30. Structural characterization suggests that the high k is a consequence of a previously unreported cubiclike short range order in the amorphous HfO{sub x} (cubic k{approx}30). The films also possess a high electrical resistivity of 10{sup 14} {Omega} cm, a breakdown strength of 3 MV cm{sup -1}, and an optical gap of 6.0 eV. Deposition at room temperature and a high deposition rate ({approx}25 nm min{sup -1}) makes these high-k amorphous HfO{sub x} films highly advantageous for plastic electronics and high throughput manufacturing.

  20. Searching for high-K isomers in the proton-rich A ∼ 80 mass region

    NASA Astrophysics Data System (ADS)

    Bai, Zhi-Jun; Jiao, Chang-Feng; Gao, Yuan; Xu, Fu-Rong

    2016-09-01

    Configuration-constrained potential-energy-surface calculations have been performed to investigate the K isomerism in the proton-rich A ∼ 80 mass region. An abundance of high-K states are predicted. These high-K states arise from two and four-quasi-particle excitations, with Kπ = 8+ and Kπ = 16+, respectively. Their excitation energies are comparatively low, making them good candidates for long-lived isomers. Since most nuclei under study are prolate spheroids in their ground states, the oblate shapes of the predicted high-K states may indicate a combination of K isomerism and shape isomerism. Supported by National Key Basic Research Program of China (2013CB834402) and National Natural Science Foundation of China (11235001, 11320101004 and 11575007)

  1. Multi-quasiparticle high-K isomeric states in deformed nuclei

    NASA Astrophysics Data System (ADS)

    Xu, F. R.; Shi, Y.; Liu, H. L.; Liang, W. Y.; Walker, P. M.; Dracoulis, G. D.

    2016-09-01

    In the past years, we have made many theoretical investigations on multi-quasiparticle high-K isomeric states. A deformation-pairing-configuration self-consistent calculation has been developed by calculating a configuration-constrained multi-quasiparticle potential energy surface (PES). The specific single-particle orbits that define the high-K configuration are identified and tracked (adiabatically blocked) by calculating the average Nilsson numbers. The deformed Woods-Saxon potential was taken to give single-particle orbits. The configuration-constrained PES takes into account the shape polarization effect. Such calculations give good results on excitation energies, deformations and other structure information about multi-quasiparticle high-K isomeric states. Many different mass regions have been investigated.

  2. Searching for high-K isomers in the proton-rich A ˜ 80 mass region

    NASA Astrophysics Data System (ADS)

    Bai, Zhi-Jun; Jiao, Chang-Feng; Gao, Yuan; Xu, Fu-Rong

    2016-09-01

    Configuration-constrained potential-energy-surface calculations have been performed to investigate the K isomerism in the proton-rich A ˜ 80 mass region. An abundance of high-K states are predicted. These high-K states arise from two and four-quasi-particle excitations, with Kπ = 8+ and Kπ = 16+, respectively. Their excitation energies are comparatively low, making them good candidates for long-lived isomers. Since most nuclei under study are prolate spheroids in their ground states, the oblate shapes of the predicted high-K states may indicate a combination of K isomerism and shape isomerism. Supported by National Key Basic Research Program of China (2013CB834402) and National Natural Science Foundation of China (11235001, 11320101004 and 11575007)

  3. Medium energy ion scattering for the high depth resolution characterisation of high-k dielectric layers of nanometer thickness

    NASA Astrophysics Data System (ADS)

    van den Berg, J. A.; Reading, M. A.; Bailey, P.; Noakes, T. Q. C.; Adelmann, C.; Popovici, M.; Tielens, H.; Conard, T.; de Gendt, S.; van Elshocht, S.

    2013-09-01

    Medium energy ion scattering (MEIS) using, typically, 100-200 keV H+ or He+ ions derives it ability to characterise nanolayers from the fact that the energy after backscattering depends (i) on the elastic energy loss suffered in a single collision with a target atom and (ii) on the inelastic energy losses on its incoming and outgoing trajectories. From the former the mass of the atom can be determined and from the latter its depth. Thus MEIS yields depth dependent compositional and structural information, with high depth resolution (sub-nm near the surface) and good sensitivity for all but the lighter masses. It is particularly well suited for the depth analysis of high-k multilayers of nanometer thickness. Accurate quantification of the depth distributions of atomic species can be obtained using suitable spectrum simulation. In the present paper, important aspects of MEIS including quantification, depth resolution and spectrum simulation are briefly discussed. The capabilities of the technique in terms of the high depth resolution layer compositional and structural information it yields, is illustrated with reference to the detailed characterisation of a range of high-k nanolayer and multilayer structures for current microelectronic devices or those still under development: (i) HfO2 and HfSiOx for gate dielectric applications, including a TiN/Al2O3/HfO2/SiO2/Si structure, (ii) TiN/SrTiO3/TiN and (iii) TiO2/Ru/TiN multilayer structures for metal-insulator-metal capacitors (MIMcaps) in DRAM applications. The unique information provided by the technique is highlighted by its clear capability to accurately quantify the composition profiles and thickness of nanolayers and complex multilayers as grown, and to identify the nature and extent of atom redistribution (e.g. intermixing, segregation) during layer deposition, annealing and plasma processing. The ability makes it a valuable tool in the development of the nanostructures that will become increasingly important as

  4. Multipulse gate-delayed range gating imaging lidar.

    PubMed

    Wu, Long; Zhao, Yuan; Zhang, Yong; Jin, Chenfei; Wu, Jie

    2011-04-15

    We present a technique to reconstruct a higher resolution of depth map of range gating imaging lidar by applying the delays of the gates to a typical range gating lidar system during the detection of each returned laser pulse with the encoding of the returned signal. With the consequent delays of the gate, the depth of the scene is extended accordingly. A multipulse gate-delayed range gating lidar system is designed to prove the resolution improvement from 6 to 1.5 m. The unchanged peak power of the laser, the widths of the laser pulse and the sampling period result in a simple structure of the lidar system. PMID:21499358

  5. Effects of high-order deformation on high-K isomers in superheavy nuclei

    SciTech Connect

    Liu, H. L.; Bertulani, C. A.; Xu, F. R.; Walker, P. M.

    2011-01-15

    Using, for the first time, configuration-constrained potential-energy-surface calculations with the inclusion of {beta}{sub 6} deformation, we find remarkable effects of the high-order deformation on the high-K isomers in {sup 254}No, the focus of recent spectroscopy experiments on superheavy nuclei. For shapes with multipolarity six, the isomers are more tightly bound and, microscopically, have enhanced deformed shell gaps at N=152 and Z=100. The inclusion of {beta}{sub 6} deformation significantly improves the description of the very heavy high-K isomers.

  6. Atomic layer deposition of crystalline SrHfO{sub 3} directly on Ge (001) for high-k dielectric applications

    SciTech Connect

    McDaniel, Martin D.; Ngo, Thong Q.; Ekerdt, John G.; Hu, Chengqing; Jiang, Aiting; Yu, Edward T.; Lu, Sirong; Smith, David J.; Posadas, Agham; Demkov, Alexander A.

    2015-02-07

    The current work explores the crystalline perovskite oxide, strontium hafnate, as a potential high-k gate dielectric for Ge-based transistors. SrHfO{sub 3} (SHO) is grown directly on Ge by atomic layer deposition and becomes crystalline with epitaxial registry after post-deposition vacuum annealing at ∼700 °C for 5 min. The 2 × 1 reconstructed, clean Ge (001) surface is a necessary template to achieve crystalline films upon annealing. The SHO films exhibit excellent crystallinity, as shown by x-ray diffraction and transmission electron microscopy. The SHO films have favorable electronic properties for consideration as a high-k gate dielectric on Ge, with satisfactory band offsets (>2 eV), low leakage current (<10{sup −5} A/cm{sup 2} at an applied field of 1 MV/cm) at an equivalent oxide thickness of 1 nm, and a reasonable dielectric constant (k ∼ 18). The interface trap density (D{sub it}) is estimated to be as low as ∼2 × 10{sup 12 }cm{sup −2 }eV{sup −1} under the current growth and anneal conditions. Some interfacial reaction is observed between SHO and Ge at temperatures above ∼650 °C, which may contribute to increased D{sub it} value. This study confirms the potential for crystalline oxides grown directly on Ge by atomic layer deposition for advanced electronic applications.

  7. The human respiratory gate

    PubMed Central

    Eckberg, Dwain L

    2003-01-01

    Respiratory activity phasically alters membrane potentials of preganglionic vagal and sympathetic motoneurones and continuously modulates their responsiveness to stimulatory inputs. The most obvious manifestation of this ‘respiratory gating’ is respiratory sinus arrhythmia, the rhythmic fluctuations of electrocardiographic R–R intervals observed in healthy resting humans. Phasic autonomic motoneurone firing, reflecting the throughput of the system, depends importantly on the intensity of stimulatory inputs, such that when levels of stimulation are low (as with high arterial pressure and sympathetic activity, or low arterial pressure and vagal activity), respiratory fluctuations of sympathetic or vagal firing are also low. The respiratory gate has a finite capacity, and high levels of stimulation override the ability of respiration to gate autonomic responsiveness. Autonomic throughput also depends importantly on other factors, including especially, the frequency of breathing, the rate at which the gate opens and closes. Respiratory sinus arrhythmia is small at rapid, and large at slow breathing rates. The strong correlation between systolic pressure and R–R intervals at respiratory frequencies reflects the influence of respiration on these two measures, rather than arterial baroreflex physiology. A wide range of evidence suggests that respiratory activity gates the timing of autonomic motoneurone firing, but does not influence its tonic level. I propose that the most enduring significance of respiratory gating is its use as a precisely controlled experimental tool to tease out and better understand otherwise inaccessible human autonomic neurophysiological mechanisms. PMID:12626671

  8. A nanomechanical Fredkin gate.

    PubMed

    Wenzler, Josef-Stefan; Dunn, Tyler; Toffoli, Tommaso; Mohanty, Pritiraj

    2014-01-01

    Irreversible logic operations inevitably discard information, setting fundamental limitations on the flexibility and the efficiency of modern computation. To circumvent the limit imposed by the von Neumann-Landauer (VNL) principle, an important objective is the development of reversible logic gates, as proposed by Fredkin, Toffoli, Wilczek, Feynman, and others. Here, we present a novel nanomechanical logic architecture for implementing a Fredkin gate, a universal logic gate from which any reversible computation can be built. In addition to verifying the truth table, we demonstrate operation of the device as an AND, OR, NOT, and FANOUT gate. Excluding losses due to resonator dissipation and transduction, which will require significant improvement in order to minimize the overall energy cost, our device requires an energy of order 10(4) kT per logic operation, similar in magnitude to state-of-the-art transistor-based technologies. Ultimately, reversible nanomechanical logic gates could play a crucial role in developing highly efficient reversible computers, with implications for efficient error correction and quantum computing. PMID:24328764

  9. Gate dielectric degradation: Pre-existing vs. generated defects

    NASA Astrophysics Data System (ADS)

    Veksler, Dmitry; Bersuker, Gennadi

    2014-01-01

    We consider the possibility that degradation of the electrical characteristics of high-k gate stacks under low voltage stresses of practical interest is caused primarily by activation of pre-existing defects rather than generation of new ones. In nFETs in inversion, in particular, defect activation is suggested to be associated with the capture of an injected electron: in this charged state, defects can participate in a fast exchange of charge carriers with the carrier reservoir (substrate or gate electrode) that constitutes the physical process underlying a variety of electrical measurements. The degradation caused by the activation of pre-existing defects, as opposed to that of new defect generation, is both reversible and exhibits a tendency to saturate through the duration of stress. By using the multi-phonon assisted charge transport description, it is demonstrated that the trap activation concept allows reproducing a variety of experimental results including stress time dependency of the threshold voltage, leakage current, charge pumping current, and low frequency noise. Continuous, long-term degradation described by the power law time dependency is shown to be determined by the activation of defects located in the interfacial SiO2 layer of the high-k gate stacks. The findings of this study can direct process optimization efforts towards reduction of as-grown precursors of the charge trapping defects as the major factor affecting reliability.

  10. Deoxyribozyme-based logic gates.

    PubMed

    Stojanovic, Milan N; Mitchell, Tiffany Elizabeth; Stefanovic, Darko

    2002-04-10

    We report herein a set of deoxyribozyme-based logic gates capable of generating any Boolean function. We construct basic NOT and AND gates, followed by the more complex XOR gate. These gates were constructed through a modular design that combines molecular beacon stem-loops with hammerhead-type deoxyribozymes. Importantly, as the gates have oligonucleotides as both inputs and output, they open the possibility of communication between various computation elements in solution. The operation of these gates is conveniently connected to a fluorescent readout.

  11. Detail of gate, gate slots, and connection between the two ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail of gate, gate slots, and connection between the two segments of the rectangular rearing tank. Pump house (1962) at entrance is in the background. View to the southwest. - Prairie Creek Fish Hatchery, Hwy. 101, Orick, Humboldt County, CA

  12. 7. DETAIL VIEW OF DAM, SHOWING ROLLER GATES, GATE PIERS, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. DETAIL VIEW OF DAM, SHOWING ROLLER GATES, GATE PIERS, HEADHOUSES AND DAM BRIDGE, LOOKING NORTHWEST, UPSTREAM - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 9, Lynxville, Crawford County, WI

  13. Cardiac gated ventilation

    SciTech Connect

    Hanson, C.W. III; Hoffman, E.A.

    1995-12-31

    There are several theoretic advantages to synchronizing positive pressure breaths with the cardiac cycle, including the potential for improving distribution of pulmonary and myocardial blood flow and enhancing cardiac output. The authors evaluated the effects of synchronizing respiration to the cardiac cycle using a programmable ventilator and electron beam CT (EBCT) scanning. The hearts of anesthetized dogs were imaged during cardiac gated respiration with a 50 msec scan aperture. Multi slice, short axis, dynamic image data sets spanning the apex to base of the left ventricle were evaluated to determine the volume of the left ventricular chamber at end-diastole and end-systole during apnea, systolic and diastolic cardiac gating. The authors observed an increase in cardiac output of up to 30% with inspiration gated to the systolic phase of the cardiac cycle in a non-failing model of the heart.

  14. Cardiac gated ventilation

    NASA Astrophysics Data System (ADS)

    Hanson, C. William, III; Hoffman, Eric A.

    1995-05-01

    There are several theoretic advantages to synchronizing positive pressure breaths with the cardiac cycle, including the potential for improving distribution of pulmonary and myocardial blood flow and enhancing cardiac output. We evaluated the effects of synchronizing respiration to the cardiac cycle using a programmable ventilator and electron beam CT (EBCT) scanning. The hearts of anesthetized dogs were imaged during cardiac gated respiration with a 50msec scan aperture. Multislice, short axis, dynamic image data sets spanning the apex to base of the left ventricle were evaluated to determine the volume of the left ventricular chamber at end-diastole and end-systole during apnea, systolic and diastolic cardiac gating. We observed an increase in cardiac output of up to 30% with inspiration gated to the systolic phase of the cardiac cycle in a nonfailing model of the heart.

  15. Silicon Nanowires with High-k Hafnium Oxide Dielectrics for Sensitive Detection of Small Nucleic Acid Oligomers

    PubMed Central

    Dorvel, Brian R.; Reddy, Bobby; Go, Jonghyun; Guevara, Carlos Duarte; Salm, Eric; Alam, Muhammad Ashraful; Bashir, Rashid

    2012-01-01

    Nanobiosensors based on silicon nanowire field effect transistors offer advantages of low cost, label-free detection, and potential for massive parallelization. As a result, these sensors have often been suggested as an attractive option for applications in Point-of-care (POC) medical diagnostics. Unfortunately, a number of performance issues such as gate leakage and current instability due to fluid contact, have prevented widespread adoption of the technology for routine use. High-k dielectrics, such as hafnium oxide (HfO2), have the known ability to address these challenges by passivating the exposed surfaces against destabilizing concerns of ion transport. With these fundamental stability issues addressed, a promising target for POC diagnostics and SiNWFET’s has been small oligonucleotides, more specifically microRNA (miRNA). MicroRNA’s are small RNA oligonucleotides which bind to messenger RNA’s, causing translational repression of proteins, gene silencing, and expressions are typically altered in several forms of cancer. In this paper, we describe a process for fabricating stable HfO2 dielectric based silicon nanowires for biosensing applications. Here we demonstrate sensing of single stranded DNA analogues to their microRNA cousins using miR-10b and miR-21 as templates, both known to be upregulated in breast cancer. We characterize the effect of surface functionalization on device performance using the miR-10b DNA analogue as the target sequence and different molecular weight poly-l-lysine as the functionalization layer. By optimizing the surface functionalization and fabrication protocol, we were able to achieve <100fM detection levels of miR-10b DNA analogue, with a theoretical limit of detection of 1fM. Moreover, the non-complementary DNA target strand, based on miR-21, showed very little response, indicating a highly sensitive and highly selective biosensing platform. PMID:22695179

  16. Silicon nanowires with high-k hafnium oxide dielectrics for sensitive detection of small nucleic acid oligomers.

    PubMed

    Dorvel, Brian R; Reddy, Bobby; Go, Jonghyun; Duarte Guevara, Carlos; Salm, Eric; Alam, Muhammad Ashraful; Bashir, Rashid

    2012-07-24

    Nanobiosensors based on silicon nanowire field effect transistors offer advantages of low cost, label-free detection, and potential for massive parallelization. As a result, these sensors have often been suggested as an attractive option for applications in point-of-care (POC) medical diagnostics. Unfortunately, a number of performance issues, such as gate leakage and current instability due to fluid contact, have prevented widespread adoption of the technology for routine use. High-k dielectrics, such as hafnium oxide (HfO(2)), have the known ability to address these challenges by passivating the exposed surfaces against destabilizing concerns of ion transport. With these fundamental stability issues addressed, a promising target for POC diagnostics and SiNWFETs has been small oligonucleotides, more specifically, microRNA (miRNA). MicroRNAs are small RNA oligonucleotides which bind to mRNAs, causing translational repression of proteins, gene silencing, and expressions are typically altered in several forms of cancer. In this paper, we describe a process for fabricating stable HfO(2) dielectric-based silicon nanowires for biosensing applications. Here we demonstrate sensing of single-stranded DNA analogues to their microRNA cousins using miR-10b and miR-21 as templates, both known to be upregulated in breast cancer. We characterize the effect of surface functionalization on device performance using the miR-10b DNA analogue as the target sequence and different molecular weight poly-l-lysine as the functionalization layer. By optimizing the surface functionalization and fabrication protocol, we were able to achieve <100 fM detection levels of the miR-10b DNA analogue, with a theoretical limit of detection of 1 fM. Moreover, the noncomplementary DNA target strand, based on miR-21, showed very little response, indicating a highly sensitive and highly selective biosensing platform.

  17. Experimental Study of Density Gradient Stabilization Effects on High-k Turbulence in NSTX

    NASA Astrophysics Data System (ADS)

    Ruiz Ruiz, J.; Guttenfelder, W.; Ren, Y.; White, A.; Kaye, S. M.; Leblanc, B. P.; Mazzucato, E.; Lee, K. C.; Domier, C. W.; Smith, D. R.; Yuh, H.

    2015-11-01

    Electron scale (high-k) ETG-turbulence is diagnosed in NSTX using a high-k microwave scattering system. We report on the stabilization effects of electron density gradient on electron-scale density fluctuations in a set of neutral beam injection (NBI) heated H-mode plasmas. The absence of high-k density fluctuations is correlated with large equilibrium density gradient, consistent with linear stabilization of ETG modes due to density gradient using the ETG linear threshold. The observed scattered power is anti-correlated with equilibrium density gradient. Corresponding linear gyrokinetic simulations using GS2 show that larger equilibrium density gradient leads to higher wavenumbers at the maximum linear growth rate. Real frequencies calculated by GS2 and experimental Doppler-subtracted plasma frame frequencies both decrease with density gradient. Nonlinear electron-scale gyrokinetic simulations were carried out with GYRO: high electron density gradient is shown to reduce electron density fluctuations, heat flux and stiffness, and to increase the ETG nonlinear threshold, reinforcing the experimental observations of density gradient stabilization of high-k turbulence. Work supported by D.O.E. contract DE-AC02-09CH11466.

  18. Adiabatically tapered hyperbolic metamaterials for dispersion control of high-k waves.

    PubMed

    West, Paul R; Kinsey, Nathaniel; Ferrera, Marcello; Kildishev, Alexander V; Shalaev, Vladimir M; Boltasseva, Alexandra

    2015-01-14

    Hyperbolic metamaterials (HMMs) have shown great promise in the optical and quantum communities due to their extremely large, broadband photonic density of states. This feature is a direct consequence of supporting photonic modes with unbounded k-vectors. While these materials support such high-k waves, they are intrinsically confined inside the HMM and cannot propagate into the far-field, rendering them impractical for many applications. Here, we demonstrate how the magnitude of k-vectors can be engineered as the propagating radiation passes through media of differing dispersion relations (including type II HMMs and dielectrics) in the in-plane direction. The total outcoupling efficiency of waves in the in-plane direction is shown to be on average 2 orders of magnitude better than standard out-of-plane outcoupling methods. In addition, the outcoupling can be further enhanced using a proposed tapered HMM waveguide that is fabricated using a shadowed glancing angle deposition technique; thereby proving the feasibility of the proposed device. Applications for this technique include converting high-k waves to low-k waves that can be out-coupled into free-space and creating extremely high-k waves that are quickly quenched. Most importantly, this method of in-plane outcoupling acts as a bridge through which waves can cross between the regimes of low-k waves in classical dielectric materials and the high-k waves in HMMs with strongly reduced reflective losses.

  19. Adiabatic gate teleportation.

    PubMed

    Bacon, Dave; Flammia, Steven T

    2009-09-18

    The difficulty in producing precisely timed and controlled quantum gates is a significant source of error in many physical implementations of quantum computers. Here we introduce a simple universal primitive, adiabatic gate teleportation, which is robust to timing errors and many control errors and maintains a constant energy gap throughout the computation above a degenerate ground state space. This construction allows for geometric robustness based upon the control of two independent qubit interactions. Further, our piecewise adiabatic evolution easily relates to the quantum circuit model, enabling the use of standard methods from fault-tolerance theory for establishing thresholds.

  20. Outlet side of gate, showing the Radial Gate, hoist mechanism ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Outlet side of gate, showing the Radial Gate, hoist mechanism and concrete walkway across the canal. The concrete baffle separating the afterbay and the cipoletti weir is in the foreground - Wellton-Mohawk Irrigation System, Radial Gate Check with Drop, Wellton Canal 9.9, West of Avenue 34 East & north of County Ninth Street, Wellton, Yuma County, AZ

  1. Exterior, looking southeast from within compound towards Main Gate, Gate ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Exterior, looking southeast from within compound towards Main Gate, Gate House center left - Beale Air Force Base, Perimeter Acquisition Vehicle Entry Phased-Array Warning System, Gate House, End of Spencer Paul Road, north of Warren Shingle Road (14th Street), Marysville, Yuba County, CA

  2. Exterior, looking northwest towards Main Gate, Gate House on left, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Exterior, looking northwest towards Main Gate, Gate House on left, Technical Equipment Building (Building 5760) in background to right - Beale Air Force Base, Perimeter Acquisition Vehicle Entry Phased-Array Warning System, Gate House, End of Spencer Paul Road, north of Warren Shingle Road (14th Street), Marysville, Yuba County, CA

  3. Hydraulic Tomography: Continuity and Discontinuity of High-K and Low-K Zones.

    PubMed

    Hochstetler, David L; Barrash, Warren; Leven, Carsten; Cardiff, Michael; Chidichimo, Francesco; Kitanidis, Peter K

    2016-03-01

    Hydraulic tomography is an emerging field and modeling method that provides a continuous hydraulic conductivity (K) distribution for an investigated region. Characterization approaches that rely on interpolation between one-dimensional (1D) profiles have limited ability to accurately identify high-K channels, juxtapositions of lenses with high K contrast, and breaches in layers or channels between such profiles. However, locating these features is especially important for groundwater flow and transport modeling, and for design and operation of in situ remediation in complex hydrogeologic environments. We use transient hydraulic tomography to estimate 3D K in a volume of 15-m diameter by 20-m saturated thickness in a highly heterogeneous unconfined alluvial (clay to sand-and-gravel) aquifer with a K range of approximately seven orders of magnitude at an active industrial site in Assemini, Sardinia, Italy. A modified Levenberg-Marquardt algorithm was used for geostatistical inversion to deal with the nonlinear nature of the highly heterogeneous system. The imaging results are validated with pumping tests not used in the tomographic inversion. These tests were conducted from three of five clusters of continuous multichannel tubing (CMTs) installed for observation in the tomographic testing. Locations of high-K continuity and discontinuity, juxtaposition of very high-K and very low-K lenses, and low-K "plugs" are evident in regions of the investigated volume where they likely would not have been identified with interpolation from 1D profiles at the positions of the pumping well and five CMT clusters. Quality assessment methods identified a suspect high-K feature between the tested volume and a lateral boundary of the model. PMID:26096272

  4. Hydraulic Tomography: Continuity and Discontinuity of High-K and Low-K Zones.

    PubMed

    Hochstetler, David L; Barrash, Warren; Leven, Carsten; Cardiff, Michael; Chidichimo, Francesco; Kitanidis, Peter K

    2016-03-01

    Hydraulic tomography is an emerging field and modeling method that provides a continuous hydraulic conductivity (K) distribution for an investigated region. Characterization approaches that rely on interpolation between one-dimensional (1D) profiles have limited ability to accurately identify high-K channels, juxtapositions of lenses with high K contrast, and breaches in layers or channels between such profiles. However, locating these features is especially important for groundwater flow and transport modeling, and for design and operation of in situ remediation in complex hydrogeologic environments. We use transient hydraulic tomography to estimate 3D K in a volume of 15-m diameter by 20-m saturated thickness in a highly heterogeneous unconfined alluvial (clay to sand-and-gravel) aquifer with a K range of approximately seven orders of magnitude at an active industrial site in Assemini, Sardinia, Italy. A modified Levenberg-Marquardt algorithm was used for geostatistical inversion to deal with the nonlinear nature of the highly heterogeneous system. The imaging results are validated with pumping tests not used in the tomographic inversion. These tests were conducted from three of five clusters of continuous multichannel tubing (CMTs) installed for observation in the tomographic testing. Locations of high-K continuity and discontinuity, juxtaposition of very high-K and very low-K lenses, and low-K "plugs" are evident in regions of the investigated volume where they likely would not have been identified with interpolation from 1D profiles at the positions of the pumping well and five CMT clusters. Quality assessment methods identified a suspect high-K feature between the tested volume and a lateral boundary of the model.

  5. The four-gate transistor

    NASA Technical Reports Server (NTRS)

    Mojarradi, M. M.; Cristoveanu, S.; Allibert, F.; France, G.; Blalock, B.; Durfrene, B.

    2002-01-01

    The four-gate transistor or G4-FET combines MOSFET and JFET principles in a single SOI device. Experimental results reveal that each gate can modulate the drain current. Numerical simulations are presented to clarify the mechanisms of operation. The new device shows enhanced functionality, due to the combinatorial action of the four gates, and opens rather revolutionary applications.

  6. Stanford, Duke, Rice,... and Gates?

    ERIC Educational Resources Information Center

    Carey, Kevin

    2009-01-01

    This article presents an open letter to Bill Gates. In his letter, the author suggests that Bill Gates should build a brand-new university, a great 21st-century institution of higher learning. This university will be unlike anything the world has ever seen. He asks Bill Gates not to stop helping existing colleges create the higher-education system…

  7. Models of HERG gating.

    PubMed

    Bett, Glenna C L; Zhou, Qinlian; Rasmusson, Randall L

    2011-08-01

    HERG (Kv11.1, KCNH2) is a voltage-gated potassium channel with unique gating characteristics. HERG has fast voltage-dependent inactivation, relatively slow deactivation, and fast recovery from inactivation. This combination of gating kinetics makes study of HERG difficult without using mathematical models. Several HERG models have been developed, with fundamentally different organization. HERG is the molecular basis of I(Kr), which plays a critical role in repolarization. We programmed and compared five distinct HERG models. HERG gating cannot be adequately replicated using Hodgkin-Huxley type formulation. Using Markov models, a five-state model is required with three closed, one open, and one inactivated state, and a voltage-independent step between some of the closed states. A fundamental difference between models is the presence/absence of a transition directly from the proximal closed state to the inactivated state. The only models that effectively reproduce HERG data have no direct closed-inactivated transition, or have a closed-inactivated transition that is effectively zero compared to the closed-open transition, rendering the closed-inactivation transition superfluous. Our single-channel model demonstrates that channels can inactivate without conducting with a flickering or bursting open-state. The various models have qualitative and quantitative differences that are critical to accurate predictions of HERG behavior during repolarization, tachycardia, and premature depolarizations. PMID:21806931

  8. Strategy Retooled at Gates

    ERIC Educational Resources Information Center

    Robelen, Erik W.

    2008-01-01

    In rolling out plans last week to revamp its high school strategy and launch a major new effort on the postsecondary front, the Bill & Melinda Gates Foundation is undertaking a more sweeping approach to grantmaking that appears aimed at reshaping some core elements of the U.S. education system. The philanthropy's agenda on secondary schools…

  9. Models of HERG Gating

    PubMed Central

    Bett, Glenna C.L.; Zhou, Qinlian; Rasmusson, Randall L.

    2011-01-01

    HERG (Kv11.1, KCNH2) is a voltage-gated potassium channel with unique gating characteristics. HERG has fast voltage-dependent inactivation, relatively slow deactivation, and fast recovery from inactivation. This combination of gating kinetics makes study of HERG difficult without using mathematical models. Several HERG models have been developed, with fundamentally different organization. HERG is the molecular basis of IKr, which plays a critical role in repolarization. We programmed and compared five distinct HERG models. HERG gating cannot be adequately replicated using Hodgkin-Huxley type formulation. Using Markov models, a five-state model is required with three closed, one open, and one inactivated state, and a voltage-independent step between some of the closed states. A fundamental difference between models is the presence/absence of a transition directly from the proximal closed state to the inactivated state. The only models that effectively reproduce HERG data have no direct closed-inactivated transition, or have a closed-inactivated transition that is effectively zero compared to the closed-open transition, rendering the closed-inactivation transition superfluous. Our single-channel model demonstrates that channels can inactivate without conducting with a flickering or bursting open-state. The various models have qualitative and quantitative differences that are critical to accurate predictions of HERG behavior during repolarization, tachycardia, and premature depolarizations. PMID:21806931

  10. High-K isomers in transactinide nuclei close to N = 162

    SciTech Connect

    Prassa, V. Nikšić, T.; Vretenar, D.; Lu, Bing-Nan; Ackermann, D.

    2015-10-15

    Transactinide nuclei around neutron number N = 162 display axially deformed equilibrium shapes, as shown in our previous analysis [1] of constrained mean-field energy surfaces and collective excitation spectra. In the present study we are particularly interested in the occurrence of high-K isomers in the axially deformed isotopes of Rf (Z = 104), Sg (Z = 106), Hs (Z = 108), and Ds (Z = 110), with neutron number N = 160 − 166 and the effect of the N=162 closure on the structure and distribution of two-quasiparticle (2qp) states. The evolution of high-K isomers is analysed in a self-consistent axially-symmetric relativistic Hartree-Bogoliubov calculation using the blocking approximation with time-reversal symmetry breaking.

  11. Spatial resolution study and power calibration of the high-k scattering system on NSTX

    SciTech Connect

    Lee, W.; Park, H. K.; Cho, M. H.; Namkung, W.; Smith, D. R.; Domier, C. W.; Luhmann, N. C. Jr

    2008-10-15

    NSTX high-k scattering system has been extensively utilized in studying the microturbulence and coherent waves. An absolute calibration of the scattering system was performed employing a new millimeter-wave source and calibrated attenuators. One of the key parameters essential for the calibration of the multichannel scattering system is the interaction length. This interaction length is significantly different from the conventional one due to the curvature and magnetic shear effect.

  12. Universal Superreplication of Unitary Gates

    NASA Astrophysics Data System (ADS)

    Chiribella, G.; Yang, Y.; Huang, C.

    2015-03-01

    Quantum states obey an asymptotic no-cloning theorem, stating that no deterministic machine can reliably replicate generic sequences of identically prepared pure states. In stark contrast, we show that generic sequences of unitary gates can be replicated deterministically at nearly quadratic rates, with an error vanishing on most inputs except for an exponentially small fraction. The result is not in contradiction with the no-cloning theorem, since the impossibility of deterministically transforming pure states into unitary gates prevents the application of the gate replication protocol to states. In addition to gate replication, we show that N parallel uses of a completely unknown unitary gate can be compressed into a single gate acting on O (log2N ) qubits, leading to an exponential reduction of the amount of quantum communication needed to implement the gate remotely.

  13. Tailoring Dielectric Properties and Energy Density of Ferroelectric Polymer Nanocomposites by High-k Nanowires.

    PubMed

    Wang, Guanyao; Huang, Xingyi; Jiang, Pingkai

    2015-08-19

    High dielectric constant (k) polymer nanocomposites have shown great potential in dielectric and energy storage applications in the past few decades. The introduction of high-k nanomaterials into ferroelectric polymers has proven to be a promising strategy for the fabrication of high-k nanocomposites. One-dimensional large-aspect-ratio nanowires exhibit superiority in enhancing k values and energy density of polymer nanocomposites in comparison to their spherical counterparts. However, the impact of their intrinsic properties on the dielectric properties of polymer nanocomposites has been seldom investigated. Herein, four kinds of nanowires (Na2Ti3O7, TiO2, BaTiO3, and SrTiO3) with different inherent characteristics are elaborately selected to fabricate high-k ferroelectric polymer nanocomposites. Dopamine functionalization facilitates the excellent dispersion of these nanowires in the ferroelectric polymer matrix because of the strong polymer/nanowire interfacial adhesion. A thorough comparative study on the dielectric properties and energy storage capability of the nanowires-based nanocomposites has been presented. The results reveal that, among the four types of nanowires, BaTiO3 NWs show the best potential in improving the energy storage capability of the proposed nanocomposites, resulting from the most signficant increase of k while retaining the rather low dielectric loss and leakage current.

  14. Ion polarization behavior in alumina under pulsed gate bias stress

    SciTech Connect

    Liu, Yu; Diallo, Abdou Karim; Katz, Howard E.

    2015-03-16

    Alkali metal ion incorporation in alumina significantly increases alumina capacitance by ion polarization. With high capacitance, ion-incorporated aluminas become promising high dielectric constant (high-k) gate dielectric materials in field-effect transistors (FETs) to enable reduced operating voltage, using oxide or organic semiconductors. Alumina capacitance can be manipulated by incorporation of alkali metal ions, including potassium (K{sup +}), sodium (Na{sup +}), and lithium (Li{sup +}), having different bond strengths with oxygen. To investigate the electrical stability of zinc tin oxide-based transistors using ion incorporated alumina as gate dielectrics, pulsed biases at different duty cycles (20%, 10%, and 2% representing 5 ms, 10 ms, and 50 ms periods, respectively) were applied to the gate electrode, sweeping the gate voltage over series of these cycles. We observed a particular bias stress-induced decrease of saturation field-effect mobility accompanied by threshold voltage shifts (ΔV{sub th}) in potassium and sodium-incorporated alumina (abbreviated as PA and SA)-based FETs at high duty cycle that persisted over multiple gate voltage sweeps, suggesting a possible creation of new defects in the semiconductor. This conclusion is also supported by the greater change in the mobility-capacitance (μC) product than in capacitance itself. Moreover, a more pronounced ΔV{sub th} over shorter times was observed in lithium-incorporated alumina (abbreviated as LA)-based transistors, suggesting trapping of electrons in existing interfacial states. ΔV{sub th} from multiple gate voltage sweeps over time were fit to stretched exponential forms. All three dielectrics show good stability using 50-ms intervals (20-Hz frequencies), corresponding to 2% duty cycles.

  15. Ion polarization behavior in alumina under pulsed gate bias stress

    NASA Astrophysics Data System (ADS)

    Liu, Yu; Diallo, Abdou Karim; Katz, Howard E.

    2015-03-01

    Alkali metal ion incorporation in alumina significantly increases alumina capacitance by ion polarization. With high capacitance, ion-incorporated aluminas become promising high dielectric constant (high-k) gate dielectric materials in field-effect transistors (FETs) to enable reduced operating voltage, using oxide or organic semiconductors. Alumina capacitance can be manipulated by incorporation of alkali metal ions, including potassium (K+), sodium (Na+), and lithium (Li+), having different bond strengths with oxygen. To investigate the electrical stability of zinc tin oxide-based transistors using ion incorporated alumina as gate dielectrics, pulsed biases at different duty cycles (20%, 10%, and 2% representing 5 ms, 10 ms, and 50 ms periods, respectively) were applied to the gate electrode, sweeping the gate voltage over series of these cycles. We observed a particular bias stress-induced decrease of saturation field-effect mobility accompanied by threshold voltage shifts (ΔVth) in potassium and sodium-incorporated alumina (abbreviated as PA and SA)-based FETs at high duty cycle that persisted over multiple gate voltage sweeps, suggesting a possible creation of new defects in the semiconductor. This conclusion is also supported by the greater change in the mobility-capacitance (μC) product than in capacitance itself. Moreover, a more pronounced ΔVth over shorter times was observed in lithium-incorporated alumina (abbreviated as LA)-based transistors, suggesting trapping of electrons in existing interfacial states. ΔVth from multiple gate voltage sweeps over time were fit to stretched exponential forms. All three dielectrics show good stability using 50-ms intervals (20-Hz frequencies), corresponding to 2% duty cycles.

  16. Direct observation of bias-dependence potential distribution in metal/HfO{sub 2} gate stack structures by hard x-ray photoelectron spectroscopy under device operation

    SciTech Connect

    Yamashita, Y.; Yoshikawa, H.; Kobayashi, K.; Chikyo, T.

    2014-01-28

    Although gate stack structures with high-k materials have been extensively investigated, there are some issues to be solved for the formation of high quality gate stack structures. In the present study, we employed hard x-ray photoelectron spectroscopy in operating devices. This method allows us to investigate bias dependent electronic states, while keeping device structures intact. Using this method, we have investigated electronic states and potential distribution in gate metal/HfO{sub 2} gate stack structures under device operation. Analysis of the core levels shifts as a function of the bias voltage indicated that a potential drop occurred at the Pt/HfO{sub 2} interface for a Pt/HfO{sub 2} gate structure, while a potential gradient was not observed at the Ru/HfO{sub 2} interface for a Ru/HfO{sub 2} gate structure. Angle resolved photoelectron spectroscopy revealed that a thicker SiO{sub 2} layer was formed at the Pt/HfO{sub 2} interface, indicating that the origin of potential drop at Pt/HfO{sub 2} interface is formation of the thick SiO{sub 2} layer at the interface. The formation of the thick SiO{sub 2} layer at the metal/high-k interface might concern the Fermi level pinning, which is observed in metal/high-k gate stack structures.

  17. A quantum Fredkin gate.

    PubMed

    Patel, Raj B; Ho, Joseph; Ferreyrol, Franck; Ralph, Timothy C; Pryde, Geoff J

    2016-03-01

    Minimizing the resources required to build logic gates into useful processing circuits is key to realizing quantum computers. Although the salient features of a quantum computer have been shown in proof-of-principle experiments, difficulties in scaling quantum systems have made more complex operations intractable. This is exemplified in the classical Fredkin (controlled-SWAP) gate for which, despite theoretical proposals, no quantum analog has been realized. By adding control to the SWAP unitary, we use photonic qubit logic to demonstrate the first quantum Fredkin gate, which promises many applications in quantum information and measurement. We implement example algorithms and generate the highest-fidelity three-photon Greenberger-Horne-Zeilinger states to date. The technique we use allows one to add a control operation to a black-box unitary, something that is impossible in the standard circuit model. Our experiment represents the first use of this technique to control a two-qubit operation and paves the way for larger controlled circuits to be realized efficiently. PMID:27051868

  18. A quantum Fredkin gate

    PubMed Central

    Patel, Raj B.; Ho, Joseph; Ferreyrol, Franck; Ralph, Timothy C.; Pryde, Geoff J.

    2016-01-01

    Minimizing the resources required to build logic gates into useful processing circuits is key to realizing quantum computers. Although the salient features of a quantum computer have been shown in proof-of-principle experiments, difficulties in scaling quantum systems have made more complex operations intractable. This is exemplified in the classical Fredkin (controlled-SWAP) gate for which, despite theoretical proposals, no quantum analog has been realized. By adding control to the SWAP unitary, we use photonic qubit logic to demonstrate the first quantum Fredkin gate, which promises many applications in quantum information and measurement. We implement example algorithms and generate the highest-fidelity three-photon Greenberger-Horne-Zeilinger states to date. The technique we use allows one to add a control operation to a black-box unitary, something that is impossible in the standard circuit model. Our experiment represents the first use of this technique to control a two-qubit operation and paves the way for larger controlled circuits to be realized efficiently. PMID:27051868

  19. A quantum Fredkin gate.

    PubMed

    Patel, Raj B; Ho, Joseph; Ferreyrol, Franck; Ralph, Timothy C; Pryde, Geoff J

    2016-03-01

    Minimizing the resources required to build logic gates into useful processing circuits is key to realizing quantum computers. Although the salient features of a quantum computer have been shown in proof-of-principle experiments, difficulties in scaling quantum systems have made more complex operations intractable. This is exemplified in the classical Fredkin (controlled-SWAP) gate for which, despite theoretical proposals, no quantum analog has been realized. By adding control to the SWAP unitary, we use photonic qubit logic to demonstrate the first quantum Fredkin gate, which promises many applications in quantum information and measurement. We implement example algorithms and generate the highest-fidelity three-photon Greenberger-Horne-Zeilinger states to date. The technique we use allows one to add a control operation to a black-box unitary, something that is impossible in the standard circuit model. Our experiment represents the first use of this technique to control a two-qubit operation and paves the way for larger controlled circuits to be realized efficiently.

  20. Band structures and band offsets of high K dielectrics on Si

    NASA Astrophysics Data System (ADS)

    Robertson, J.

    2002-05-01

    Various high dielectric constant oxides will be used as insulator in ferroelectric memories, dynamic random access memories, and as the gate dielectric material in future complementary metal oxide semiconductor (CMOS) technology. These oxides which have moderately wide bandgaps provide a good test of our understanding of Schottky barrier heights and band offsets at semiconductor interfaces. Metal induced gap states (MIGS) are found to give a good description of these interfaces. The electronic structure and band offsets of these oxides are calculated. It is found that Ta 2O 5 and SrTiO 3 have small or vanishing conduction band offsets on Si. La 2O 3, Y 2O 3, ZrO 2, HfO 2, Al 2O 3 and silicates like ZrSiO 4 have offsets over 1.4 eV for both electrons and holes, making them better gate dielectrics.

  1. High-k dielectrics on (100) and (110) n-InAs: Physical and electrical characterizations

    SciTech Connect

    Wang, C. H. Hsu, W. C.; Doornbos, G.; Astromskas, G.; Vellianitis, G.; Oxland, R.; Holland, M. C.; Passlack, M.; Huang, M. L.; Lin, C. H.; Hsieh, C. H.; Chang, Y. S.; Lee, T. L.; Chen, Y. Y.; Diaz, C. H.; Ramvall, P.; Lind, E.; Wernersson, L.-E.; Droopad, R.

    2014-04-15

    Two high-k dielectric materials (Al{sub 2}O{sub 3} and HfO{sub 2}) were deposited on n-type (100) and (110) InAs surface orientations to investigate physical properties of the oxide/semiconductor interfaces and the interface trap density (D{sub it}). X-ray photoelectron spectroscopy analyses (XPS) for native oxides of (100) and (110) as-grown n-InAs epi wafers show an increase in As-oxide on the (100) surface and an increase in InOx on the (110) surface. In addition, XPS analyses of high-k (Al{sub 2}O{sub 3} and HfO{sub 2}) on n-InAs epi show that the intrinsic native oxide difference between (100) and (110) epi surfaces were eliminated by applying conventional in-situ pre-treatment (TriMethyAluminium (TMA)) before the high-k deposition. The capacitance-voltage (C-V) characterization of HfO{sub 2} and Al{sub 2}O{sub 3} MOSCAPs on both types of n-InAs surfaces shows very similar C-V curves. The interface trap density (D{sub it}) profiles show D{sub it} minima of 6.1 × 10{sup 12}/6.5 × 10{sup 12} and 6.6 × 10{sup 12}/7.3 × 10{sup 12} cm{sup −2} eV{sup −1} for Al{sub 2}O{sub 3} and HfO{sub 2}, respectively for (100) and (110) InAs surfaces. The similar interface trap density (D{sub it}) on (100) and (110) surface orientation were observed, which is beneficial to future InAs FinFET device with both (100) and (110) surface channel orientations present.

  2. Enhancement mode AlGaN/GaN MOS high-electron-mobility transistors with ZrO2 gate dielectric deposited by atomic layer deposition

    NASA Astrophysics Data System (ADS)

    Anderson, Travis J.; Wheeler, Virginia D.; Shahin, David I.; Tadjer, Marko J.; Koehler, Andrew D.; Hobart, Karl D.; Christou, Aris; Kub, Francis J.; Eddy, Charles R., Jr.

    2016-07-01

    Advanced applications of AlGaN/GaN high-electron-mobility transistors (HEMTs) in high-power RF and power switching are driving the need for insulated gate technology. We present a metal-oxide-semiconductor (MOS) gate structure using atomic-layer-deposited ZrO2 as a high-k, high-breakdown gate dielectric for reduced gate leakage and a recessed barrier structure for enhancement mode operation. Compared to a Schottky metal-gate HEMT, the recessed MOS-HEMT structure demonstrated a reduction in the gate leakage current by 4 orders of magnitude and a threshold voltage shift of +6 V to a record +3.99 V, enabled by a combination of a recessed barrier structure and negative oxide charge.

  3. Enhancement mode AlGaN/GaN MOS high-electron-mobility transistors with ZrO2 gate dielectric deposited by atomic layer deposition

    NASA Astrophysics Data System (ADS)

    Anderson, Travis J.; Wheeler, Virginia D.; Shahin, David I.; Tadjer, Marko J.; Koehler, Andrew D.; Hobart, Karl D.; Christou, Aris; Kub, Francis J.; Eddy, Charles R., Jr.

    2016-07-01

    Advanced applications of AlGaN/GaN high-electron-mobility transistors (HEMTs) in high-power RF and power switching are driving the need for insulated gate technology. We present a metal–oxide–semiconductor (MOS) gate structure using atomic-layer-deposited ZrO2 as a high-k, high-breakdown gate dielectric for reduced gate leakage and a recessed barrier structure for enhancement mode operation. Compared to a Schottky metal-gate HEMT, the recessed MOS-HEMT structure demonstrated a reduction in the gate leakage current by 4 orders of magnitude and a threshold voltage shift of +6 V to a record +3.99 V, enabled by a combination of a recessed barrier structure and negative oxide charge.

  4. ONE SHAKE GATE FORMER

    DOEpatents

    Kalibjian, R.; Perez-Mendez, V.

    1957-08-20

    An improved circuit for forming square pulses having substantially short and precise durations is described. The gate forming circuit incorporates a secondary emission R. F. pentode adapted to receive input trigger pulses amd having a positive feedback loop comnected from the dynode to the control grid to maintain conduction in response to trigger pulses. A short circuited pulse delay line is employed to precisely control the conducting time of the tube and a circuit for squelching spurious oscillations is provided in the feedback loop.

  5. Compact gate valve

    DOEpatents

    Bobo, Gerald E.

    1977-01-01

    This invention relates to a double-disc gate valve which is compact, comparatively simple to construct, and capable of maintaining high closing pressures on the valve discs with low frictional forces. The valve casing includes axially aligned ports. Mounted in the casing is a sealed chamber which is pivotable transversely of the axis of the ports. The chamber contains the levers for moving the valve discs axially, and an actuator for the levers. When an external drive means pivots the chamber to a position where the discs are between the ports and axially aligned therewith, the actuator for the levers is energized to move the discs into sealing engagement with the ports.

  6. Tide gate valve

    SciTech Connect

    Raftis, S. G.

    1985-01-08

    A tide gate check valve in which at least three converging sides are provided at a tapered region of a flexible sleeve, so that on reverse back pressure build-up of fluid, reverse fluid flow is prevented, while the valve sleeve does not invert or collapse. The present configuration features embedded reinforcing elements for resisting inversion or collapsing when the back pressure builds up. This feature is especially important for large-sized conduits of 36'' or 72'' diameter, or even larger, such as are common in storm sewer applications.

  7. Elemental maps in human allantochorial placental vessels cells: 1. High K + and acetylcholine effects

    NASA Astrophysics Data System (ADS)

    Michelet-Habchi, C.; Barberet, Ph.; Dutta, R. K.; Guiet-Bara, A.; Bara, M.; Moretto, Ph.

    2003-09-01

    Regulation of vascular tone in the fetal extracorporeal circulation most likely depends on circulating hormones, local paracrine mechanisms and changes in membrane potential of vascular smooth muscle cells (VSMCs) and of vascular endothelial cells (VECs). The membrane potential is a function of the physiological activities of ionic channels (particularly, K + and Ca 2+ channels in these cells). These channels regulate the ionic distribution into these cells. Micro-particle induced X-ray emission (PIXE) analysis was applied to determine the ionic composition of VSMC and of VEC in the placental human allantochorial vessels in a physiological survival medium (Hanks' solution) modified by the addition of acetylcholine (ACh: which opens the calcium-sensitive K + channels, K Ca) and of high concentration of K + (which blocks the voltage-sensitive K + channels, K df). In VSMC (media layer), the addition of ACh induced no modification of the Na, K, Cl, P, S, Mg and Ca concentrations and high K + medium increased significantly the Cl and K concentrations, the other ion concentrations remaining constant. In endothelium (VEC), ACh addition implicated a significant increase of Na and K concentration, and high K + medium, a significant increase in Cl and K concentration. These results indicated the importance of K df, K Ca and K ATP channels in the regulation of K + intracellular distribution in VSMC and VEC and the possible intervention of a Na-K-2Cl cotransport and corroborated the previous electrophysiological data.

  8. Influence of the octupole mode on nuclear high-K isomeric properties

    NASA Astrophysics Data System (ADS)

    Minkov, Nikolay; Walker, Phil

    2014-05-01

    The influence of quadrupole-octupole deformations on the energy and magnetic properties of high-K isomeric states in even-even actinide (U, Pu, Cm, Fm, No), rare-earth (Nd, Sm and Gd), and superheavy (^{270}\\text{Ds}) nuclei is examined within a deformed shell model with pairing interaction. The neutron two-quasiparticle (2qp) isomeric energies and magnetic dipole moments are calculated over a wide range in the plane of quadrupole and octupole deformations. In most cases the magnetic moments exhibit a pronounced sensitivity to the octupole deformation. At the same time, the calculations outline three different groups of nuclei: with pronounced, shallow, and missing minima in the 2qp energy surfaces with respect to the octupole deformation. The result indicates regions of nuclei with octupole softness as well as with possible octupole deformation in the high-K isomeric states. These findings show the need for further theoretical analysis as well as of detailed experimental measurements of magnetic moments in heavy deformed nuclei.

  9. 12. INTERIOR VIEW OF GATE OPERATOR ROOM, SHOWING SLIDES GATE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. INTERIOR VIEW OF GATE OPERATOR ROOM, SHOWING SLIDES GATE OPERATORS, LOOKING NORTHWEST. - Sacramento River Water Treatment Plant Intake Pier & Access Bridge, Spanning Sacramento River approximately 175 feet west of eastern levee on river; roughly .5 mile downstream from confluence of Sacramento & American Rivers, Sacramento, Sacramento County, CA

  10. 16. Little Hell Gate Bridge with Big Hell Gate Bridge ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    16. Little Hell Gate Bridge with Big Hell Gate Bridge in background. Wards Island, New York Co., NY. Sec. 4207, MP 8.02. - Northeast Railroad Corridor, Amtrak Route between New Jersey/New York & New York/Connecticut State Lines, New York County, NY

  11. 3. TAINTER GATES (LEFT FOREGROUND) AND ROLLING SECTOR GATE AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. TAINTER GATES (LEFT FOREGROUND) AND ROLLING SECTOR GATE AND SPILLWAY (BACKGROUND) OF THE NORTH CHANNEL DAM, LOOKING SOUTH. - Washington Water Power Company Post Falls Power Plant, North Channel Dam, West of intersection of Spokane & Fourth Streets, Post Falls, Kootenai County, ID

  12. 5. GATE 5, INTAKE CHANNEL LOOKING SOUTH; WATER FROM GATE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. GATE 5, INTAKE CHANNEL LOOKING SOUTH; WATER FROM GATE 5 ENTERED DITCH AND IRRIGATED HONDIUS' FIELDS. - Hondius Water Line, 1.6 miles Northwest of Park headquarters building & 1 mile Northwest of Beaver Meadows entrance station, Estes Park, Larimer County, CO

  13. Plasma-enhanced atomic layer deposition and etching of high-k gadolinium oxide

    SciTech Connect

    Vitale, Steven A.; Wyatt, Peter W.; Hodson, Chris J.

    2012-01-15

    Atomic layer deposition (ALD) of high-quality gadolinium oxide thin films is achieved using Gd(iPrCp){sub 3} and O{sub 2} plasma. Gd{sub 2}O{sub 3} growth is observed from 150 to 350 deg. C, though the optical properties of the film improve at higher temperature. True layer-by-layer ALD growth of Gd{sub 2}O{sub 3} occurred in a relatively narrow window of temperature and precursor dose. A saturated growth rate of 1.4 A/cycle was observed at 250 deg. C. As the temperature increases, high-quality films are deposited, but the growth mechanism appears to become CVD-like, indicating the onset of precursor decomposition. At 250 deg. C, the refractive index of the film is stable at {approx}1.80 regardless of other deposition conditions, and the measured dispersion characteristics are comparable to those of bulk Gd{sub 2}O{sub 3}. XPS data show that the O/Gd ratio is oxygen deficient at 1.3, and that it is also very hygroscopic. The plasma etching rate of the ALD Gd{sub 2}O{sub 3} film in a high-density helicon reactor is very low. Little difference is observed in etching rate between Cl{sub 2} and pure Ar plasmas, suggesting that physical sputtering dominates the etching. A threshold bias power exists below which etching does not occur; thus it may be possible to etch a metal gate material and stop easily on the Gd{sub 2}O{sub 3} gate dielectric. The Gd{sub 2}O{sub 3} film has a dielectric constant of about 16, exhibits low C-V hysteresis, and allows a 50 x reduction in gate leakage compared to SiO{sub 2}. However, the plasma enhanced atomic layer deposition (PE-ALD) process causes formation of an {approx}1.8 nm SiO{sub 2} interfacial layer, and generates a fixed charge of -1.21 x 10{sup 12} cm{sup -2}, both of which may limit use of PE-ALD Gd{sub 2}O{sub 3} as a gate dielectric.

  14. Dry-etching properties of TiN for metal/high-k gate stack using BCl{sub 3}-based inductively coupled plasma

    SciTech Connect

    Kim, Dong-Pyo; Yang Xue; Woo, Jong-Chang; Um, Doo-Seung; Kim, Chang-Il

    2009-11-15

    The etch rate of TiN film and the selectivities of TiN/SiO{sub 2} and TiN/HfO{sub 2} were systematically investigated in Cl{sub 2}/BCl{sub 3}/Ar plasmas as functions of Cl{sub 2} flow rate, radio-frequency (rf) power, and direct-current (dc) bias voltage under different substrate temperatures of 10 and 80 degree sign C. The etch rate of TiN films increased with increasing Cl{sub 2} flow rate, rf power, and dc-bias voltage at a fixed substrate temperature. In addition, the etch rate of TiN films at 80 degree sign C were higher than that at 10 degree sign C when other plasma parameters were fixed. However, the selectivities of TiN/SiO{sub 2} and TiN/HfO{sub 2} showed different tendencies compared with etch-rate behavior as a function of rf power and dc bias voltage. The relative-volume densities of Ar (750.0 nm), Cl (725.2 nm), and Cl{sup +} (386.6 nm) were monitored with an optical-emission spectroscopy. When rf power increased, the relative-volume densities of all studied particles were increased. X-ray photoelectron spectroscopy was carried out to detect nonvolatile etch by-products from the surface, and nonvolatile peaks (TiCl{sub x} bonds) in Ti 2p and Cl 2p were observed due to their high melting points. Based on the experimental results, we can conclude that the TiN etch is dependent on the substrate temperature when other plasma parameters are fixed. This can be explained by the enhanced chemical pathway with the assistance of ion bombardment.

  15. The influence of carbon doping on the performance of Gd{sub 2}O{sub 3} as high-k gate dielectric

    SciTech Connect

    Shekhter, P.; Yehezkel, S.; Shriki, A.; Eizenberg, M.; Chaudhuri, A. R.; Osten, H. J.; Laha, A.

    2014-12-29

    One of the approaches for overcoming the issue of leakage current in modern metal-oxide-semiconductor devices is utilizing the high dielectric constants of lanthanide based oxides. We investigated the effect of carbon doping directly into Gd{sub 2}O{sub 3} layers on the performance of such devices. It was found that the amount of carbon introduced into the dielectric is above the solubility limit; carbon atoms enrich the oxide-semiconductor interface and cause a significant shift in the flat band voltage of the stack. Although the carbon atoms slightly degrade this interface, this method has a potential for tuning the flat band voltage of such structures.

  16. Promotion of granule cell survival by high K+ or excitatory amino acid treatment and Ca2+/calmodulin-dependent protein kinase activity.

    PubMed

    Hack, N; Hidaka, H; Wakefield, M J; Balázs, R

    1993-11-01

    Cerebellar granule cells in culture develop survival requirements which can be met either by chronic membrane depolarization (25 mM K+) or by stimulation of ionotropic excitatory amino acid receptors. We observed previously that this trophic effect is mediated via Ca2+ influx, either through dihydropyridine-sensitive, voltage-dependent calcium channels (activated directly by high K+ or indirectly by kainate) or through N-methyl-D-aspartate receptor-linked ion channels. Steps after Ca2+ entry in the transduction cascade mediating the survival-supporting effect of high K+ and excitatory amino acids have now been examined. Using protein kinase inhibitors (H-7, polymixin B and gangliosides), and modulating protein kinase C activity by treatment with the phorbol ester 12-O-tetradecanoylphorbol-13-acetate, we obtained evidence against the involvement of protein kinase C and cyclic nucleotide-dependent protein kinases in the transduction cascade. On the other hand, calmidazolium (employed as a calmodulin inhibitor) counteracted the trophic effect of elevated K+ with high potency (IC50 0.3 microM), which exceeded by approximately 10-fold the potency for the blockade by the drug of voltage-sensitive calcium channels. The potency of calmidazolium in interfering with the N-methyl-D-aspartate rescue of cells was also much higher in comparison with the inhibition of 45Ca2+ influx through N-methyl-D-aspartate receptor-linked channels. Our results indicated that after calmodulin the next step in the trophic effects involves Ca2+/calmodulin-dependent protein kinase II activity. KN-62, a fairly specific antagonist of this enzyme, compromised elevated K+ or excitatory amino acid-supported cell survival with high potency (IC50 2.5 microM). In the relevant concentration range, KN-62 had little or no effect on Ca2+ entry through either voltage- or N-methyl-D-aspartate receptor-gated channels. Combining information on the toxic action of glutamate in "mature" granule cells with the

  17. Gates Learns to Think Big

    ERIC Educational Resources Information Center

    Robelen, Erik W.

    2006-01-01

    This article discusses how the philanthropy of Microsoft Corp software magnate co-chairs, Bill Gates and his wife Melinda, are reshaping the American high school nowadays. Gates and his wife have put the issue on the national agenda like never before, with a commitment of more than 1.3 billion US dollars this decade toward the foundation's agenda…

  18. Penn State DOE GATE Program

    SciTech Connect

    Anstrom, Joel

    2012-08-31

    The Graduate Automotive Technology Education (GATE) Program at The Pennsylvania State University (Penn State) was established in October 1998 pursuant to an award from the U.S. Department of Energy (U.S. DOE). The focus area of the Penn State GATE Program is advanced energy storage systems for electric and hybrid vehicles.

  19. Hybrid gate dielectric materials for unconventional electronic circuitry.

    PubMed

    Ha, Young-Geun; Everaerts, Ken; Hersam, Mark C; Marks, Tobin J

    2014-04-15

    Recent advances in semiconductor performance made possible by organic π-electron molecules, carbon-based nanomaterials, and metal oxides have been a central scientific and technological research focus over the past decade in the quest for flexible and transparent electronic products. However, advances in semiconductor materials require corresponding advances in compatible gate dielectric materials, which must exhibit excellent electrical properties such as large capacitance, high breakdown strength, low leakage current density, and mechanical flexibility on arbitrary substrates. Historically, conventional silicon dioxide (SiO2) has dominated electronics as the preferred gate dielectric material in complementary metal oxide semiconductor (CMOS) integrated transistor circuitry. However, it does not satisfy many of the performance requirements for the aforementioned semiconductors due to its relatively low dielectric constant and intransigent processability. High-k inorganics such as hafnium dioxide (HfO2) or zirconium dioxide (ZrO2) offer some increases in performance, but scientists have great difficulty depositing these materials as smooth films at temperatures compatible with flexible plastic substrates. While various organic polymers are accessible via chemical synthesis and readily form films from solution, they typically exhibit low capacitances, and the corresponding transistors operate at unacceptably high voltages. More recently, researchers have combined the favorable properties of high-k metal oxides and π-electron organics to form processable, structurally well-defined, and robust self-assembled multilayer nanodielectrics, which enable high-performance transistors with a wide variety of unconventional semiconductors. In this Account, we review recent advances in organic-inorganic hybrid gate dielectrics, fabricated by multilayer self-assembly, and their remarkable synergy with unconventional semiconductors. We first discuss the principals and functional

  20. Graphene liquid crystal retarded percolation for new high-k materials

    PubMed Central

    Yuan, Jinkai; Luna, Alan; Neri, Wilfrid; Zakri, Cécile; Schilling, Tanja; Colin, Annie; Poulin, Philippe

    2015-01-01

    Graphene flakes with giant shape anisotropy are extensively used to establish connectedness electrical percolation in various heterogeneous systems. However, the percolation behaviour of graphene flakes has been recently predicted to be far more complicated than generally anticipated on the basis of excluded volume arguments. Here we confirm experimentally that graphene flakes self-assemble into nematic liquid crystals below the onset of percolation. The competition of percolation and liquid crystal transition provides a new route towards high-k materials. Indeed, near-percolated liquid-crystalline graphene-based composites display unprecedented dielectric properties with a dielectric constant improved by 260-fold increase as compared with the polymer matrix, while maintaining the loss tangent as low as 0.4. This performance is shown to depend on the structure of monodomains of graphene liquid-crystalline phases. Insights into how the liquid crystal phase transition interferes with percolation transition and thus alters the dielectric constant are discussed. PMID:26567720

  1. Graphene liquid crystal retarded percolation for new high-k materials

    NASA Astrophysics Data System (ADS)

    Yuan, Jinkai; Luna, Alan; Neri, Wilfrid; Zakri, Cécile; Schilling, Tanja; Colin, Annie; Poulin, Philippe

    2015-11-01

    Graphene flakes with giant shape anisotropy are extensively used to establish connectedness electrical percolation in various heterogeneous systems. However, the percolation behaviour of graphene flakes has been recently predicted to be far more complicated than generally anticipated on the basis of excluded volume arguments. Here we confirm experimentally that graphene flakes self-assemble into nematic liquid crystals below the onset of percolation. The competition of percolation and liquid crystal transition provides a new route towards high-k materials. Indeed, near-percolated liquid-crystalline graphene-based composites display unprecedented dielectric properties with a dielectric constant improved by 260-fold increase as compared with the polymer matrix, while maintaining the loss tangent as low as 0.4. This performance is shown to depend on the structure of monodomains of graphene liquid-crystalline phases. Insights into how the liquid crystal phase transition interferes with percolation transition and thus alters the dielectric constant are discussed.

  2. A charge transport study in diamond, surface passivated by high-k dielectric oxides

    SciTech Connect

    Kovi, Kiran Kumar Majdi, Saman; Gabrysch, Markus; Isberg, Jan

    2014-11-17

    The recent progress in the growth of high-quality single-crystalline diamond films has sparked interest in the realization of efficient diamond power electronic devices. However, finding a suitable passivation is essential to improve the reliability and electrical performance of devices. In the current work, high-k dielectric materials such as aluminum oxide and hafnium oxide were deposited by atomic layer deposition on intrinsic diamond as a surface passivation layer. The hole transport properties in the diamond films were evaluated and compared to unpassivated films using the lateral time-of-flight technique. An enhancement of the near surface hole mobility in diamond films of up to 27% is observed when using aluminum oxide passivation.

  3. Theory of an improved vertical power MOSFET using high-k insulator

    NASA Astrophysics Data System (ADS)

    Huang, Mingmin; Chen, Xingbi

    2015-12-01

    An improved structure of the vertical power MOSFET using high-k insulator (Hk-MOSFET), which has a better relationship between specific on-resistance (Ron) and breakdown voltage (VB) than the conventional Hk-MOSFET and the superjunction MOSFET, is studied. An analytic model of this improved Hk-MOSFET is proposed, which can be used to well explain the physical reason of the improvement as well as to obtain an optimal design. It is found that the theoretical results match well with the numerical simulation results, where the errors of VB and Ron are both less than 7%. Moreover, the numerical simulation results show that, with the guidance of the proposed analytic model, Ron of the improved Hk-MOSFET can be optimized to be about 30%-50% lower than that of the conventional Hk-MOSFET with VB = 300-1000 V.

  4. Graphene liquid crystal retarded percolation for new high-k materials.

    PubMed

    Yuan, Jinkai; Luna, Alan; Neri, Wilfrid; Zakri, Cécile; Schilling, Tanja; Colin, Annie; Poulin, Philippe

    2015-11-16

    Graphene flakes with giant shape anisotropy are extensively used to establish connectedness electrical percolation in various heterogeneous systems. However, the percolation behaviour of graphene flakes has been recently predicted to be far more complicated than generally anticipated on the basis of excluded volume arguments. Here we confirm experimentally that graphene flakes self-assemble into nematic liquid crystals below the onset of percolation. The competition of percolation and liquid crystal transition provides a new route towards high-k materials. Indeed, near-percolated liquid-crystalline graphene-based composites display unprecedented dielectric properties with a dielectric constant improved by 260-fold increase as compared with the polymer matrix, while maintaining the loss tangent as low as 0.4. This performance is shown to depend on the structure of monodomains of graphene liquid-crystalline phases. Insights into how the liquid crystal phase transition interferes with percolation transition and thus alters the dielectric constant are discussed.

  5. Lead zirconate titanate on base metal foils: An approach for embedded high-K passive components

    SciTech Connect

    Maria, J.-P.; Cheek, K.; Streiffer, S. K.; Kim, S.-H.; Dunn, G.; Kingon, A. I.

    2000-01-26

    An approach for embedding high-K dielectric thin films into polymer packages has been developed. Pb{sub 0.85}La{sub 0.15}(Zr{sub 0.52}Ti{sub 0.48}){sub 0.96}O{sub 3} thin films were prepared by chemical solution deposition on 50 {micro}m thick Ni-coated Cu foils. Sputter deposited Ni top electrodes completed the all base-metal capacitor stack. After high temperature N{sub 2} crystallization anneals, the PLZT composition showed reduction resistance while the base-metal foils remained flexible. Capacitance density and Loss tangent values range between 300 and 400 nF/cm{sup 2} and 0.01 and 0.02 from 1 to 1,000 kHz respectively. These properties represent a 2 to 3 order of magnitude improvement over available embedded capacitor technologies for polymeric packages.

  6. Demonstration of hetero-gate-dielectric tunneling field-effect transistors (HG TFETs)

    NASA Astrophysics Data System (ADS)

    Choi, Woo Young; Lee, Hyun Kook

    2016-06-01

    The steady scaling-down of semiconductor device for improving performance has been the most important issue among researchers. Recently, as low-power consumption becomes one of the most important requirements, there have been many researches about novel devices for low-power consumption. Though scaling supply voltage is the most effective way for low-power consumption, performance degradation is occurred for metal-oxide-semiconductor field-effect transistors (MOSFETs) when supply voltage is reduced because subthreshold swing (SS) of MOSFETs cannot be lower than 60 mV/dec. Thus, in this thesis, hetero-gate-dielectric tunneling field-effect transistors (HG TFETs) are investigated as one of the most promising alternatives to MOSFETs. By replacing source-side gate insulator with a high- k material, HG TFETs show higher on-current, suppressed ambipolar current and lower SS than conventional TFETs. Device design optimization through simulation was performed and fabrication based on simulation demonstrated that performance of HG TFETs were better than that of conventional TFETs. Especially, enlargement of gate insulator thickness while etching gate insulator at the source side was improved by introducing HF vapor etch process. In addition, the proposed HG TFETs showed higher performance than our previous results by changing structure of sidewall spacer by high- k etching process.

  7. Impact of post metal annealing on gate work function engineering for advanced MOS applications

    NASA Astrophysics Data System (ADS)

    Kumar, S. Sachin; Prasad, Amitesh; Sinha, Amrita; Raut, Pratikhya; Das, Palash; Mahato, S. S.; Mallik, S.

    2016-05-01

    Ultra thin HfO2 high-k gate dielectric has been deposited directly on strained Si0.81Ge0.19 by Atomic Layer Deposition (ALD) technique. The influence of different types of metal gate electrodes (Al, Au, Pt) on electrical characteristics of Metal-Oxide-Semiconductor capacitors has been studied. Our results show that the electrical characteristics of MOS device are highly dependent on the gate electrodes used. The dependency of electrical characteristics on post metal annealing was studied in detail. The measured flat band (Vfb) and hysteresis (ΔVfb) from high frequency C-V characteristics were used to study the pre-existing traps in the dielectric. Impact of PMA on interface state density (Dit), border trap density (Nbt) and oxide trap density (Qf/q) of high-k gate stack were also examined for all the devices. The Nbt and frequency dispersion significantly reduces to ~2.77x1010 cm-2 and ~11.34 % respectively in case of Al electrode with a Dit value of ~4x1012 eV-1cm-2 after PMA (350°C) in N2, suggesting an improvement in device performance while Pt electrode shows a much less value of ΔVfb (~0.02 V) and Dit (~3.44x1012 eV-1cm-2) after PMA.

  8. Ruthenium based metals using atomic vapor deposition for gate electrode applications

    NASA Astrophysics Data System (ADS)

    Choi, Changhwan; Ando, Takashi; Narayanan, Vijay

    2011-02-01

    The impacts of ruthenium-based metal gate electrodes (Ru,RuOx,RuSiOx) with atomic vapor deposition (AVD) on flatband voltage (VFB) and equivalent oxide thickness (EOT) are demonstrated using a low temperature (<400 °C) process. Increasing thickness of Ru and RuOx exhibits higher VFB, attributed to filling oxygen vacancies [Vo] in high-k gate dielectric with oxygen supplied from AVD metal gate electrodes upon annealing. Ru is efficient to attain a higher work-function and thinner EOT compared to RuOx and RuSiOx. Subsequent physical-vapor-deposition (PVD) TiN capping on AVD metals blocks oxygen out-diffusion, leading to higher VFB than PVD W or AVD TiN capping.

  9. Defectivity control of aluminum chemical mechanical planarization in replacement metal gate process of MOSFET

    NASA Astrophysics Data System (ADS)

    Jin, Zhang; Yuling, Liu; Chenqi, Yan; Yangang, He; Baohong, Gao

    2016-04-01

    The replacement metal gate (RMG) defectivity performance control is very challenging in high-k metal gate (HKMG) chemical mechanical polishing (CMP). In this study, three major defect types, including fall-on particles, micro-scratch and corrosion have been investigated. The research studied the effects of polishing pad, pressure, rotating speed, flow rate and post-CMP cleaning on the three kinds of defect, which finally eliminated the defects and achieved good surface morphology. This study will provide an important reference value for the future research of aluminum metal gate CMP. Project supported by the Major National Science and Technology Special Projects (No. 2009ZX02308), the Natural Science Foundation for the Youth of Hebei Province (Nos. F2012202094, F2015202267), and the Outstanding Youth Science and Technology Innovation Fund of Hebei University of Technology (No. 2013010).

  10. Investigation of the analysis parameters and background subtraction for high-k materials with atom probe tomography.

    PubMed

    Mutas, S; Klein, C; Gerstl, S S A

    2011-05-01

    In this paper we present depth profiles of a high-k layer consisting of HfO(2) with an embedded sub-nm thick ZrO(2) layer obtained with atom probe tomography (APT). In order to determine suitable measurement parameters for reliable, reproducible, and quantitative analysis, we have investigated the influence of the laser energy and the specimen temperature on the resulting elemental composition. In addition we devise a procedure for local background subtraction both for the composition and the depth scale that is crucial for gaining reproducible results. We find that the composition of the high-k material remains unaffected even for extreme laser energies and base temperatures, while higher laser energies lead to an accumulation of silicon at the upper interface of the high-k layer. Furthermore we show that APT is capable of providing sub-nm depth resolution for high-k materials with high reproducibility, good compositional accuracy, and high measurement yield.

  11. The Meaning of High K2O Volcanism In the U.S. Cordillera

    NASA Astrophysics Data System (ADS)

    Putirka, K. D.; Busby, C.

    2010-12-01

    K2O contents provide a highly effective discriminant between volcanic rocks erupted in the Cascades and Basin-and Range-provinces, with Cascades volcanics having lower K2O contents at a given SiO2. To differentiate these suites, we use a K-index, where K-index = K2Oobserved - 0.12[SiO2] + 5.1 (oxides in wt. %). In the Sierra Nevada, regional K2O contents are not controlled by wall-rock assimilation. In addition, none are candidates for K-metasomatism, and none are likely to be derived by partial melting of a K-metasomatized source. As to the latter issue, even volcanic rocks with the highest K2O in the Sierra Nevada have K2O/Na2O <5, and most such ratios are <3. In contrast, K-metasomatized rocks have K2O/Na2O >5, and as high as 30-40 (Brooks and Snee (1996). Also, Sierra-wide K2O variations are not connected to indices of subduction-related mantle enrichments (such as La/Nb, Ba/Nb or Sr/P2O5), and so K2O is unconnected to regional variations in source composition. K2O contents are instead controlled by the degree of partial melting (F) in the mantle source and fractional crystallization. Putirka and Busby (2007) show that maximum K2O in the Sierra increases with increasing crust thickness, and this relationship also holds across the U.S. the Cordillera (at 39oN latitude). This relationship implies that low F magmas more easily transit thick, low-density upper crust (Putirka and Busby, 2007), which is a consequence of the fact that low F melts are enriched not just in K2O, but also in H2O, which greatly lowers magma density (Ochs and Lange, 1999). This model can explain the contrast in Cascade and Basin-and-Range K2O contents: the modern Cascades are built on the thinner crust of accreted terranes, while typical Basin-and-Range volcanics are erupted on older, and thicker, cratonized crust. Mean crust density, however, cannot be the only explanation of high K2O. In the central Sierra Nevada, the Colorado River Extensional Corridor, and at the Lunar Crater

  12. A simulation-based proposed high-k heterostructure AlGaAs/Si junctionless n-type tunnel FET

    NASA Astrophysics Data System (ADS)

    Balmukund Rahi, Shiromani; Ghosh, Bahniman; Asthana, Pranav

    2014-11-01

    We propose a heterostructure junctionless tunnel field effect transistor (HJL-TFET) using AlGaAs/Si. In the proposed HJL-TFET, low band gap silicon is used in the source side and higher band gap AlGaAs in the drain side. The whole AlGaAs/Si region is heavily doped n-type. The proposed HJL-TFET uses two isolated gates (named gate, gate1) with two different work functions (gate = 4.2 eV, gate1 = 5.2 eV respectively). The 2-D nature of HJL-TFET current flow is studied. The proposed structure is simulated in Silvaco with different gate dielectric materials. This structure exhibits a high on current in the range of 1.4 × 10-6 A/μm, the off current remains as low as 9.1 × 10-14 A/μm. So ION/IOFF ratio of ≃ 108 is achieved. Point subthreshold swing has also been reduced to a value of ≃ 41 mV/decade for TiO2 gate material.

  13. 49 CFR 234.223 - Gate arm.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Gate arm. 234.223 Section 234.223 Transportation... SYSTEMS Maintenance, Inspection, and Testing Maintenance Standards § 234.223 Gate arm. Each gate arm, when... maintained in a condition sufficient to be clearly viewed by approaching highway users. Each gate arm...

  14. Reversible logic gates on Physarum Polycephalum

    SciTech Connect

    Schumann, Andrew

    2015-03-10

    In this paper, we consider possibilities how to implement asynchronous sequential logic gates and quantum-style reversible logic gates on Physarum polycephalum motions. We show that in asynchronous sequential logic gates we can erase information because of uncertainty in the direction of plasmodium propagation. Therefore quantum-style reversible logic gates are more preferable for designing logic circuits on Physarum polycephalum.

  15. Perpendicular magnetic anisotropy in thin ferromagnetic films adjacent to high-k oxides

    NASA Astrophysics Data System (ADS)

    Xu, Meng; Bi, Chong; Rosales, Marcus; Newhouse-Illige, Ty; Almasi, Hamid; Wang, Weigang

    2015-03-01

    Perpendicular magnetic anisotropy (PMA) in thin ferromagnetic films has attracted a great deal of attention due to interesting physics and promising application in spintronic devices. The strength of PMA is often found to be strongly influenced by the adjacent heavy metal layer and oxide layer. A strong interest has emerged recently to control the PMA of these ultra-thin films by electric fields. Here we report the fabrication and characterization of perpendicularly magnetized 3d transitional metal films next to high-k oxides such as HfO2 and ZrO2. We have investigated structural, magnetic and transport properties of these films. The PMA strongly depends on the thickness of the ferromagnetic layers and the interfacial oxidation level of the bilayers. We will also discuss electric field controlled magnetic properties in these systems. This work was supported in part by NSF (ECCS-1310338) and by C-SPIN, one of six centers of STARnet, a Semiconductor Research Corporation program, sponsored by MARCO and DARPA.

  16. High-k Dielectric Passivation: Novel Considerations Enabling Cell Specific Lysis Induced by Electric Fields.

    PubMed

    Wassermann, Klemens J; Barth, Sven; Keplinger, Franz; Noehammer, Christa; Peham, Johannes R

    2016-08-24

    A better understanding of the electrodynamic behavior of cells interacting with electric fields would allow for novel scientific insights and would lead to the next generation of cell manipulation, diagnostics, and treatment. Here, we introduce a promising electrode design by using metal oxide high-k dielectric passivation. The thermally generated dielectric passivation layer enables efficient electric field coupling to the fluid sample comprising cells while simultaneously decoupling the electrode ohmically from the electrolyte, allowing for better control and adjustability of electric field effects due to reduced electrochemical reactions at the electrode surface. This approach demonstrates cell-size specific lysis with electric fields in a microfluidic flow-through design resulting in 99.8% blood cell lysis at 6 s exposure without affecting the viability of Gram-positive and Gram-negative bacterial spike-ins. The advantages of this new approach can support next-generation investigations of electrodynamics in biological systems and their exploitation for cell manipulation in multiple fields of medicine, life science, and industry. PMID:27466697

  17. Identification of yrast high-K intrinsic states in {sup 188}Os

    SciTech Connect

    Modamio, V.; Jungclaus, A.; Podolyak, Zs.; Shi, Y.; Xu, F. R.; Algora, A.; Escrig, D.; Fraile, L. M.; Marginean, N.; Martinez, T.; Napoli, D. R.; Schwengner, R.; Ur, C. A.

    2009-02-15

    The high-spin structure of the Z=76 nucleus {sup 188}Os has been studied using the incomplete fusion reaction {sup 7}Li+{sup 186}W. A K{sup {pi}}=10{sup +} band has been established up to spin (24{sup +}) and its crossing with the ground-state band has been studied. In addition, intrinsic high-K states have been identified and on top of two of them, K{sup {pi}}=7{sup -} and K{sup {pi}}=10{sup -}, regular bands have been observed. The K{sup {pi}}=16{sup +} and K{sup {pi}}=18{sup +} states are yrast whereas the K{sup {pi}}=14{sup +} level lies only 33 keV above the yrast line and decays with a low reduced hindrance of f{sub {nu}}<1.3 to the ground-state band ({delta}K=14). The results are discussed by means of a systematic comparison with the even-even neighboring nucleus {sup 186}Os. Configuration-constrained multiquasiparticle potential-energy-surface calculations have been performed to identify the configurations of multiquasiparticle states.

  18. Psychometrics and life history strategy: the structure and validity of the High K Strategy Scale.

    PubMed

    Copping, Lee T; Campbell, Anne; Muncer, Steven

    2014-03-22

    In this paper, we critically review the conceptualization and implementation of psychological measures of life history strategy associated with Differential K theory. The High K Strategy Scale (HKSS: Giosan, 2006) was distributed to a large British sample (n = 809) with the aim of assessing its factor structure and construct validity in relation to theoretically relevant life history variables: age of puberty, age of first sexual encounter, and number of sexual partners. Exploratory and confirmatory factor analyses indicated that the HKSS in its current form did not show an adequate statistical fit to the data. Modifications to improve fit indicated four correlated factors (personal capital, environmental stability, environmental security, and social capital). Later puberty in women was positively associated with measures of the environment and personal capital. Among men, contrary to Differential K predictions but in line with female mate preferences, earlier sexual debut and more sexual partners were positively associated with more favorable environments and higher personal and social capital. We raise concerns about the use of psychometric indicators of lifestyle and personality as proxies for life history strategy when they have not been validated against objective measures derived from contemporary life history theory and when their status as causes, mediators, or correlates has not been investigated.

  19. The Gates, 1979-2005

    ERIC Educational Resources Information Center

    School Arts: The Art Education Magazine for Teachers, 2005

    2005-01-01

    One art critic called it pure Despite the mixed reviews of Christo and Jeanne-Claude's temporary art installation in New York's Central Park, the public reaction to The Gates was largely positive.The Gates consisted of 7,500 orange PVC frames straddling the park's walkways that varied in widths from 5 1/2 feet to 18 feet. Eight-foot-long ripstop…

  20. Input states for quantum gates

    SciTech Connect

    Gilchrist, A.; White, A.G.; Munro, W.J.

    2003-04-01

    We examine three possible implementations of nondeterministic linear optical controlled NOT gates with a view to an in-principle demonstration in the near future. To this end we consider demonstrating the gates using currently available sources, such as spontaneous parametric down conversion and coherent states, and current detectors only able to distinguish between zero and many photons. The demonstration is possible in the coincidence basis and the errors introduced by the nonoptimal input states and detectors are analyzed.

  1. Quantum gates with topological phases

    SciTech Connect

    Ionicioiu, Radu

    2003-09-01

    We investigate two models for performing topological quantum gates with the Aharonov-Bohm (AB) and Aharonov-Casher (AC) effects. Topological one- and two-qubit Abelian phases can be enacted with the AB effect using charge qubits, whereas the AC effect can be used to perform all single-qubit gates (Abelian and non-Abelian) for spin qubits. Possible experimental setups suitable for a solid-state implementation are briefly discussed.

  2. Latest design of gate valves

    SciTech Connect

    Kurzhofer, U.; Stolte, J.; Weyand, M.

    1996-12-01

    Babcock Sempell, one of the most important valve manufacturers in Europe, has delivered valves for the nuclear power industry since the beginning of the peaceful application of nuclear power in the 1960s. The latest innovation by Babcock Sempell is a gate valve that meets all recent technical requirements of the nuclear power technology. At the moment in the United States, Germany, Sweden, and many other countries, motor-operated gate and globe valves are judged very critically. Besides the absolute control of the so-called {open_quotes}trip failure,{close_quotes} the integrity of all valve parts submitted to operational forces must be maintained. In case of failure of the limit and torque switches, all valve designs have been tested with respect to the quality of guidance of the gate. The guidances (i.e., guides) shall avoid a tilting of the gate during the closing procedure. The gate valve newly designed by Babcock Sempell fulfills all these characteristic criteria. In addition, the valve has cobalt-free seat hardfacing, the suitability of which has been proven by friction tests as well as full-scale blowdown tests at the GAP of Siemens in Karlstein, West Germany. Babcock Sempell was to deliver more than 30 gate valves of this type for 5 Swedish nuclear power stations by autumn 1995. In the presentation, the author will report on the testing performed, qualifications, and sizing criteria which led to the new technical design.

  3. Charge-plasma based dual-material and gate-stacked architecture of junctionless transistor for enhanced analog performance

    NASA Astrophysics Data System (ADS)

    Amin, S. Intekhab; Sarin, R. K.

    2015-12-01

    Charge plasma based doping-less dual material double gate (DL-DMDG) junctionless transistor (JLT) is proposed. This paper also demonstrate the potential impact of gate stacking (GS) (high-k + Sio2) on DL-DMDG (DL-GSDMDG) JLT device. The efficient charge plasma is created in an intrinsic silicon film to form n + source/drain (S/D) by selecting proper work function of S/D electrode which helps to minimize threshold voltage fluctuation that occurs in a heavily doped JLT device. The analog performance parameters are analyzed for both the device structures. Results are also compared with conventional dual material double gate (DMDG) and gate stacked dual material double gate (GSDMDG) JLT devices. A DL-DMDG JLT device shows improved early voltage (VEA), intrinsic gain (AV = gm/gDS) and reduced output conductance (gDS) as compared to conventional DMDG and GSDMDG JLT devices. These values are further improved for DL-GSDMDG JLT. The effect of control gate length (L1) for a fixed gate length (L = L1+L2) are also analyzed.

  4. Low Na, High K Diet and the Role of Aldosterone in BK-Mediated K Excretion

    PubMed Central

    Cornelius, Ryan J.; Wen, Donghai; Li, Huaqing; Yuan, Yang; Wang-France, Jun; Warner, Paige C.; Sansom, Steven C.

    2015-01-01

    A low Na, high K diet (LNaHK) is associated with a low rate of cardiovascular (CV) disease in many societies. Part of the benefit of LNaHK relies on its diuretic effects; however, the role of aldosterone (aldo) in the diuresis is not understood. LNaHK mice exhibit an increase in renal K secretion that is dependent on the large, Ca-activated K channel, (BK-α with accessory BK-β4; BK-α/β4). We hypothesized that aldo causes an osmotic diuresis by increasing BK-α/β4-mediated K secretion in LNaHK mice. We found that the plasma aldo concentration (P[aldo]) was elevated by 10-fold in LNaHK mice compared with control diet (Con) mice. We subjected LNaHK mice to either sham surgery (sham), adrenalectomy (ADX) with low aldo replacement (ADX-LA), or ADX with high aldo replacement (ADX-HA). Compared to sham, the urinary flow, K excretion rate, transtubular K gradient (TTKG), and BK-α and BK-β4 expressions, were decreased in ADX-LA, but not different in ADX-HA. BK-β4 knockout (β4KO) and WT mice exhibited similar K clearance and TTKG in the ADX-LA groups; however, in sham and ADX-HA, the K clearance and TTKG of β4KO were less than WT. In response to amiloride treatment, the osmolar clearance was increased in WT Con, decreased in WT LNaHK, and unchanged in β4KO LNaHK. These data show that the high P[aldo] of LNaHK mice is necessary to generate a high rate of BK-α/β4-mediated K secretion, which creates an osmotic diuresis that may contribute to a reduction in CV disease. PMID:25607984

  5. Goosenest Volcano, southern Oregon: High K[sub 2]O, BA and Sr basaltic andesite extrusives

    SciTech Connect

    Mertzman, S.A. . Dept. of Geosciences)

    1992-01-01

    Goosenest Volcano, a cinder cone with coeval lava flows, is located nearly 5 miles WNW of the south entrance into Crater Lake National Park. A summit crater unmodified by glacial erosion but with a blanket of Mazama pumice, suggests the age of latest activity to be between 20,000 and 6850 B.P. The pyroclastics and lavas from Goosenest are augite olivine basaltic andesites, with a strong tendency for these minerals to form 2--5 mm in diameter glomeroporphyritic clumps [+-] plagioclase. Three samples from the cone (2 bombs and 1 spatter agglutinate) and five from lava flows were analyzed for major and trace elements through XRF and ICP techniques. These extrusive are calc-alkaline medium to high K[sub 2]O basaltic andesites; in particular, SiO[sub 2] ranges from 53 to 54 wt. %, K[sub 2]O from 1.39 to 1.94, MgO from 6.3 to 7.3, Ba from 774 to 1,069 ppm and Sr from 1,463 to 1,951 ppm. With increasing K[sub 2]O: P[sub 2]O[sub 5], Ba, Be, Ce, La, Sr, and Zr increase in concentration while Ni, Cr, and Co decrease. All major elements are virtually constant or scatter randomly; Y,V,Sc, and Yb follow the same pattern. The lower Al[sub 2]O[sub 3] content (16 to 17 wt.%) precludes the addition of a large plagioclase component as an explanation of the high Sr content. Batch partial melting of a mineralogically homogeneous source that has been fluxed by variable amounts of an LILE-rich fluid phase whose ultimate origin is tied to the subduction process, is a likely scheme which explains the unusual chemical composition of the Gossenest extrusive rocks.

  6. Quantum gate-set tomography

    NASA Astrophysics Data System (ADS)

    Blume-Kohout, Robin

    2014-03-01

    Quantum information technology is built on (1) physical qubits and (2) precise, accurate quantum logic gates that transform their states. Developing quantum logic gates requires good characterization - both in the development phase, where we need to identify a device's flaws so as to fix them, and in the production phase, where we need to make sure that the device works within specs and predict residual error rates and types. This task falls to quantum state and process tomography. But until recently, protocols for tomography relied on a pre-existing and perfectly calibrated reference frame comprising the measurements (and, for process tomography, input states) used to characterize the device. In practice, these measurements are neither independent nor perfectly known - they are usually implemented via exactly the same gates that we are trying to characterize! In the past year, several partial solutions to this self-consistency problem have been proposed. I will present a framework (gate set tomography, or GST) that addresses and resolves this problem, by self-consistently characterizing an entire set of quantum logic gates on a black-box quantum device. In particular, it contains an explicit closed-form protocol for linear-inversion gate set tomography (LGST), which is immune to both calibration error and technical pathologies like local maxima of the likelihood (which plagued earlier methods). GST also demonstrates significant (multiple orders of magnitude) improvements in efficiency over standard tomography by using data derived from long sequences of gates (much like randomized benchmarking). GST has now been applied to qubit devices in multiple technologies. I will present and discuss results of GST experiments in technologies including a single trapped-ion qubit and a silicon quantum dot qubit. Sandia National Laboratories is a multiprogram laboratory operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U

  7. Quantum gates by periodic driving

    PubMed Central

    Shi, Z. C.; Wang, W.; Yi, X. X.

    2016-01-01

    Topological quantum computation has been extensively studied in the past decades due to its robustness against decoherence. One way to realize the topological quantum computation is by adiabatic evolutions—it requires relatively long time to complete a gate, so the speed of quantum computation slows down. In this work, we present a method to realize single qubit quantum gates by periodic driving. Compared to adiabatic evolution, the single qubit gates can be realized at a fixed time much shorter than that by adiabatic evolution. The driving fields can be sinusoidal or square-well field. With the sinusoidal driving field, we derive an expression for the total operation time in the high-frequency limit, and an exact analytical expression for the evolution operator without any approximations is given for the square well driving. This study suggests that the period driving could provide us with a new direction in regulations of the operation time in topological quantum computation. PMID:26911900

  8. Impact of starting measurement voltage relative to flat-band voltage position on the capacitance-voltage hysteresis and on the defect characterization of InGaAs/high-k metal-oxide-semiconductor stacks

    NASA Astrophysics Data System (ADS)

    Vais, Abhitosh; Franco, Jacopo; Lin, Han-Chung; Collaert, Nadine; Mocuta, Anda; De Meyer, Kristin; Thean, Aaron

    2015-11-01

    In this work, we discuss how the position of the flat band voltage with respect to the starting voltage of the C-V measurement sweep can influence the estimation of the hysteresis in high-k/InGaAs MOS devices. We show that, with the support of experimental data and conceptual oxide defect band calculations, the interpretation and subsequent parameter extraction from flat-band voltage shifts observed in III-V MOS devices is more complex as compared to Si gate stacks. It is demonstrated that such complication arises due to the wider distribution of defect levels in the dielectric band gap in the case of InGaAs/high-k stack as compared to standard Si/SiO2/HfO2 MOS. In particular, for Al2O3 deposited on InGaAs, two wide, partially overlapping oxide defect bands are identified, centered ˜1.5 eV and ˜0.5 eV above and below the channel conduction band, respectively. Such defect levels are expected to affect the device operation and reliability.

  9. Time delays in gated radiotherapy.

    PubMed

    Smith, Wendy L; Becker, Nathan

    2009-07-28

    In gated radiotherapy, the accuracy of treatment delivery is determined by the accuracy with which both the imaging and treatment beams are gated. If the time delays (the time between the target entering/leaving the gated region and the first/last image acquired or treatment beam on/off) for the imaging and treatment systems are in the opposite directions, they may increase the required internal target volume (ITV) margin, above that indicated by the tolerance for either system measured individually. We measured a gating system's time delay on 3 fluoroscopy systems, and 3 linear accelerator treatment beams, using a motion phantom of known geometry, varying gating type (amplitude vs. phase), beam energy, dose rate, and period. The average beam on imaging time delays were -0.04 +/- 0.05 s (amplitude, 1 SD), -0.11 +/- 0.04 s (phase); while the average beam off imaging time delays were -0.18 +/- 0.08 s (amplitude) and -0.15 +/- 0.04 s (phase). The average beam on treatment time delays were 0.09 +/- 0.02 s (amplitude, 1 SD), 0.10 +/- 0.03 s (phase); while the average beam off time delays for treatment beams were 0.08 +/- 0.02 s (amplitude) and 0.07 +/- 0.02 s (phase). The negative value indicates the images were acquired early, and the positive values show the treatment beam was triggered late. We present a technique for calculating the margin necessary to account for time delays and found that the difference between the imaging and treatment time delays required a significant increase in the ITV margin in the direction of tumor motion at the gated level.

  10. Localizing a gate in CFTR.

    PubMed

    Gao, Xiaolong; Hwang, Tzyh-Chang

    2015-02-24

    Experimental and computational studies have painted a picture of the chloride permeation pathway in cystic fibrosis transmembrane conductance regulator (CFTR) as a short narrow tunnel flanked by wider inner and outer vestibules. Although these studies also identified a number of transmembrane segments (TMs) as pore-lining, the exact location of CFTR's gate(s) remains unknown. Here, using a channel-permeant probe, [Au(CN)2](-), we provide evidence that CFTR bears a gate that coincides with the predicted narrow section of the pore defined as residues 338-341 in TM6. Specifically, cysteines introduced cytoplasmic to the narrow region (i.e., positions 344 in TM6 and 1148 in TM12) can be modified by intracellular [Au(CN)2](-) in both open and closed states, corroborating the conclusion that the internal vestibule does not harbor a gate. However, cysteines engineered to positions external to the presumed narrow region (e.g., 334, 335, and 337 in TM6) are all nonreactive toward cytoplasmic [Au(CN)2](-) in the absence of ATP, whereas they can be better accessed by extracellular [Au(CN)2](-) when the open probability is markedly reduced by introducing a second mutation, G1349D. As [Au(CN)2](-) and chloride ions share the same permeation pathway, these results imply a gate is situated between amino acid residues 337 and 344 along TM6, encompassing the very segment that may also serve as the selectivity filter for CFTR. The unique position of a gate in the middle of the ion translocation pathway diverges from those seen in ATP-binding cassette (ABC) transporters and thus distinguishes CFTR from other members of the ABC transporter family. PMID:25675504

  11. Trapped ion scaling with pulsed fast gates

    NASA Astrophysics Data System (ADS)

    Bentley, C. D. B.; Carvalho, A. R. R.; Hope, J. J.

    2015-10-01

    Fast entangling gates for trapped ion pairs offer vastly improved gate operation times relative to implemented gates, as well as approaches to trap scaling. Gates on a neighbouring ion pair only involve local ions when performed sufficiently fast, and we find that even a fast gate between a pair of distant ions with few degrees of freedom restores all the motional modes given more stringent gate speed conditions. We compare pulsed fast gate schemes, defined by a timescale faster than the trap period, and find that our proposed scheme has less stringent requirements on laser repetition rate for achieving arbitrary gate time targets and infidelities well below 10-4. By extending gate schemes to ion crystals, we explore the effect of ion number on gate fidelity for coupling two neighbouring ions in large crystals. Inter-ion distance determines the gate time, and a factor of five increase in repetition rate, or correspondingly the laser power, reduces the infidelity by almost two orders of magnitude. We also apply our fast gate scheme to entangle the first and last ions in a crystal. As the number of ions in the crystal increases, significant increases in the laser power are required to provide the short gate times corresponding to fidelity above 0.99.

  12. Effect of Thermal Budget on the Electrical Characterization of Atomic Layer Deposited HfSiO/TiN Gate Stack MOSCAP Structure

    PubMed Central

    Khan, Z. N.; Ahmed, S.; Ali, M.

    2016-01-01

    Metal Oxide Semiconductor (MOS) capacitors (MOSCAP) have been instrumental in making CMOS nano-electronics realized for back-to-back technology nodes. High-k gate stacks including the desirable metal gate processing and its integration into CMOS technology remain an active research area projecting the solution to address the requirements of technology roadmaps. Screening, selection and deposition of high-k gate dielectrics, post-deposition thermal processing, choice of metal gate structure and its post-metal deposition annealing are important parameters to optimize the process and possibly address the energy efficiency of CMOS electronics at nano scales. Atomic layer deposition technique is used throughout this work because of its known deposition kinetics resulting in excellent electrical properties and conformal structure of the device. The dynamics of annealing greatly influence the electrical properties of the gate stack and consequently the reliability of the process as well as manufacturable device. Again, the choice of the annealing technique (migration of thermal flux into the layer), time-temperature cycle and sequence are key parameters influencing the device’s output characteristics. This work presents a careful selection of annealing process parameters to provide sufficient thermal budget to Si MOSCAP with atomic layer deposited HfSiO high-k gate dielectric and TiN gate metal. The post-process annealing temperatures in the range of 600°C -1000°C with rapid dwell time provide a better trade-off between the desirable performance of Capacitance-Voltage hysteresis and the leakage current. The defect dynamics is thought to be responsible for the evolution of electrical characteristics in this Si MOSCAP structure specifically designed to tune the trade-off at low frequency for device application. PMID:27571412

  13. Effect of Thermal Budget on the Electrical Characterization of Atomic Layer Deposited HfSiO/TiN Gate Stack MOSCAP Structure.

    PubMed

    Khan, Z N; Ahmed, S; Ali, M

    2016-01-01

    Metal Oxide Semiconductor (MOS) capacitors (MOSCAP) have been instrumental in making CMOS nano-electronics realized for back-to-back technology nodes. High-k gate stacks including the desirable metal gate processing and its integration into CMOS technology remain an active research area projecting the solution to address the requirements of technology roadmaps. Screening, selection and deposition of high-k gate dielectrics, post-deposition thermal processing, choice of metal gate structure and its post-metal deposition annealing are important parameters to optimize the process and possibly address the energy efficiency of CMOS electronics at nano scales. Atomic layer deposition technique is used throughout this work because of its known deposition kinetics resulting in excellent electrical properties and conformal structure of the device. The dynamics of annealing greatly influence the electrical properties of the gate stack and consequently the reliability of the process as well as manufacturable device. Again, the choice of the annealing technique (migration of thermal flux into the layer), time-temperature cycle and sequence are key parameters influencing the device's output characteristics. This work presents a careful selection of annealing process parameters to provide sufficient thermal budget to Si MOSCAP with atomic layer deposited HfSiO high-k gate dielectric and TiN gate metal. The post-process annealing temperatures in the range of 600°C -1000°C with rapid dwell time provide a better trade-off between the desirable performance of Capacitance-Voltage hysteresis and the leakage current. The defect dynamics is thought to be responsible for the evolution of electrical characteristics in this Si MOSCAP structure specifically designed to tune the trade-off at low frequency for device application.

  14. Effect of Thermal Budget on the Electrical Characterization of Atomic Layer Deposited HfSiO/TiN Gate Stack MOSCAP Structure.

    PubMed

    Khan, Z N; Ahmed, S; Ali, M

    2016-01-01

    Metal Oxide Semiconductor (MOS) capacitors (MOSCAP) have been instrumental in making CMOS nano-electronics realized for back-to-back technology nodes. High-k gate stacks including the desirable metal gate processing and its integration into CMOS technology remain an active research area projecting the solution to address the requirements of technology roadmaps. Screening, selection and deposition of high-k gate dielectrics, post-deposition thermal processing, choice of metal gate structure and its post-metal deposition annealing are important parameters to optimize the process and possibly address the energy efficiency of CMOS electronics at nano scales. Atomic layer deposition technique is used throughout this work because of its known deposition kinetics resulting in excellent electrical properties and conformal structure of the device. The dynamics of annealing greatly influence the electrical properties of the gate stack and consequently the reliability of the process as well as manufacturable device. Again, the choice of the annealing technique (migration of thermal flux into the layer), time-temperature cycle and sequence are key parameters influencing the device's output characteristics. This work presents a careful selection of annealing process parameters to provide sufficient thermal budget to Si MOSCAP with atomic layer deposited HfSiO high-k gate dielectric and TiN gate metal. The post-process annealing temperatures in the range of 600°C -1000°C with rapid dwell time provide a better trade-off between the desirable performance of Capacitance-Voltage hysteresis and the leakage current. The defect dynamics is thought to be responsible for the evolution of electrical characteristics in this Si MOSCAP structure specifically designed to tune the trade-off at low frequency for device application. PMID:27571412

  15. Gated compressor, distortionless signal limiter

    NASA Technical Reports Server (NTRS)

    Woodbury, R. C. (Inventor)

    1974-01-01

    A distortionless gated compressor for limiting the amplitude of a signal so as not to produce undesired signal levels responsive thereto is disclosed. The gated compressor includes a distortionless multiplier which multiplies an AC signal from a factor defined by a DC control signal. The compressor includes a plurality of channels each responsive to a signal produced in response to the multiplier's output. When the signal supplied to any channel exceeds a prescribed level, the level of the DC control signal is reduced to reduce the multiplier's output level and thereby prevent the signal applied to any channel from exceeding its prescribed level.

  16. HELLS GATE ROADLESS AREA, ARIZONA.

    USGS Publications Warehouse

    Conway, Clay M.; McColly, Robert A.

    1984-01-01

    Although no mineral-resource potential was identified in the Hells Gate Roadless Area during mineral surveys, the area is largely underlain by a regionally extensive Proterozoic granite-rhyolite complex which is tin-bearing. The geologic setting precludes the occurrence of fossil fuel resources and no other energy resources were identified. The potential for tin and associated metals in the Hells Gate Roadless Area and the region cannot be fully evaluated at this point. The granophyre and the upper part of the granite pluton along the northwestern margin of the area should be explored.

  17. Dual gated nuclear cardiac images

    SciTech Connect

    Zubal, I.G.; Bennett, G.W.; Bizais, Y.; Brill, A.B.

    1984-02-01

    A data acquisition system has been developed to collect camera events simultaneously with continually digitized electrocardiograph signals and respiratory flow measurements. Software processing of the list mode data creates more precisely gated cardiac frames. Additionally, motion blur due to heart movement during breathing is reduced by selecting events within a specific respiratory phase. Thallium myocardium images of a healthy volunteer show increased definition. This technique of combined cardiac and respiratory gating has the potential of improving the detectability of small lesions, and the characterization of cardiac wall motion.

  18. Reduced carbonic fluid and possible nature of high K magmas of Kamchatka.

    NASA Astrophysics Data System (ADS)

    Simakin, Alexander; Zelensky, Michael; Salova, Tamara

    2014-05-01

    High potassium magmatism in Kamchatka is usually interpreted as reflection of the small degree mantle melting in back arc environment. Strong eruption of Tolbachik volcano located in typical subduction magmatism setting and lasted for several months in 2012-2013 argues against such interpretation. Erupted basaltic magmas contain up to 2.5-3.5 wt.% of K2O. They bear all attributes of high-K magmas such as high Ba (600 ppm) and Zr (250 ppm) contents [Volynets et al., 2013]. Moreover recent [Ponamareva et al., 2013] estimates of the volume of the compositionally similar early Holocene pyroclastics from located nearby Plosky volcano give significant value of ca 10 km3. Syneruptive probing of the fluid on Tolbachik [Zelensky, in preparation] yields high CO2 and SO2content and reveals micro-inclusions of elemental carbon and native alloys of Ni-Fe, Pt and Pt-Ag. These observations stay for the intrinsic reduced carbon-bearing nature of this fluid. We suggest that nature of the fluid plays decisive role in the potassium magma specialization. New experimental data on the melting with reduced carbon bearing fluid supports this suggestion. Experiments have been performed in IHPV at P=2-5 kbar and T=900-1000oC. Initial content of CO in the dry CO2-CO mixture was about 14 wt.%, maximum final water content of H2O in the final fluid was about 13 wt.%. At dehydration melting through CO2-CO fluid transport of the spilitized basaltic andesite we get melt with up to 330 ppm of ZrO2 and 9 wt.% of K2O (source rock contains only 1 wt.% K2O). With oxidized carbonic fluid normal sodium bearing melt was produced. Carbon enrichment of the mantle fluid can be explained as follows. Current geodynamic regime and volcanism in Kamchatka are affected by geologically recent accretion of Kronotsky paleoarc approximately 5 Myrs ago (northern part). In the new geodynamic model [Simakin, 2013] at the certain rheologic parameters accreted terrains are overstepped by subduction zone with temporary

  19. Dynamic gating window for compensation of baseline shift in respiratory-gated radiation therapy

    SciTech Connect

    Pepin, Eric W.; Wu Huanmei; Shirato, Hiroki

    2011-04-15

    Purpose: To analyze and evaluate the necessity and use of dynamic gating techniques for compensation of baseline shift during respiratory-gated radiation therapy of lung tumors. Methods: Motion tracking data from 30 lung tumors over 592 treatment fractions were analyzed for baseline shift. The finite state model (FSM) was used to identify the end-of-exhale (EOE) breathing phase throughout each treatment fraction. Using duty cycle as an evaluation metric, several methods of end-of-exhale dynamic gating were compared: An a posteriori ideal gating window, a predictive trend-line-based gating window, and a predictive weighted point-based gating window. These methods were evaluated for each of several gating window types: Superior/inferior (SI) gating, anterior/posterior beam, lateral beam, and 3D gating. Results: In the absence of dynamic gating techniques, SI gating gave a 39.6% duty cycle. The ideal SI gating window yielded a 41.5% duty cycle. The weight-based method of dynamic SI gating yielded a duty cycle of 36.2%. The trend-line-based method yielded a duty cycle of 34.0%. Conclusions: Dynamic gating was not broadly beneficial due to a breakdown of the FSM's ability to identify the EOE phase. When the EOE phase was well defined, dynamic gating showed an improvement over static-window gating.

  20. Impact of Asymmetric Dual-k Spacer in the Underlap Regions of Sub 20 nm NMOSFET with Gate Stack

    NASA Astrophysics Data System (ADS)

    Chakraborty, Shramana; Dasgupta, Arpan; Das, Rahul; Kundu, Atanu; Sarkar, Chandan K.

    2016-10-01

    This paper shows the systematic study of underlap double gate (U-DG) NMOSFETs with Gate Stack (GS) under the influence of dual-k spacers at the different underlap regions. In highly scaled devices, underlap is used at the Source and Drain side so as to reduce the short channel effects (SCE's) but at the cost of low on current (ION) and increased channel resistance. The high-k spacers are used to counter this problem. The ION is improved but at the cost of highly enhanced parasitic capacitances. This paper explores the possibility of using asymmetric dual-k spacer at the source underlap side so as to counter the shortcomings of high-k spacers in highly scaled devices on the basis of analog parameters: ION, gm, gm/ID, and intrinsic gain, gmRo and RF performance in terms of parasitic gate capacitance (Cgs, Cgd and Cgg),gate to source/drain resistances (Rgs and Rgd), transport delay (τm), the unity current gain cut-off frequency (fT) and the maximum frequency of oscillation (fmax). A single stage amplifier performance is also analyzed where it has been seen that the asymmetric dual-k spacer at the source underlap side gives better performance as compared to the other devices under comparison.

  1. High k dielectrics on silicon: Effects of processing on nanostructure and properties

    NASA Astrophysics Data System (ADS)

    Das, Anirban

    High permittivity hafnia, HfO2, and hafnium silicate, HfSiO 4, are the most promising candidates to replace oxide (SiOx) or oxynitride (SiOxNy) based gate dielectrics in future generation CMOS devices. In this thesis, the effects of processing (deposition techniques, post deposition annealing, nitridation) on nanostructure evolution (crystallization, phase segregation, interlayer growth), changes in nanochemistry (impurity content, interfacial reaction, interdiffusion, oxygen diffusion, paramagnetic charge centers) and properties (EOT, oxide charges) of atomic layer deposited (ALD) Hf-O/Hf-Si-O films on Si, with different interlayers (IL), were studied. A variety of analytical techniques including XRD, RBS, XPS, SIMS, AFM, HRTEM, STEM-EELS and EPR were used. In general, PEALD Hf-O films deposited using metal-organic precursors showed a higher C and H and lower Cl content compared to thermal ALD films using halide based precursors. Also, as-deposited ALD films (Hf-O/IL/Si) showed the formation of Hf-O-Si bonds at the Hf-O/IL interface, with increasing tendency in the presence of a chemical oxide interlayer and upon oxygen annealing. Upon post deposition annealing (PDA) of ALD Hf-O films up to 1000°C, m-HfO2 was the stable crystalline phase. It was observed that the chemical oxide interlayer grew significantly during PDA in oxygen, the rate of which was a f (t, T) due to oxygen diffusion. Additionally, an annealed Hf-O stack (i.e., target Hf-O thickness of 4.0 nm/1.2 nm nitrided chemical oxide interlayer/Si) showed a chemically diffused HfSiOx region (2 nm) in between pure HfO2 (2 nm) and the interlayer (1.2 nm) as a result of interdiffusion and interfacial reactions. Therefore, a three-layer capacitor model was used to determine the respective contributions to the total EOT. Moreover, to correlate the presence of defects with density of interfacial states, as-deposited ALD Hf-O/chemical oxide IL/Si stacks were shown to be EPR active at 8K, due to Pb0, Pb1 type

  2. P-channel silicone gate FET

    NASA Technical Reports Server (NTRS)

    Ostis, S.; Woo, D. S.

    1973-01-01

    Modified fabrication technique for P-channel MOSFET devices eliminates problems involving gate placement and gate overlap. Technique provides self-aligned gate, eliminating complexity of mask aligning. Devices produced by this process are considerably faster than conventional MOSFET's and process increases yield.

  3. Double-disc gate valve

    DOEpatents

    Wheatley, Seth J.

    1979-01-01

    This invention relates to an improvement in a conventional double-disc gate valve having a vertically movable gate assembly including a wedge, spreaders slidably engaged therewtih, a valve disc carried by the spreaders. When the gate assembly is lowered to a selected point in the valve casing, the valve discs are moved transversely outward to close inlet and outlet ports in the casing. The valve includes hold-down means for guiding the disc-and-spreader assemblies as they are moved transversely outward and inward. If such valves are operated at relatively high differential pressures, they sometimes jam during opening. Such jamming has been a problem for many years in gate valves used in gaseous diffusion plants for the separtion of uranium isotopes. The invention is based on the finding that the above-mentioned jamming results when the outlet disc tilts about its horizontal axis in a certain way during opening of the valve. In accordance with the invention, tilting of the outlet disc is maintained at a tolerable value by providing the disc with a rigid downwardly extending member and by providing the casing with a stop for limiting inward arcuate movement of the member to a preselected value during opening of the valve.

  4. Bill Gates eyes healthcare market.

    PubMed

    Dunbar, C

    1995-02-01

    The entrepreneurial spirit is still top in Bill Gates' mind as he look toward healthcare and other growth industries. Microsoft's CEO has not intention of going the way of other large technology companies that became obsolete before they could compete today.

  5. Developing ICALL Tools Using GATE

    ERIC Educational Resources Information Center

    Wood, Peter

    2008-01-01

    This article discusses the use of the General Architecture for Text Engineering (GATE) as a tool for the development of ICALL and NLP applications. It outlines a paradigm shift in software development, which is mainly influenced by projects such as the Free Software Foundation. It looks at standards that have been proposed to facilitate the…

  6. Poly(methyl methacrylate) as a self-assembled gate dielectric for graphene field-effect transistors

    SciTech Connect

    Sanne, A.; Movva, H. C. P.; Kang, S.; McClellan, C.; Corbet, C. M.; Banerjee, S. K.

    2014-02-24

    We investigate poly(methyl methacrylate) (PMMA) as a low thermal budget organic gate dielectric for graphene field effect-transistors (GFETs) based on a simple process flow. We show that high temperature baking steps above the glass transition temperature (∼130 °C) can leave a self-assembled, thin PMMA film on graphene, where we get a gate dielectric almost for “free” without additional atomic layer deposition type steps. Electrical characterization of GFETs with PMMA as a gate dielectric yields a dielectric constant of k = 3.0. GFETs with thinner PMMA dielectrics have a lower dielectric constant due to decreased polarization arising from neutralization of dipoles and charged carriers as baking temperatures increase. The leakage through PMMA gate dielectric increases with decreasing dielectric thickness and increasing electric field. Unlike conventional high-k gate dielectrics, such low-k organic gate dielectrics are potentially attractive for devices such as the proposed Bilayer pseudoSpin Field-Effect Transistor or flexible high speed graphene electronics.

  7. Resonant gate driver with efficient gate energy recovery and switching loss reduction

    NASA Astrophysics Data System (ADS)

    Kim, I.-G.; Kwak, S.-S.

    2016-04-01

    This article describes a novel resonant gate driver for charging the gate capacitor of power metal-oxide semiconductor field-effect-transistors (MOSFETs) that operate at a high switching frequency in power converters. The proposed resonant gate driver is designed with three small MOSFETs to build up the inductor current in addition to an inductor for temporary energy storage. The proposed resonant gate driver recovers the CV2 gate loss, which is the largest loss dissipated in the gate resistance in conventional gate drivers. In addition, the switching loss is reduced at the instants of turn on and turn off in the power MOSFETs of power converters by using the proposed gate driver. Mathematical analyses of the total loss appearing in the gate driver circuit and the switching loss reduction in the power switch of power converters are discussed. Finally, the proposed resonant gate driver is verified with experimental results at a switching frequency of 1 MHz.

  8. Environmental noise reduction for holonomic quantum gates

    SciTech Connect

    Parodi, Daniele; Zanghi, Nino; Sassetti, Maura; Solinas, Paolo

    2007-07-15

    We study the performance of holonomic quantum gates, driven by lasers, under the effect of a dissipative environment modeled as a thermal bath of oscillators. We show how to enhance the performance of the gates by a suitable choice of the loop in the manifold of the controllable parameters of the laser. For a simplified, albeit realistic model, we find the surprising result that for a long time evolution the performance of the gate (properly estimated in terms of average fidelity) increases. On the basis of this result, we compare holonomic gates with the so-called stimulated raman adiabatic passage (STIRAP) gates.

  9. Integration of atomic layer deposited high-k dielectrics on GaSb via hydrogen plasma exposure

    NASA Astrophysics Data System (ADS)

    Ruppalt, Laura B.; Cleveland, Erin R.; Champlain, James G.; Bennett, Brian R.; Prokes, Sharka M.

    2014-12-01

    In this letter we report the efficacy of a hydrogen plasma pretreatment for integrating atomic layer deposited (ALD) high-k dielectric stacks with device-quality p-type GaSb(001) epitaxial layers. Molecular beam eptiaxy-grown GaSb surfaces were subjected to a 30 minute H2/Ar plasma treatment and subsequently removed to air. High-k HfO2 and Al2O3/HfO2 bilayer insulating films were then deposited via ALD and samples were processed into standard metal-oxide-semiconductor (MOS) capacitors. The quality of the semiconductor/dielectric interface was probed by current-voltage and variable-frequency admittance measurements. Measurement results indicate that the H2-plamsa pretreatment leads to a low density of interface states nearly independent of the deposited dielectric material, suggesting that pre-deposition H2-plasma exposure, coupled with ALD of high-k dielectrics, may provide an effective means for achieving high-quality GaSb MOS structures for advanced Sb-based digital and analog electronics.

  10. Integration of atomic layer deposited high-k dielectrics on GaSb via hydrogen plasma exposure

    SciTech Connect

    Ruppalt, Laura B. Cleveland, Erin R.; Champlain, James G.; Bennett, Brian R.; Prokes, Sharka M.

    2014-12-15

    In this letter we report the efficacy of a hydrogen plasma pretreatment for integrating atomic layer deposited (ALD) high-k dielectric stacks with device-quality p-type GaSb(001) epitaxial layers. Molecular beam eptiaxy-grown GaSb surfaces were subjected to a 30 minute H{sub 2}/Ar plasma treatment and subsequently removed to air. High-k HfO{sub 2} and Al{sub 2}O{sub 3}/HfO{sub 2} bilayer insulating films were then deposited via ALD and samples were processed into standard metal-oxide-semiconductor (MOS) capacitors. The quality of the semiconductor/dielectric interface was probed by current-voltage and variable-frequency admittance measurements. Measurement results indicate that the H{sub 2}-plamsa pretreatment leads to a low density of interface states nearly independent of the deposited dielectric material, suggesting that pre-deposition H{sub 2}-plasma exposure, coupled with ALD of high-k dielectrics, may provide an effective means for achieving high-quality GaSb MOS structures for advanced Sb-based digital and analog electronics.

  11. Dipole correlation effects on the local field and the effective dielectric constant in composite dielectrics containing high-k inclusions.

    PubMed

    Allahyarov, Elshad; Löwen, Hartmut; Zhu, Lei

    2016-07-28

    Mixing dielectric polymers with high permittivity (high-k) inclusions can affect their electrical properties. In actuation applications of dielectric elastomers, the polarized inclusions generate additional volume polarization-related electrostriction. In energy storage applications, it is possible to store more energy in dielectric composites because of additional polarization of the inclusions and interfaces. However, mixing an electroactive polymer with high-k inclusions also brings several disadvantages. The expulsion of the field from the interior of high-k fillers and the presence of two poles on the filler surface along the applied field direction result in higher local fields EL near the inclusion poles. The resulting field enhancement lowers the breakdown field (Eb) threshold for the material and therefore compromises the actuation and energy storage capabilities of dielectric composites. To mitigate this issue, the dependence of EL on the morphology of inclusion distribution, the field localization effect in chained configurations, and the role of the dipole-dipole correlation effects in the enhancement of the dipolar field of inclusions are analyzed. We show that the dipolar correlation effects are strong in large inclusion composites and their contribution to the inclusion dipole moment μ and to the local fields EL can reach 30-50%. A new method for deriving the composite permittivity from the field EL distribution, based on a caged probe technique, is also presented. PMID:27357433

  12. On the interest of carbon-coated plasma reactor for advanced gate stack etching processes

    SciTech Connect

    Ramos, R.; Cunge, G.; Joubert, O.

    2007-03-15

    In integrated circuit fabrication the most wide spread strategy to achieve acceptable wafer-to-wafer reproducibility of the gate stack etching process is to dry-clean the plasma reactor walls between each wafer processed. However, inherent exposure of the reactor walls to fluorine-based plasma leads to formation and accumulation of nonvolatile fluoride residues (such as AlF{sub x}) on reactor wall surfaces, which in turn leads to process drifts and metallic contamination of wafers. To prevent this while keeping an Al{sub 2}O{sub 3} reactor wall material, a coating strategy must be used, in which the reactor is coated by a protective layer between wafers. It was shown recently that deposition of carbon-rich coating on the reactor walls allows improvements of process reproducibility and reactor wall protection. The authors show that this strategy results in a higher ion-to-neutral flux ratio to the wafer when compared to other strategies (clean or SiOCl{sub x}-coated reactors) because the carbon walls load reactive radical densities while keeping the same ion current. As a result, the etching rates are generally smaller in a carbon-coated reactor, but a highly anisotropic etching profile can be achieved in silicon and metal gates, whose etching is strongly ion assisted. Furthermore, thanks to the low density of Cl atoms in the carbon-coated reactor, silicon etching can be achieved almost without sidewall passivation layers, allowing fine critical dimension control to be achieved. In addition, it is shown that although the O atom density is also smaller in the carbon-coated reactor, the selectivity toward ultrathin gate oxides is not reduced dramatically. Furthermore, during metal gate etching over high-k dielectric, the low level of parasitic oxygen in the carbon-coated reactor also allows one to minimize bulk silicon reoxidation through HfO{sub 2} high-k gate dielectric. It is then shown that the BCl{sub 3} etching process of the HfO{sub 2} high-k material is highly

  13. SEMICONDUCTOR TECHNOLOGY: TaN wet etch for application in dual-metal-gate integration technology

    NASA Astrophysics Data System (ADS)

    Yongliang, Li; Qiuxia, Xu

    2009-12-01

    Wet-etch etchants and the TaN film method for dual-metal-gate integration are investigated. Both HF/HN O3/H2O and NH4OH/H2O2 solutions can etch TaN effectively, but poor selectivity to the gate dielectric for the HF/HNO3/H2O solution due to HF being included in HF/HNO3/H2O, and the fact that TaN is difficult to etch in the NH4OH/H2O2 solution at the first stage due to the thin TaOxNy layer on the TaN surface, mean that they are difficult to individually apply to dual-metal-gate integration. A two-step wet etching strategy using the HF/HNO3/H2O solution first and the NH4OH/H2O2 solution later can fully remove thin TaN film with a photo-resist mask and has high selectivity to the HfSiON dielectric film underneath. High-k dielectric film surfaces are smooth after wet etching of the TaN metal gate and MOSCAPs show well-behaved C-V and Jg-Vg characteristics, which all prove that the wet etching of TaN has little impact on electrical performance and can be applied to dual-metal-gate integration technology for removing the first TaN metal gate in the PMOS region.

  14. Microscale Digital Vacuum Electronic Gates

    NASA Technical Reports Server (NTRS)

    Manohara, Harish (Inventor); Mojarradi, Mohammed M. (Inventor)

    2014-01-01

    Systems and methods in accordance with embodiments of the invention implement microscale digital vacuum electronic gates. In one embodiment, a microscale digital vacuum electronic gate includes: a microscale field emitter that can emit electrons and that is a microscale cathode; and a microscale anode; where the microscale field emitter and the microscale anode are disposed within at least a partial vacuum; where the microscale field emitter and the microscale anode are separated by a gap; and where the potential difference between the microscale field emitter and the microscale anode is controllable such that the flow of electrons between the microscale field emitter and the microscale anode is thereby controllable; where when the microscale anode receives a flow of electrons, a first logic state is defined; and where when the microscale anode does not receive a flow of electrons, a second logic state is defined.

  15. Voltage-Gated Hydrophobic Nanopores

    SciTech Connect

    Lavrik, Nickolay V

    2011-01-01

    Hydrophobicity is a fundamental property that is responsible for numerous physical and biophysical aspects of molecular interactions in water. Peculiar behavior is expected for water in the vicinity of hydrophobic structures, such as nanopores. Indeed, hydrophobic nanopores can be found in two distinct states, dry and wet, even though the latter is thermodynamically unstable. Transitions between these two states are kinetically hindered in long pores but can be much faster in shorter pores. As it is demonstrated for the first time in this paper, these transitions can be induced by applying a voltage across a membrane with a single hydrophobic nanopore. Such voltage-induced gating in single nanopores can be realized in a reversible manner through electrowetting of inner walls of the nanopores. The resulting I-V curves of such artificial hydrophobic nanopores mimic biological voltage-gated channels.

  16. Gated high speed optical detector

    NASA Technical Reports Server (NTRS)

    Green, S. I.; Carson, L. M.; Neal, G. W.

    1973-01-01

    The design, fabrication, and test of two gated, high speed optical detectors for use in high speed digital laser communication links are discussed. The optical detectors used a dynamic crossed field photomultiplier and electronics including dc bias and RF drive circuits, automatic remote synchronization circuits, automatic gain control circuits, and threshold detection circuits. The equipment is used to detect binary encoded signals from a mode locked neodynium laser.

  17. Voltage-gated Proton Channels

    PubMed Central

    DeCoursey, Thomas E.

    2014-01-01

    Voltage-gated proton channels, HV1, have vaulted from the realm of the esoteric into the forefront of a central question facing ion channel biophysicists, namely the mechanism by which voltage-dependent gating occurs. This transformation is the result of several factors. Identification of the gene in 2006 revealed that proton channels are homologues of the voltage-sensing domain of most other voltage-gated ion channels. Unique, or at least eccentric, properties of proton channels include dimeric architecture with dual conduction pathways, perfect proton selectivity, a single-channel conductance ~103 smaller than most ion channels, voltage-dependent gating that is strongly modulated by the pH gradient, ΔpH, and potent inhibition by Zn2+ (in many species) but an absence of other potent inhibitors. The recent identification of HV1 in three unicellular marine plankton species has dramatically expanded the phylogenetic family tree. Interest in proton channels in their own right has increased as important physiological roles have been identified in many cells. Proton channels trigger the bioluminescent flash of dinoflagellates, facilitate calcification by coccolithophores, regulate pH-dependent processes in eggs and sperm during fertilization, secrete acid to control the pH of airway fluids, facilitate histamine secretion by basophils, and play a signaling role in facilitating B-cell receptor mediated responses in B lymphocytes. The most elaborate and best-established functions occur in phagocytes, where proton channels optimize the activity of NADPH oxidase, an important producer of reactive oxygen species. Proton efflux mediated by HV1 balances the charge translocated across the membrane by electrons through NADPH oxidase, minimizes changes in cytoplasmic and phagosomal pH, limits osmotic swelling of the phagosome, and provides substrate H+ for the production of H2O2 and HOCl, reactive oxygen species crucial to killing pathogens. PMID:23798303

  18. Voltage-gated proton channels.

    PubMed

    Decoursey, Thomas E

    2012-04-01

    Voltage-gated proton channels, HV1, have vaulted from the realm of the esoteric into the forefront of a central question facing ion channel biophysicists, namely, the mechanism by which voltage-dependent gating occurs. This transformation is the result of several factors. Identification of the gene in 2006 revealed that proton channels are homologues of the voltage-sensing domain of most other voltage-gated ion channels. Unique, or at least eccentric, properties of proton channels include dimeric architecture with dual conduction pathways, perfect proton selectivity, a single-channel conductance approximately 10(3) times smaller than most ion channels, voltage-dependent gating that is strongly modulated by the pH gradient, ΔpH, and potent inhibition by Zn(2+) (in many species) but an absence of other potent inhibitors. The recent identification of HV1 in three unicellular marine plankton species has dramatically expanded the phylogenetic family tree. Interest in proton channels in their own right has increased as important physiological roles have been identified in many cells. Proton channels trigger the bioluminescent flash of dinoflagellates, facilitate calcification by coccolithophores, regulate pH-dependent processes in eggs and sperm during fertilization, secrete acid to control the pH of airway fluids, facilitate histamine secretion by basophils, and play a signaling role in facilitating B-cell receptor mediated responses in B-lymphocytes. The most elaborate and best-established functions occur in phagocytes, where proton channels optimize the activity of NADPH oxidase, an important producer of reactive oxygen species. Proton efflux mediated by HV1 balances the charge translocated across the membrane by electrons through NADPH oxidase, minimizes changes in cytoplasmic and phagosomal pH, limits osmotic swelling of the phagosome, and provides substrate H(+) for the production of H2O2 and HOCl, reactive oxygen species crucial to killing pathogens.

  19. Modes of glutamate receptor gating

    PubMed Central

    Popescu, Gabriela K

    2012-01-01

    Abstract The time course of excitatory synaptic currents, the major means of fast communication between neurons of the central nervous system, is encoded in the dynamic behaviour of post-synaptic glutamate-activated channels. First-pass attempts to explain the glutamate-elicited currents with mathematical models produced reaction mechanisms that included only the most basic functionally defined states: resting vs. liganded, closed vs. open, responsive vs. desensitized. In contrast, single-molecule observations afforded by the patch-clamp technique revealed an unanticipated kinetic multiplicity of transitions: from microseconds-lasting flickers to minutes-long modes. How these kinetically defined events impact the shape of the synaptic response, how they relate to rearrangements in receptor structure, and whether and how they are physiologically controlled represent currently active research directions. Modal gating, which refers to the slowest, least frequently observed ion-channel transitions, has been demonstrated for representatives of all ion channel families. However, reaction schemes have been largely confined to the short- and medium-range time scales. For glutamate receptors as well, modal gating has only recently come under rigorous scrutiny. This article reviews the evidence for modal gating of glutamate receptors and the still developing hypotheses about the mechanism(s) by which modal shifts occur and the ways in which they may impact the time course of synaptic transmission. PMID:22106181

  20. Atom-ion quantum gate

    SciTech Connect

    Doerk, Hauke; Idziaszek, Zbigniew; Calarco, Tommaso

    2010-01-15

    Ultracold collisions of ions with neutral atoms in traps are studied. Recently, ultracold atom-ion systems have become available in experimental setups, where their quantum states can be coherently controlled. This control allows for an implementation of quantum information processing, combining the advantages of charged and neutral particles. The state-dependent dynamics that is a necessary ingredient for quantum computation schemes is provided in this case by the short-range interaction forces that depend on the hyperfine states of both particles. In this work, a theoretical description of spin-state-dependent trapped atom-ion collisions is developed in the framework of a multichannel quantum-defect theory and an effective single-channel model is formulated that reduces the complexity of the problem. Based on this description, a two-qubit phase gate between a {sup 135}Ba{sup +} ion and a {sup 87}Rb atom is simulated using a realistic combination of the singlet and triplet scattering lengths. The gate process is optimized and accelerated with the help of optimal control techniques. The result is a gate fidelity of 1-10{sup -3} within 350 mus.

  1. Monolithic transistor gate energy recovery system

    NASA Technical Reports Server (NTRS)

    Rippel, Wally E. (Inventor)

    1989-01-01

    Energy is recovered from an insulated gate semiconductor switch, such as a MOSFET, that is otherwise lost in the gate capacitance by producing a notch in the gate control voltage for an interval B following an interval A after initial application of a gate control voltage pulse for turning the switch on, and a notch for an interval C following termination of the gate control voltage pulse followed by interval D during which the switch is turned on again, where each interval is a period .DELTA.T given by ##EQU1## L.sub.s is the inductance (discrete and/or parasitic) in series with the gate electrode of the insulated gate semiconductor switch, and C.sub.in is the capacitance of that switch between its gate and source electrodes. The interval .DELTA.T may be provided directly by timing in a pulse forming circuit for the gate control voltage applied, or adaptively by sensing the gate voltage v.sub.g and comparing it with fixed progressively higher voltages v.sub.1, v.sub.2 and v.sub.3, where v.sub.2 is intermediate v.sub.1 and v.sub.3 which correspond to the lower and upper levels of v.sub.g as the switch is turned off and on.

  2. High-k ZrO2/Al2O3 bilayer on hydrogenated diamond: Band configuration, breakdown field, and electrical properties of field-effect transistors

    NASA Astrophysics Data System (ADS)

    Liu, J. W.; Liao, M. Y.; Imura, M.; Koide, Y.

    2016-09-01

    A band configuration of a high-k ZrO2/Al2O3 bilayer on hydrogenated diamond (H-diamond), a breakdown field (EB) of the ZrO2/Al2O3 bilayer, and an effect of gate-drain distance (dG-D) on electrical properties of ZrO2/Al2O3/H-diamond metal-insulator-semiconductor field-effect transistors (MISFETs) have been investigated. The Al2O3 and ZrO2 layers are successively deposited on H-diamond by atomic layer deposition (ALD) and sputtering-deposition (SD) techniques, respectively. The thin ALD-Al2O3 buffer layer with 4.0 nm thickness plays a role in protecting the H-diamond surface from being damaged by the plasma discharge during SD-ZrO2 deposition. The ZrO2/Al2O3 heterojunction has a type I band structure with valence and conduction band offsets of 0.6 ± 0.2 and 1.0 ± 0.2 eV, respectively. The valence band offset between ZrO2 and H-diamond is deduced to be 2.3 ± 0.2 eV. The EB of the ZrO2/Al2O3 bilayer is measured to be 5.2 MV cm-1, which is larger than that of the single ZrO2 layer due to the existence of the ALD-Al2O3 buffer layer. The dependence of dG-D on drain-source current maximum (IDS,max), on-resistance (RON), threshold voltage (VTH), and extrinsic transconductance maximum (gm,max) of the MISFETs has been investigated. With increasing dG-D from 4 to 18 μm, the absolute IDS,max decreases from 72.7 to 40.1 mA mm-1, and the RON increases linearly from 83.3 ± 5 to 158.7 ± 5 Ω mm. Variation of VTH values of around 1.0 V is observed, and the gm,max is in the range between 8.0 ± 0.1 and 13.1 ± 0.1 mS mm-1.

  3. Cognitive mechanisms associated with auditory sensory gating

    PubMed Central

    Jones, L.A.; Hills, P.J.; Dick, K.M.; Jones, S.P.; Bright, P.

    2016-01-01

    Sensory gating is a neurophysiological measure of inhibition that is characterised by a reduction in the P50 event-related potential to a repeated identical stimulus. The objective of this work was to determine the cognitive mechanisms that relate to the neurological phenomenon of auditory sensory gating. Sixty participants underwent a battery of 10 cognitive tasks, including qualitatively different measures of attentional inhibition, working memory, and fluid intelligence. Participants additionally completed a paired-stimulus paradigm as a measure of auditory sensory gating. A correlational analysis revealed that several tasks correlated significantly with sensory gating. However once fluid intelligence and working memory were accounted for, only a measure of latent inhibition and accuracy scores on the continuous performance task showed significant sensitivity to sensory gating. We conclude that sensory gating reflects the identification of goal-irrelevant information at the encoding (input) stage and the subsequent ability to selectively attend to goal-relevant information based on that previous identification. PMID:26716891

  4. Contact gating at GHz frequency in graphene

    PubMed Central

    Wilmart, Q.; Inhofer, A.; Boukhicha, M.; Yang, W.; Rosticher, M.; Morfin, P.; Garroum, N.; Fève, G.; Berroir, J.-M.; Plaçais, B.

    2016-01-01

    The paradigm of graphene transistors is based on the gate modulation of the channel carrier density by means of a local channel gate. This standard architecture is subject to the scaling limit of the channel length and further restrictions due to access and contact resistances impeding the device performance. We propose a novel design, overcoming these issues by implementing additional local gates underneath the contact region which allow a full control of the Klein barrier taking place at the contact edge. In particular, our work demonstrates the GHz operation of transistors driven by independent contact gates. We benchmark the standard channel and novel contact gating and report for the later dynamical transconductance levels at the state of the art. Our finding may find applications in electronics and optoelectronics whenever there is need to control independently the Fermi level and the electrostatic potential of electronic sources or to get rid of cumbersome local channel gates. PMID:26879709

  5. Contact gating at GHz frequency in graphene

    NASA Astrophysics Data System (ADS)

    Wilmart, Q.; Inhofer, A.; Boukhicha, M.; Yang, W.; Rosticher, M.; Morfin, P.; Garroum, N.; Fève, G.; Berroir, J.-M.; Plaçais, B.

    2016-02-01

    The paradigm of graphene transistors is based on the gate modulation of the channel carrier density by means of a local channel gate. This standard architecture is subject to the scaling limit of the channel length and further restrictions due to access and contact resistances impeding the device performance. We propose a novel design, overcoming these issues by implementing additional local gates underneath the contact region which allow a full control of the Klein barrier taking place at the contact edge. In particular, our work demonstrates the GHz operation of transistors driven by independent contact gates. We benchmark the standard channel and novel contact gating and report for the later dynamical transconductance levels at the state of the art. Our finding may find applications in electronics and optoelectronics whenever there is need to control independently the Fermi level and the electrostatic potential of electronic sources or to get rid of cumbersome local channel gates.

  6. Gating current "fractionation" in crayfish giant axons.

    PubMed Central

    Starkus, J G; Rayner, M D

    1991-01-01

    Effects of changes in initial conditions on the magnitude and kinetics of gating current and sodium current were studied in voltage-clamped, internally-perfused, crayfish giant axons. We examined the effects of changes in holding potential, inactivating prepulses, and recovery from inactivation in axons with intact fast inactivation. We also studied the effects of brief interpulse intervals in axons pretreated with chloramine-T for removal of fast inactivation. We find marked effects of gating current kinetics induced by both prepulse inactivation and brief interpulse intervals. The apparent changes in gating current relaxation rates cannot be explained simply by changes in gating charge magnitude (charge immobilization) combined with "Cole-Moore-type" time shifts. Rather they appear to indicate selective suppression of kinetically-identifiable components within the control gating currents. Our results provide additional support for a model involving parallel, nonidentical, gating particles. PMID:1760505

  7. Direct transitions from high-K isomers to low-K bands -- {gamma} softness or coriolis coupling

    SciTech Connect

    Shimizu, Yoshifumi R.; Narimatsu, Kanako; Ohtsubo, Shin-Ichi

    1996-12-31

    Recent measurements of direct transitions from high-K isomers to low-K bands reveal severe break-down of the K-selection rule and pose the problem of how to understand the mechanism of such K-violation. The authors recent systematic calculations by using a simple {gamma}-tunneling model reproduced many of the observed hindrances, indicating the importance of the {gamma} softness. However, there are some data which cannot be explained in terms of the {gamma}-degree of freedom. In this talk, the authors also discuss the results of conventional Coriolis coupling calculations, which is considered to be another important mechanism.

  8. Interface Engineering for Atomic Layer Deposited Alumina Gate Dielectric on SiGe Substrates.

    PubMed

    Zhang, Liangliang; Guo, Yuzheng; Hassan, Vinayak Vishwanath; Tang, Kechao; Foad, Majeed A; Woicik, Joseph C; Pianetta, Piero; Robertson, John; McIntyre, Paul C

    2016-07-27

    Optimization of the interface between high-k dielectrics and SiGe substrates is a challenging topic due to the complexity arising from the coexistence of Si and Ge interfacial oxides. Defective high-k/SiGe interfaces limit future applications of SiGe as a channel material for electronic devices. In this paper, we identify the surface layer structure of as-received SiGe and Al2O3/SiGe structures based on soft and hard X-ray photoelectron spectroscopy. As-received SiGe substrates have native SiOx/GeOx surface layers, where the GeOx-rich layer is beneath a SiOx-rich surface. Silicon oxide regrows on the SiGe surface during Al2O3 atomic layer deposition, and both SiOx and GeOx regrow during forming gas anneal in the presence of a Pt gate metal. The resulting mixed SiOx-GeOx interface layer causes large interface trap densities (Dit) due to distorted Ge-O bonds across the interface. In contrast, we observe that oxygen-scavenging Al top gates decompose the underlying SiOx/GeOx, in a selective fashion, leaving an ultrathin SiOx interfacial layer that exhibits dramatically reduced Dit. PMID:27345195

  9. Efficient construction of three- and four-qubit quantum gates by global entangling gates

    NASA Astrophysics Data System (ADS)

    Ivanov, Svetoslav S.; Ivanov, Peter A.; Vitanov, Nikolay V.

    2015-03-01

    We present improved circuits for the Toffoli gate and the control-swap (Fredkin) gate using three and four global two-qubit gates, respectively. This is a nearly double speedup compared to the conventional circuits, which require five (for Toffoli) and seven (for Fredkin) local two-qubit gates. We apply the same approach to construct the conditional four-qubit phase gate by seven global two-qubit gates. We also present construction of the Toffoli and Fredkin gates with five global gates in systems with nearest-neighbor interactions. Our constructions do not employ ancilla qubits or ancilla internal states and are particularly well suited for ion qubits and for circuit QED systems, where the entangling operations can be implemented by global addressing.

  10. Fabrication of the gating nanopore device

    NASA Astrophysics Data System (ADS)

    Taniguchi, Masateru; Tsutsui, Makusu; Yokota, Kazumichi; Kawai, Tomoji

    2009-09-01

    We synthesized gating nanopores with embedded nanogap electrodes in a solid-state nanopore using an 11-step nanofabrication process. We were able to detect Au nanoparticles passing through a 30-nm-diameter gating nanopore via an electric current between nanoelectrodes. The electric current was proportional to the duration of translocation time. The gating nanopore is expected to be a next-generated nanosystem that can be applied to single-molecule sensors.

  11. Approaching Defect-free Amorphous Silicon Nitride by Plasma-assisted Atomic Beam Deposition for High Performance Gate Dielectric

    NASA Astrophysics Data System (ADS)

    Tsai, Shu-Ju; Wang, Chiang-Lun; Lee, Hung-Chun; Lin, Chun-Yeh; Chen, Jhih-Wei; Shiu, Hong-Wei; Chang, Lo-Yueh; Hsueh, Han-Ting; Chen, Hung-Ying; Tsai, Jyun-Yu; Lu, Ying-Hsin; Chang, Ting-Chang; Tu, Li-Wei; Teng, Hsisheng; Chen, Yi-Chun; Chen, Chia-Hao; Wu, Chung-Lin

    2016-06-01

    In the past few decades, gate insulators with a high dielectric constant (high-k dielectric) enabling a physically thick but dielectrically thin insulating layer, have been used to replace traditional SiOx insulator and to ensure continuous downscaling of Si-based transistor technology. However, due to the non-silicon derivative natures of the high-k metal oxides, transport properties in these dielectrics are still limited by various structural defects on the hetero-interfaces and inside the dielectrics. Here, we show that another insulating silicon compound, amorphous silicon nitride (a-Si3N4), is a promising candidate of effective electrical insulator for use as a high-k dielectric. We have examined a-Si3N4 deposited using the plasma-assisted atomic beam deposition (PA-ABD) technique in an ultra-high vacuum (UHV) environment and demonstrated the absence of defect-related luminescence; it was also found that the electronic structure across the a-Si3N4/Si heterojunction approaches the intrinsic limit, which exhibits large band gap energy and valence band offset. We demonstrate that charge transport properties in the metal/a-Si3N4/Si (MNS) structures approach defect-free limits with a large breakdown field and a low leakage current. Using PA-ABD, our results suggest a general strategy to markedly improve the performance of gate dielectric using a nearly defect-free insulator.

  12. Approaching Defect-free Amorphous Silicon Nitride by Plasma-assisted Atomic Beam Deposition for High Performance Gate Dielectric

    PubMed Central

    Tsai, Shu-Ju; Wang, Chiang-Lun; Lee, Hung-Chun; Lin, Chun-Yeh; Chen, Jhih-Wei; Shiu, Hong-Wei; Chang, Lo-Yueh; Hsueh, Han-Ting; Chen, Hung-Ying; Tsai, Jyun-Yu; Lu, Ying-Hsin; Chang, Ting-Chang; Tu, Li-Wei; Teng, Hsisheng; Chen, Yi-Chun; Chen, Chia-Hao; Wu, Chung-Lin

    2016-01-01

    In the past few decades, gate insulators with a high dielectric constant (high-k dielectric) enabling a physically thick but dielectrically thin insulating layer, have been used to replace traditional SiOx insulator and to ensure continuous downscaling of Si-based transistor technology. However, due to the non-silicon derivative natures of the high-k metal oxides, transport properties in these dielectrics are still limited by various structural defects on the hetero-interfaces and inside the dielectrics. Here, we show that another insulating silicon compound, amorphous silicon nitride (a-Si3N4), is a promising candidate of effective electrical insulator for use as a high-k dielectric. We have examined a-Si3N4 deposited using the plasma-assisted atomic beam deposition (PA-ABD) technique in an ultra-high vacuum (UHV) environment and demonstrated the absence of defect-related luminescence; it was also found that the electronic structure across the a-Si3N4/Si heterojunction approaches the intrinsic limit, which exhibits large band gap energy and valence band offset. We demonstrate that charge transport properties in the metal/a-Si3N4/Si (MNS) structures approach defect-free limits with a large breakdown field and a low leakage current. Using PA-ABD, our results suggest a general strategy to markedly improve the performance of gate dielectric using a nearly defect-free insulator. PMID:27325155

  13. Approaching Defect-free Amorphous Silicon Nitride by Plasma-assisted Atomic Beam Deposition for High Performance Gate Dielectric.

    PubMed

    Tsai, Shu-Ju; Wang, Chiang-Lun; Lee, Hung-Chun; Lin, Chun-Yeh; Chen, Jhih-Wei; Shiu, Hong-Wei; Chang, Lo-Yueh; Hsueh, Han-Ting; Chen, Hung-Ying; Tsai, Jyun-Yu; Lu, Ying-Hsin; Chang, Ting-Chang; Tu, Li-Wei; Teng, Hsisheng; Chen, Yi-Chun; Chen, Chia-Hao; Wu, Chung-Lin

    2016-01-01

    In the past few decades, gate insulators with a high dielectric constant (high-k dielectric) enabling a physically thick but dielectrically thin insulating layer, have been used to replace traditional SiOx insulator and to ensure continuous downscaling of Si-based transistor technology. However, due to the non-silicon derivative natures of the high-k metal oxides, transport properties in these dielectrics are still limited by various structural defects on the hetero-interfaces and inside the dielectrics. Here, we show that another insulating silicon compound, amorphous silicon nitride (a-Si3N4), is a promising candidate of effective electrical insulator for use as a high-k dielectric. We have examined a-Si3N4 deposited using the plasma-assisted atomic beam deposition (PA-ABD) technique in an ultra-high vacuum (UHV) environment and demonstrated the absence of defect-related luminescence; it was also found that the electronic structure across the a-Si3N4/Si heterojunction approaches the intrinsic limit, which exhibits large band gap energy and valence band offset. We demonstrate that charge transport properties in the metal/a-Si3N4/Si (MNS) structures approach defect-free limits with a large breakdown field and a low leakage current. Using PA-ABD, our results suggest a general strategy to markedly improve the performance of gate dielectric using a nearly defect-free insulator. PMID:27325155

  14. Four Great Gates: Dilemmas, Directions and Distractions in Educational Research

    ERIC Educational Resources Information Center

    Delamont, Sara

    2005-01-01

    In James Elroy Flecker's poem "The Gates of Damascus", the poet imagines four exits from the safe comfortable city to the outside world. Each gate takes the traveller into a different set of temptations and dangers. The Aleppo Gate leads to trade and commerce, the Mecca Gate is for faith and pilgrimage, the Lebanon Gate is for exploration and the…

  15. Gate engineered performance of single molecular transistor

    NASA Astrophysics Data System (ADS)

    Ray, S. J.

    2016-05-01

    The operation, performance and electrostatics of multigated Single Molecular Transistor (SMT) devices are investigated using first-principles based density functional theory calculations for planar (pentacene) and non-planar (sucrose) molecules as islands. It has been found that the incorporation of larger numbers of gates allows enhanced electrostatic control in the SMT operation which has been quantified from the energy calculations and estimation of the gate capacitances. The effect of multiple gates is more dominant for a non-planar molecule than a planar molecule within an SMT which indicates the usefulness of such multi-gate architectures for future nanoelectronic devices.

  16. Entanglement and Quantum Logical Gates. Part II.

    NASA Astrophysics Data System (ADS)

    Dalla Chiara, M. L.; Leporini, R.; Sergioli, G.

    2015-12-01

    We introduce the notion of proper unitary connective-gate and we prove that entanglement cannot be characterized by such gates. We consider then a larger class of gates (called pseudo-unitary gates), which contains both the unitary and the anti-unitary quantum operations. By using a mixed language (a proper extension of the standard quantum computational language), we show how a logical characterization of entanglement is possible in the framework of a mixed semantics, which generalizes both the unitary and the pseudo-unitary quantum computational semantics.

  17. Effect of film properties for non-linear DPL model in a nanoscale MOSFET with high-k material: ZrO2/HfO2/La2O3

    NASA Astrophysics Data System (ADS)

    Shomali, Zahra; Ghazanfarian, Jafar; Abbassi, Abbas

    2015-07-01

    Numerical simulation of non-linear non-Fourier heat conduction within a nano-scale metal-oxide-semiconductor field-effect transistor (MOSFET) is presented under the framework of Dual-Phase-Lag model including the boundary phonon scattering. The MOSFET is modeled in four cases of: (I) thin silicon slab, (II) including uniform heat generation, (III) double-layered buried oxide MOSFET with uniform heat generation in silicon-dioxide layer, and (IV) high-k/metal gate transistor. First, four cases are studied under four conditions of (a) constant bulk and (b) constant film thermal properties, (c) temperature-dependent properties of bulk silicon, and (d) temperature-dependent thermal properties of film silicon. The heat source and boundary conditions are similar to what existed in a real MOSFET. It is concluded that in all cases, considering the film properties lowers the temperature jump due to the reduction of the Knudsen number. Furthermore, the speed of heat flux penetration for film properties is less than that of the cases concerning bulk properties. Also, considering the temperature-dependent properties drastically changes the temperature and heat flux distributions within the transistor, which increases the diffusion speed and more, decreases the steady state time. Calculations for case (III) presents that all previous studies have underestimated the value of the peak temperature rise by considering the constant bulk properties of silicon. Also, it is found that among the high-k dielectrics investigated in case (IV), zirconium dioxide shows the least peak temperature rise. This presents that zirconium dioxide is a good candidate as far as the thermal issues are concerned.

  18. Gated Seebeck Using Polymerized Ionic Liquid Gate Dielectrics

    NASA Astrophysics Data System (ADS)

    Thomas, Elayne; Popere, Bhooshan; Fang, Haiyu; Chabinyc, Michael; Segalman, Rachel

    Thermoelectric materials have the ability to convert a temperature gradient into usable electrical power via the Seebeck effect. This phenomenon is directly related to the material's Seebeck coefficient and electrical conductivity, which are in turn linked to its electron (or hole) mobility and carrier concentration. Organic semiconductors show promise for thermoelectric applications due to their flexibility and low-temperature manufacturing techniques; however, the role of ionized dopants on charge transport in these materials remains poorly understood. In this work, we use polymerized ionic liquids (PILs) as a gate dielectric in organic field-effect transistors to directly control the concentration of charges in the conducting channel. We report a method to tune the carrier concentration in the transistor channel via electrostatic gate modulation. We observe carrier concentration levels that are comparable to traditional doping methods with the added ability to precisely tune the concentration of charges induced. With this process, we aim to gather new information on the effect of ions on the performance of organic semiconductors in hopes of better understanding charge transport in conducting polymers on a molecular level.

  19. TiO2/GeOxNy stacked gate dielectrics for Ge-MOSFETs

    NASA Astrophysics Data System (ADS)

    Bera, M. K.; Mahata, C.; Chakraborty, A. K.; Nandi, S. K.; Tiwari, Jitendra N.; Hung, Jui-Yi; Maiti, C. K.

    2007-12-01

    In this work, we present the results of physical and electrical characterization of Ti-based high-k gate dielectrics on Ge substrates. Titanium tetrakis iso- propoxide (TTIP) was used as the organometallic source for the deposition of ultra-thin TiO2 films on p-Ge (1 0 0) at low temperature (<200 °C) by plasma enhanced chemical vapor deposition (PECVD) technique in a microwave (700 W, 2.45 GHz) plasma cavity discharge system at a pressure of ~65 Pa. The presence of an ultra-thin lossy GeO2 interfacial layer between the deposited high-k film and the substrate, results in frequency-dependent capacitance-voltage (C-V) characteristics in strong accumulation and a high interface state density (~1013 cm-2 eV-1). To improve the electrical properties, nitrogen engineering has been employed to convert the lossy GeO2 interfacial layer to its oxynitride, thus forming TiO2/GeOxNy/Ge stacked-gate structure with improved interface/electrical properties. Different N sources, such as NO, NH3 and NO/NH3, have been used for nitrogen engineering. XPS and Raman spectroscopy analyses have been used for surface morphological study. Electrical properties, such as gate leakage current density, interface state density, charge trapping, flatband voltage shift, etc, have been studied in detail for TiO2/GeOxNy/Ge MIS capacitors using the current-voltage (I-V), capacitance-voltage (C-V), conductance-voltage (G-V) and stress (both constant voltage and current) measurements. Although a significant improvement in electrical characteristics has been observed after nitridation in general, the formation of the interfacial GeOxNy layer, obtained from NO-plasma nitridation, is found to provide the maximum improvement among all the nitridation techniques used in this study. It is shown that the insertion of an ultra-thin oxynitride (GeOxNy) interfacial layer is advantageous for producing gate-quality TiO2 high-k dielectric stacks on Ge substrates.

  20. The impact of energy barrier height on border traps in the metal insulator semicondoctor gate stacks on III-V semiconductors

    NASA Astrophysics Data System (ADS)

    Yoshida, Shinichi; Taniguchi, Satoshi; Minari, Hideki; Lin, Dennis; Ivanov, Tsvetan; Watanabe, Heiji; Nakazawa, Masashi; Collaert, Nadine; Thean, Aaron

    2016-08-01

    We investigated the effect of a thin interfacial layer (IL) made of silicon or germanium between high-k dielectrics and III-V semiconductors on the frequency dispersion of the capacitance-voltage (C-V) curves in detail. We demonstrated experimentally that the frequency dispersion at accumulation voltage is strongly dependent on the energy barrier height (ΦB) between high-k dielectrics and semiconductors. It was revealed that the improvement of frequency dispersion for n-type III-V semiconductors with IL is attributed to the increase in ΦB realized by inserting Ge IL. Moreover, the border trap density did not necessarily decrease with IL through the assessment of border trap density using a distributed bulk-oxide trap model. Finally, we proved that it is important to increase ΦB to suppress the carrier exchange and improve high-k/III-V gate stack reliability.

  1. The impact of energy barrier height on border traps in the metal insulator semicondoctor gate stacks on III–V semiconductors

    NASA Astrophysics Data System (ADS)

    Yoshida, Shinichi; Taniguchi, Satoshi; Minari, Hideki; Lin, Dennis; Ivanov, Tsvetan; Watanabe, Heiji; Nakazawa, Masashi; Collaert, Nadine; Thean, Aaron

    2016-08-01

    We investigated the effect of a thin interfacial layer (IL) made of silicon or germanium between high-k dielectrics and III–V semiconductors on the frequency dispersion of the capacitance–voltage (C–V) curves in detail. We demonstrated experimentally that the frequency dispersion at accumulation voltage is strongly dependent on the energy barrier height (ΦB) between high-k dielectrics and semiconductors. It was revealed that the improvement of frequency dispersion for n-type III–V semiconductors with IL is attributed to the increase in ΦB realized by inserting Ge IL. Moreover, the border trap density did not necessarily decrease with IL through the assessment of border trap density using a distributed bulk-oxide trap model. Finally, we proved that it is important to increase ΦB to suppress the carrier exchange and improve high-k/III–V gate stack reliability.

  2. 1. VIEW NORTHWEST, GENERAL VIEW OF GATE, DRAIN CHANNEL AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. VIEW NORTHWEST, GENERAL VIEW OF GATE, DRAIN CHANNEL AND BUILDING SHELTERING GATE OPERATING MECHANISM - Norwich Water Power Company, Canal Drain Gate, West bank of Shetucket River opposite Twelfth Street, Greenville section, Norwich, New London County, CT

  3. 17. DETAIL VIEW OF TAINTER GATE, SHOWING SUBMERSIBLE (LEFT) AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    17. DETAIL VIEW OF TAINTER GATE, SHOWING SUBMERSIBLE (LEFT) AND NONSUBMERSIBLE (RIGHT) GATES, PIERS AND DAM BRIDGE, WITH ROLLER GATE HEADHOUSE IN BACKGROUND, LOOKING NORTHEAST - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 10, Guttenberg, Clayton County, IA

  4. 23. DETAIL VIEW OF SUBMERSIBLE TAINTER GATE, SHOWING TRUNNION PIN, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    23. DETAIL VIEW OF SUBMERSIBLE TAINTER GATE, SHOWING TRUNNION PIN, GATE ARM AND GATE GAUGE, LOOKING SOUTHEAST - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 10, Guttenberg, Clayton County, IA

  5. 2. DETAIL OF CONTROL GATE ADJACENT TO LIFT LOCK NO. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. DETAIL OF CONTROL GATE ADJACENT TO LIFT LOCK NO. 7; THIS CONTROL GATE IS A 1980s RECONSTRUCTION. - Illinois & Michigan Canal, Lift Lock No. 7 & Control Gate, East side of DuPage River, Channahon, Will County, IL

  6. Terahertz amplification in RTD-gated HEMTs with a grating-gate wave coupling topology

    NASA Astrophysics Data System (ADS)

    Condori Quispe, Hugo O.; Encomendero-Risco, Jimy J.; Xing, Huili Grace; Sensale-Rodriguez, Berardi

    2016-08-01

    We theoretically analyze the operation of a terahertz amplifier consisting of a resonant-tunneling-diode gated high-electron-mobility transistor (RTD-gated HEMT) in a grating-gate topology. In these devices, the key element enabling substantial power gain is the efficient coupling of terahertz waves into and out of plasmons in the RTD-gated HEMT channel, i.e., the gain medium, via the grating-gate itself, part of the active device, rather than by an external antenna structure as discussed in previous works, therefore potentially enabling terahertz amplification with associated power gains >40 dB.

  7. Transparently wrap-gated semiconductor nanowire arrays for studies of gate-controlled photoluminescence

    SciTech Connect

    Nylund, Gustav; Storm, Kristian; Torstensson, Henrik; Wallentin, Jesper; Borgström, Magnus T.; Hessman, Dan; Samuelson, Lars

    2013-12-04

    We present a technique to measure gate-controlled photoluminescence (PL) on arrays of semiconductor nanowire (NW) capacitors using a transparent film of Indium-Tin-Oxide (ITO) wrapping around the nanowires as the gate electrode. By tuning the wrap-gate voltage, it is possible to increase the PL peak intensity of an array of undoped InP NWs by more than an order of magnitude. The fine structure of the PL spectrum reveals three subpeaks whose relative peak intensities change with gate voltage. We interpret this as gate-controlled state-filling of luminescing quantum dot segments formed by zincblende stacking faults in the mainly wurtzite NW crystal structure.

  8. Protected gates for topological quantum field theories

    NASA Astrophysics Data System (ADS)

    Beverland, Michael E.; Buerschaper, Oliver; Koenig, Robert; Pastawski, Fernando; Preskill, John; Sijher, Sumit

    2016-02-01

    We study restrictions on locality-preserving unitary logical gates for topological quantum codes in two spatial dimensions. A locality-preserving operation is one which maps local operators to local operators — for example, a constant-depth quantum circuit of geometrically local gates, or evolution for a constant time governed by a geometrically local bounded-strength Hamiltonian. Locality-preserving logical gates of topological codes are intrinsically fault tolerant because spatially localized errors remain localized, and hence sufficiently dilute errors remain correctable. By invoking general properties of two-dimensional topological field theories, we find that the locality-preserving logical gates are severely limited for codes which admit non-abelian anyons, in particular, there are no locality-preserving logical gates on the torus or the sphere with M punctures if the braiding of anyons is computationally universal. Furthermore, for Ising anyons on the M-punctured sphere, locality-preserving gates must be elements of the logical Pauli group. We derive these results by relating logical gates of a topological code to automorphisms of the Verlinde algebra of the corresponding anyon model, and by requiring the logical gates to be compatible with basis changes in the logical Hilbert space arising from local F-moves and the mapping class group.

  9. Automatically closing swing gate closure assembly

    DOEpatents

    Chang, Shih-Chih; Schuck, William J.; Gilmore, Richard F.

    1988-01-01

    A swing gate closure assembly for nuclear reactor tipoff assembly wherein the swing gate is cammed open by a fuel element or spacer but is reliably closed at a desired closing rate primarily by hydraulic forces in the absence of a fuel charge.

  10. Reconstruction of dynamic gated cardiac SPECT

    SciTech Connect

    Jin Mingwu; Yang Yongyi; King, Michael A.

    2006-11-15

    In this paper we propose an image reconstruction procedure which aims to unify gated single photon emission computed tomography (SPECT) and dynamic SPECT into a single method. We divide the cardiac cycle into a number of gate intervals as in gated SPECT, but treat the tracer distribution for each gate as a time-varying signal. By using both dynamic and motion-compensated temporal regularization, our reconstruction procedure will produce an image sequence that shows both cardiac motion and time-varying tracer distribution simultaneously. To demonstrate the proposed reconstruction method, we simulated gated cardiac perfusion imaging using the gated mathematical cardiac-torso (gMCAT) phantom with Tc99m-Teboroxime as the imaging agent. Our results show that the proposed method can produce more accurate reconstruction of gated dynamic images than independent reconstruction of individual gate frames with spatial smoothness alone. In particular, our results show that the former could improve the contrast to noise ratio of a simulated perfusion defect by as much as 100% when compared to the latter.

  11. Retaining latch for a water pit gate

    DOEpatents

    Beale, Arden R.

    1997-01-01

    A retaining latch for use in a hazardous materials storage or handling facility to adjustably retain a water pit gate in a gate frame. A retaining latch is provided comprising a latch plate which is rotatably mounted to each end of the top of the gate and a recessed opening, formed in the gate frame, for engaging an edge of the latch plate. The latch plate is circular in profile with one side cut away or flat, such that the latch plate is D-shaped. The remaining circular edge of the latch plate comprises steps of successively reduced thickness. The stepped edge of the latch plate fits inside a recessed opening formed in the gate frame. As the latch plate is rotated, alternate steps of the latch plate are engaged by the recessed opening. When the latch plate is rotated such that the flat portion of the latch plate faces the recessed opening in the gate frame, there is no connection between the opening and the latch plate and the gate is unlatched from the gate frame.

  12. Metric optimized gating for fetal cardiac MRI.

    PubMed

    Jansz, Michael S; Seed, Mike; van Amerom, Joshua F P; Wong, Derek; Grosse-Wortmann, Lars; Yoo, Shi-Joon; Macgowan, Christopher K

    2010-11-01

    Phase-contrast magnetic resonance imaging can be used to complement echocardiography for the evaluation of the fetal heart. Cardiac imaging typically requires gating with peripheral hardware; however, a gating signal is not readily available in utero. No successful application of existing technologies to human fetal phase-contrast magnetic resonance imaging has been reported to date in the literature. The purpose of this work is to develop a technique for phase-contrast magnetic resonance imaging of the fetal heart that does not require measurement of a gating signal. Metric optimized gating involves acquiring data without gating and retrospectively determining the proper reconstruction by optimizing an image metric. The effects of incorrect gating on phase contrast images were investigated, and the time-entropy of the series of images was found to provide a good measure of the level of corruption. The technique was validated with a pulsatile flow phantom, experiments with adult volunteers, and in vivo application in the fetal population. Images and flow curves from these measurements are presented. Additionally, numerical simulations were used to investigate the degree to which heart rate variability affects the reconstruction process. Metric optimized gating enables imaging with conventional phase-contrast magnetic resonance imaging sequences in the absence of a gating signal, permitting flow measurements in the great vessels in utero.

  13. Quantum logic gates for superconducting resonator qudits

    SciTech Connect

    Strauch, Frederick W.

    2011-11-15

    We study quantum information processing using superpositions of Fock states in superconducting resonators as quantum d-level systems (qudits). A universal set of single and coupled logic gates is theoretically proposed for resonators coupled by superconducting circuits of Josephson junctions. These gates use experimentally demonstrated interactions and provide an attractive route to quantum information processing using harmonic oscillator modes.

  14. Retaining latch for a water pit gate

    DOEpatents

    Beale, A.R.

    1997-11-18

    A retaining latch is described for use in a hazardous materials storage or handling facility to adjustably retain a water pit gate in a gate frame. A retaining latch is provided comprising a latch plate which is rotatably mounted to each end of the top of the gate and a recessed opening, formed in the gate frame, for engaging an edge of the latch plate. The latch plate is circular in profile with one side cut away or flat, such that the latch plate is D-shaped. The remaining circular edge of the latch plate comprises steps of successively reduced thickness. The stepped edge of the latch plate fits inside a recessed opening formed in the gate frame. As the latch plate is rotated, alternate steps of the latch plate are engaged by the recessed opening. When the latch plate is rotated such that the flat portion of the latch plate faces the recessed opening in the gate frame, there is no connection between the opening and the latch plate and the gate is unlatched from the gate frame. 4 figs.

  15. Dual-Gate p-GaN Gate High Electron Mobility Transistors for Steep Subthreshold Slope.

    PubMed

    Bae, Jong-Ho; Lee, Jong-Ho

    2016-05-01

    A steep subthreshold slope characteristic is achieved through p-GaN gate HEMT with dual-gate structure. Obtained subthreshold slope is less than 120 μV/dec. Based on the measured and simulated data obtained from single-gate device, breakdown of parasitic floating-base bipolar transistor and floating gate charged with holes are responsible to increase abruptly in drain current. In the dual-gate device, on-current degrades with high temperature but subthreshold slope is not changed. To observe the switching speed of dual-gate device and transient response of drain current are measured. According to the transient responses of drain current, switching speed of the dual-gate device is about 10(-5) sec.

  16. Enhanced plasmonic resonant excitation in a grating gated field-effect transistor with supplemental gates.

    PubMed

    Guo, Nan; Hu, Wei-Da; Chen, Xiao-Shuang; Wang, Lin; Lu, Wei

    2013-01-28

    An alternative-grating gated AlGaN/GaN field-effect transistor (FET) is proposed by considering the slit regions to be covered by a highly doped semiconductor acting as supplemental gates. The plasmonic resonant absorption spectra are studied at THz frequencies using the FDTD method. The 2DEGs, under supplemental gates, modulated by a positive voltage, can make the excitation of the higher order plasmon modes under metallic fingers more efficient in comparison to ungated regions in common slit-grating gate transistors. Moreover, the supplemental gates can confine the electric field of dipole oscillation between metallic gate fingers under THz radiation. The competition of the near-field enhancement and screening effect of the supplemental gate fingers results in the intensity of the higher order plasmon resonances being maximized at increased doping concentration. Our results demonstrate the possibility of significant improvement in the excitation of plasmon resonances in FETs for THz detection.

  17. Dual-Gate p-GaN Gate High Electron Mobility Transistors for Steep Subthreshold Slope.

    PubMed

    Bae, Jong-Ho; Lee, Jong-Ho

    2016-05-01

    A steep subthreshold slope characteristic is achieved through p-GaN gate HEMT with dual-gate structure. Obtained subthreshold slope is less than 120 μV/dec. Based on the measured and simulated data obtained from single-gate device, breakdown of parasitic floating-base bipolar transistor and floating gate charged with holes are responsible to increase abruptly in drain current. In the dual-gate device, on-current degrades with high temperature but subthreshold slope is not changed. To observe the switching speed of dual-gate device and transient response of drain current are measured. According to the transient responses of drain current, switching speed of the dual-gate device is about 10(-5) sec. PMID:27483846

  18. Gating of Permanent Molds for ALuminum Casting

    SciTech Connect

    David Schwam; John F. Wallace; Tom Engle; Qingming Chang

    2004-03-30

    This report summarizes a two-year project, DE-FC07-01ID13983 that concerns the gating of aluminum castings in permanent molds. The main goal of the project is to improve the quality of aluminum castings produced in permanent molds. The approach taken was determine how the vertical type gating systems used for permanent mold castings can be designed to fill the mold cavity with a minimum of damage to the quality of the resulting casting. It is evident that somewhat different systems are preferred for different shapes and sizes of aluminum castings. The main problems caused by improper gating are entrained aluminum oxide films and entrapped gas. The project highlights the characteristic features of gating systems used in permanent mold aluminum foundries and recommends gating procedures designed to avoid common defects. The study also provides direct evidence on the filling pattern and heat flow behavior in permanent mold castings.

  19. Logic gates based on ion transistors.

    PubMed

    Tybrandt, Klas; Forchheimer, Robert; Berggren, Magnus

    2012-01-01

    Precise control over processing, transport and delivery of ionic and molecular signals is of great importance in numerous fields of life sciences. Integrated circuits based on ion transistors would be one approach to route and dispense complex chemical signal patterns to achieve such control. To date several types of ion transistors have been reported; however, only individual devices have so far been presented and most of them are not functional at physiological salt concentrations. Here we report integrated chemical logic gates based on ion bipolar junction transistors. Inverters and NAND gates of both npn type and complementary type are demonstrated. We find that complementary ion gates have higher gain and lower power consumption, as compared with the single transistor-type gates, which imitates the advantages of complementary logics found in conventional electronics. Ion inverters and NAND gates lay the groundwork for further development of solid-state chemical delivery circuits. PMID:22643898

  20. Logic gates based on ion transistors

    NASA Astrophysics Data System (ADS)

    Tybrandt, Klas; Forchheimer, Robert; Berggren, Magnus

    2012-05-01

    Precise control over processing, transport and delivery of ionic and molecular signals is of great importance in numerous fields of life sciences. Integrated circuits based on ion transistors would be one approach to route and dispense complex chemical signal patterns to achieve such control. To date several types of ion transistors have been reported; however, only individual devices have so far been presented and most of them are not functional at physiological salt concentrations. Here we report integrated chemical logic gates based on ion bipolar junction transistors. Inverters and NAND gates of both npn type and complementary type are demonstrated. We find that complementary ion gates have higher gain and lower power consumption, as compared with the single transistor-type gates, which imitates the advantages of complementary logics found in conventional electronics. Ion inverters and NAND gates lay the groundwork for further development of solid-state chemical delivery circuits.

  1. Searching for high-k RE2O3 nanoparticles embedded in SiO2 glass matrix

    NASA Astrophysics Data System (ADS)

    Mukherjee, S.; Lin, Y. H.; Kao, T. H.; Chou, C. C.; Yang, H. D.

    2012-03-01

    Significant experimental effort has been explored to search and characterize high-k materials with magnetodielectric effect (MDE) of series of rare earth (RE) oxide (RE2O3) nanoparticles (NPs) embedded in SiO2 glass matrix by a sol-gel route. Properly annealed sol-gel glass (in which RE = Sm, Gd, and Er) shows colossal response of dielectric constant along with diffuse phase transition and MDE around room temperature. The radial distribution functions, reconstructed from extended x-ray absorption fine structure, show the shortening of RE3 + -O depending on the RE2O3 NP size, which is consistent with oxygen vacancy induced dielectric anomaly. The magnetoresistive MDE is very much conditioned by magnetic property of RE2O3 NP grain, the degree of deformation of the lattice and constituent host.

  2. Distribution of anomalously high K2O volcanic rocks in Arizona: metasomatism at the Picacho Peak detachment fault.

    USGS Publications Warehouse

    Brooks, W.E.

    1986-01-01

    Metasomatized Tertiary lavas with anomalously high K2O and lower Na2O content are distributed within the NW-trending extensional terrain of SW Arizona. These rocks are common near core-complex-related detachment faults at Picacho Peak and the Harcuvar Mountains and in listric-faulted terrain at the Vulture Mountains. These rocks are also enriched in Zr but depleted in MgO. Fine-grained, euhedral orthoclase (adularia) is the dominant K-mineral; other secondary introduced minerals are quartz and calcite. Spatial association of metasomatism with the detachment faults suggests that detachment provided a conduit for hydrothermal fluids that altered the initial chemistry of the Tertiary volcanics and charged the upper plate rocks with mineralizing fluids that carried Zr and Ba, along with Au, Ag and Cu during detachment 17-18 m.y. ago.-L.C.H.

  3. Mechanical properties of low- and high-k dielectric thin films: A surface Brillouin light scattering study

    NASA Astrophysics Data System (ADS)

    Zizka, J.; King, S.; Every, A. G.; Sooryakumar, R.

    2016-04-01

    Surface Brillouin light scattering measurements are used to determine the elastic constants of nano-porous low-k SiOC:H (165 nm) and high-k HfO2 (25 nm) as well as BN:H (100 nm) films grown on Si substrates. In addition, the study investigates the mechanical properties of ultra-thin (25 nm) blanket TiN cap layers often used as hard masks for patterning, and their effects on the underlying low-k dielectrics that support a high level of interconnected porosity. Depending on the relative material properties of individual component layers, the acoustic modes manifest as confined, propagating, or damped resonances in the light scattering spectra, thereby enabling the mechanical properties of the ultra-thin films to be determined.

  4. Connections between high-K and low-K states in the s-process nucleus {sup 176}Lu

    SciTech Connect

    Dracoulis, G. D.; Lane, G. J.; Byrne, A. P.; Kondev, F. G.; Carpenter, M. P.; Janssens, R. V. F.; Lauritsen, T.; Lister, C. J.; Seweryniak, D.; Chowdhury, P.

    2010-01-15

    Gamma-ray branches that connect high-K states to low-K states in the s-process nucleus {sup 176}Lu were observed, thus providing a link between the 58 Gyr, 7{sup -} ground state and the 5.3 h, 1{sup -} isomeric state. High sensitivity and unambiguous placement were achieved through the study of the decay of the 58 {mu}s K{sup {pi}}=14{sup +} isomer using {gamma}-{gamma}-coincidence measurements. The large number of decay paths from the isomer provides a means of populating a broad selection of states from above, resulting, paradoxically, in higher sensitivity than in cases where low-spin input reactions are used. The out-of band decay widths important for excitation processes in stars are quantified.

  5. KGS-HighK: A Fortran 90 program for simulation of hydraulic tests in highly permeable aquifers

    USGS Publications Warehouse

    Zhan, X.; Butler, J.J.

    2006-01-01

    Slug and pumping tests (hydraulic tests) are frequently used by hydrogeologists to obtain in-situ estimates of the transmissive and storage properties of a formation (Streltsova, 1988; Kruseman and de Ridder, 1990; Butler, 1998). In aquifers of high hydraulic conductivity, hydraulic tests are affected by mechanisms that are not considered in the analysis of tests in less permeable media (Bredehoeft et al., 1966). Inertia-induced oscillations in hydraulic head are the most common manifestation of such mechanisms. Over the last three decades, a number of analytical solutions that incorporate these mechanisms have been developed for the analysis of hydraulic tests in highly permeable aquifers (see Butler and Zhan (2004) for a review of this previous work). These solutions, however, are restricted to a subset of the conditions commonly encountered in the field. Recently, a more general solution has been developed that builds on this previous work to remove many of the limitations imposed by these earlier approaches (Butler and Zhan, 2004). The purpose of this note is to present a Fortran 90 program, KGS-HighK, for the evaluation of this new solution. This note begins with a brief overview of the conceptual model that motivated the development of the solution of Butler and Zhan (2004) for pumping- and slug-induced flow to/from a central well. The major steps in the derivation of that solution are described, but no details are given. Instead, a Mathematica notebook is provided for those interested in the derivation details. The key algorithms used in KGS-HighK are then described and the program structure is briefly outlined. A field example is provided to demonstrate program performance. The note concludes with a short summary section. ?? 2005 Elsevier Ltd. All rights reserved.

  6. Seeding Atomic Layer Deposition of High-k Dielectrics on Epitaxial Graphene with Organic Self-assembled Monolayers

    SciTech Connect

    Alaboson, Justice M. P.; Wang, Qing Hua; Emery, Jonathan D.; Lipson, Albert L.; Bedzyk, Michael J.; Elam, Jeffrey W.; Pellin, Michael J.; Hersam, Mark C.

    2011-06-28

    The development of high-performance graphene-based nanoelectronics requires the integration of ultrathin and pinhole-free high-k dielectric films with graphene at the wafer scale. Here, we demonstrate that self-assembled monolayers of perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) act as effective organic seeding layers for atomic layer deposition (ALD) of HfO₂ and Al₂O₃ on epitaxial graphene on SiC(0001). The PTCDA is deposited via sublimation in ultrahigh vacuum and shown to be highly ordered with low defect density by molecular-resolution scanning tunneling microscopy. Whereas identical ALD conditions lead to incomplete and rough dielectric deposition on bare graphene, the chemical functionality provided by the PTCDA seeding layer yields highly uniform and conformal films. The morphology and chemistry of the dielectric films are characterized by atomic force microscopy, ellipsometry, cross-sectional scanning electron microscopy, and X-ray photoelectron spectroscopy, while high-resolution X-ray reflectivity measurements indicate that the underlying graphene remains intact following ALD. Using the PTCDA seeding layer, metal-oxide-graphene capacitors fabricated with a 3 nm Al₂O₃ and 10 nm HfO₂ dielectric stack show high capacitance values of ~700 nF/cm² and low leakage currents of ~5 × 10{sup –9} A/cm² at 1 V applied bias. These results demonstrate the viability of sublimated organic self-assembled monolayers as seeding layers for high-k dielectric films in graphene-based nanoelectronics.

  7. Gate leakage mechanisms in strained Si devices

    NASA Astrophysics Data System (ADS)

    Yan, L.; Olsen, S. H.; Kanoun, M.; Agaiby, R.; O'Neill, A. G.

    2006-11-01

    This work investigates gate leakage mechanisms in advanced strained Si /SiGe metal-oxide-semiconductor field-effect transistor (MOSFET) devices. The impact of virtual substrate Ge content, epitaxial material quality, epitaxial layer structure, and device processing on gate oxide leakage characteristics are analyzed in detail. In state of the art MOSFETs, gate oxides are only a few nanometers thick. In order to minimize power consumption, leakage currents through the gate must be controlled. However, modifications to the energy band structure, Ge diffusion due to high temperature processing, and Si /SiGe material quality may all affect gate oxide leakage in strained Si devices. We show that at high oxide electric fields where gate leakage is dominated by Fowler-Nordheim tunneling, tensile strained Si MOSFETs exhibit lower leakage levels compared with bulk Si devices. This is a direct result of strain-induced splitting of the conduction band states. However, for device operating regimes at lower oxide electric fields Poole-Frenkel emissions contribute to strained Si gate leakage and increase with increasing virtual substrate Ge content. The emissions are shown to predominantly originate from surface roughness generating bulk oxide traps, opposed to Ge diffusion, and can be improved by introducing a high temperature anneal. Gate oxide interface trap density exhibits a dissimilar behavior and is highly sensitive to Ge atoms at the oxidizing surface, degrading with increasing thermal budget. Consequently advanced strained Si /SiGe devices are inadvertently subject to a potential tradeoff between power consumption (gate leakage current) and device reliability (gate oxide interface quality).

  8. Locking apparatus for gate valves

    DOEpatents

    Fabyan, Joseph; Williams, Carl W.

    1988-01-01

    A locking apparatus for fluid operated valves having a piston connected to the valve actuator which moves in response to applied pressure within a cylinder housing having a cylinder head, a catch block is secured to the piston, and the cylinder head incorporates a catch pin. Pressure applied to the cylinder to open the valve moves the piston adjacent to the cylinder head where the catch pin automatically engages the catch block preventing futher movement of the piston or premature closure of the valve. Application of pressure to the cylinder to close the valve, retracts the catch pin, allowing the valve to close. Included are one or more selector valves, for selecting pressure application to other apparatus depending on the gate valve position, open or closed, protecting such apparatus from damage due to premature closing caused by pressure loss or operational error.

  9. Locking apparatus for gate valves

    DOEpatents

    Fabyan, J.; Williams, C.W.

    A locking apparatus for fluid operated valves having a piston connected to the valve actuator which moves in response to applied pressure within a cylinder housing having a cylinder head, a catch block is secured to the piston, and the cylinder head incorporates a catch pin. Pressure applied to the cylinder to open the valve moves the piston adjacent to the cylinder head where the catch pin automatically engages the catch block preventing further movement of the piston or premature closure of the valve. Application of pressure to the cylinder to close the valve, retracts the catch pin, allowing the valve to close. Included are one or more selector valves, for selecting pressure application to other apparatus depending on the gate valve position, open or closed, protecting such apparatus from damage due to premature closing caused by pressure loss or operational error.

  10. Determination of the density of the defect states in Hf{sub 0.5}Zr{sub 0.5}O{sub 2} high-k film Deposited by using rf-magnetron sputtering technique

    SciTech Connect

    Lu, W.; Lu, J. X.; Ou, X.; Liu, X. J.; Cao, Y. Q.; Li, A. D.; Xu, B.; Xia, Y. D.; Yin, J.; Liu, Z. G.

    2014-08-15

    A memory structure Pt/Al{sub 2}O{sub 3}/Hf{sub 0.5}Zr{sub 0.5}O{sub 2}/Al{sub 2}O{sub 3}/p-Si was fabricated by using atomic layer deposition and rf-magnetron sputtering techniques, and its microstructure has been investigated by using the high resolution transmission electron microscopy (HRTEM). By measuring the applied gate voltage dependence of the capacitance for the memory structure, the planar density of the trapped charges in Hf{sub 0.5}Zr{sub 0.5}O{sub 2} high-k film was estimated as 6.63 × 10{sup 12} cm{sup −2}, indicating a body defect density of larger than 2.21 × 10{sup 19} cm{sup −3}. It is observed that the post-annealing in N{sub 2} can reduces the defect density in Hf{sub 0.5}Zr{sub 0.5}O{sub 2} film, which was ascribed to the occupancy of oxygen vacancies by nitrogen atoms.

  11. Oxygen migration in TiO{sub 2}-based higher-k gate stacks

    SciTech Connect

    Kim, Sang Bum; Brown, Stephen L.; Rossnagel, Stephen M.; Bruley, John; Copel, Matthew; Hopstaken, Marco J. P.; Narayanan, Vijay; Frank, Martin M.

    2010-03-15

    We report on the stability of high-permittivity (high-k) TiO{sub 2} films incorporated in metal-oxide-silicon capacitor structures with a TiN metal gate electrode, focusing on oxygen migration. Titanium oxide films are deposited by either Ti sputtering [physical vapor deposition (PVD)] followed by radical shower oxidation or by plasma-enhanced atomic layer deposition (PEALD) from titanium isopropoxide (Ti{l_brace}OCH(CH{sub 3}){sub 2{r_brace}4}) and O{sub 2} plasma. Both PVD and PEALD films result in near-stoichiometric TiO{sub 2} prior to high-temperature annealing. We find that dopant activation anneals of TiO{sub 2}-containing gate stacks at 1000 deg. C cause 5 A or more of additional SiO{sub 2} to be formed at the gate-dielectric/Si-channel interface. Furthermore, we demonstrate for the first time that oxygen released from TiO{sub 2} diffuses through the TiN gate electrode and oxidizes the poly-Si contact. The thickness of this upper SiO{sub 2} layer continues to increase with increasing TiO{sub 2} thickness, while the thickness of the regrown SiO{sub 2} at the gate-dielectric/Si interface saturates. The upper SiO{sub 2} layer degrades gate stack capacitance, and simultaneously the oxygen-deficient TiO{sub x} becomes a poor insulator. In an attempt to mitigate O loss from the TiO{sub 2}, top and bottom Al{sub 2}O{sub 3} layers are added to the TiO{sub 2} gate dielectric as oxygen barriers. However, they are found to be ineffective, due to Al{sub 2}O{sub 3}-TiO{sub 2} interdiffusion during activation annealing. Bottom HfO{sub 2}/Si{sub 3}N{sub 4} interlayers are found to serve as more effective oxygen barriers, reducing, though not preventing, oxygen downdiffusion.

  12. Voltage-Gated Sodium Channels

    NASA Astrophysics Data System (ADS)

    Hanck, Dorothy A.; Fozzard, Harry A.

    Voltage-gated sodium channels subserve regenerative excitation throughout the nervous system, as well as in skeletal and cardiac muscle. This excitation results from a voltage-dependent mechanism that increases regeneratively and selectively the sodium conductance of the channel e-fold for a 4-7 mV depolarization of the membrane with time constants in the range of tens of microseconds. Entry of Na+ into the cell without a companion anion depolarizes the cell. This depolarization, called the action potential, is propagated at rates of 1-20 meters/sec. In nerve it subserves rapid transmission of information and, in muscle cells, coordinates the trigger for contraction. Sodium-dependent action potentials depolarize the membrane to inside positive values of about 30-40 mV (approaching the electrochemical potential for the transmembrane sodium gradient). Repolarization to the resting potential (usually between -60 and -90 mV) occurs because of inactivation (closure) of sodium channels, which is assisted in different tissues by variable amounts of activation of voltage-gated potassium channels. This sequence results in all-or-nothing action potentials in nerve and fast skeletal muscle of 1-2 ms duration, and in heart muscle of 100-300 ms duration. Recovery of regenerative excitation, i.e., recovery of the ability of sodium channels to open, occurs after restoration of the resting potential with time constants of a few to several hundreds of milliseconds, depending on the channel isoform, and this rate controls the minimum interval for repetitive action potentials (refractory period).

  13. Low-voltage and hysteresis-free organic thin-film transistors employing solution-processed hybrid bilayer gate dielectrics

    SciTech Connect

    Ha, Tae-Jun

    2014-07-28

    This study presents a promising approach to realize low-voltage (<3 V) organic thin-film transistors (OTFTs) exhibiting improved electrical and optical stability. Such device performance results from the use of solution-processed hybrid bilayer gate dielectrics consisting of zirconium dioxide (high-k dielectric) and amorphous fluoropolymer, CYTOP{sup ®} (low-k dielectric). Employing a very thin amorphous fluoropolymer film reduces interfacial defect-states by repelling water molecules and other aqueous chemicals from an organic semiconductor active layer due to the hydrophobic surface-property. The chemically clean interface, stemming from decrease in density of trap states improves all the key device properties such as field-effect mobility, threshold voltage, and sub-threshold swing. Furthermore, degradation by electrical bias-stress and photo-induced hysteresis were suppressed in OTFTs employing hybrid bilayer gate dielectrics.

  14. Graduate Automotive Technology Education (GATE) Center

    SciTech Connect

    Jeffrey Hodgson; David Irick

    2005-09-30

    The Graduate Automotive Technology Education (GATE) Center at the University of Tennessee, Knoxville has completed its sixth year of operation. During this period the Center has involved thirteen GATE Fellows and ten GATE Research Assistants in preparing them to contribute to advanced automotive technologies in the center's focus area: hybrid drive trains and control systems. Eighteen GATE students have graduated, and three have completed their course work requirements. Nine faculty members from three departments in the College of Engineering have been involved in the GATE Center. In addition to the impact that the Center has had on the students and faculty involved, the presence of the center has led to the acquisition of resources that probably would not have been obtained if the GATE Center had not existed. Significant industry interaction such as internships, equipment donations, and support for GATE students has been realized. The value of the total resources brought to the university (including related research contracts) exceeds $4,000,000. Problem areas are discussed in the hope that future activities may benefit from the operation of the current program.

  15. Cardiac imaging using gated magnetic resonance

    SciTech Connect

    Lanzer, P.; Botvinick, E.H.; Schiller, N.B.

    1984-01-01

    To overcome the limitations of magnetic resonance (MR) cardiac imaging using nongated data acquisition, three methods for acquiring a gating signal, which could be applied in the presence of a magnetic field, were tested; an air-filled plethysmograph, a laser-Doppler capillary perfusion flowmeter, and an electrocardiographic gating device. The gating signal was used for timing of MR imaging sequences (IS). Application of each gating method yielded significant improvements in structural MR image resolution of the beating heart, although with both plethysmography and laser-Doppler velocimetry it was difficult to obtain cardiac images from the early portion of the cardiac cycle due to an intrinsic delay between the ECG R wave and peripheral detection of the gating signal. Variations in the temporal relationship between the R wave and plethysmographic and laser-Doppler signals produced inconsistencies in the timing of IS. Since the ECG signal is virtually free of these problems, the preferable gating technique is IS synchronization with an electrocardiogram. The gated images acquired with this method provide sharp definition of internal cardiac morphology and can be temporarily referenced to end diastole and end systole or intermediate points.

  16. Stay vane and wicket gate relationship study

    SciTech Connect

    None, None

    2005-01-19

    This report evaluates potential environmental and performance gains that can be achieved in a Kaplan turbine through non-structural modifications to stay vane and wicket gate assemblies. This summary is based primarily on data and conclusions drawn from models and studies of Lower Granite Dam. Based on this investigation, the study recommends (1) a proof of concept at Lower Granite Dam to establish predicted improvements for the existing turbine and to further refine the stay vane wicket gate designs for fish passage; and (2) consideration of the stay vane wicket gate systems in any future turbine rehabilitation studies.

  17. The Pan-African high-K calc-alkaline peraluminous Elat granite from southern Israel: geology, geochemistry and petrogenesis

    NASA Astrophysics Data System (ADS)

    Eyal, M.; Litvinovsky, B. A.; Katzir, Y.; Zanvilevich, A. N.

    2004-10-01

    Calc-alkaline leucocratic granites that were emplaced at the late post-collision stage of the Pan-African orogeny are abundant in the northern half of the Arabian-Nubian Shield. Commonly, they are referred to as the Younger Granite II suite. In southern Israel such rocks are known as Elat granite. Studies of these rocks enable to recognize two types of granites: coarse-grained, massive Elat granite (EG), and fine- to medium-grained Shahmon gneissic granite (SGG). Both granite types are high-K and peraluminous ( ASI ranges from 1.03 to 1.16). They are similar in modal composition, mineral and whole-rock chemistry. Within the EG, a noticeable distinction in whole-rock chemistry and mineral composition is observed between rocks making up different plutons. In particular, the granite of Wadi Shelomo, as compared to the Rehavam pluton, is enriched in SiO 2, FeO∗, K 2O, Ba, Zr, Th, LREE and impoverished in MgO, Na 2O, Sr, and HREE. The Eu/Eu∗ values in the granite are low, up to 0.44. Mass-balance calculations suggest that chemical and mineralogical variations were caused by fractionation of ˜16 wt.% plagioclase from the parental Rehavam granite magma at temperature of 760-800 °C (muscovite-biotite geothermometer). The Rb-Sr isochrons yielded a date of 623 ± 24 Ma for the EG, although high value of age-error does not allow to constrain time of emplacement properly. The Rb-Sr date for SGG is 640 ± 9 Ma; however, it is likely that this date points to the time of metamorphism. A survey of the literature shows that peraluminous, high-K granites, similar to the EG, are abundant among the Younger Granite II plutons in the Sinai Peninsula and Eastern Desert, Egypt. They were emplaced at the end of the batholithic (late post-collision) stage. The most appropriate model for the generation of the peraluminous granitic magma is partial melting of metapelite and metagreywacke.

  18. Gate assisted turn-off thyristor with cathode shunts and dynamic gate

    NASA Technical Reports Server (NTRS)

    Schlegel, E. S.; Page, D. J.

    1976-01-01

    A 1,000-V, 200-A gate-assisted turn-off thyristor (GATT) is described, whose design features include an interdigitated shunted cathode, a dynamic gate, a means for optimizing the carrier lifetime level, and a bypass diode. The device physics of gate-assisted turn-off are reviewed. Based on this, improvements in the design are described. It is shown that a prime failure mode can be eliminated and that the gate-assist signal voltage can be substantially decreased by employing a shunted cathode emitter. The test data show excellent turn-on characteristics due to the dynamic gate and the long perimeter of the edge of the main cathode. Turn-off times as short as 3 microsec are obtained. The combination of controlling the carrier lifetime with a precisely controlled and easily variable irradiation dose of high energy electrons with gate assist current provides for simple, precision tailoring of the device characteristics to the intended application.

  19. 30 CFR 57.19100 - Shaft landing gates.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Shaft landing gates. 57.19100 Section 57.19100... Shafts § 57.19100 Shaft landing gates. Shaft landings shall be equipped with substantial safety gates so constructed that materials will not go through or under them; gates shall be closed except when loading...

  20. 30 CFR 57.19100 - Shaft landing gates.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Shaft landing gates. 57.19100 Section 57.19100... Shafts § 57.19100 Shaft landing gates. Shaft landings shall be equipped with substantial safety gates so constructed that materials will not go through or under them; gates shall be closed except when loading...

  1. 30 CFR 57.19100 - Shaft landing gates.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Shaft landing gates. 57.19100 Section 57.19100... Shafts § 57.19100 Shaft landing gates. Shaft landings shall be equipped with substantial safety gates so constructed that materials will not go through or under them; gates shall be closed except when loading...

  2. 30 CFR 57.19100 - Shaft landing gates.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Shaft landing gates. 57.19100 Section 57.19100... Shafts § 57.19100 Shaft landing gates. Shaft landings shall be equipped with substantial safety gates so constructed that materials will not go through or under them; gates shall be closed except when loading...

  3. 30 CFR 56.19100 - Shaft landing gates.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Shaft landing gates. 56.19100 Section 56.19100... § 56.19100 Shaft landing gates. Shaft landings shall be equipped with substantial safety gates so constructed that materials will not go through or under them; gates shall be closed except when loading...

  4. 30 CFR 57.19100 - Shaft landing gates.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Shaft landing gates. 57.19100 Section 57.19100... Shafts § 57.19100 Shaft landing gates. Shaft landings shall be equipped with substantial safety gates so constructed that materials will not go through or under them; gates shall be closed except when loading...

  5. 30 CFR 56.19100 - Shaft landing gates.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Shaft landing gates. 56.19100 Section 56.19100... § 56.19100 Shaft landing gates. Shaft landings shall be equipped with substantial safety gates so constructed that materials will not go through or under them; gates shall be closed except when loading...

  6. 30 CFR 56.19100 - Shaft landing gates.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Shaft landing gates. 56.19100 Section 56.19100... § 56.19100 Shaft landing gates. Shaft landings shall be equipped with substantial safety gates so constructed that materials will not go through or under them; gates shall be closed except when loading...

  7. 30 CFR 56.19100 - Shaft landing gates.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Shaft landing gates. 56.19100 Section 56.19100... § 56.19100 Shaft landing gates. Shaft landings shall be equipped with substantial safety gates so constructed that materials will not go through or under them; gates shall be closed except when loading...

  8. 30 CFR 56.19100 - Shaft landing gates.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Shaft landing gates. 56.19100 Section 56.19100... § 56.19100 Shaft landing gates. Shaft landings shall be equipped with substantial safety gates so constructed that materials will not go through or under them; gates shall be closed except when loading...

  9. 7. DETAIL VIEW OF TAINTER GATE PIER AND NONSUBMERSIBLE TAINTER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. DETAIL VIEW OF TAINTER GATE PIER AND NON-SUBMERSIBLE TAINTER GATES DURING ERECTION, SHOWING LEFT GATE IN OPEN POSITION AND RIGHT GATE IN CLOSED POSITION, LOOKING NORTH (UPSTREAM). NOTE TEMPORARY SERVICE BRIDGE. - Upper Mississippi River 9-Foot Channel Project, Lock & Dam 26R, Alton, Madison County, IL

  10. A tunneling current density model for ultra thin HfO2 high-k dielectric material based MOS devices

    NASA Astrophysics Data System (ADS)

    Maity, Niladri Pratap; Maity, Reshmi; Thapa, R. K.; Baishya, Srimanta

    2016-07-01

    In this paper, an analytical model for evaluation of tunneling current density of ultra thin MOS devices is presented. The impacts of the promising high-k dielectric material, HfO2 on the current density model have been carried out. In this work, improvement in the results is brought in by taking into account the barrier height lowering due to the image force effect. The considered voltage range is from 0 to ψ1/e i.e., 0 < V < ψ1/e, where ψ1 is the barrier height at the interface of metal and the oxide. Initially we are neglecting the image force effect for a MOS device consisting asymmetric barrier. Later, image force effect of ultra thin oxide layer has been introduced for practical potential barrier by superimposing the potential barrier on the trapezoidal barrier. Theoretical predictions are compared with the results obtained by the 2-D numerical device simulator ATLAS and published experimental results. Excellent agreements among the three are observed.

  11. Thermodynamics and kinetic behaviors of thickness-dependent crystallization in high-k thin films deposited by atomic layer deposition

    SciTech Connect

    Nie, Xianglong; Ma, Fei; Ma, Dayan; Xu, Kewei

    2015-01-15

    Atomic layer deposition is adopted to prepare HfO{sub 2} and Al{sub 2}O{sub 3} high-k thin films. The HfO{sub 2} thin films are amorphous at the initial growth stage, but become crystallized when the film thickness (h) exceeds a critical value (h{sub critical}{sup *}). This phase transition from amorphous to crystalline is enhanced at higher temperatures and is discussed, taking into account the effect of kinetic energy. At lower temperatures, the amorphous state can be maintained even when h>h{sub critical}{sup *} owing to the small number of activated atoms. However, the number of activated atoms increases with the temperature, allowing crystallization to occur even in films with smaller thickness. The Al{sub 2}O{sub 3} thin films, on the other hand, maintain their amorphous state independent of the film thickness and temperature owing to the limited number of activated atoms. A thermodynamic model is proposed to describe the thickness-dependent phase transition.

  12. Tb{sub 2}O{sub 3} thin films: An alternative candidate for high-k dielectric applications

    SciTech Connect

    Gray, Nathan W.; Prestgard, Megan C.; Tiwari, Ashutosh

    2014-12-01

    We are reporting the growth and structural, optical, and dielectric properties of Tb{sub 2}O{sub 3}, a relatively unexplored high-k dielectric material. A pulsed-laser deposition technique was used to grow Tb{sub 2}O{sub 3} thin-films on four different substrates: Si(100), SrTiO{sub 3}(100), LaAlO{sub 3}(100), and MgO(100). High-resolution X-ray diffraction and transmission electron microscopy results confirmed that film growth in an oxygen-rich (10{sup −1 }Torr) environment yields nearly single-crystal C-phase films, while a low-oxygen (10{sup −6 }Torr) environment growth results in the formation of monoclinic polycrystalline B-phase films. Optical transmission measurements showed that the bandgap of Tb{sub 2}O{sub 3} is direct in nature with a value of 2.8 eV and 3.4 eV for the cubic and monoclinic phases, respectively. By measuring the capacitance of test devices, quite high dielectric constants of 13.5 and 24.9 were obtained for the B- and C-phase Tb{sub 2}O{sub 3} films, respectively.

  13. Geology and 40Ar/39Ar geochronology of the medium- to high-K Tanaga volcanic cluster, western Aleutians

    USGS Publications Warehouse

    Jicha, Brian R.; Coombs, Michelle L.; Calvert, Andrew T.; Singer, Brad S.

    2012-01-01

    We used geologic mapping and geochemical data augmented by 40Ar/39Ar dating to establish an eruptive chronology for the Tanaga volcanic cluster in the western Aleutian arc. The Tanaga volcanic cluster is unique in comparison to other central and western Aleutian volcanoes in that it consists of three closely spaced, active, volumetrically significant edifices (Sajaka, Tanaga, and Takawangha), the eruptive products of which have unusually high K2O contents. Thirty-five new 40Ar/39Ar ages obtained in two different laboratories constrain the duration of Pleistocene–Holocene subaerial volcanism to younger than 295 ka. The eruptive activity has been mostly continuous for the last 150 k.y., unlike most other well-characterized arc volcanoes, which tend to grow in discrete pulses. More than half of the analyzed Tanaga volcanic cluster lavas are basalts that have erupted throughout the lifetime of the cluster, although a considerable amount of basaltic andesite and basaltic trachyandesite has also been produced since 200 ka. Major- and trace-element variations suggest that magmas from Sajaka and Tanaga volcanoes are likely to have crystallized pyroxene and/or amphibole at greater depths than the older Takawangha magmas, which experienced a larger percentage of plagioclase-dominated fractionation at shallower depths. Magma output from Takawangha has declined over the last 86 k.y. At ca. 19 ka, the focus of magma flux shifted to the west beneath Tanaga and Sajaka volcanoes, where hotter, more mafic magma erupted.

  14. Transfer-Free Fabrication of Graphene Scaffolds on High-k Dielectrics from Metal-Organic Oligomers.

    PubMed

    Pang, Qingqing; Wang, Deyan; Wang, Xiuyan; Feng, Shaoguang; Clark, Michael B; Li, Qiaowei

    2016-09-28

    In situ fabrication of graphene scaffold-ZrO2 nanofilms is achieved by thermal annealing of Zr-based metal-organic oligomers on SiO2 substrates. The structural similarities of the aromatic moieties in the ligand (phenyl-, naphthyl-, anthryl-, and pyrenyl-) compared to graphene play a major role in the ordering of the graphene scaffolds obtained. The depth profiling analysis reveals ultrathin carbon-pure or carbon-rich surfaces of the graphene scaffold-ZrO2 nanofilms. The graphene scaffolds with ∼96.0% transmittance in the visible region and 4.8 nm in thickness can be grown with this non-chemical vapor deposition method. Furthermore, the heterogeneous graphene scaffold-ZrO2 nanofilms show a low sheet resistance of 17.0 kΩ per square, corresponding to electrical conductivity of 3197 S m(-1). The strategy provides a facile method to fabricate graphene scaffolds directly on high-k dielectrics without transferring process, paving the way for its application in fabricating electronic devices. PMID:27580799

  15. Distribution of anomalously high K2O volcanic rocks in Arizona: Metasomatism at the Picacho Peak detachment fault

    NASA Astrophysics Data System (ADS)

    Brooks, William E.

    1986-04-01

    Metasomatized Tertiary lavas with anomalously high K2O and low Na2O content are distributed within the northwest-trending Miocene extensional terrane of southwestern Arizona. These rocks are common near core-complex related detachment faults at Picacho Peak and the Harcuvar Mountains and in listric-faulted terrane at the Vulture Mountains. In addition to systematic changes in K2O and Na2O, the rocks have been enriched in Zr and depleted in MgO. Secondary, introduced minerals include orthoclase, quartz, and calcite. Fine-grained, euhedral orthoclase (var. adularia), from 2 to 10 μm, is the dominant potassium mineral. Metasomatic changes at Picacho Peak are spatially associated with a major detachment fault. Thus, it is interpreted that detachment provided a conduit for hydrothermal fluids that altered the initial chemical composition of the Tertiary volcanics by potassium metasomatism and charged the upper-plate rocks with mineralizing fluids that carried Zr and Ba, along with Au, Ag, and Cu, during detachment 17 18 Ma.

  16. Integrated photonic quantum gates for polarization qubits

    PubMed Central

    Crespi, Andrea; Ramponi, Roberta; Osellame, Roberto; Sansoni, Linda; Bongioanni, Irene; Sciarrino, Fabio; Vallone, Giuseppe; Mataloni, Paolo

    2011-01-01

    The ability to manipulate quantum states of light by integrated devices may open new perspectives both for fundamental tests of quantum mechanics and for novel technological applications. However, the technology for handling polarization-encoded qubits, the most commonly adopted approach, is still missing in quantum optical circuits. Here we demonstrate the first integrated photonic controlled-NOT (CNOT) gate for polarization-encoded qubits. This result has been enabled by the integration, based on femtosecond laser waveguide writing, of partially polarizing beam splitters on a glass chip. We characterize the logical truth table of the quantum gate demonstrating its high fidelity to the expected one. In addition, we show the ability of this gate to transform separable states into entangled ones and vice versa. Finally, the full accessibility of our device is exploited to carry out a complete characterization of the CNOT gate through a quantum process tomography. PMID:22127062

  17. Synthesizing Biomolecule-based Boolean Logic Gates

    PubMed Central

    Miyamoto, Takafumi; Razavi, Shiva; DeRose, Robert; Inoue, Takanari

    2012-01-01

    One fascinating recent avenue of study in the field of synthetic biology is the creation of biomolecule-based computers. The main components of a computing device consist of an arithmetic logic unit, the control unit, memory, and the input and output devices. Boolean logic gates are at the core of the operational machinery of these parts, hence to make biocomputers a reality, biomolecular logic gates become a necessity. Indeed, with the advent of more sophisticated biological tools, both nucleic acid- and protein-based logic systems have been generated. These devices function in the context of either test tubes or living cells and yield highly specific outputs given a set of inputs. In this review, we discuss various types of biomolecular logic gates that have been synthesized, with particular emphasis on recent developments that promise increased complexity of logic gate circuitry, improved computational speed, and potential clinical applications. PMID:23526588

  18. Generalized Toffoli gates using qudit catalysis

    SciTech Connect

    Ionicioiu, Radu; Spiller, Timothy P.; Munro, William J.

    2009-07-15

    We present quantum networks for a n-qubit controlled gate C{sup n-1}(U) which use a higher-dimensional (qudit) ancilla as a catalyzer. In its simplest form the network has only n two-particle gates (qubit-qudit)--this is the minimum number of two-body interactions needed to couple all n+1 subsystems (n qubits plus one ancilla). This class of controlled gates includes the generalized Toffoli gate C{sup n-1}(X) on n qubits, which plays an important role in several quantum algorithms and error correction. A particular example implementing this model is given by the dispersive limit of a generalized Jaynes-Cummings Hamiltonian of an effective spin s interacting with a cavity mode.

  19. Extending Double Optical Gating to the Midinfrared

    NASA Astrophysics Data System (ADS)

    Gorman, Timothy; Camper, Antoine; Agostini, Pierre; Dimauro, Louis

    2015-05-01

    In the past decade there has been great interest in creating broadband isolated attosecond pulses (IAPs). Primarily these IAPs have been generated using Ti:Sapphire 800nm short pulses, namely through spatiotemporal gating with the attosecond lighthouse technique, amplitude gating, polarization gating, and double optical gating (DOG). Here we present theoretical calculations and experimental investigations into extending DOG to using a 2 μm driving wavelength, the benefits of which include extended harmonic cutoff and longer input driving pulse durations. It is proposed that broadband IAPs with cutoffs extending up to 250 eV can be generated in Argon by using >30 fs pulses from the passively-CEP stabilized 2 μm idler out of an optical parametric amplifier combined with a collinear DOG experimental setup.

  20. Digital gate pulse generator for cycloconverter control

    DOEpatents

    Klein, Frederick F.; Mutone, Gioacchino A.

    1989-01-01

    The present invention provides a digital gate pulse generator which controls the output of a cycloconverter used for electrical power conversion applications by determining the timing and delivery of the firing pulses to the switching devices in the cycloconverter. Previous gate pulse generators have been built with largely analog or discrete digital circuitry which require many precision components and periodic adjustment. The gate pulse generator of the present invention utilizes digital techniques and a predetermined series of values to develop the necessary timing signals for firing the switching device. Each timing signal is compared with a reference signal to determine the exact firing time. The present invention is significantly more compact than previous gate pulse generators, responds quickly to changes in the output demand and requires only one precision component and no adjustments.

  1. Active gated imaging in driver assistance system

    NASA Astrophysics Data System (ADS)

    Grauer, Yoav

    2014-04-01

    In this paper, we shall present the active gated imaging system (AGIS) in relation to the automotive field. AGIS is based on a fast-gated camera and pulsed illuminator, synchronized in the time domain to record images of a certain range of interest. A dedicated gated CMOS imager sensor and near infra-red (NIR) pulsed laser illuminator, is presented in this paper to provide active gated technology. In recent years, we have developed these key components and learned the system parameters, which are most beneficial to nighttime (in all weather conditions) driving in terms of field of view, illumination profile, resolution, and processing power. We shall present our approach of a camera-based advanced driver assistance systems (ADAS) named BrightEye™, which makes use of the AGIS technology in the automotive field.

  2. Gated STED microscopy with time-gated single-photon avalanche diode

    PubMed Central

    Hernández, Iván Coto; Buttafava, Mauro; Boso, Gianluca; Diaspro, Alberto; Tosi, Alberto; Vicidomini, Giuseppe

    2015-01-01

    Stimulated emission depletion (STED) microscopy provides fluorescence imaging with sub-diffraction resolution. Experimentally demonstrated at the end of the 90s, STED microscopy has gained substantial momentum and impact only in the last few years. Indeed, advances in many fields improved its compatibility with everyday biological research. Among them, a fundamental step was represented by the introduction in a STED architecture of the time-gated detection, which greatly reduced the complexity of the implementation and the illumination intensity needed. However, the benefits of the time-gated detection came along with a reduction of the fluorescence signal forming the STED microscopy images. The maximization of the useful (within the time gate) photon flux is then an important aspect to obtain super-resolved images. Here we show that by using a fast-gated single-photon avalanche diode (SPAD), i.e. a detector able to rapidly (hundreds picoseconds) switch-on and -off can improve significantly the signal-to-noise ratio (SNR) of the gated STED image. In addition to an enhancement of the image SNR, the use of the fast-gated SPAD reduces also the system complexity. We demonstrate these abilities both on calibration and biological sample. The experiments were carried on a gated STED microscope based on a STED beam operating in continuous-wave (CW), although the fast-gated SPAD is fully compatible with gated STED implementations based on pulsed STED beams. PMID:26114044

  3. Smart gating membranes with in situ self-assembled responsive nanogels as functional gates

    PubMed Central

    Luo, Feng; Xie, Rui; Liu, Zhuang; Ju, Xiao-Jie; Wang, Wei; Lin, Shuo; Chu, Liang-Yin

    2015-01-01

    Smart gating membranes, inspired by the gating function of ion channels across cell membranes, are artificial membranes composed of non-responsive porous membrane substrates and responsive gates in the membrane pores that are able to dramatically regulate the trans-membrane transport of substances in response to environmental stimuli. Easy fabrication, high flux, significant response and strong mechanical strength are critical for the versatility of such smart gating membranes. Here we show a novel and simple strategy for one-step fabrication of smart gating membranes with three-dimensionally interconnected networks of functional gates, by self-assembling responsive nanogels on membrane pore surfaces in situ during a vapor-induced phase separation process for membrane formation. The smart gating membranes with in situ self-assembled responsive nanogels as functional gates show large flux, significant response and excellent mechanical property simultaneously. Because of the easy fabrication method as well as the concurrent enhancement of flux, response and mechanical property, the proposed smart gating membranes will expand the scope of membrane applications, and provide ever better performances in their applications. PMID:26434387

  4. Gate fidelity fluctuations and quantum process invariants

    SciTech Connect

    Magesan, Easwar; Emerson, Joseph; Blume-Kohout, Robin

    2011-07-15

    We characterize the quantum gate fidelity in a state-independent manner by giving an explicit expression for its variance. The method we provide can be extended to calculate all higher order moments of the gate fidelity. Using these results, we obtain a simple expression for the variance of a single-qubit system and deduce the asymptotic behavior for large-dimensional quantum systems. Applications of these results to quantum chaos and randomized benchmarking are discussed.

  5. Advanced logic gates for ultrafast network interchanges

    NASA Astrophysics Data System (ADS)

    Islam, Mohammed N.

    1995-08-01

    By overcoming speed bottlenecks from electronic switching as well as optical/electronic conversions, all-optical logic gates can permit further exploitation of the nearly 40 THz of bandwidth available from optical fibers. We focus on the use of optical solitons and all-optical logic gates to implement ultrafast ``interchanges'' or switching nodes on packet networks with speeds of 100 Gbit/s or greater. For example, all-optical logic gates have been demonstrated with speeds up to 200 Gbit/s, and they may be used to decide whether to add or drop a data packet. The overall goal of our effort is to demonstrate the key enabling technologies and their combination for header processing in 100 Gbit/s, time-division-multiplexed, packed switched networks. Soliton-based fiber logic gates are studied with the goal of combining attractive features of soliton-dragging logic gates, nonlinear loop mirrors, and erbium-doped fiber amplifiers to design logic gates with optimum switching energy, contrast ratio, and timing sensitivity. First, the experimental and numerical work studies low-latency soliton logic gates based on frequency shifts associated with cross-phase modulation. In preliminary experiments, switching in 15 m long low-birefringent fibers has been demonstrated with a contrast ratio of 2.73:1. Using dispersion-shifted fiber in the gate should lower the switching energy and improve the contrast ratio. Next, the low-birefringent fiber can be cross-spliced and wrapped into a nonlinear optical loop mirror to take advantage of mechanisms from both soliton dragging and loop mirrors. The resulting device can have low switching energy and a timing window that results from a combination of soliton dragging and the loop mirror mechanisms.

  6. Multipulse interferometric frequency-resolved optical gating

    SciTech Connect

    Siders, C.W.; Siders, J.L.W.; Omenetto, F.G.; Taylor, A.J.

    1999-04-01

    The authors review multipulse interferometric frequency-resolved optical gating (MI-FROG) as a technique, uniquely suited for pump-probe coherent spectroscopy using amplified visible and near-infrared short-pulse systems and/or emissive targets, for time-resolving ultrafast phase shifts and intensity changes. Application of polarization-gate MI-FROG to the study of ultrafast ionization in gases is presented.

  7. Blanket Gate Would Address Blocks Of Memory

    NASA Technical Reports Server (NTRS)

    Lambe, John; Moopenn, Alexander; Thakoor, Anilkumar P.

    1988-01-01

    Circuit-chip area used more efficiently. Proposed gate structure selectively allows and restricts access to blocks of memory in electronic neural-type network. By breaking memory into independent blocks, gate greatly simplifies problem of reading from and writing to memory. Since blocks not used simultaneously, share operational amplifiers that prompt and read information stored in memory cells. Fewer operational amplifiers needed, and chip area occupied reduced correspondingly. Cost per bit drops as result.

  8. Quantum teleportation of optical quantum gates.

    PubMed

    Bartlett, Stephen D; Munro, William J

    2003-03-21

    We show that a universal set of gates for quantum computation with optics can be quantum teleported through the use of EPR entangled states, homodyne detection, and linear optics and squeezing operations conditioned on measurement outcomes. This scheme may be used for fault-tolerant quantum computation in any optical scheme (qubit or continuous-variable). The teleportation of nondeterministic nonlinear gates employed in linear optics quantum computation is discussed.

  9. GaTe semiconductor for radiation detection

    DOEpatents

    Payne, Stephen A.; Burger, Arnold; Mandal, Krishna C.

    2009-06-23

    GaTe semiconductor is used as a room-temperature radiation detector. GaTe has useful properties for radiation detectors: ideal bandgap, favorable mobilities, low melting point (no evaporation), non-hygroscopic nature, and availability of high-purity starting materials. The detector can be used, e.g., for detection of illicit nuclear weapons and radiological dispersed devices at ports of entry, in cities, and off shore and for determination of medical isotopes present in a patient.

  10. Boolean gates on actin filaments

    NASA Astrophysics Data System (ADS)

    Siccardi, Stefano; Tuszynski, Jack A.; Adamatzky, Andrew

    2016-01-01

    Actin is a globular protein which forms long polar filaments in the eukaryotic cytoskeleton. Actin networks play a key role in cell mechanics and cell motility. They have also been implicated in information transmission and processing, memory and learning in neuronal cells. The actin filaments have been shown to support propagation of voltage pulses. Here we apply a coupled nonlinear transmission line model of actin filaments to study interactions between voltage pulses. To represent digital information we assign a logical TRUTH value to the presence of a voltage pulse in a given location of the actin filament, and FALSE to the pulse's absence, so that information flows along the filament with pulse transmission. When two pulses, representing Boolean values of input variables, interact, then they can facilitate or inhibit further propagation of each other. We explore this phenomenon to construct Boolean logical gates and a one-bit half-adder with interacting voltage pulses. We discuss implications of these findings on cellular process and technological applications.

  11. Range gated strip proximity sensor

    DOEpatents

    McEwan, Thomas E.

    1996-01-01

    A range gated strip proximity sensor uses one set of sensor electronics and a distributed antenna or strip which extends along the perimeter to be sensed. A micro-power RF transmitter is coupled to the first end of the strip and transmits a sequence of RF pulses on the strip to produce a sensor field along the strip. A receiver is coupled to the second end of the strip, and generates a field reference signal in response to the sequence of pulse on the line combined with received electromagnetic energy from reflections in the field. The sensor signals comprise pulses of radio frequency signals having a duration of less than 10 nanoseconds, and a pulse repetition rate on the order of 1 to 10 MegaHertz or less. The duration of the radio frequency pulses is adjusted to control the range of the sensor. An RF detector feeds a filter capacitor in response to received pulses on the strip line to produce a field reference signal representing the average amplitude of the received pulses. When a received pulse is mixed with a received echo, the mixing causes a fluctuation in the amplitude of the field reference signal, providing a range-limited Doppler type signature of a field disturbance.

  12. Range gated strip proximity sensor

    DOEpatents

    McEwan, T.E.

    1996-12-03

    A range gated strip proximity sensor uses one set of sensor electronics and a distributed antenna or strip which extends along the perimeter to be sensed. A micro-power RF transmitter is coupled to the first end of the strip and transmits a sequence of RF pulses on the strip to produce a sensor field along the strip. A receiver is coupled to the second end of the strip, and generates a field reference signal in response to the sequence of pulse on the line combined with received electromagnetic energy from reflections in the field. The sensor signals comprise pulses of radio frequency signals having a duration of less than 10 nanoseconds, and a pulse repetition rate on the order of 1 to 10 MegaHertz or less. The duration of the radio frequency pulses is adjusted to control the range of the sensor. An RF detector feeds a filter capacitor in response to received pulses on the strip line to produce a field reference signal representing the average amplitude of the received pulses. When a received pulse is mixed with a received echo, the mixing causes a fluctuation in the amplitude of the field reference signal, providing a range-limited Doppler type signature of a field disturbance. 6 figs.

  13. Gramicidin channels are internally gated.

    PubMed

    Jones, Tyson L; Fu, Riqiang; Nielson, Frederick; Cross, Timothy A; Busath, David D

    2010-04-21

    Gramicidin channels are archetypal molecular subjects for solid-state NMR studies and investigations of single-channel or cation conductance. Until now, the transitions between on and off conductance states have been thought, based on multichannel studies, to represent monomer <--> dimer reactions. Here we use a single-molecule deposition method (vesicle fusion to a planar bilayer) to show that gramicidin dimer channels do not normally dissociate when conductance terminates. Furthermore, the observation of two 13C peaks in solid-state NMR indicates very stable dichotomous conformations for both the first and second peptide bonds in the monomers, and a two-dimensional chemical exchange spectrum with a 12-s mixing time demonstrates that the Val1 carbonyl conformations exchange slowly, with lifetimes of several seconds. It is proposed that gramicidin channels are gated by small conformational changes in the channel near the permeation pathway. These studies demonstrate how regulation of conformations governing closed <--> open transitions may be achieved and studied at the molecular level.

  14. Sensory gating deficits in parents of schizophrenics

    SciTech Connect

    Waldo, M.; Madison, A.; Freedman, R.

    1995-12-18

    Although schizophrenia clusters in families, it is not inherited in Mendelian fashion. This suggests that there may be alternative phenotypic expressions of genes that convey risk for schizophrenia, such as more elementary physiological or biochemical defects. One proposed phenotype is impaired inhibitory gating of the auditory evoked potential to repeated stimuli. Normally, the amplitude of the P50 response to the second stimulus is significantly less than the response to the first, but this gating of response is generally impaired in schizophrenia. Clinically unaffected individuals within a pedigree who have both an ancestral and descendant history of schizophrenia may be useful for studying whether this physiological defect is a possible alternative phenotype. We have studied inhibitory gating of the auditory P50 response to pairs of auditory stimuli in 17 nuclear families. In 11, there was one parent who had another relative with a chronic psychotic illness, in addition to the schizophrenic proband. AR of the parents with family histories of schizophrenia had gating of the P50 response similar to their schizophrenia offspring, whereas only 7% of the parents without family history had gating of the P50 response in the abnormal range. These results support loss of gating of the auditory P50 wave as an inherited deficit related to schizophrenia and suggest that studies of parents may help elucidate the neurobiological expression of genes that convey risk for schizophrenia. 36 refs., 2 figs., 2 tabs.

  15. Radiation-Insensitive Inverse Majority Gates

    NASA Technical Reports Server (NTRS)

    Manohara, Harish; Mojarradi, Mohammad

    2008-01-01

    To help satisfy a need for high-density logic circuits insensitive to radiation, it has been proposed to realize inverse majority gates as microscopic vacuum electronic devices. In comparison with solid-state electronic devices ordinarily used in logic circuits, vacuum electronic devices are inherently much less adversely affected by radiation and extreme temperatures. The proposed development would involve state-of-the-art micromachining and recent advances in the fabrication of carbon-nanotube-based field emitters. A representative three-input inverse majority gate would be a monolithic, integrated structure that would include three gate electrodes, six bundles of carbon nanotubes (serving as electron emitters) at suitable positions between the gate electrodes, and an overhanging anode. The bundles of carbon nanotubes would be grown on degenerately doped silicon substrates that would be parts of the monolithic structure. The gate electrodes would be fabricated as parts of the monolithic structure by means of a double-silicon-on-insulator process developed at NASA's Jet Propulsion Laboratory. The tops of the bundles of carbon nanotubes would lie below the plane of the tops of the gate electrodes. The particular choice of shapes, dimensions, and relative positions of the electrodes and bundles of carbon nanotubes would provide for both field emission of electrons from the bundles of carbon nanotubes and control of the electron current to obtain the inverse majority function, which is described in the paper.

  16. Gated entry into the ciliary compartment.

    PubMed

    Takao, Daisuke; Verhey, Kristen J

    2016-01-01

    Cilia and flagella play important roles in cell motility and cell signaling. These functions require that the cilium establishes and maintains a unique lipid and protein composition. Recent work indicates that a specialized region at the base of the cilium, the transition zone, serves as both a barrier to entry and a gate for passage of select components. For at least some cytosolic proteins, the barrier and gate functions are provided by a ciliary pore complex (CPC) that shares molecular and mechanistic properties with nuclear gating. Specifically, nucleoporins of the CPC limit the diffusional entry of cytosolic proteins in a size-dependent manner and enable the active transport of large molecules and complexes via targeting signals, importins, and the small G protein Ran. For membrane proteins, the septin protein SEPT2 is part of the barrier to entry whereas the gating function is carried out and/or regulated by proteins associated with ciliary diseases (ciliopathies) such as nephronophthisis, Meckel–Gruber syndrome and Joubert syndrome. Here, we discuss the evidence behind these models of ciliary gating as well as the similarities to and differences from nuclear gating. PMID:26472341

  17. High-Confidence Quantum Gate Tomography

    NASA Astrophysics Data System (ADS)

    Johnson, Blake; da Silva, Marcus; Ryan, Colm; Kimmel, Shelby; Donovan, Brian; Ohki, Thomas

    2014-03-01

    Debugging and verification of high-fidelity quantum gates requires the development of new tools and protocols to unwrap the performance of the gate from the rest of the sequence. Randomized benchmarking tomography[2] allows one to extract full information of the unital portion of the gate with high confidence. We report experimental confirmation of the technique's applicability to quantum gate tomography. We show that the method is robust to common experimental imperfections such as imperfect single-shot readout and state preparation. We also demonstrate the ability to characterize non-Clifford gates. To assist in the experimental implementation we introduce two techniques. ``Atomic Cliffords'' use phase ramping and frame tracking to allow single-pulse implementation of the full group of single-qubit Clifford gates. Domain specific pulse sequencers allow rapid implementation of the many thousands of sequences needed. This research was funded by the Office of the Director of National Intelligence (ODNI), Intelligence Advanced Research Projects Activity (IARPA), through the Army Research Office contract no. W911NF-10-1-0324.

  18. Gate-set tomography and beyond

    NASA Astrophysics Data System (ADS)

    Blume-Kohout, Robin

    Four years ago, there was no reliable way to characterize and debug quantum gates. Process tomography required perfectly pre-calibrated gates, while randomized benchmarking only yielded an overall error rate. Gate-set tomography (GST) emerged around 2012-13 in several variants (most notably at IBM; see PRA 87, 062119) to address this need, providing complete and calibration-free characterization of gates. At Sandia, we have pushed the capabilities of GST well beyond these initial goals. In this talk, I'll demonstrate our open web interface, show how we characterize gates with accuracy at the Heisenberg limit, discuss how we put error bars on the results, and present experimental GST estimates with 1e-5 error bars. I'll also present preliminary results of GST on 2-qubit gates, including a brief survey of the tricks we use to make it possible. I'll conclude with an analysis of GST's limitations (e.g., it scales poorly), and the techniques under development for characterizing and debugging larger (3+ qubit) systems.

  19. Shielded silicon gate complementary MOS integrated circuit.

    NASA Technical Reports Server (NTRS)

    Lin, H. C.; Halsor, J. L.; Hayes, P. J.

    1972-01-01

    An electrostatic shield for complementary MOS integrated circuits was developed to minimize the adverse effects of stray electric fields created by the potentials in the metal interconnections. The process is compatible with silicon gate technology. N-doped polycrystalline silicon was used for all the gates and the shield. The effectiveness of the shield was demonstrated by constructing a special field plate over certain transistors. The threshold voltages obtained on an oriented silicon substrate ranged from 1.5 to 3 V for either channel. Integrated inverters performed satisfactorily from 3 to 15 V, limited at the low end by the threshold voltages and at the high end by the drain breakdown voltage of the n-channel transistors. The stability of the new structure with an n-doped silicon gate as measured by the shift in C-V curve under 200 C plus or minus 20 V temperature-bias conditions was better than conventional aluminum gate or p-doped silicon gate devices, presumably due to the doping of gate oxide with phosphorous.

  20. Cardiac gating with a pulse oximeter for dual-energy imaging

    NASA Astrophysics Data System (ADS)

    Shkumat, N. A.; Siewerdsen, J. H.; Dhanantwari, A. C.; Williams, D. B.; Paul, N. S.; Yorkston, J.; Van Metter, R.

    2008-11-01

    The development and evaluation of a prototype cardiac gating system for double-shot dual-energy (DE) imaging is described. By acquiring both low- and high-kVp images during the resting phase of the cardiac cycle (diastole), heart misalignment between images can be reduced, thereby decreasing the magnitude of cardiac motion artifacts. For this initial implementation, a fingertip pulse oximeter was employed to measure the peripheral pulse waveform ('plethysmogram'), offering potential logistic, cost and workflow advantages compared to an electrocardiogram. A gating method was developed that accommodates temporal delays due to physiological pulse propagation, oximeter waveform processing and the imaging system (software, filter-wheel, anti-scatter Bucky-grid and flat-panel detector). Modeling the diastolic period allowed the calculation of an implemented delay, timp, required to trigger correctly during diastole at any patient heart rate (HR). The model suggests a triggering scheme characterized by two HR regimes, separated by a threshold, HRthresh. For rates at or below HRthresh, sufficient time exists to expose on the same heartbeat as the plethysmogram pulse [timp(HR) = 0]. Above HRthresh, a characteristic timp(HR) delays exposure to the subsequent heartbeat, accounting for all fixed and variable system delays. Performance was evaluated in terms of accuracy and precision of diastole-trigger coincidence and quantitative evaluation of artifact severity in gated and ungated DE images. Initial implementation indicated 85% accuracy in diastole-trigger coincidence. Through the identification of an improved HR estimation method (modified temporal smoothing of the oximeter waveform), trigger accuracy of 100% could be achieved with improved precision. To quantify the effect of the gating system on DE image quality, human observer tests were conducted to measure the magnitude of cardiac artifact under conditions of successful and unsuccessful diastolic gating. Six observers

  1. Respiratory gating in positron emission tomography: A quantitative comparison of different gating schemes

    SciTech Connect

    Dawood, Mohammad; Buether, Florian; Lang, Norbert; Schober, Otmar; Schaefers, Klaus P

    2007-07-15

    Respiratory gating is used for reducing the effects of breathing motion in a wide range of applications from radiotherapy treatment to diagnostical imaging. Different methods are feasible for respiratory gating. In this study seven gating methods were developed and tested on positron emission tomography (PET) listmode data. The results of seven patient studies were compared quantitatively with respect to motion and noise. (1) Equal and (2) variable time-based gating methods use only the time information of the breathing cycle to define respiratory gates. (3) Equal and (4) variable amplitude-based gating approaches utilize the amplitude of the respiratory signal. (5) Cycle-based amplitude gating is a combination of time and amplitude-based techniques. A baseline correction was applied to methods (3) and (4) resulting in two new approaches: Baseline corrected (6) equal and (7) variable amplitude-based gating. Listmode PET data from seven patients were acquired together with a respiratory signal. Images were reconstructed applying the seven gating methods. Two parameters were used to quantify the results: Motion was measured as the displacement of the heart due to respiration and noise was defined as the standard deviation of pixel intensities in a background region. The amplitude-based approaches (3) and (4) were superior to the time-based methods (1) and (2). The improvement in capturing the motion was more than 30% (up to 130%) in all subjects. The variable time (2) and amplitude (4) methods had a more uniform noise distribution among all respiratory gates compared to equal time (1) and amplitude (3) methods. Baseline correction did not improve the results. Out of seven different respiratory gating approaches, the variable amplitude method (4) captures the respiratory motion best while keeping a constant noise level among all respiratory phases.

  2. Etching characteristics of high-k dielectric HfO{sub 2} thin films in inductively coupled fluorocarbon plasmas

    SciTech Connect

    Takahashi, Kazuo; Ono, Kouichi; Setsuhara, Yuichi

    2005-11-15

    Inductively coupled fluorocarbon (CF{sub 4}/Ar and C{sub 4}F{sub 8}/Ar) plasmas were used to etch HfO{sub 2}, which is a promising high-dielectric-constant material for the gate of complementary metal-oxide-semiconductor devices. The etch rates of HfO{sub 2} in CF{sub 4}/Ar plasmas exceeded those in C{sub 4}F{sub 8}/Ar plasmas. The tendency for etch rates to become higher in fluorine-rich (high F/C ratio) conditions indicates that HfO{sub 2} can be chemically etched by fluorine-containing species. In C{sub 4}F{sub 8}/Ar plasmas with a high Ar dilution ratio, the etch rate of HfO{sub 2} increased with increasing bias power. The etch rate of Si, however, decreased with bias power, suggesting that the deposition of carbon-containing species increased with increasing the power and inhibited the etching of Si. The HfO{sub 2}/Si selectivity monotonically increased with increasing power, then became more than 5 at the highest tested bias power. The carbon-containing species to inhibit etching of Si play an important role in enhancing the HfO{sub 2}/Si selectivity in C{sub 4}F{sub 8}/Ar plasmas.

  3. Room temperature Si {delta}-growth on Ge incorporating high-K dielectric for metal oxide semiconductor applications

    SciTech Connect

    Hong, Augustin J.; Ogawa, Masaaki; Wang, Kang L.; Wang Yong; Zou Jin; Xu Zheng; Yang Yang

    2008-07-14

    A low temperature Al{sub 2}O{sub 3}/4 monolayer amorphous Si gate stack process was demonstrated on p-type Ge wafers using atomic layer deposition and molecular beam epitaxy. Multifrequency capacitance-voltage (C-V) and current-voltage (I-V) characteristics showed excellent electrical properties of the Pt/Al{sub 2}O{sub 3}/4 ML Si/Ge metal oxide semiconductor capacitor. No kinks from 1 MHz to 4 kHz and a leakage current density of 2.6x10{sup -6} A/cm{sup 2} at 1 V with an equivalent oxide thickness of 2.5 nm. The interface characterization using a conductance method showed that interface trap density at the near midgap was 8x10{sup 12} eV{sup -1} cm{sup -2} and a mean capture cross section of holes was extracted to be 10{sup -16} cm{sup 2}.

  4. Inadequacy of high K+/nigericin for calibrating BCECF. I. Estimating steady-state intracellular pH.

    PubMed

    Boyarsky, G; Hanssen, C; Clyne, L A

    1996-10-01

    Intracellular pH (pHi) was measured in single vascular smooth muscle (VSM) cells, cultured from rabbit abdominal aorta, using 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein (BCECF) on a microscope-based fluorescence system. Three lines of evidence are presented that using nigericin along with high external K+ to calibrate intracellular BCECF produces systematic errors in pHi. 1) The intrinsic buffering power (beta int), measured using weak bases (e.g., ammonium), was 2.5 times smaller than that measured using weak acids (e.g., propionic acid). This discrepancy became small if pHi had really been approximately 0.2 lower than what was estimated using nigericin-calibrated pHi values. 2) Total cellular buffering power (beta tot) in the presence of CO2/HCO-3 was measured and found to be much smaller than could account for the beta int, together with the contribution of CO2/HCO3 (beta CO2: assumed to be an open system buffer). If the true pHi values were approximately 0.2-0.4 lower than our nigericin-calibrated values, then the sum of beta int and beta CO2 equals beta tot. 3) A null technique was utilized for bracketing steady-state pHi; estimates of steady-state pHi using this null technique were approximately 0.2 lower than the high K+/nigericin-calibrated estimates. Four other cell types were examined: rat hepatocytes, rat corticotrophs, human keratinocytes, and rabbit fibroblasts. These other cells also displayed discrepancies between null and nigericin estimates of steady-state pHi, as well as differences between buffering power assessed using weak bases and acids. Finally, one potential source for these discrepancies is described: selecting an inappropriate external K+ to use with nigericin can produce systematic errors in pHi of approximately 0.1. PMID:8897819

  5. Schottky barrier height reduction for metal/n-InP by inserting ultra-thin atomic layer deposited high-k dielectrics

    SciTech Connect

    Zheng, Shan; Yang, Wen; Sun, Qing-Qing E-mail: linchen@fudan.edu.cn; Zhou, Peng; Wang, Peng-Fei; Wei Zhang, David; Chen, Lin; Xiao, Fei

    2013-12-23

    Fermi level pinning at metal/n-InP interface and effective Schottky barrier height (Φ{sub B,eff}) were optimized by inserting ultrathin dielectrics in this work. Comparing the inserted monolayer and bilayer high-k dielectrics, we demonstrated that the introduction of bilayer dielectrics can further reduce Φ{sub B,eff} (from 0.49 eV to 0.22 eV) than the monolayer dielectric (from 0.49 eV to 0.32 eV) even though the overall dielectric thickness was thicker. The additional dipole formed at high-k/high-k interfaces could be used to expound the mechanism. This work proposed an effective solution to reduce resistance contacts for InP based transistors and Schottky barrier transistors.

  6. Gated SIT Vidicon Streak Tube

    NASA Astrophysics Data System (ADS)

    Dunbar, D. L.; Yates, G. J.; Black, J. P.

    1986-01-01

    A recently developed prototype streak tube designed to produce high gain and resolution by incorporating the streak and readout functions in one envelope thereby minimizing photon-to-charge transformations and eliminating external coupling losses is presented. The tube is based upon a grid-gated Silicon-Intensified-Target Vidicon (SITV) with integral Focus Projection Scan (FPS) TV readout. Demagnifying electron optics (m=0.63) in the image section map the 40-mm-diameter photocathode image unto a 25-mm-diameter silicon target where gains >= 103 are achieved with only 10 KV accelerating voltage. This is compared with much lower gains (~ 50) at much higher voltages (~ 30 KV) reported for streak tubes using phosphor screens. Because SIT technology is well established means for electron imaging in vacuum, such fundamental problems as "backside thinning" required for electron imaging unto CCDs do not exist. The high spatial resolution (~ 30 1p/mm), variable scan formats, and high speed electrostatic deflection (250 mm2 areas are routinely rastered with 256 scan lines in 1.6 ms) available from FPS readout add versatility not available in CCD devices. Theoretical gain and spatial resolution for this design (developed jointly by Los Alamos National Laboratory and General Electric Co.) are compared with similar calculations and measured data obtained for RCA 73435 streaks fiber optically coupled to (1) 25-mm-diameter SIT FPS vidicons and (2) 40-mm-diameter MCPTs (proximity-focused microchannel plate image intensifier tubes) fiber optically coupled to 18-mm-diameter Sb2S3 FPS vidicons. Sweep sensitivity, shutter ratio, and record lengths for nanosecond duration (20 to 200 ns) streak applications are discussed.

  7. Annealing effects of in-depth profile and band discontinuity in TiN/LaO/HfSiO/SiO{sub 2}/Si gate stack structure studied by angle-resolved photoemission spectroscopy from backside

    SciTech Connect

    Toyoda, S.; Kumigashira, H.; Oshima, M.; Kamada, H.; Tanimura, T.; Ohtsuka, T.; Hata, Y.; Niwa, M.

    2010-01-25

    We have investigated annealing effects on in-depth profile and band discontinuity for a metal gate/high-k gate stack structure on a Si substrate using backside angle-resolved photoemission spectroscopy with synchrotron radiation. In-depth profiles analyzed from angle-resolved photoemission spectroscopy show that La atoms diffuse through the HfSiO layer and reach interfacial SiO{sub 2} layers by rapid thermal annealing. Chemical shift of Si 2p core-level spectra suggests that there are changes in the band discontinuity at the high-k/SiO{sub 2} interface, which is well related to the V{sub th} shift based on the interface dipole model.

  8. Gallium arsenide processing for gate array logic

    NASA Technical Reports Server (NTRS)

    Cole, Eric D.

    1989-01-01

    The development of a reliable and reproducible GaAs process was initiated for applications in gate array logic. Gallium Arsenide is an extremely important material for high speed electronic applications in both digital and analog circuits since its electron mobility is 3 to 5 times that of silicon, this allows for faster switching times for devices fabricated with it. Unfortunately GaAs is an extremely difficult material to process with respect to silicon and since it includes the arsenic component GaAs can be quite dangerous (toxic) especially during some heating steps. The first stage of the research was directed at developing a simple process to produce GaAs MESFETs. The MESFET (MEtal Semiconductor Field Effect Transistor) is the most useful, practical and simple active device which can be fabricated in GaAs. It utilizes an ohmic source and drain contact separated by a Schottky gate. The gate width is typically a few microns. Several process steps were required to produce a good working device including ion implantation, photolithography, thermal annealing, and metal deposition. A process was designed to reduce the total number of steps to a minimum so as to reduce possible errors. The first run produced no good devices. The problem occurred during an aluminum etch step while defining the gate contacts. It was found that the chemical etchant attacked the GaAs causing trenching and subsequent severing of the active gate region from the rest of the device. Thus all devices appeared as open circuits. This problem is being corrected and since it was the last step in the process correction should be successful. The second planned stage involves the circuit assembly of the discrete MESFETs into logic gates for test and analysis. Finally the third stage is to incorporate the designed process with the tested circuit in a layout that would produce the gate array as a GaAs integrated circuit.

  9. Heralded quantum gates with integrated error detection in optical cavities.

    PubMed

    Borregaard, J; Kómár, P; Kessler, E M; Sørensen, A S; Lukin, M D

    2015-03-20

    We propose and analyze heralded quantum gates between qubits in optical cavities. They employ an auxiliary qubit to report if a successful gate occurred. In this manner, the errors, which would have corrupted a deterministic gate, are converted into a nonunity probability of success: once successful, the gate has a much higher fidelity than a similar deterministic gate. Specifically, we describe that a heralded, near-deterministic controlled phase gate (CZ gate) with the conditional error arbitrarily close to zero and the success probability that approaches unity as the cooperativity of the system, C, becomes large. Furthermore, we describe an extension to near-deterministic N-qubit Toffoli gate with a favorable error scaling. These gates can be directly employed in quantum repeater networks to facilitate near-ideal entanglement swapping, thus greatly speeding up the entanglement distribution.

  10. Sliding-gate valve for use with abrasive materials

    DOEpatents

    Ayers, Jr., William J.; Carter, Charles R.; Griffith, Richard A.; Loomis, Richard B.; Notestein, John E.

    1985-01-01

    The invention is a flow and pressure-sealing valve for use with abrasive solids. The valve embodies special features which provide for long, reliable operating lifetimes in solids-handling service. The valve includes upper and lower transversely slidable gates, contained in separate chambers. The upper gate provides a solids-flow control function, whereas the lower gate provides a pressure-sealing function. The lower gate is supported by means for (a) lifting that gate into sealing engagement with its seat when the gate is in its open and closed positions and (b) lowering the gate out of contact with its seat to permit abrasion-free transit of the gate between its open and closed positions. When closed, the upper gate isolates the lower gate from the solids. Because of this shielding action, the sealing surface of the lower gate is not exposed to solids during transit or when it is being lifted or lowered. The chamber containing the lower gate normally is pressurized slightly, and a sweep gas is directed inwardly across the lower-gate sealing surface during the vertical translation of the gate.

  11. BK channels: multiple sensors, one activation gate.

    PubMed

    Yang, Huanghe; Zhang, Guohui; Cui, Jianmin

    2015-01-01

    Ion transport across cell membranes is essential to cell communication and signaling. Passive ion transport is mediated by ion channels, membrane proteins that create ion conducting pores across cell membrane to allow ion flux down electrochemical gradient. Under physiological conditions, majority of ion channel pores are not constitutively open. Instead, structural region(s) within these pores breaks the continuity of the aqueous ion pathway, thereby serves as activation gate(s) to control ions flow in and out. To achieve spatially and temporally regulated ion flux in cells, many ion channels have evolved sensors to detect various environmental stimuli or the metabolic states of the cell and trigger global conformational changes, thereby dynamically operate the opening and closing of their activation gate. The sensors of ion channels can be broadly categorized as chemical sensors and physical sensors to respond to chemical (such as neural transmitters, nucleotides and ions) and physical (such as voltage, mechanical force and temperature) signals, respectively. With the rapidly growing structural and functional information of different types of ion channels, it is now critical to understand how ion channel sensors dynamically control their gates at molecular and atomic level. The voltage and Ca(2+) activated BK channels, a K(+) channel with an electrical sensor and multiple chemical sensors, provide a unique model system for us to understand how physical and chemical energy synergistically operate its activation gate.

  12. BK channels: multiple sensors, one activation gate

    PubMed Central

    Yang, Huanghe; Zhang, Guohui; Cui, Jianmin

    2015-01-01

    Ion transport across cell membranes is essential to cell communication and signaling. Passive ion transport is mediated by ion channels, membrane proteins that create ion conducting pores across cell membrane to allow ion flux down electrochemical gradient. Under physiological conditions, majority of ion channel pores are not constitutively open. Instead, structural region(s) within these pores breaks the continuity of the aqueous ion pathway, thereby serves as activation gate(s) to control ions flow in and out. To achieve spatially and temporally regulated ion flux in cells, many ion channels have evolved sensors to detect various environmental stimuli or the metabolic states of the cell and trigger global conformational changes, thereby dynamically operate the opening and closing of their activation gate. The sensors of ion channels can be broadly categorized as chemical sensors and physical sensors to respond to chemical (such as neural transmitters, nucleotides and ions) and physical (such as voltage, mechanical force and temperature) signals, respectively. With the rapidly growing structural and functional information of different types of ion channels, it is now critical to understand how ion channel sensors dynamically control their gates at molecular and atomic level. The voltage and Ca2+ activated BK channels, a K+ channel with an electrical sensor and multiple chemical sensors, provide a unique model system for us to understand how physical and chemical energy synergistically operate its activation gate. PMID:25705194

  13. Cylindrical gate valve apparatus and method

    SciTech Connect

    Hynes, J. H.; Morrill, C. D.

    1985-04-30

    A safety valve is disclosed which may be installed on an offshore wellhead above the tubing head and below the Christmas tree. The valve has a housing with upper and lower vertical passages and a lateral housing passage. A cylindrical gate is disposed within the lateral passage and includes a ''T'' shaped passage therein. The gate may be moved laterally and angularly within the lateral passage. During completion or workover of the well, the gate is moved laterally until the upper and lower vertical passages are in full open communication to run drills, hangers or other large diameter devices into the well via a BOP which may be attached to the top of the housing. During normal production, the gate may be laterally moved into the intersection of the vertical and lateral passages and the small through head part of the ''T'' passage serves to provide a vertical flow path through the production bore which is sealed off from the larger upper and lower vertical passages. Flow through side outlets in the housing is possible through the base of the ''T'' passage. The gate may be angularly moved to have production to the lateral outlets via the head part of the ''T'' when the base part of the ''T'' is aligned with production tubing. Should the need arise, the valve may be angularly rotated to a position where the fluid flow path of the production tubing is completely shut in.

  14. Comparative band alignment of plasma-enhanced atomic layer deposited high-k dielectrics on gallium nitride

    SciTech Connect

    Yang Jialing; Eller, Brianna S.; Zhu Chiyu; England, Chris; Nemanich, Robert J.

    2012-09-01

    Al{sub 2}O{sub 3} films, HfO{sub 2} films, and HfO{sub 2}/Al{sub 2}O{sub 3} stacked structures were deposited on n-type, Ga-face, GaN wafers using plasma-enhanced atomic layer deposition (PEALD). The wafers were first treated with a wet-chemical clean to remove organics and an in-situ combined H{sub 2}/N{sub 2} plasma at 650 Degree-Sign C to remove residual carbon contamination, resulting in a clean, oxygen-terminated surface. This cleaning process produced slightly upward band bending of 0.1 eV. Additional 650 Degree-Sign C annealing after plasma cleaning increased the upward band bending by 0.2 eV. After the initial clean, high-k oxide films were deposited using oxygen PEALD at 140 Degree-Sign C. The valence band and conduction band offsets (VBOs and CBOs) of the Al{sub 2}O{sub 3}/GaN and HfO{sub 2}/GaN structures were deduced from in-situ x-ray and ultraviolet photoemission spectroscopy (XPS and UPS). The valence band offsets were determined to be 1.8 and 1.4 eV, while the deduced conduction band offsets were 1.3 and 1.0 eV, respectively. These values are compared with the theoretical calculations based on the electron affinity model and charge neutrality level model. Moreover, subsequent annealing had little effect on these offsets; however, the GaN band bending did change depending on the annealing and processing. An Al{sub 2}O{sub 3} layer was investigated as an interfacial passivation layer (IPL), which, as results suggest, may lead to improved stability, performance, and reliability of HfO{sub 2}/IPL/GaN structures. The VBOs were {approx}0.1 and 1.3 eV, while the deduced CBOs were 0.6 and 1.1 eV for HfO{sub 2} with respect to Al{sub 2}O{sub 3} and GaN, respectively.

  15. Phlogopite-clinopyroxenite nodules from high-K magmas, Roccamonfina Volcano, Italy: evidence for a low-pressure metasomatic origin

    NASA Astrophysics Data System (ADS)

    Giannetti, Bernardino; Luhr, James F.

    1990-12-01

    Dense nodules containing phlogopite (Mg-number > 80), clinopyroxene, and vesicular glass with subordinate olivine and Cr-spinel are found at Roccamonfina Volcano in pyroclastic deposits of widely varying ages and compositions. Significantly, phlogopite has never been observed as a phenocryst in any volcanic rock at Roccamonfina. In the nodules, phlogopite shows a variety of reaction textures in relation to both clinopyroxene and olivine. Each of the major minerals and glass is compositionally homogeneous within a single nodule, and the suite as a whole shows systematic correlations of Mg-number among these phases. Clinopyroxene (En 40-47) and olivine (Fo 81-87) compositions closely match phenocryst compositions from basic lavas at Roccamonfina, but Cr-spinel compositions strongly diverge from those in Roccamonfina volcanic rocks. Sr and Nd isotopic compositions of whole-rock nodules and constituent minerals fall within the field for high-K series (HKS) volcanic rocks, although minor isotopic disequilibrium is noted among minerals of individual nodules. Euhedral crystals are enclosed by interstitial glass, indicating that the glasses represent residual melts and are not products of in-situ partial melting. Of analyzed glasses from five nodules, three are ne-normative and compositionally similar to HKS tephrite magma compositions, one is hy-normative and similar to low-K series (LKS) trachyandesites, and the other has larnite in the norm and is unlike any known volcanic rock. In addition to other more basic host rock types, phlogopite pyroxenites are found within voluminous pyroclastics ranging from leucite tephrites to highly evolved phonolites and trachytes. These rocks have strong depletions in Sr, Ba, and Eu, consistent with extensive fractionation in low-pressure magma chambers. Consequently the phlogopite pyroxenites are also constrained to have formed at low pressures. This interpretation conflicts with several previous hypotheses for the origin of similar

  16. Impact of oxidation and reduction annealing on the electrical properties of Ge/La2O3/ZrO2 gate stacks.

    PubMed

    Henkel, Christoph; Hellström, Per-Erik; Ostling, Mikael; Stöger-Pollach, Michael; Bethge, Ole; Bertagnolli, Emmerich

    2012-08-01

    The paper addresses the passivation of Germanium surfaces by using layered La2O3/ZrO2 high-k dielectrics deposited by Atomic Layer Deposition to be applied in Ge-based MOSFET devices. Improved electrical properties of these multilayered gate stacks exposed to oxidizing and reducing ambient during thermal post treatment in presence of thin Pt cap layers are demonstrated. The results suggest the formation of thin intermixed La x Ge y O z interfacial layers with thicknesses controllable by oxidation time. This formation is further investigated by XPS, EDX/EELS and TEM analysis. An additional reduction annealing treatment further improves the electrical properties of the gate dielectrics in contact with the Ge substrate. As a result low interface trap densities on (1 0 0) Ge down to 3 × 10(11) eV(-1) cm(-2) are demonstrated. The formation of the high-k La x Ge y O z layer is in agreement with the oxide densification theory and may explain the improved interface trap densities. The scaling potential of the respective layered gate dielectrics used in Ge-based MOS-based device structures to EOT of 1.2 nm or below is discussed. A trade-off between improved interface trap density and a lowered equivalent oxide thickness is found. PMID:23483756

  17. Impact of oxidation and reduction annealing on the electrical properties of Ge/La2O3/ZrO2 gate stacks

    PubMed Central

    Henkel, Christoph; Hellström, Per-Erik; Östling, Mikael; Stöger-Pollach, Michael; Bethge, Ole; Bertagnolli, Emmerich

    2012-01-01

    The paper addresses the passivation of Germanium surfaces by using layered La2O3/ZrO2 high-k dielectrics deposited by Atomic Layer Deposition to be applied in Ge-based MOSFET devices. Improved electrical properties of these multilayered gate stacks exposed to oxidizing and reducing ambient during thermal post treatment in presence of thin Pt cap layers are demonstrated. The results suggest the formation of thin intermixed LaxGeyOz interfacial layers with thicknesses controllable by oxidation time. This formation is further investigated by XPS, EDX/EELS and TEM analysis. An additional reduction annealing treatment further improves the electrical properties of the gate dielectrics in contact with the Ge substrate. As a result low interface trap densities on (1 0 0) Ge down to 3 × 1011 eV−1 cm−2 are demonstrated. The formation of the high-k LaxGeyOz layer is in agreement with the oxide densification theory and may explain the improved interface trap densities. The scaling potential of the respective layered gate dielectrics used in Ge-based MOS-based device structures to EOT of 1.2 nm or below is discussed. A trade-off between improved interface trap density and a lowered equivalent oxide thickness is found. PMID:23483756

  18. Mechanisms for plasma etching of HfO{sub 2} gate stacks with Si selectivity and photoresist trimming

    SciTech Connect

    Shoeb, Juline; Kushner, Mark J.

    2009-11-15

    To minimize leakage currents resulting from the thinning of the insulator in the gate stack of field effect transistors, high-dielectric constant (high-k) metal oxides, and HfO{sub 2} in particular, are being implemented as a replacement for SiO{sub 2}. To speed the rate of processing, it is desirable to etch the gate stack (e.g., metal gate, antireflection layers, and dielectric) in a single process while having selectivity to the underlying Si. Plasma etching using Ar/BCl{sub 3}/Cl{sub 2} mixtures effectively etches HfO{sub 2} while having good selectivity to Si. In this article, results from integrated reactor and feature scale modeling of gate-stack etching in Ar/BCl{sub 3}/Cl{sub 2} plasmas, preceded by photoresist trimming in Ar/O{sub 2} plasmas, are discussed. It was found that BCl{sub n} species react with HfO{sub 2}, which under ion impact, form volatile etch products such as B{sub m}OCl{sub n} and HfCl{sub n}. Selectivity to Si is achieved by creating Si-B bonding as a precursor to the deposition of a BCl{sub n} polymer which slows the etch rate relative to HfO{sub 2}. The low ion energies required to achieve this selectivity then challenge one to obtain highly anisotropic profiles in the metal gate portion of the stack. Validation was performed with data from literature. The effect of bias voltage and key reactant probabilities on etch rate, selectivity, and profile are discussed.

  19. Four-gate transistor analog multiplier circuit

    NASA Technical Reports Server (NTRS)

    Mojarradi, Mohammad M. (Inventor); Blalock, Benjamin (Inventor); Cristoloveanu, Sorin (Inventor); Chen, Suheng (Inventor); Akarvardar, Kerem (Inventor)

    2011-01-01

    A differential output analog multiplier circuit utilizing four G.sup.4-FETs, each source connected to a current source. The four G.sup.4-FETs may be grouped into two pairs of two G.sup.4-FETs each, where one pair has its drains connected to a load, and the other par has its drains connected to another load. The differential output voltage is taken at the two loads. In one embodiment, for each G.sup.4-FET, the first and second junction gates are each connected together, where a first input voltage is applied to the front gates of each pair, and a second input voltage is applied to the first junction gates of each pair. Other embodiments are described and claimed.

  20. Majorana fermions in nanowires without gating superconductors

    NASA Astrophysics Data System (ADS)

    Lin, Chien-Hung; Hui, Hoi Yin; Sau, Jay; Das Sarma, Sankar

    2011-03-01

    Majorana fermions have been proposed to be realizable at the end of the semiconductor nanowire on top of an s-wave superconductor [1,2]. These proposals require gating the nanowire directly in contact with a superconductor which may be difficult in experiments. We analyze [1,2] in configurations where the wire is only gated away from the superconductor. We show that some signatures of the Majorana mode remain but the Majorana mode is not localized and hence not suitable for quantum computation. Therefore we propose an 1D periodic heterostructure which can support localized Majorana modes at the end of the wire without gating on the superconductor. This work is supported by DARPA-QuEST, JQI-NSF-PFC, and LPS-NSA.

  1. Clinically applicable gated cardiac computed tomography

    SciTech Connect

    Cipriano, P.R.; Nassi, M.; Brody, W.R.

    1983-03-01

    Several attempts have been made to improve cardiac images obtained with x-ray transmission computed tomography (CT) by stopping cardiac motion through electrocardiographic gating. These methods reconstruct images that correspond to time intervals of the cardiac cycle identified by electrocardiography using either a pulsed x-ray beam at a selected time in the cardiac cycle or selected measurements in retrospect from regularly pulsed measurements made over several cardiac cycles. Missing CT angles of view (line integrals) have been a major problem contributing to degradation of such gated cardiac CT images. A new method for CT reconstruction from an incomplete set of projection data is presented that can be used clinically with a standard fan-beam reconstruction algorithm to improve gated cardiac CT images.

  2. Hydrophobic gating in single and multiple nanopores

    NASA Astrophysics Data System (ADS)

    Innes, Laura Michele

    The ion transport properties of hydrophobic conical nanopores in polymer films in the presence of a salt solution were studied. The purpose of this study was to develop a hydrophobic gating mechanism similar to those seen in biological channels. Current-voltage curves were measured to determine if the gating behavior was present in hydrophobic modified nanopores, which would be seen as a zero ion current for small voltages and a finite ion current for larger voltages. It is shown, that for a single nanopore to gate water, it must be partially modified such that there are hydrophobic and hydrophilic islands on the pore walls. Similar experiments were also done with 105 pores/cm2 mutlipore samples.

  3. Transversal Clifford gates on folded surface codes

    NASA Astrophysics Data System (ADS)

    Moussa, Jonathan E.

    2016-10-01

    Surface and color codes are two forms of topological quantum error correction in two spatial dimensions with complementary properties. Surface codes have lower-depth error detection circuits and well-developed decoders to interpret and correct errors, while color codes have transversal Clifford gates and better code efficiency in the number of physical qubits needed to achieve a given code distance. A formal equivalence exists between color codes and folded surface codes, but it does not guarantee the transferability of any of these favorable properties. However, the equivalence does imply the existence of constant-depth circuit implementations of logical Clifford gates on folded surface codes. We achieve and improve this result by constructing two families of folded surface codes with transversal Clifford gates. This construction is presented generally for qudits of any dimension. The specific application of these codes to universal quantum computation based on qubit fusion is also discussed.

  4. The Airport Gate Assignment Problem: A Survey

    PubMed Central

    Ghaleb, Mageed A.; Salem, Ahmed M.

    2014-01-01

    The airport gate assignment problem (AGAP) is one of the most important problems operations managers face daily. Many researches have been done to solve this problem and tackle its complexity. The objective of the task is assigning each flight (aircraft) to an available gate while maximizing both conveniences to passengers and the operational efficiency of airport. This objective requires a solution that provides the ability to change and update the gate assignment data on a real time basis. In this paper, we survey the state of the art of these problems and the various methods to obtain the solution. Our survey covers both theoretical and real AGAP with the description of mathematical formulations and resolution methods such as exact algorithms, heuristic algorithms, and metaheuristic algorithms. We also provide a research trend that can inspire researchers about new problems in this area. PMID:25506074

  5. Active gated imaging for automotive safety applications

    NASA Astrophysics Data System (ADS)

    Grauer, Yoav; Sonn, Ezri

    2015-03-01

    The paper presents the Active Gated Imaging System (AGIS), in relation to the automotive field. AGIS is based on a fast gated-camera equipped with a unique Gated-CMOS sensor, and a pulsed Illuminator, synchronized in the time domain to record images of a certain range of interest which are then processed by computer vision real-time algorithms. In recent years we have learned the system parameters which are most beneficial to night-time driving in terms of; field of view, illumination profile, resolution and processing power. AGIS provides also day-time imaging with additional capabilities, which enhances computer vision safety applications. AGIS provides an excellent candidate for camera-based Advanced Driver Assistance Systems (ADAS) and the path for autonomous driving, in the future, based on its outstanding low/high light-level, harsh weather conditions capabilities and 3D potential growth capabilities.

  6. Operational life prediction on gating image intensifier

    NASA Astrophysics Data System (ADS)

    Dong, Yu-hui; Shen, Zhi-guo; Li, Zhong-li

    2009-07-01

    Operational life is one of the important parameters to evaluate second and super second generation image intensifiers. It can be used not only to monitor manufacturing technique in product line, then the technology on photocathode processing, MCP degassing and MCP producing can be adjusted promptly, but also to eliminate the image intensifiers which have hidden risk on operational life as early as possible. Recently gating image intensifiers are used widely, method to estimate the operational life of gating image intensifier related to its practical operate mode and working condition need to be established urgently. The least square method to analyze the operational life test data in product line was introduced in this paper. Now the data can be analyzed with convenient statistic analyze function on Excel. Using "worksheet function" and "chart wizard" and "data analysis" on Excel to do the least square method calculation, spreadsheets are established to do complex data calculation with worksheet functions. Based on them, formulas to monitor the technology parameters were derived, and the conclusion that the operational life was only related to the decrease slope of photocathode exponential fit curve was made. The decrease slope of photocathode sensitivity exponential fit curve and the decrease percent of the exponential fit photocathode sensitivity can be used to evaluate the qualification of the operational life rapidly. The mathematic models for operational life prediction on image intensifier and gating image intensifier are established respectively based on the acceptable values of the decrease percent of the exponential fit photocathode sensitivity and the expecting signal to noise ratio. The equations predicting the operational life related to duty cycle and input light level on gating image intensifier were derived, and the relationship between them were discussed too. The theory foundation were made herein, so the user can select proper gating image

  7. Maritime target identification in gated viewing imagery

    NASA Astrophysics Data System (ADS)

    Hammer, Marcus; Hebel, Marcus; Arens, Michael

    2015-10-01

    The growing interest in unmanned surface vehicles, accident avoidance for naval vessels and automated maritime surveillance leads to a growing need for automatic detection, classification and pose estimation of maritime objects in medium and long ranges. Laser radar imagery is a well proven tool for near to medium range, but up to now for higher distances neither the sensor range nor the sensor resolution was satisfying. As a result of the mentioned limitations of laser radar imagery the potential of laser illuminated gated viewing for automated classification and pose estimation was investigated. The paper presents new techniques for segmentation, pose estimation and model-based identification of naval vessels in gated viewing imagery in comparison with the corresponding results of long range data acquired with a focal plane array laser radar system. The pose estimation in the gated viewing data is directly connected with the model-based identification which makes use of the outline of the object. By setting a sufficient narrow gate, the distance gap between the upper part of the ship and the background leads to an automatic segmentation. By setting the gate the distance to the object is roughly known. With this distance and the imaging properties of the camera, the width of the object perpendicular to the line of sight can be calculated. For each ship in the model library a set of possible 2D appearances in the known distance is calculated and the resulting contours are compared with the measured 2D outline. The result is a match error for each reasonable orientation of each model of the library. The result gained from the gated viewing data is compared with the results of target identification by laser radar imagery of the same maritime objects.

  8. Coherent spaces, Boolean rings and quantum gates

    NASA Astrophysics Data System (ADS)

    Vourdas, A.

    2016-10-01

    Coherent spaces spanned by a finite number of coherent states, are introduced. Their coherence properties are studied, using the Dirac contour representation. It is shown that the corresponding projectors resolve the identity, and that they transform into projectors of the same type, under displacement transformations, and also under time evolution. The set of these spaces, with the logical OR and AND operations is a distributive lattice, and with the logical XOR and AND operations is a Boolean ring (Stone's formalism). Applications of this Boolean ring into classical CNOT gates with n-ary variables, and also quantum CNOT gates with coherent states, are discussed.

  9. Cyclic groups and quantum logic gates

    NASA Astrophysics Data System (ADS)

    Pourkia, Arash; Batle, J.; Raymond Ooi, C. H.

    2016-10-01

    We present a formula for an infinite number of universal quantum logic gates, which are 4 by 4 unitary solutions to the Yang-Baxter (Y-B) equation. We obtain this family from a certain representation of the cyclic group of order n. We then show that this discrete family, parametrized by integers n, is in fact, a small sub-class of a larger continuous family, parametrized by real numbers θ, of universal quantum gates. We discuss the corresponding Yang-Baxterization and related symmetries in the concomitant Hamiltonian.

  10. Gated IR Images of Shocked Surfaces

    SciTech Connect

    S. S. Lutz; W. D. Turley; P. M. Rightley; L. E. Primas

    2001-06-01

    Gated infrared (IR) images have been taken of a series of shocked surface geometries in tin. Metal coupons machined with steps and flats were mounted directly to the high explosive. The explosive was point-initiated and 500-ns to 1-microsecond-wide gated images of the target were taken immediately following shock breakout using a Santa Barbara Focalplane InSb camera (SBF-134). Spatial distributions of surface radiance were extracted from the images of the shocked samples and found to be non-single-valued. Several geometries were modeled using CTH, a two-dimensional Eulerian hydrocode.

  11. Properties of coherence-gated wavefront sensing.

    PubMed

    Rueckel, Markus; Denk, Winfried

    2007-11-01

    Coherence-gated wavefront sensing (CGWS) allows the determination of wavefront aberrations in strongly scattering tissue and their correction by adaptive optics. This allows, e.g., the restoration of the diffraction limit in light microscopy. Here, we develop a model, based on ray tracing of ballistic light scattered from a set of discrete scatterers, to characterize CGWS performance as it depends on coherence length, scatterer density, coherence-gate position, and polarization. The model is evaluated by using Monte Carlo simulation and verified against experimental measurements. We show, in particular, that all aberrations needed for adaptive wavefront restoration are correctly sensed if circularly polarized light is used. PMID:17975579

  12. Gated IR Images of Shocked Surfaces

    NASA Astrophysics Data System (ADS)

    Lutz, Stephen S.; Turley, W. Dale; Rightley, Paul M.; Primas, Lori E.

    2002-07-01

    Gated infrared (IR) images have been taken of a series of shocked surface geometries in tin. Metal coupons machined with steps and flats were mounted directly to the high explosive. The explosive was point-initiated and 500-ns to 1-microsecond-wide gated images of the target were taken immediately following shock breakout using a Santa Barbara Focalplane InSb camera (SBF-134). Spatial distributions of surface radiance were extracted from the images of the shocked samples and found to be non-single-valued. Several surfaces were modeled using CTH, a 2- or 3-dimensional Eulerian hydrocode.

  13. Gated IR images of shocked surfaces.

    SciTech Connect

    Lutz, S. S.; Turley, W. D.; Rightley, P. M.; Primas, L. E.

    2001-01-01

    Gated infrared (IR) images have been taken of a series of shocked surface geometries in tin. Metal coupons machined with steps and flats were mounted directly to the high explosive. The explosive was point-initiated and 500-ns to 1-microsecond-wide gated images of the target were taken immediately following shock breakout using a Santa Barbara Focalplane InSb camera (SBF-134). Spatial distributions of surface radiance were extracted from the images of the shocked samples and found to be non-single-valued. Several geometries were modeled using CTH, a two-dimensional Eulerian hydrocode.

  14. Single-qubit gates by graph scattering

    NASA Astrophysics Data System (ADS)

    Underwood, Michael S.; Blumer, Benjamin A.; Feder, David L.

    2012-02-01

    Continuous-time quantum walkers with tightly peaked momenta can simulate quantum computations by scattering off finite graphs. We enumerate all single-qubit gates that can be enacted by scattering off a single graph on up to n=9 vertices at certain momentum values, and provide numerical evidence that the number of such gates grows exponentially with n. The single-qubit rotations are about axes distributed roughly uniformly on the Bloch sphere, and rotations by both rational and irrational multiples of π are found.

  15. 5. DETAIL VIEW OF DAM, SHOWING ROLLER AND TAINTER GATES, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. DETAIL VIEW OF DAM, SHOWING ROLLER AND TAINTER GATES, GATE PIERS, HEADHOUSES AND DAM BRIDGE, LOOKING NORTHWEST, UPSTREAM - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 9, Lynxville, Crawford County, WI

  16. 6. DETAIL VIEW OF TAINTER GATE PIER AND NONSUBMERSIBLE TAINTER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. DETAIL VIEW OF TAINTER GATE PIER AND NON-SUBMERSIBLE TAINTER GATE, SHOWING MAIN LOCK IN BACKGROUND, LOOKING NORTH (UPSTREAM) - Upper Mississippi River 9-Foot Channel Project, Lock & Dam 26R, Alton, Madison County, IL

  17. 1. General view of crossing gate tower, taken in 1916 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. General view of crossing gate tower, taken in 1916 (courtesy of Erie Railroad Company) (photocopy) - Erie Railway, Crossing Gate Tower, West side of Lincoln Street, 100 feet South of Concord Street, Union City, Erie County, PA

  18. 11. DETAIL OF UPSTREAM FACE OF SLUICE GATE CONTROLS FROM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. DETAIL OF UPSTREAM FACE OF SLUICE GATE CONTROLS FROM CATWALK, SHOWING GATE LIFTING GEARS (TOP) AND GEAR SHAFTS (BOTTOM). VIEW TO SOUTHWEST. - Boise Project, Boise River Diversion Dam, Across Boise River, Boise, Ada County, ID

  19. 12. DETAIL VIEW OF CIRCULAR BRONZE ROLLER GATE POSITION GAUGE, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. DETAIL VIEW OF CIRCULAR BRONZE ROLLER GATE POSITION GAUGE, ROLLER GATE PIER HOUSE, TYPE 2A, DAM - Mississippi River 9-Foot Channel Project, Lock & Dam No. 11, Upper Mississippi River, Dubuque, Dubuque County, IA

  20. 1. UPPER SEGMENT OF SPILLWAY CHANNEL, DRUM GATES ALONG SIDE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. UPPER SEGMENT OF SPILLWAY CHANNEL, DRUM GATES ALONG SIDE OF CHANNEL, LOOKING SOUTH (up the channel) - Tieton Dam, Spillway & Drum Gates, South & East side of State Highway 12, Naches, Yakima County, WA

  1. 4. SPILLWAY DRUM GATES AND CHANNEL, LOOKING NORTHEAST (upstream face ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. SPILLWAY DRUM GATES AND CHANNEL, LOOKING NORTHEAST (upstream face and Control House in background) - Tieton Dam, Spillway & Drum Gates, South & East side of State Highway 12, Naches, Yakima County, WA

  2. 12. MESSRS. MAUREK AND QUIST RAISING GATE TO ALLOW FIRST ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. MESSRS. MAUREK AND QUIST RAISING GATE TO ALLOW FIRST WATER TO PASS (IT TOOK SIX MEN 30 MINUTES TO RAISE THE GATE FIVE FEET) - Upper Souris National Wildlife Refuge, Dam 96, Souris River Basin, Foxholm, Surrey (England), ND

  3. 5. DETAIL VIEW OF THE RADIAL GATE AT THE OUTLET ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. DETAIL VIEW OF THE RADIAL GATE AT THE OUTLET WORKS AT DAM 96, LOOKING WEST. THE GATE IS IN THE DOWN POSITION, ALLOWING PARTIAL DISCHARGE. - Upper Souris National Wildlife Refuge, Dam 96, Souris River Basin, Foxholm, Surrey (England), ND

  4. 5. DETAIL VIEW OF RADIAN GATE (LEFT, IN RAISED POSITION) ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. DETAIL VIEW OF RADIAN GATE (LEFT, IN RAISED POSITION) AND HAND- OPERATED GATE HOISTS (RIGHT), LOOKING WEST - Upper Souris National Wildlife Refuge, Dam 87, Souris River Basin, Foxholm, Surrey (England), ND

  5. 13. WATER BEING RELEASED THRU 4 X 4 GATE AT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. WATER BEING RELEASED THRU 4 X 4 GATE AT DAM 96 TO PROVIDE WATER CUSHION PRIOR TO OPENING RADIAL GATE - Upper Souris National Wildlife Refuge, Dam 96, Souris River Basin, Foxholm, Surrey (England), ND

  6. 37. VIEW OF AUXILIARY LOCK MITER GATE, WITH MAIN LOCK ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    37. VIEW OF AUXILIARY LOCK MITER GATE, WITH MAIN LOCK UPSTREAM MITER GATE AND UPSTREAM GUIDE WALL IN BACKGROUND, LOOKING NORTHEAST - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 4, Alma, Buffalo County, WI

  7. 3. DETAIL VIEW OF DAM, SHOWING ROLLER AND TAINTER GATES, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. DETAIL VIEW OF DAM, SHOWING ROLLER AND TAINTER GATES, GATE PIERS, HEADHOUSES AND DAM BRIDGES, LOOKING SOUTH, DOWNSTREAM - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 4, Alma, Buffalo County, WI

  8. UPSTREAM LOCK GATE DETAIL AND DOG HOUSE. NOTE ARM AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    UPSTREAM LOCK GATE DETAIL AND DOG HOUSE. NOTE ARM AND GEARING FOR CONTROLLING LOCK GATE. LOOKING WEST SOUTHWEST. - Illinois Waterway, Brandon Road Lock and Dam , 1100 Brandon Road, Joliet, Will County, IL

  9. DOWNSTREAM LOCK GATE DETAIL VIEW WITH DOG HOUSE. NOTE CONTROL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DOWNSTREAM LOCK GATE DETAIL VIEW WITH DOG HOUSE. NOTE CONTROL ARM AND GEAR FOR GATE. LOOKING NORTHWEST. - Illinois Waterway, Dresden Island Lock and Dam , 7521 North Lock Road, Channahon, Will County, IL

  10. XML-based Gating Descriptions in Flow Cytometry

    PubMed Central

    Spidlen, Josef; Leif, Robert; Moore, Wayne; Roederer, Mario; Brinkman, Ryan R.

    2008-01-01

    Background The lack of software interoperability with respect to gating due to lack of a standardized mechanism for data exchange has traditionally been a bottleneck preventing reproducibility of flow cytometry (FCM) data analysis and the usage of multiple analytical tools. Methods To facilitate interoperability among FCM data analysis tools, members of the International Society for the Advancement of Cytometry (ISAC) Data Standards Task Force (DSTF) have developed an XML-based mechanism to formally describe gates (Gating-ML). Results Gating-ML, an open specification for encoding gating, data transformations and compensation, has been adopted by the ISAC DSTF as a Candidate Recommendation (CR). Conclusions Gating-ML can facilitate exchange of gating descriptions the same way that FCS facilitated for exchange of raw FCM data. Its adoption will open new collaborative opportunities as well as possibilities for advanced analyses and methods development. The ISAC DSTF is satisfied that the standard addresses the requirements for a gating exchange standard. PMID:18773465

  11. 15. OVERALL VIEW OF UPSTREAM FACE OF LIFT GATE SECTION ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. OVERALL VIEW OF UPSTREAM FACE OF LIFT GATE SECTION WITH TAINTER GATE SECTION OF SPILLWAY TO THE LEFT. VIEW TO SOUTHWEST. - Starved Rock Locks & Dam, Illinois Waterway River mile 231, Peru, La Salle County, IL

  12. 19. STAIRWAY TO TAINTER GATE SECTION OF SPILLWAY, SHOWING STEAM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    19. STAIRWAY TO TAINTER GATE SECTION OF SPILLWAY, SHOWING STEAM PIPES EMERGING FROM BOILERHOUSE (RIGHT) AND CONCRETE TAINTER GATE COUNTER WEIGHTS (BACKGROUND RIGHT). VIEW TO SOUTH. - Starved Rock Locks & Dam, Illinois Waterway River mile 231, Peru, La Salle County, IL

  13. 10. UPSTREAM SIDE OF UPPER MITER GATES SHOWING STOWED LEFT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. UPSTREAM SIDE OF UPPER MITER GATES SHOWING STOWED LEFT WING OF UPPER GUARD GATE (FAR LEFT). VIEW TO NORTHWEST. - Starved Rock Locks & Dam, Illinois Waterway River mile 231, Peru, La Salle County, IL

  14. 10. FACING SOUTH FROM WALKWAY OVER HEADRACE TOWARD TRASH GATE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. FACING SOUTH FROM WALKWAY OVER HEADRACE TOWARD TRASH GATE (BOTTOM) AND MILL NO. 1. NOTE GATE HOIST CRANKS ON LEFT, WHEELS ON RIGHT. - Prattville Manufacturing Company, Number One, 242 South Court Street, Prattville, Autauga County, AL

  15. 2. ALABAMA GATES LOOKING SOUTHEAST ALONG LINED CHANNEL, NOTE CHEMICAL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. ALABAMA GATES LOOKING SOUTHEAST ALONG LINED CHANNEL, NOTE CHEMICAL PURIFICATION TANK IN DISTANCE FOR KEEPING DOWN GROWTH OF ALGAE - Los Angeles Aqueduct, Alabama Gates, Los Angeles, Los Angeles County, CA

  16. NORTH GATE AT 11TH AVENUE (490 NORTH & 900 EAST), ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    NORTH GATE AT 11TH AVENUE (490 NORTH & 900 EAST), SALT LAKE CITY, UT. VIEW LOOKING SOUTH AT CEMETERY'S NORTH GATE (WPA PROJECT, 1938-1941). - Salt Lake City Cemetery, 200 N Street, Salt Lake City, Salt Lake County, UT

  17. WEST PIER OF NORTH GATE (490 NORTH & 900 EAST), ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    WEST PIER OF NORTH GATE (490 NORTH & 900 EAST), SALT LAKE CITY, UT. VIEW LOOKING SOUTH AT THE WEST PIER OF THE CEMETERY'S NORTH GATE. - Salt Lake City Cemetery, 200 N Street, Salt Lake City, Salt Lake County, UT

  18. Improved Classical Simulation of Quantum Circuits Dominated by Clifford Gates

    NASA Astrophysics Data System (ADS)

    Bravyi, Sergey; Gosset, David

    2016-06-01

    We present a new algorithm for classical simulation of quantum circuits over the Clifford+T gate set. The runtime of the algorithm is polynomial in the number of qubits and the number of Clifford gates in the circuit but exponential in the number of T gates. The exponential scaling is sufficiently mild that the algorithm can be used in practice to simulate medium-sized quantum circuits dominated by Clifford gates. The first demonstrations of fault-tolerant quantum circuits based on 2D topological codes are likely to be dominated by Clifford gates due to a high implementation cost associated with logical T gates. Thus our algorithm may serve as a verification tool for near-term quantum computers which cannot in practice be simulated by other means. To demonstrate the power of the new method, we performed a classical simulation of a hidden shift quantum algorithm with 40 qubits, a few hundred Clifford gates, and nearly 50 T gates.

  19. 4. VIEW NORTHWEST, INTERIOR OF GATEHOUSE, SHOWING ROW OF GATE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. VIEW NORTHWEST, INTERIOR OF GATEHOUSE, SHOWING ROW OF GATE OPERATING MECHANISMS; HEIGHT OF STEMS INDICATES FOREGROUND GATE IS OPEN - Norwich Water Power Company, Headgates, West bank of Shetucket River opposite Fourteenth Street, Greenville section, Norwich, New London County, CT

  20. 5. VIEW OF INCLINED OUTLET GATE WHEEL, STEM AND STEM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. VIEW OF INCLINED OUTLET GATE WHEEL, STEM AND STEM GUIDE, (12' DIAMETER HARDESTY MODEL 112 CIRCULAR GATE), LOOKING NORTHEAST - High Mountain Dams in Bonneville Unit, Island Lake Dam, Wasatch National Forest, Kamas, Summit County, UT

  1. 5. VIEW OF UPRIGHT OUTLET GATE, STEM, STEM GUIDE AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. VIEW OF UPRIGHT OUTLET GATE, STEM, STEM GUIDE AND WHEEL (10' HARDESTY CAST IRON VERTICAL LIFT GATE), LOOKING WEST - High Mountain Dams in Bonneville Unit, Weir Lake Dam, Wasatch National Forest, Kamas, Summit County, UT

  2. 4. VIEW OF INCLINED OUTLET GATE, STEM, STEM GUIDE AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. VIEW OF INCLINED OUTLET GATE, STEM, STEM GUIDE AND WHEEL (10' HARDESTY VERTICAL LIFT GATE), LOOKING NORTHWEST - High Mountain Dams in Bonneville Unit, Pot Lake Dam, Wasatch National Forest, Kamas, Summit County, UT

  3. 6. VIEW SHOWING INCLINED OUTLET GATE WHEEL, STEM AND STEM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. VIEW SHOWING INCLINED OUTLET GATE WHEEL, STEM AND STEM GUIDE (18' HARDESTY GATE), LOOKING SOUTHEAST - High Mountain Dams in Bonneville Unit, Long Lake Dam, Wasatch National Forest, Kamas, Summit County, UT

  4. 7. VIEW OF INCLINED OUTLET GATE WHEEL, STEM AND STEM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. VIEW OF INCLINED OUTLET GATE WHEEL, STEM AND STEM GUIDE (15' HARDESTY MODEL 115 GATE), LOOKING NORTHWEST - High Mountain Dams in Bonneville Unit, Marjorie Lake Dam, Wasatch National Forest, Kamas, Summit County, UT

  5. 7. VIEW OF UPRIGHT OUTLET GATE, WHEEL STEM AND STEM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. VIEW OF UPRIGHT OUTLET GATE, WHEEL STEM AND STEM GUIDE (14' DIAMETER CIRCULAR CALCO CAST IRON SLIDE GATE), LOOKING SOUTHEAST - High Mountain Dams in Bonneville Unit, Fire Lake Dam, Wasatch National Forest, Kamas, Summit County, UT

  6. 5. VIEW OF UPRIGHT OUTLET GATE WHEEL, STEM AND STEM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. VIEW OF UPRIGHT OUTLET GATE WHEEL, STEM AND STEM GUIDE (HARDESTY CAST IRON RECTANGULAR SLIDE GATE), LOOKING SOUTHWEST - High Mountain Dams in Bonneville Unit, Lost Lake Dam, Kamas, Summit County, UT

  7. 14. DETAILS OF GATE OPERATING MECHANISM, SHOWING RACK SECTION, CUT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. DETAILS OF GATE OPERATING MECHANISM, SHOWING RACK SECTION, CUT TEETH, CAST TEETH, GATE PINION (1907) - Nine Mile Hydroelectric Development, Powerhouse, State Highway 291 along Spokane River, Nine Mile Falls, Spokane County, WA

  8. 7. South gate to Migel Estate and Farm along original ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. South gate to Migel Estate and Farm along original alignment. Gate located at intersection of Orange Turnpike and Harriman Heights Road. View looking north. - Orange Turnpike, Parallel to new Orange Turnpike, Monroe, Orange County, NY

  9. Learning robust pulses for generating universal quantum gates

    PubMed Central

    Dong, Daoyi; Wu, Chengzhi; Chen, Chunlin; Qi, Bo; Petersen, Ian R.; Nori, Franco

    2016-01-01

    Constructing a set of universal quantum gates is a fundamental task for quantum computation. The existence of noises, disturbances and fluctuations is unavoidable during the process of implementing quantum gates for most practical quantum systems. This paper employs a sampling-based learning method to find robust control pulses for generating a set of universal quantum gates. Numerical results show that the learned robust control fields are insensitive to disturbances, uncertainties and fluctuations during the process of realizing universal quantum gates. PMID:27782219

  10. Influence of Underlap on Gate Stack DG-MOSFET for analytical study of Analog/RF performance

    NASA Astrophysics Data System (ADS)

    Kundu, Atanu; Dasgupta, Arpan; Das, Rahul; Chakraborty, Shramana; Dutta, Arka; Sarkar, Chandan K.

    2016-06-01

    In this paper, the characteristics of 18 nm Underlap Double Gate (U-DG) NMOSFET with gate stack, (GS) are presented. The high-k dielectric as gate insulator under consideration is Hafnium Dioxide (HfO2). The SiO2 padding reduces the effect of scattering at the silicon and oxide interface. The ratio of on current to off current is used for optimizing the underlap length. The Analog and RF performance comparison are shown in this paper considering the drain current (Id), the transconductance (gm), the intrinsic gain (gmRo), the intrinsic capacitances (Cgs, Cgd), the intrinsic resistances (Rgs, Rgd), the transport delay (τm), the intrinsic inductance (Hsd), the unity current gain cut-off frequency (fT) and the maximum frequency of oscillation (fmax). RF parameters are extracted using the Non Quasi Static (NQS) model of the U-DG MOSFET. The performance of single stage amplifiers using the devices is also analyzed. The sharpest transition is shown in case of U-DG-GS MOSFET with optimized underlap length and enhancement in the intrinsic capacitances and resistances, and unity Gain Bandwidth product in case of devices with GS.

  11. Influence of Underlap on Gate Stack DG-MOSFET for analytical study of Analog/RF performance

    NASA Astrophysics Data System (ADS)

    Kundu, Atanu; Dasgupta, Arpan; Das, Rahul; Chakraborty, Shramana; Dutta, Arka; Sarkar, Chandan K.

    2016-06-01

    In this paper, the characteristics of 18 nm Underlap Double Gate (U-DG) NMOSFET with gate stack, (GS) are presented. The high-k dielectric as gate insulator under consideration is Hafnium Dioxide (HfO2). The SiO2 padding reduces the effect of scattering at the silicon and oxide interface. The ratio of on current to off current is used for optimizing the underlap length. The Analog and RF performance comparison are shown in this paper considering the drain current (Id), the transconductance (gm), the intrinsic gain (gmRo), the intrinsic capacitances (Cgs, Cgd), the intrinsic resistances (Rgs, Rgd), the transport delay (τm), the intrinsic inductance (Hsd), the unity current gain cut-off frequency (fT) and the maximum frequency of oscillation (fmax). RF parameters are extracted using the Non Quasi Static (NQS) model of the U-DG MOSFET. The performance of single stage amplifiers using the devices is also analyzed. The sharpest transition is shown in case of U-DG-GS MOSFET with optimized underlap length and enhancement in the intrinsic capacitances and resistances, and unity Gain Bandwidth product in case of devices with GS.

  12. Detail of elevation gauge, radial gate hoist mechanism, and concrete ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail of elevation gauge, radial gate hoist mechanism, and concrete walkway on top of the gate. View to the south-southwest - Wellton-Mohawk Irrigation System, Radial Gate Check with Drop, Wellton Canal 9.9, West of Avenue 34 East & north of County Ninth Street, Wellton, Yuma County, AZ

  13. 14 CFR 417.217 - Overflight gate analysis.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 4 2011-01-01 2011-01-01 false Overflight gate analysis. 417.217 Section..., DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH SAFETY Flight Safety Analysis § 417.217 Overflight gate... analysis must include an overflight gate analysis. The analysis must establish the portion of a...

  14. 30 CFR 56.19070 - Closing cage doors or gates.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Closing cage doors or gates. 56.19070 Section 56.19070 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Hoisting Hoisting Procedures § 56.19070 Closing cage doors or gates. Cage doors or gates shall be...

  15. 30 CFR 57.19070 - Closing cage doors or gates.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Closing cage doors or gates. 57.19070 Section 57.19070 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Hoisting Hoisting Procedures § 57.19070 Closing cage doors or gates. Cage doors or gates shall be...

  16. 30 CFR 56.19070 - Closing cage doors or gates.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Closing cage doors or gates. 56.19070 Section 56.19070 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Hoisting Hoisting Procedures § 56.19070 Closing cage doors or gates. Cage doors or gates shall be...

  17. 30 CFR 56.19070 - Closing cage doors or gates.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Closing cage doors or gates. 56.19070 Section 56.19070 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Hoisting Hoisting Procedures § 56.19070 Closing cage doors or gates. Cage doors or gates shall be...

  18. 30 CFR 57.19070 - Closing cage doors or gates.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Closing cage doors or gates. 57.19070 Section 57.19070 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Hoisting Hoisting Procedures § 57.19070 Closing cage doors or gates. Cage doors or gates shall be...

  19. 14 CFR 417.217 - Overflight gate analysis.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Overflight gate analysis. 417.217 Section..., DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH SAFETY Flight Safety Analysis § 417.217 Overflight gate... analysis must include an overflight gate analysis. The analysis must establish the portion of a...

  20. 30 CFR 57.19070 - Closing cage doors or gates.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Closing cage doors or gates. 57.19070 Section 57.19070 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Hoisting Hoisting Procedures § 57.19070 Closing cage doors or gates. Cage doors or gates shall be...

  1. 30 CFR 56.19070 - Closing cage doors or gates.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Closing cage doors or gates. 56.19070 Section 56.19070 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Hoisting Hoisting Procedures § 56.19070 Closing cage doors or gates. Cage doors or gates shall be...

  2. 30 CFR 57.19070 - Closing cage doors or gates.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Closing cage doors or gates. 57.19070 Section 57.19070 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Hoisting Hoisting Procedures § 57.19070 Closing cage doors or gates. Cage doors or gates shall be...

  3. 14 CFR 417.217 - Overflight gate analysis.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 4 2012-01-01 2012-01-01 false Overflight gate analysis. 417.217 Section..., DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH SAFETY Flight Safety Analysis § 417.217 Overflight gate... analysis must include an overflight gate analysis. The analysis must establish the portion of a...

  4. Intake side of the gate. The reservoir, stilling well, and ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Intake side of the gate. The reservoir, stilling well, and drop to the main canal channel are visible beyond the gate - Wellton-Mohawk Irrigation System, Radial Gate Check with Drop, Wellton Canal 9.9, West of Avenue 34 East & north of County Ninth Street, Wellton, Yuma County, AZ

  5. View of Sandbox and Spill Gate above Irving Powerhouse. The ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of Sandbox and Spill Gate above Irving Powerhouse. The Sandbox and Spill Gate are covered by the shed. Looking southeast - Childs-Irving Hydroelectric Project, Irving System, Sandbox & Spill Gate, Forest Service Road 708/502, Camp Verde, Yavapai County, AZ

  6. 30 CFR 56.19070 - Closing cage doors or gates.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Closing cage doors or gates. 56.19070 Section 56.19070 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Hoisting Hoisting Procedures § 56.19070 Closing cage doors or gates. Cage doors or gates shall be...

  7. 30 CFR 57.19070 - Closing cage doors or gates.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Closing cage doors or gates. 57.19070 Section 57.19070 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Hoisting Hoisting Procedures § 57.19070 Closing cage doors or gates. Cage doors or gates shall be...

  8. SUPPRESSION OF AFTERPULSING IN PHOTOMULTIPLIERS BY GATING THE PHOTOCATHODE

    EPA Science Inventory

    A number of gating schemes to minimize the long-term afterpulse signal in photomultipliers have been evaluated. Blocking the excitation pulse by gating the photocathode was found to reduce the gate-on afterpulse background by a factor of 230 over that for nongated operation. Thi...

  9. High-fidelity gates in quantum dot spin qubits.

    PubMed

    Koh, Teck Seng; Coppersmith, S N; Friesen, Mark

    2013-12-01

    Several logical qubits and quantum gates have been proposed for semiconductor quantum dots controlled by voltages applied to top gates. The different schemes can be difficult to compare meaningfully. Here we develop a theoretical framework to evaluate disparate qubit-gating schemes on an equal footing. We apply the procedure to two types of double-dot qubits: the singlet-triplet and the semiconducting quantum dot hybrid qubit. We investigate three quantum gates that flip the qubit state: a DC pulsed gate, an AC gate based on logical qubit resonance, and a gate-like process known as stimulated Raman adiabatic passage. These gates are all mediated by an exchange interaction that is controlled experimentally using the interdot tunnel coupling g and the detuning [Symbol: see text], which sets the energy difference between the dots. Our procedure has two steps. First, we optimize the gate fidelity (f) for fixed g as a function of the other control parameters; this yields an f(opt)(g) that is universal for different types of gates. Next, we identify physical constraints on the control parameters; this yields an upper bound f(max) that is specific to the qubit-gate combination. We show that similar gate fidelities (~99:5%) should be attainable for singlet-triplet qubits in isotopically purified Si, and for hybrid qubits in natural Si. Considerably lower fidelities are obtained for GaAs devices, due to the fluctuating magnetic fields ΔB produced by nuclear spins.

  10. 15. VIEW SHOWING WATER FLOWING THROUGH THE ORIGINAL DIVERSION GATE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. VIEW SHOWING WATER FLOWING THROUGH THE ORIGINAL DIVERSION GATE FROM THE OUTLET CHANNEL INTO THE BY-PASS CHANNEL LEADING TO THE ORIGINAL SOURIS RIVER CHANNEL (Note: this gate has since been replaced with concrete diversion gates, see HAER Photograph No ND-3-A-7) - Upper Souris National Wildlife Refuge, Dam 83, Souris River Basin, Foxholm, Surrey (England), ND

  11. 2. CLOSEUP OF SOUTH FACADE OF UPPER FALLS GATE HOUSE, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. CLOSEUP OF SOUTH FACADE OF UPPER FALLS GATE HOUSE, SHOWING TRASH RACKS, REMOVABLE STEEL DOORS, TRASH RAKE STRUCTURE, AND DERRICK, WINCH AND CABLE GATE LIFTING DEVICE, LOOKING SOUTH/SOUTHWEST. - Washington Water Power Spokane River Upper Falls Hydroelectric Development, Gate House, Spokane River, approximately 0.5 mile northeast of intersection of Spokane Falls Boulevard & Post Street, Spokane, Spokane County, WA

  12. Redesign of the GATE PET coincidence sorter

    NASA Astrophysics Data System (ADS)

    Strydhorst, Jared; Buvat, Irène

    2016-09-01

    The GATE software platform, based on the Geant4 toolkit for simulating particle interactions with matter, enables simulation of, among other medical imaging and treatment systems, positron emission tomography. However, at least one publication (Moraes et al 2015 Phys. Med. 31 43-8) has reported discrepancies between the expected results and those obtained using GATE simulations, specifically with respect to the coincidence sorter which processes single events detected by the scanner to find coincidence pairs. In particular, the current software appears to overestimate the number of ‘true’ coincidence pairs when in multi-window mode, while the delayed coincidence window, used to estimate the randoms present in the prompt coincidence window, underestimates the randoms. Both effects are particularly evident at high count rates. We have investigated this discrepancy and reproduced the reported problems. We have also rewritten the relevant portion of the GATE code to correct the issue. In this note we describe the modifications to the coincidence sorter and repeat the simulations which previously showed unexpected results. Some discrepancies remain in the estimation of the randoms with the single-window mode which are a consequence of the algorithm itself. In multi-window mode however, the simulation agrees exactly with the expected results. The modifications to the coincidence sorter code will be incorporated into the next release of GATE (> version 7.2).

  13. Pulse Shaping Entangling Gates and Error Supression

    NASA Astrophysics Data System (ADS)

    Hucul, D.; Hayes, D.; Clark, S. M.; Debnath, S.; Quraishi, Q.; Monroe, C.

    2011-05-01

    Control of spin dependent forces is important for generating entanglement and realizing quantum simulations in trapped ion systems. Here we propose and implement a composite pulse sequence based on the Molmer-Sorenson gate to decrease gate infidelity due to frequency and timing errors. The composite pulse sequence uses an optical frequency comb to drive Raman transitions simultaneously detuned from trapped ion transverse motional red and blue sideband frequencies. The spin dependent force displaces the ions in phase space, and the resulting spin-dependent geometric phase depends on the detuning. Voltage noise on the rf electrodes changes the detuning between the trapped ions' motional frequency and the laser, decreasing the fidelity of the gate. The composite pulse sequence consists of successive pulse trains from counter-propagating frequency combs with phase control of the microwave beatnote of the lasers to passively suppress detuning errors. We present the theory and experimental data with one and two ions where a gate is performed with a composite pulse sequence. This work supported by the U.S. ARO, IARPA, the DARPA OLE program, the MURI program; the NSF PIF Program; the NSF Physics Frontier Center at JQI; the European Commission AQUTE program; and the IC postdoc program administered by the NGA.

  14. Redesign of the GATE PET coincidence sorter

    NASA Astrophysics Data System (ADS)

    Strydhorst, Jared; Buvat, Irène

    2016-09-01

    The GATE software platform, based on the Geant4 toolkit for simulating particle interactions with matter, enables simulation of, among other medical imaging and treatment systems, positron emission tomography. However, at least one publication (Moraes et al 2015 Phys. Med. 31 43–8) has reported discrepancies between the expected results and those obtained using GATE simulations, specifically with respect to the coincidence sorter which processes single events detected by the scanner to find coincidence pairs. In particular, the current software appears to overestimate the number of ‘true’ coincidence pairs when in multi-window mode, while the delayed coincidence window, used to estimate the randoms present in the prompt coincidence window, underestimates the randoms. Both effects are particularly evident at high count rates. We have investigated this discrepancy and reproduced the reported problems. We have also rewritten the relevant portion of the GATE code to correct the issue. In this note we describe the modifications to the coincidence sorter and repeat the simulations which previously showed unexpected results. Some discrepancies remain in the estimation of the randoms with the single-window mode which are a consequence of the algorithm itself. In multi-window mode however, the simulation agrees exactly with the expected results. The modifications to the coincidence sorter code will be incorporated into the next release of GATE (> version 7.2).

  15. Gating systems for high voltage thyristor valves

    SciTech Connect

    Lips, H.P.; Pauli, M. )

    1988-07-01

    The requirements on gating systems for thyristor valves used in High Voltage Direct Current and Static Var Compensator systems are listed. Different techniques used to meet these requirements are discussed with a view on the specific service condition of the particular application and illustrated by service performance.

  16. Corner Office Interview: Gates Foundation's Deborah Jacobs

    ERIC Educational Resources Information Center

    Miller, Rebecca

    2010-01-01

    U.S. libraries gave the world a top talent when Deborah Jacobs left her transformational role as City Librarian of Seattle in 2008 to head the Bill & Melinda Gates Foundation's Global Libraries program, the international sibling to the U.S. Libraries program. The initiative fosters national-scale projects with grantees in transitioning countries…

  17. Gates Fund Creates Plan for College Completion

    ERIC Educational Resources Information Center

    Gose, Ben

    2008-01-01

    The Bill & Melinda Gates Foundation plans to spend several hundred million dollars over the next five years to double the number of low-income young people who complete a college degree or certificate program by age 26. Foundation officials described the ambitious plan to an exclusive group of education leaders, citing 2025 as a target goal. If…

  18. Slime mould gates, roads and sensors

    NASA Astrophysics Data System (ADS)

    Adamatzky, Andrew

    2015-03-01

    The photographs present a wide range of problems solved by the slime mould P. polycephalum: imitation of human-made transport pathways, realisation of Boolean logical gates, fabrication of self-repairing routable biowires, implementation of delay elements in computing circuits, computational geometry, sensors and a would-be nervous system...

  19. A fail-safe CMOS logic gate

    NASA Technical Reports Server (NTRS)

    Bobin, V.; Whitaker, S.

    1990-01-01

    This paper reports a design technique to make Complex CMOS Gates fail-safe for a class of faults. Two classes of faults are defined. The fail-safe design presented has limited fault-tolerance capability. Multiple faults are also covered.

  20. Automatic parameter extraction technique for gate leakage current modeling in double gate MOSFET

    NASA Astrophysics Data System (ADS)

    Darbandy, Ghader; Gneiting, Thomas; Alius, Heidrun; Alvarado, Joaquín; Cerdeira, Antonio; Iñiguez, Benjamin

    2013-11-01

    Direct Tunneling (DT) and Trap Assisted Tunneling (TAT) gate leakage current parameters have been extracted and verified considering automatic parameter extraction approach. The industry standard package IC-CAP is used to extract our leakage current model parameters. The model is coded in Verilog-A and the comparison between the model and measured data allows to obtain the model parameter values and parameters correlations/relations. The model and parameter extraction techniques have been used to study the impact of parameters in the gate leakage current based on the extracted parameter values. It is shown that the gate leakage current depends on the interfacial barrier height more strongly than the barrier height of the dielectric layer. There is almost the same scenario with respect to the carrier effective masses into the interfacial layer and the dielectric layer. The comparison between the simulated results and available measured gate leakage current transistor characteristics of Trigate MOSFETs shows good agreement.

  1. The regulation of respiration of guinea pig taenia coli in high-K medium: the role of nicotinamide-adenine dinucleotide, adenosine diphosphate and Ca++.

    PubMed

    Tsuda, S; Urakawa, N; Saito, Y; Fukami, J

    1975-10-01

    In an attempt to elucidate the regulation mechanism of respiration in the smooth muscle cell, we investigated the roles of nicotinamide-adenine dinucleotide (NAD), adenosine diphosphate (ADP) and Ca++ in the muscle respiration using the tissues and subcellular fractions from guinea pig taenia coli. The tension in the strips of taenia coli increased with a concomitant increase in O2 consumption in high-K medium (40 mM K) containing 2.5 mM Ca. 10(-3) M amytal and 10(-5)M ouabain decreased the high-K induced tension and O2 consumption of the muscle. 10(-4)M 2,4-dinitrophenol (DNP) relieved the decreased respiration induced by ouabain, but not that with amytal. From these data it is suggested that NADH-linked respiration plays an important role in the respiration of the muscle. Ca++ in concentrations ranging from 0.5 to 2.5 mM in the high-K medium resulted in an increase in tension and in O2 concumption progressively. In spectrophotometric observations of subcellular fractions of the taenia coli, ADP increased in absorbance change at 340 m mu. Such occurred in mitochondrial fractions and was initiated by the addition of NADH. Therefore it is deduced that the increase in ADP level of the cytoplasm is primarily due to a contraction triggered by Ca++ thus stimulating respiration. On the other hand, at 0.1 mM of Ca++ concentration, the muscle strip increased O2 consumption without tension development in high-K medium. In the spectrophotometric observations, Ca++ and Sr++ increased the absorbance change in the homogenate and in the mitochondrial fraction. Hence, it seems that one part of the Ca++ entering into the smooth muscle treated with the high-K increased O2 consumption in mitochondia independent of an increase in muscle tension. From these results it is concluded that NADH-linked respiration plays an important role in the smooth muscle respiration in high-K medium and that ADP and Ca++ also play a role in regulating respiration. PMID:176493

  2. Allosteric gating mechanism underlies the flexible gating of KCNQ1 potassium channels

    PubMed Central

    Osteen, Jeremiah D.; Barro-Soria, Rene; Robey, Seth; Sampson, Kevin J.; Kass, Robert S.; Larsson, H. Peter

    2012-01-01

    KCNQ1 (Kv7.1) is a unique member of the superfamily of voltage-gated K+ channels in that it displays a remarkable range of gating behaviors tuned by coassembly with different β subunits of the KCNE family of proteins. To better understand the basis for the biophysical diversity of KCNQ1 channels, we here investigate the basis of KCNQ1 gating in the absence of β subunits using voltage-clamp fluorometry (VCF). In our previous study, we found the kinetics and voltage dependence of voltage-sensor movements are very similar to those of the channel gate, as if multiple voltage-sensor movements are not required to precede gate opening. Here, we have tested two different hypotheses to explain KCNQ1 gating: (i) KCNQ1 voltage sensors undergo a single concerted movement that leads to channel opening, or (ii) individual voltage-sensor movements lead to channel opening before all voltage sensors have moved. Here, we find that KCNQ1 voltage sensors move relatively independently, but that the channel can conduct before all voltage sensors have activated. We explore a KCNQ1 point mutation that causes some channels to transition to the open state even in the absence of voltage-sensor movement. To interpret these results, we adopt an allosteric gating scheme wherein KCNQ1 is able to transition to the open state after zero to four voltage-sensor movements. This model allows for widely varying gating behavior, depending on the relative strength of the opening transition, and suggests how KCNQ1 could be controlled by coassembly with different KCNE family members. PMID:22509038

  3. COHERENTLY DEDISPERSED GATED IMAGING OF MILLISECOND PULSARS

    SciTech Connect

    Roy, Jayanta; Bhattacharyya, Bhaswati

    2013-03-10

    Motivated by the need for rapid localization of newly discovered faint millisecond pulsars (MSPs), we have developed a coherently dedispersed gating correlator. This gating correlator accounts for the orbital motions of MSPs in binaries while folding the visibilities with a best-fit topocentric rotational model derived from a periodicity search in a simultaneously generated beamformer output. Unique applications of the gating correlator for sensitive interferometric studies of MSPs are illustrated using the Giant Metrewave Radio Telescope (GMRT) interferometric array. We could unambiguously localize five newly discovered Fermi MSPs in the on-off gated image plane with an accuracy of {+-}1''. Immediate knowledge of such a precise position enables the use of sensitive coherent beams of array telescopes for follow-up timing observations which substantially reduces the use of telescope time ({approx}20 Multiplication-Sign for the GMRT). In addition, a precise a priori astrometric position reduces the effect of large covariances in the timing fit (with discovery position, pulsar period derivative, and an unknown binary model), which in-turn accelerates the convergence to the initial timing model. For example, while fitting with the precise a priori position ({+-}1''), the timing model converges in about 100 days, accounting for the effect of covariance between the position and pulsar period derivative. Moreover, such accurate positions allow for rapid identification of pulsar counterparts at other wave bands. We also report a new methodology of in-beam phase calibration using the on-off gated image of the target pulsar, which provides optimal sensitivity of the coherent array removing possible temporal and spacial decoherences.

  4. Statistical Determination of the Gating Windows for Respiratory-Gated Radiotherapy Using a Visible Guiding System

    PubMed Central

    Oh, Se An; Yea, Ji Woon

    2016-01-01

    Respiratory-gated radiation therapy (RGRT) is used to minimize the radiation dose to normal tissue in lung-cancer patients. Although determining the gating window in the respiratory phase of patients is important in RGRT, it is not easy. Our aim was to determine the optimal gating window when using a visible guiding system for RGRT. Between April and October 2014, the breathing signals of 23 lung-cancer patients were recorded with a real-time position management (RPM) respiratory gating system (Varian, USA). We performed statistical analysis with breathing signals to find the optimal gating window for guided breathing in RGRT. When we compared breathing signals before and after the breathing training, 19 of the 23 patients showed statistically significant differences (p < 0.05). The standard deviation of the respiration signals after breathing training was lowest for phases of 30%–70%. The results showed that the optimal gating window in RGRT is 40% (30%–70%) with respect to repeatability for breathing after respiration training with the visible guiding system. RGRT was performed with the RPM system to confirm the usefulness of the visible guiding system. The RPM system and our visible guiding system improve the respiratory regularity, which in turn should improve the accuracy and efficiency of RGRT. PMID:27228097

  5. Statistical Determination of the Gating Windows for Respiratory-Gated Radiotherapy Using a Visible Guiding System.

    PubMed

    Oh, Se An; Yea, Ji Woon; Kim, Sung Kyu

    2016-01-01

    Respiratory-gated radiation therapy (RGRT) is used to minimize the radiation dose to normal tissue in lung-cancer patients. Although determining the gating window in the respiratory phase of patients is important in RGRT, it is not easy. Our aim was to determine the optimal gating window when using a visible guiding system for RGRT. Between April and October 2014, the breathing signals of 23 lung-cancer patients were recorded with a real-time position management (RPM) respiratory gating system (Varian, USA). We performed statistical analysis with breathing signals to find the optimal gating window for guided breathing in RGRT. When we compared breathing signals before and after the breathing training, 19 of the 23 patients showed statistically significant differences (p < 0.05). The standard deviation of the respiration signals after breathing training was lowest for phases of 30%-70%. The results showed that the optimal gating window in RGRT is 40% (30%-70%) with respect to repeatability for breathing after respiration training with the visible guiding system. RGRT was performed with the RPM system to confirm the usefulness of the visible guiding system. The RPM system and our visible guiding system improve the respiratory regularity, which in turn should improve the accuracy and efficiency of RGRT.

  6. G4-FETs as Universal and Programmable Logic Gates

    NASA Technical Reports Server (NTRS)

    Johnson, Travis; Fijany, Amir; Mojarradi, Mohammad; Vatan, Farrokh; Toomarian, Nikzad; Kolawa, Elizabeth; Cristoloveanu, Sorin; Blalock, Benjamin

    2007-01-01

    An analysis of a patented generic silicon- on-insulator (SOI) electronic device called a G4-FET has revealed that the device could be designed to function as a universal and programmable logic gate. The universality and programmability could be exploited to design logic circuits containing fewer discrete components than are required for conventional transistor-based circuits performing the same logic functions. A G4-FET is a combination of a junction field-effect transistor (JFET) and a metal oxide/semiconductor field-effect transistor (MOSFET) superimposed in a single silicon island and can therefore be regarded as two transistors sharing the same body. A G4-FET can also be regarded as a single transistor having four gates: two side junction-based gates, a top MOS gate, and a back gate activated by biasing of the SOI substrate. Each of these gates can be used to control the conduction characteristics of the transistor; this possibility creates new options for designing analog, radio-frequency, mixed-signal, and digital circuitry. With proper choice of the specific dimensions for the gates, channels, and ancillary features of the generic G4-FET, the device could be made to function as a three-input, one-output logic gate. As illustrated by the truth table in the top part of the figure, the behavior of this logic gate would be the inverse (the NOT) of that of a majority gate. In other words, the device would function as a NOT-majority gate. By simply adding an inverter, one could obtain a majority gate. In contrast, to construct a majority gate in conventional complementary metal oxide/semiconductor (CMOS) circuitry, one would need four three-input AND gates and a four-input OR gate, altogether containing 32 transistors.

  7. Accuracy and Consistency of Respiratory Gating in Abdominal Cancer Patients

    SciTech Connect

    Ge, Jiajia; Santanam, Lakshmi; Yang, Deshan; Parikh, Parag J.

    2013-03-01

    Purpose: To evaluate respiratory gating accuracy and intrafractional consistency for abdominal cancer patients treated with respiratory gated treatment on a regular linear accelerator system. Methods and Materials: Twelve abdominal patients implanted with fiducials were treated with amplitude-based respiratory-gated radiation therapy. On the basis of daily orthogonal fluoroscopy, the operator readjusted the couch position and gating window such that the fiducial was within a setup margin (fiducial-planning target volume [f-PTV]) when RPM indicated “beam-ON.” Fifty-five pre- and post-treatment fluoroscopic movie pairs with synchronized respiratory gating signal were recorded. Fiducial motion traces were extracted from the fluoroscopic movies using a template matching algorithm and correlated with f-PTV by registering the digitally reconstructed radiographs with the fluoroscopic movies. Treatment was determined to be “accurate” if 50% of the fiducial area stayed within f-PTV while beam-ON. For movie pairs that lost gating accuracy, a MATLAB program was used to assess whether the gating window was optimized, the external-internal correlation (EIC) changed, or the patient moved between movies. A series of safety margins from 0.5 mm to 3 mm was added to f-PTV for reassessing gating accuracy. Results: A decrease in gating accuracy was observed in 44% of movie pairs from daily fluoroscopic movies of 12 abdominal patients. Three main causes for inaccurate gating were identified as change of global EIC over time (∼43%), suboptimal gating setup (∼37%), and imperfect EIC within movie (∼13%). Conclusions: Inconsistent respiratory gating accuracy may occur within 1 treatment session even with a daily adjusted gating window. To improve or maintain gating accuracy during treatment, we suggest using at least a 2.5-mm safety margin to account for gating and setup uncertainties.

  8. Multi-frequency inversion-charge pumping for charge separation and mobility analysis in high-k/InGaAs metal-oxide-semiconductor field-effect transistors

    SciTech Connect

    Djara, V.; Cherkaoui, K.; Negara, M. A.; Hurley, P. K.

    2015-11-28

    An alternative multi-frequency inversion-charge pumping (MFICP) technique was developed to directly separate the inversion charge density (N{sub inv}) from the trapped charge density in high-k/InGaAs metal-oxide-semiconductor field-effect transistors (MOSFETs). This approach relies on the fitting of the frequency response of border traps, obtained from inversion-charge pumping measurements performed over a wide range of frequencies at room temperature on a single MOSFET, using a modified charge trapping model. The obtained model yielded the capture time constant and density of border traps located at energy levels aligned with the InGaAs conduction band. Moreover, the combination of MFICP and pulsed I{sub d}-V{sub g} measurements enabled an accurate effective mobility vs N{sub inv} extraction and analysis. The data obtained using the MFICP approach are consistent with the most recent reports on high-k/InGaAs.

  9. Characterization of a Common-Gate Amplifier Using Ferroelectric Transistors

    NASA Technical Reports Server (NTRS)

    Hunt, Mitchell; Sayyah, Rana; MacLeod, Todd C.; Ho, Fat D.

    2011-01-01

    In this paper, the empirical data collected through experiments performed using a FeFET in the common-gate amplifier circuit is presented. The FeFET common-gate amplifier was characterized by varying all parameters in the circuit, such as load resistance, biasing of the transistor, and input voltages. Due to the polarization of the ferroelectric layer, the particular behavior of the FeFET common-gate amplifier presents interesting results. Furthermore, the differences between a FeFET common-gate amplifier and a MOSFET common-gate amplifier are examined.

  10. Polymer electrolyte gating of carbon nanotube network transistors.

    PubMed

    Ozel, Taner; Gaur, Anshu; Rogers, John A; Shim, Moonsub

    2005-05-01

    Network behavior in single-walled carbon nanotubes (SWNTs) is examined by polymer electrolyte gating. High gate efficiencies, low voltage operation, and the absence of hysteresis in polymer electrolyte gating lead to a convenient and effective method of analyzing transport in SWNT networks. Furthermore, the ability to control carrier type with chemical groups of the host polymer allows us to examine both electron and hole conduction. Comparison to back gate measurements is made on channel length scaling. Frequency measurements are also made giving an upper limit of approximately 300 Hz switching speed for poly(ethylene oxide)/LiClO(4) gated SWNT thin film transistors. PMID:15884892

  11. 101. Photocopied August 1978. GENERAL VIEW OF COMPLETED COMPENSATING GATES ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    101. Photocopied August 1978. GENERAL VIEW OF COMPLETED COMPENSATING GATES LOOKING NORTHWEST, AUGUST 5, 1916. THE COMPLETED 8 AMERICAN GATES ARE IN THE CENTER OF THE PHOTO: THE FIRST 4 CANADIAN GATES ARE IN THE BACKGROUND AT THE RIGHT. GATES 5-8 HAVE NOT BEEN BUILT, NEITHER HAS THE DIKE CONNECTING GATE 16 (FAR LEFT) WITH THE DIKE OF THE GOVERNMENT HYDROELECTRIC PLANT HEAD RACE. THE BREAKWATER IN FRONT OF THE WORKS HAS NOT YET BEEN DREDGED OUT. (708) - Michigan Lake Superior Power Company, Portage Street, Sault Ste. Marie, Chippewa County, MI

  12. Edge-on gating effect in molecular wires.

    PubMed

    Lo, Wai-Yip; Bi, Wuguo; Li, Lianwei; Jung, In Hwan; Yu, Luping

    2015-02-11

    This work demonstrates edge-on chemical gating effect in molecular wires utilizing the pyridinoparacyclophane (PC) moiety as the gate. Different substituents with varied electronic demands are attached to the gate to simulate the effect of varying gating voltages similar to that in field-effect transistor (FET). It was observed that the orbital energy level and charge carrier's tunneling barriers can be tuned by changing the gating group from strong electron acceptors to strong electron donors. The single molecule conductance and current-voltage characteristics of this molecular system are truly similar to those expected for an actual single molecular transistor. PMID:25603411

  13. Gate-controlled ultraviolet photo-etching of graphene edges

    SciTech Connect

    Mitoma, Nobuhiko; Nouchi, Ryo

    2013-11-11

    The chemical reactivity of graphene under ultraviolet (UV) light irradiation is investigated under positive and negative gate electric fields. Graphene edges are selectively etched when negative gate voltages are applied while the reactivity is significantly suppressed for positive gate voltages. Oxygen adsorption onto graphene is significantly affected by the Fermi level of the final state achieved during previous electrical measurements. UV irradiation after negative-to-positive gate sweeps causes predominant oxygen desorption while UV irradiation after gate sweeps in the opposite direction causes etching of graphene edges.

  14. Experimental teleportation of a quantum controlled-NOT gate.

    PubMed

    Huang, Yun-Feng; Ren, Xi-Feng; Zhang, Yong-Sheng; Duan, Lu-Ming; Guo, Guang-Can

    2004-12-10

    Teleportation of quantum gates is a critical step for the implementation of quantum networking and teleportation-based models of quantum computation. We report an experimental demonstration of teleportation of the prototypical quantum controlled-NOT (CNOT) gate. Assisted with linear optical manipulations, photon entanglement produced from parametric down-conversion, and postselection from the coincidence measurements, we teleport the quantum CNOT gate from acting on local qubits to acting on remote qubits. The quality of the quantum gate teleportation is characterized through the method of quantum process tomography, with an average fidelity of 0.84 demonstrated for the teleported gate. PMID:15697787

  15. Experimental teleportation of a quantum controlled-NOT gate.

    PubMed

    Huang, Yun-Feng; Ren, Xi-Feng; Zhang, Yong-Sheng; Duan, Lu-Ming; Guo, Guang-Can

    2004-12-10

    Teleportation of quantum gates is a critical step for the implementation of quantum networking and teleportation-based models of quantum computation. We report an experimental demonstration of teleportation of the prototypical quantum controlled-NOT (CNOT) gate. Assisted with linear optical manipulations, photon entanglement produced from parametric down-conversion, and postselection from the coincidence measurements, we teleport the quantum CNOT gate from acting on local qubits to acting on remote qubits. The quality of the quantum gate teleportation is characterized through the method of quantum process tomography, with an average fidelity of 0.84 demonstrated for the teleported gate.

  16. Designing robust unitary gates: Application to concatenated composite pulses

    SciTech Connect

    Ichikawa, Tsubasa; Bando, Masamitsu; Kondo, Yasushi; Nakahara, Mikio

    2011-12-15

    We propose a simple formalism to design unitary gates robust against given systematic errors. This formalism generalizes our previous observation [Y. Kondo and M. Bando, J. Phys. Soc. Jpn. 80, 054002 (2011)] that vanishing dynamical phase in some composite gates is essential to suppress pulse-length errors. By employing our formalism, we derive a composite unitary gate which can be seen as a concatenation of two known composite unitary operations. The obtained unitary gate has high fidelity over a wider range of error strengths compared to existing composite gates.

  17. Genetic algorithm approach to aircraft gate reassignment problem

    SciTech Connect

    Gu, Y.; Chung, C.A.

    1999-10-01

    The aircraft gate reassignment problem occurs when the departure of an incoming aircraft is delayed or a delay occurs in flight. If the delay is significant enough to delay the arrival of subsequent incoming aircraft at the assigned gate, the airline must revise the gate assignments to minimize extra delay times. This paper describes a genetic algorithm approach to solving the gate reassignment problem. By using a global search technique on quantified information, this genetic algorithm approach can efficiently find minimum extra delayed time solutions that are as effective or more effective than solutions generated by experienced gate managers.

  18. Retention and Switching Kinetics of Protonated Gate Field Effect Transistors

    SciTech Connect

    DEVINE,R.A.B.; HERRERA,GILBERT V.

    2000-06-27

    The switching and memory retention time has been measured in 50 {micro}m gatelength pseudo-non-volatile memory MOSFETs containing, protonated 40 nm gate oxides. Times of the order of 3.3 seconds are observed for fields of 3 MV cm{sup {minus}1}. The retention time with protons placed either at the gate oxide/substrate or gate oxide/gate electrode interfaces is found to better than 96% after 5,000 seconds. Measurement of the time dependence of the source-drain current during switching provides clear evidence for the presence of dispersive proton transport through the gate oxide.

  19. Retention and switching kinetics of protonated gate field effect transistors

    SciTech Connect

    DEVINE,R.A.B.; HERRERA,GILBERT V.

    2000-05-23

    The switching and memory retention time has been measured in 50 {micro}m gatelength pseudo-non-volatile memory MOSFETS containing, protonated 40 nm gate oxides. Times of the order of 3.3 seconds are observed for fields of 3 MV cm{sup {minus}1}. The retention time with protons placed either at the gate oxide/substrate or gate oxide/gate electrode interfaces is found to better than 96{percent} after 5,000 seconds. Measurement of the time dependence of the source-drain current during switching provides clear evidence for the presence of dispersive proton transport through the gate oxide.

  20. Gating of Permanent Molds for Aluminum Casting

    SciTech Connect

    David Schwam; John F. Wallace; Tom Engle; Qingming Chang

    2004-01-01

    This report summarizes a two-year project, DE-FC07-011D13983 that concerns the gating of aluminum castings in permanent molds. The main goal of the project is to improve the quality of aluminum castings produced in permanent molds. The approach taken was to determine how the vertical type gating systems used for permanent mold castings can be designed to fill the mold cavity with a minimum of damage to the quality of the resulting casting. It is evident that somewhat different systems are preferred for different shapes and sizes of aluminum castings. The main problems caused by improper gating are entrained aluminum oxide films and entrapped gas. The project highlights the characteristic features of gating systems used in permanent mold aluminum foundries and recommends gating procedures designed to avoid common defects. The study also provides direct evidence on the filling pattern and heat flow behavior in permanent mold castings. Equipment and procedure for real time X-Ray radiography of molten aluminum flow into permanent molds have been developed. Other studies have been conducted using water flow and behavior of liquid aluminum in sand mold using real time photography. This investigation utilizes graphite molds transparent to X-Rays making it possible to observe the flow pattern through a number of vertically oriented grating systems. These have included systems that are choked at the base of a rounded vertical sprue and vertical gating systems with a variety of different ingates into the bottom of a mold cavity. These systems have also been changed to include gating systems with vertical and horizontal gate configurations. Several conclusions can be derived from this study. A sprue-well, as designed in these experiments, does not eliminate the vena contracta. Because of the swirling at the sprue-base, the circulating metal begins to push the entering metal stream toward the open runner mitigating the intended effect of the sprue-well. Improved designs of