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Sample records for hf-based high-k gate

  1. Hf-based high-k materials for Si nanocrystal floating gate memories

    PubMed Central

    2011-01-01

    Pure and Si-rich HfO2 layers fabricated by radio frequency sputtering were utilized as alternative tunnel oxide layers for high-k/Si-nanocrystals-SiO2/SiO2 memory structures. The effect of Si incorporation on the properties of Hf-based tunnel layer was investigated. The Si-rich SiO2 active layers were used as charge storage layers, and their properties were studied versus deposition conditions and annealing treatment. The capacitance-voltage measurements were performed to study the charge trapping characteristics of these structures. It was shown that with specific deposition conditions and annealing treatment, a large memory window of about 6.8 V is achievable at a sweeping voltage of ± 6 V, indicating the utility of these stack structures for low-operating-voltage nonvolatile memory devices. PMID:21711676

  2. 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.

  3. Process-induced positive charges in Hf-based gate stacks

    NASA Astrophysics Data System (ADS)

    Zhao, C. Z.; Zhang, J. F.; Chang, M. H.; Peaker, A. R.; Hall, S.; Groeseneken, G.; Pantisano, L.; De Gendt, S.; Heyns, M.

    2008-01-01

    Hf-based gate stacks will replace SiON as a gate dielectric even though our understanding of them is incomplete. For an unoptimized SiO2 layer, an exposure to H2 at a temperature over 450 °C can lead to positive charging. In this work, we will show that a thermal exposure of Hf-based gate stacks to H2 can also induce a large amount of positive charge (˜1013 cm-2). There is little information available on this process-induced positive charge (PIPC) and the objective of this work is to fill this knowledge gap. The work is divided into two parts: an investigation of the features and properties of PIPC, followed by an exploration of its dependence on process conditions. It will be shown that PIPC does not originate from the generation of interface states, is stable both thermally and electrically, and has a large sample-to-sample variation. It consists of two components: fixed and mobile. Regarding its dependence on process conditions, PIPC occurs in both HfO2 and Hf-silicate stacks, in devices with either TaN or poly-Si gates, and in both p metal-oxide-semiconductor field-effect transistors (pMOSFETs) and nMOSFETs. PIPC is generally enhanced by nitridation, although it can also be observed in some Hf-based gate stacks without nitridation.

  4. Reliability study of Zr and Al incorporated Hf based high-k dielectric deposited by advanced processing

    NASA Astrophysics Data System (ADS)

    Bhuyian, Md Nasir Uddin

    Hafnium-based high-kappa dielectric materials have been successfully used in the industry as a key replacement for SiO2 based gate dielectrics in order to continue CMOS device scaling to the 22-nm technology node. Further scaling according to the device roadmap requires the development of oxides with higher kappa values in order to scale the equivalent oxide thickness (EOT) to 0.7 nm or below while achieving low defect densities. In addition, next generation devices need to meet challenges like improved channel mobility, reduced gate leakage current, good control on threshold voltage, lower interface state density, and good reliability. In order to overcome these challenges, improvements of the high-kappa film properties and deposition methods are highly desirable. In this dissertation, a detail study of Zr and Al incorporated HfO 2 based high-kappa dielectrics is conducted to investigate improvement in electrical characteristics and reliability. To meet scaling requirements of the gate dielectric to sub 0.7 nm, Zr is added to HfO2 to form Hf1-xZrxO2 with x=0, 0.31 and 0.8 where the dielectric film is deposited by using various intermediate processing conditions, like (i) DADA: intermediate thermal annealing in a cyclical deposition process; (ii) DSDS: similar cyclical process with exposure to SPA Ar plasma; and (iii) As-Dep: the dielectric deposited without any intermediate step. MOSCAPs are formed with TiN metal gate and the reliability of these devices is investigated by subjecting them to a constant voltage stress in the gate injection mode. Stress induced flat-band voltage shift (DeltaVFB), stress induced leakage current (SILC) and stress induced interface state degradation are observed. DSDS samples demonstrate the superior characteristics whereas the worst degradation is observed for DADA samples. Time dependent dielectric breakdown (TDDB) shows that DSDS Hf1-xZrxO2 (x=0.8) has the superior characteristics with reduced oxygen vacancy, which is affiliated to

  5. In-line high-K/metal gate monitoring using picosecond ultrasonics

    NASA Astrophysics Data System (ADS)

    Hsu, C. W.; Huang, R. P.; Chen, J.; Tan, J.; Huang, H. F.; Lin, Welch; Hsieh, Y. L.; Tsao, W. C.; Chen, C. H.; Lin, Y. M.; Lin, C. H.; Hsu, H. K.; Liu, K.; Huang, C. C.; Wu, J. Y.; Dai, J.; Mukundhan, P.

    2013-04-01

    High-K/metal gate technology, introduced by Intel, to replace the conventional oxide gate dielectric and polysilicon gate has truly revolutionized transistor technology more than any other change over the last 40 years. First introduced at the 45nm node, this complex process has now been adopted for advanced nodes. The capability of picosecond ultrasonic measurements (PULSETM) for in-line monitoring of High-K/metal gate structures was evaluated and the benefits of this technology for measuring various structures including SRAM, pad array, and line array key with excellent correlation to cross sectional TEM was demonstrated. We have shown that, only a direct measurement of SRAM structures can represent true variations of the metal gate height due to CMP process and is strongly affected by the design and layout of pattern, including pattern density, dummy design, and spacing. The small spot, non-contact, non-destructive nature of this technology allows for in-line measurements directly on these structures with excellent repeatability at a very high throughput.

  6. 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

  7. Divergent dielectric characteristics in cascaded high-K gate stacks with reverse gradient bandgap structures

    NASA Astrophysics Data System (ADS)

    Tsai, Meng-Chen; Cheng, Po-Hsien; Lee, Min-Hung; Lin, Hsin-Chih; Chen, Miin-Jang

    2016-07-01

    The characteristics of cascaded high-K gate stacks with reverse dielectric sequence, TiO2/ZrO2/Al2O3 and Al2O3/ZrO2/ TiO2, on the Si substrate were investigated. The reverse sequence with different gradient bandgap structure gives rise to distinct conduction pathways, resulting in significant divergence of the leakage current density (J g) and the capacitance equivalent thickness (CET). The trapping sites in the high-permittivity TiO2 layer dominate the leakage current paths and strongly impact the conductance and the capacitance of the cascaded high-K gate stacks. Thus, a low CET of 1.05 nm and a low J g of ˜5  ×  10-4 A cm-2 were achieved due to effective suppression of the leakage current through the traps of TiO2 in the cascaded TiO2/ZrO2/Al2O3 gate stack. In addition, the TiO2 layer gets crystallized in the cascaded TiO2/ZrO2/Al2O3 structure to achieve a higher capacitance because of the intermixing between TiO2 and ZrO2 due to the different reactivity of the precursors for Ti and Zr. This study demonstrates a way to effectively incorporate the high permittivity and low-bandgap materials, such as TiO2, into high-K gate stacks, to further improve device scaling.

  8. Floating Gate Memory with Biomineralized Nanodots Embedded in High-k Gate Dielectric

    NASA Astrophysics Data System (ADS)

    Ohara, Kosuke; Yamashita, Ichiro; Yaegashi, Toshitake; Moniwa, Masahiro; Yoshimaru, Masaki; Uraoka, Yukiharu

    2009-09-01

    The memory properties of a nanodot-type floating gate memory with Co bio-nanodots (Co-BNDs) embedded in HfO2 were investigated. High-density and uniform Co-BNDs were adsorbed on the HfO2 tunnel oxide using ferritin. The fabricated metal oxide semiconductor (MOS) capacitor exhibited a capacitance-voltage (C-V) curve with large hysteresis. The memory window size was 30 times higher than that of the MOS capacitor with a SiO2 gate oxide. Not only a large memory window but also excellent charge retention and reliability characteristics were obtained for a MOS field-effect transistor (MOSFET). This research confirmed that the proposed memory is promising for use in next-generation memory devices.

  9. 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.

  10. High-k perovskite gate oxide BaHfO3

    NASA Astrophysics Data System (ADS)

    Kim, Young Mo; Park, Chulkwon; Ha, Taewoo; Kim, Useong; Kim, Namwook; Shin, Juyeon; Kim, Youjung; Yu, Jaejun; Kim, Jae Hoon; Char, Kookrin

    2017-01-01

    We have investigated epitaxial BaHfO3 as a high-k perovskite dielectric. From x-ray diffraction measurement, we confirmed the epitaxial growth of BaHfO3 on BaSnO3 and MgO. We measured optical and dielectric properties of the BaHfO3 gate insulator; the optical bandgap, the dielectric constant, and the breakdown field. Furthermore, we fabricated a perovskite heterostructure field effect transistor using epitaxial BaHfO3 as a gate insulator and La-doped BaSnO3 as a channel layer on SrTiO3 substrate. To reduce the threading dislocations and enhance the electrical properties of the channel, an undoped BaSnO3 buffer layer was grown on SrTiO3 substrates before the channel layer deposition. The device exhibited a field effect mobility value of 52.7 cm2 V-1 s-1, a Ion/Ioff ratio higher than 107, and a subthreshold swing value of 0.80 V dec-1. We compare the device performances with those of other field effect transistors based on BaSnO3 channels and different gate oxides.

  11. 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.

  12. MBE and ALD grown High k Dielectrics Gate Stacks on GaN

    NASA Astrophysics Data System (ADS)

    Chang, Y. C.; Lee, K. Y.; Lee, W. C.; Lin, T. D.; Lee, Y. J.; Huang, M. L.; Hong, M.; Kwo, J.; Wang, Y. H.

    2007-03-01

    III-nitride compound semiconductors are attractive for high-temperature and high-power MOSFET applications due to their intrinsic properties of wide band gap, high breakdown field, and high saturation velocity under high fields. In this work GaN-based high k MOS diodes were fabricated using MBE-grown Ga2O3(Gd2O3), MBE-grown HfO2 and ALD-grown HfO2 as the gate dielectrics with dielectric constants of 14.7, 17.4 and 16.5, respectively. All MOS diodes exhibited low leakage (<10-6 A/cm^2 at Vfb+1) and well behaved capacitance-voltage curves with a low interfacial density of states of ˜10^11 cm-2eV-1. Energy-band diagrams of the MOS structures have been determined by extracting valance-band offset (δEV) from HR-XPS and with the bandgaps of the oxides. For example, the ALD-grown HfO2-GaN at the interfaces gave approximately δEC and δEV of 1.2 eV and 1.1 eV, respectively.

  13. Analytical modeling of the direct tunneling current through high-k gate stacks for long-channel cylindrical surrounding-gate MOSFETs

    NASA Astrophysics Data System (ADS)

    Lina, Shi; Yiqi, Zhuang; Cong, Li; Dechang, Li

    2014-03-01

    An analytical direct tunneling gate current model for cylindrical surrounding gate (CSG) MOSFETs with high-k gate stacks is developed. It is found that the direct tunneling gate current is a strong function of the gate's oxide thickness, but that it is less affected by the change in channel radius. It is also revealed that when the thickness of the equivalent oxide is constant, the thinner the first layer, the smaller the direct tunneling gate current. Moreover, it can be seen that the dielectric with a higher dielectric constant shows a lower tunneling current than expected. The accuracy of the analytical model is verified by the good agreement of its results with those obtained by the three-dimensional numerical device simulator ISE.

  14. 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.

  15. Physics based analytical model for surface potential and subthreshold current of cylindrical Schottky Barrier gate all around MOSFET with high-k gate stack

    NASA Astrophysics Data System (ADS)

    Kumar, Manoj; Haldar, Subhasis; Gupta, Mridula; Gupta, R. S.

    2016-02-01

    A physics-based analytical model for Schottky Barrier (SB) Cylindrical Gate All Around (CGAA) MOSFET with high-k dielectric is presented with Evanescent Mode Analysis (EMA). The electrostatic potential is obtained using the Superposition method. An exact expression for threshold voltage and subthreshold slope is also obtained. The proposed model also includes the effect of Barrier height lowering at metal semiconductor interface along with the effect of high-k (HfO2) gate stack. Diffusion current and tunneling currents are combined to evaluate the total subthreshold current. The analytical results so obtained are compared with simulated data and they are in good agreement. The proposed model of SB-CGAA device with high-k dielectric is very useful for the design and optimization for high current and improved performance.

  16. Systematic study of interfacial reactions induced by metal electrodes in high-k/InGaAs gate stacks

    NASA Astrophysics Data System (ADS)

    Yoshida, S.; Lin, D.; Vais, A.; Alian, A.; Franco, J.; El Kazzi, S.; Mols, Y.; Miyanami, Y.; Nakazawa, M.; Collaert, N.; Watanabe, H.; Thean, A.

    2016-10-01

    We systematically studied the effects of metal electrodes on high-k/InGaAs gate stacks and observed that the remote reactions—both oxidation and reduction—at the interface between the high-k dielectrics and InGaAs were thermodynamically initiated by the metal electrodes. Metal electrodes with negative Gibbs free energies (e.g., Pd) resulted in the oxidation of the InGaAs surface during the forming-gas annealing. In contrast, with TiN electrodes, which have a positive Gibbs free energy, the native III-V oxides underwent the reduction between the high-k dielectrics and InGaAs. We demonstrated that the reduction of native III-V oxides by metal electrodes improved the interface quality of the high-k/InGaAs gate stacks and produced an interface trap density (Dit) at the mid-gap with a value as low as 5.2 × 1011 cm-2 eV-1 with a scaled capacitance-equivalent thickness.

  17. 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.

  18. Electrical characterization of thulium silicate interfacial layers for integration in high-k/metal gate CMOS technology

    NASA Astrophysics Data System (ADS)

    Dentoni Litta, Eugenio; Hellström, Per-Erik; Henkel, Christoph; Östling, Mikael

    2014-08-01

    This work presents a characterization of the electrical properties of thulium silicate thin films, within the scope of a possible application as IL (interfacial layer) in scaled high-k/metal gate CMOS technology. Silicate formation is investigated over a wide temperature range (500-900 °C) through integration in MOS capacitor structures and analysis of the resulting electrical properties. The results are compared to those obtained from equivalent devices integrating lanthanum silicate interfacial layers. The thulium silicate IL is formed through a gate-last CMOS-compatible process flow, providing IL EOT of 0.1-0.3 nm at low formation temperature and interface state density at flatband condition below 2 × 1011 cm-2 eV-1. The effects of a possible integration in a gate-first process flow with a maximum thermal budget of 1000 °C are also evaluated, achieving an IL EOT of 0.2-0.5 nm, an interface state density at flatband condition ∼1 × 1011 cm-2 eV-1 and a reduction in gate leakage current density of one order of magnitude compared to the same stack without IL.

  19. High K Oxide Insulated Gate Group III Nitride-Based FETs

    DTIC Science & Technology

    2014-03-21

    AND ADDRESS(ES) Kansas State University 2 Fairchild Hall Manhattan , KS 66506-1103 3. DATES COVERED (From - To) 04/05/2009-03/20/2014 5a. CONTRACT...NUMBER 5b. GRANT NUMBER N00014-09-1-1160 5c. PROGRAM ELEMENT NUMBER 5d. PROJECT NUMBER 09PRE09471-00 5e. TASK NUMBER 5f. WORK UNIT NUMBER 9...results indicate the promising potential of incorporation gate dielectric in future GaN devices. This project supported two students who completed

  20. Band offsets of high K gate oxides on III-V semiconductors

    NASA Astrophysics Data System (ADS)

    Robertson, J.; Falabretti, B.

    2006-07-01

    III-V semiconductors have high mobility and will be used in field effect transistors with the appropriate gate dielectric. The dielectrics must have band offsets over 1eV to inhibit leakage. The band offsets of various gate dielectrics including HfO2, Al2O3, Gd2O3, Si3N4, and SiO2 on III-V semiconductors such as GaAs, InAs, GaSb, and GaN have been calculated using the method of charge neutrality levels. Generally, the conduction band offsets are found to be over 1eV, so they should inhibit leakage for these dielectrics. On the other hand, SrTiO3 has minimal conduction band offset. The valence band offsets are also reasonably large, except for Si nitride on GaN and Sc2O3 on GaN which are 0.6-0.8eV. There is reasonable agreement with experiment where it exists, although the GaAs :SrTiO3 case is even worse in experiment.

  1. 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.

  2. Two methods of tuning threshold voltage of bulk FinFETs with replacement high-k metal-gate stacks

    NASA Astrophysics Data System (ADS)

    Xu, Miao; Zhu, Huilong; Zhang, Yanbo; Xu, Qiuxia; Zhang, Yongkui; Qin, Changliang; Zhang, Qingzhu; Yin, Huaxiang; Xu, Hao; Chen, Shuai; Luo, Jun; Li, Chunlong; Zhao, Chao; Ye, Tianchun

    2017-03-01

    In this work, we propose two threshold voltage (VTH) tuning methods for bulk FinFETs with replacement high-k metal gate. The first method is to perform a vertical implantation into fin structure after dummy gate removal, self-aligned forming halo & punch through stop pocket (halo & PTSP) doping profile. The second method is to execute P+/BF2+ ion implantations into the single common work function (WF) layer in N-/P-FinFETs, respectively. These two methods have been investigated by TCAD simulations and MOS-capacitor experiments respectively, and then integrated into FinFET fabrication successfully. Experimental results show that the halo & PTSP doping profile can reduce VTH roll off and total variation. With P+/BF2+ doped WF layer, the VTH-sat shift -0.43 V/+1.26 V for N-FinFETs and -0.75 V/+0.11 V for P-FinFETs, respectively, with gate length of 500 nm. The proposed two methods are simple and effective for FinFET VTH tuning, and have potential for future application of massive production.

  3. Al2O3 nanocrystals embedded in amorphous Lu2O3 high-k gate dielectric for floating gate memory application

    NASA Astrophysics Data System (ADS)

    Yuan, C. L.; Chan, M. Y.; Lee, P. S.; Darmawan, P.; Setiawan, Y.

    2007-04-01

    The integration of nanoparticles has high potential in technological applications and opens up possibilities of the development of new devices. Compared to the conventional floating gate memory, a structure containing nanocrystals embedded in dielectrics shows high potential to produce a memory with high endurance, low operating voltage, fast write-erase speeds and better immunity to soft errors [S. Tiwari, F. Rana, H. Hanafi et al. 1996 Appl.Phys. Lett. 68, 1377]. A significant improvement on data retention [J. J. Lee, X. Wang et al. 2003 Proceedings of the VLSI Technol. Symposium, p33] can be observed when discrete nanodots are used instead of continuous floating gate as charge storage nodes because local defect related leakage can be reduced efficiently. Furthermore, using a high-k dielectric in place of the conventional SiO2 based dielectric, nanodots flash memory is able to achieve significantly improved programming efficiency and data retention [A. Thean and J. -P. Leburton, 2002 IEEE Potentials 21, 35; D. W. Kim, T. Kim and S. K. Banerjee, 2003 IEEE Trans. Electron Devices 50, 1823]. We have recently successfully developed a method to produce nanodots embedded in high-k gate dielectrics [C. L. Yuan, P. Darmawan, Y. Setiawan and P. S. Lee, 2006 Electrochemical and Solid-State Letters 9, F53; C. L. Yuan, P. Darmawan, Y. Setiawan and P. S. Lee, 2006 Europhys. Lett. 74, 177]. In this paper, we fabricated the memory structure of Al2O3 nanocrystals embedded in amorphous Lu2O3 high k dielectric using pulsed laser ablation. The mean size and density of the Al2O3 nanocrystals are estimated to be about 5 nm and 7x1011 cm-2, respectively. Good electrical performances in terms of large memory window and good data retention were observed. Our preparation method is simple, fast and economical.

  4. Schottky barrier SOI-MOSFETs with high-k La2O3/ZrO2 gate dielectrics

    PubMed Central

    Henkel, C.; Abermann, S.; Bethge, O.; Pozzovivo, G.; Klang, P.; Stöger-Pollach, M.; Bertagnolli, E.

    2011-01-01

    Schottky barrier SOI-MOSFETs incorporating a La2O3/ZrO2 high-k dielectric stack deposited by atomic layer deposition are investigated. As the La precursor tris(N,N′-diisopropylformamidinato) lanthanum is used. As a mid-gap metal gate electrode TiN capped with W is applied. Processing parameters are optimized to issue a minimal overall thermal budget and an improved device performance. As a result, the overall thermal load was kept as low as 350, 400 or 500 °C. Excellent drive current properties, low interface trap densities of 1.9 × 1011 eV−1 cm−2, a low subthreshold slope of 70-80 mV/decade, and an ION/IOFF current ratio greater than 2 × 106 are obtained. PMID:21461054

  5. 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.

  6. 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.

  7. Simulation of quantum dot floating gate MOSFET memory performance using various high-k material as tunnel oxide

    NASA Astrophysics Data System (ADS)

    Aji, Adha Sukma; Darma, Yudi

    2012-06-01

    In this paper, performance of quantum dot floating gate MOSFET memory is simulated by replacing the SiO2 tunnel oxide with high-Κ material. There are three high-k material simulated in this paper, HfO2, ZrO2, and Y2O3. As we know that high-Κ material is used nowadays to reduce leakage current, so this paper demonstrates the application of high-Κ material to reduce leakage current in non-volatile memory quantum dot based floating gate MOSFET. Simulation results of this paper show the leakage current can be suppressed by using high-Κ material as tunnel oxide up to 10 times. Furthermore, this paper also shows that the memory performance can be properly sustained. The writing and erasing time are depend on tunneling current probability which calculated using transfer matrix method. The writing time and erasing time for HfO2 and ZrO2 are 150 nanosecond and 15 nanosecond.

  8. 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.

  9. 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.

  10. Electrical and Structural Characteristics of High-k Gate Dielectrics with Epitaxial Si3N4 Interfacial Layer on Si(111)

    NASA Astrophysics Data System (ADS)

    Sim, Hyunjun; Samantaray, Chandan B.; Lee, Taeho; Yeom, Hanwoong; Hwang, Hyunsang

    2004-12-01

    In this study, the electrical and structural characteristics of Gd2O3 gate dielectrics with an epitaxial Si3N4 interfacial layer grown on Si(111) were investigated. Compared with control Gd2O3 gate dielectrics deposited on HF-last treated Si (111), the Gd2O3 gate dielectrics with an epitaxial Si3N4 interfacial layer exhibited excellent electrical characteristics such as low leakage current density and low interface state density. These characteristics are due to a high-quality interfacial layer formation on Si. Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy were employed to analyze the structures of the gate dielectrics and interfacial layer. High-k gate dielectrics with an epitaxial Si3N4 interfacial layer have considerable potential for future use in sub-0.1 μm metal oxide semiconductor field-effect transistors (MOSFETs).

  11. A threshold-voltage model for small-scaled GaAs nMOSFET with stacked high-k gate dielectric

    NASA Astrophysics Data System (ADS)

    Chaowen, Liu; Jingping, Xu; Lu, Liu; Hanhan, Lu; Yuan, Huang

    2016-02-01

    A threshold-voltage model for a stacked high-k gate dielectric GaAs MOSFET is established by solving a two-dimensional Poisson's equation in channel and considering the short-channel, DIBL and quantum effects. The simulated results are in good agreement with the Silvaco TCAD data, confirming the correctness and validity of the model. Using the model, impacts of structural and physical parameters of the stack high-k gate dielectric on the threshold-voltage shift and the temperature characteristics of the threshold voltage are investigated. The results show that the stacked gate dielectric structure can effectively suppress the fringing-field and DIBL effects and improve the threshold and temperature characteristics, and on the other hand, the influence of temperature on the threshold voltage is overestimated if the quantum effect is ignored. Project supported by the National Natural Science Foundation of China (No. 61176100).

  12. 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.

  13. Enhanced analog performance of doping-less dual material and gate stacked architecture of junctionless transistor with high-k spacer

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

    The potential effectiveness of high-k spacer for the enhanced analog performance of doping-less dual material double-gate (DL-DMDG) junctionless transistor (JLT) is proposed. The impact of gate stacked (GS = SiO2 + high-k) architecture on DL-DMDG is also demonstrated. The charge plasma technique is used to form n + source/drain in an intrinsic silicon film by proper selection of source/drain electrode work function. The analog parameters are analyzed for DL-DMDG JLT with high-k spacer (DL-DMDG-HK) and gate stacked architecture of DL-DMDG-HK (DL-GSDMDG-HK). The results are compared with DL-DMDG JLT and its gate stacked architecture (DL-GSDMDG) JLT. The DL-DMDG-HK JLT shows improved electrostatic integrity with enhanced on-state current, transconductance (g m), early voltage (V EA) and intrinsic gain (A V ) as compared to DL-DMDG and DL-GSDMDG-JLTs. Moreover, DL-GSDMDG-HK further enhances these figures of merits (FOMs).

  14. High-performance GaAs metal-oxide-semiconductor capacitor by using NbAlON as high-k gate dielectric

    NASA Astrophysics Data System (ADS)

    Liu, L. N.; Choi, H. W.; Xu, J. P.; Lai, P. T.

    2017-03-01

    A GaAs metal-oxide-semiconductor (MOS) capacitor using NbAlON as a gate dielectric with different Nb contents is fabricated. Experimental results show that the k value and crystallization temperature of the AlON dielectric can be improved by Nb incorporation, together with reduction in negative oxide charges. However, the interface quality and gate leakage become poorer as the Nb content increases, as confirmed by TEM and X-ray photoelectron spectroscopy results. Therefore, through comprehensively considering the advantages and disadvantages, the sample with a Nb/(Al+Nb) atomic ratio of 62.5% exhibits the best characteristics: high k value (23.3), low interface-state density (2.7 × 1012 cm-2/eV), small hysteresis (55 mV), small frequency dispersion, and low gate leakage current (2.66 × 10-5A/cm2 at Vfb + 1 V). By comparing with reported GaAs MOS devices with different high-k gate dielectrics, it can be suggested that NbAlON is a promising gate dielectric material to achieve excellent electrical performance for GaAs MOS devices.

  15. 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.

  16. 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.

  17. 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.

  18. 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).

  19. W versus Co-Al as Gate Fill-Metal for Aggressively Scaled Replacement High-k/Metal Gate Devices for (Sub-)22 nm Technology Nodes

    NASA Astrophysics Data System (ADS)

    Veloso, Anabela; Aik Chew, Soon; Schram, Tom; Dekkers, Harold; Van Ammel, Annemie; Witters, Thomas; Tielens, Hilde; Heylen, Nancy; Devriendt, Katia; Sebaai, Farid; Brus, Stephan; Ragnarsson, Lars-Åke; Pantisano, Luigi; Eneman, Geert; Carbonell, Laure; Richard, Olivier; Favia, Paola; Geypen, Jef; Bender, Hugo; Higuchi, Yuichi; Phatak, Anup; Thean, Aaron; Horiguchi, Naoto

    2013-04-01

    In this work we provide a comprehensive evaluation of a novel, low-resistance Co-Al alloy vs W to fill aggressively scaled gates with high aspect-ratios [gate height (Hgate) ˜50-60 nm, gate length (Lgate) ≥20-25 nm]. We demonstrate that, with careful liner/barrier materials selection and tuning, well-behaved devices are obtained, showing: tight gate resistance (Rgate) distributions down to Lgate˜20 nm, low threshold voltage (VT) values, comparable DC and bias temperature instability (BTI) behavior, and improved RF response. The impact of fill-metals intrinsic stress, including the presence of occasional voids in narrow W-gates, on devices fabrication and performance is also explored.

  20. Electric field-induced transport modulation in VO{sub 2} FETs with high-k oxide/organic parylene-C hybrid gate dielectric

    SciTech Connect

    Wei, Tingting; Kanki, Teruo E-mail: h-tanaka@sanken.osaka-u.ac.jp; Chikanari, Masashi; Tanaka, Hidekazu E-mail: h-tanaka@sanken.osaka-u.ac.jp; Fujiwara, Kohei

    2016-02-01

    We report on the observation of reversible and immediate resistance switching by high-k oxide Ta{sub 2}O{sub 5}/organic parylene-C hybrid dielectric-gated VO{sub 2} 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 VO{sub 2} through the electrostatic field-induced transport modulation.

  1. 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.

  2. Effective Work Function Engineering for Aggressively Scaled Planar and Multi-Gate Fin Field-Effect Transistor-Based Devices with High-k Last Replacement Metal Gate Technology

    NASA Astrophysics Data System (ADS)

    Veloso, Anabela; Aik Chew, Soon; Higuchi, Yuichi; Ragnarsson, Lars-Åke; Simoen, Eddy; Schram, Tom; Witters, Thomas; Van Ammel, Annemie; Dekkers, Harold; Tielens, Hilde; Devriendt, Katia; Heylen, Nancy; Sebaai, Farid; Brus, Stephan; Favia, Paola; Geypen, Jef; Bender, Hugo; Phatak, Anup; Chen, Michael S.; Lu, Xinliang; Ganguli, Seshadri; Lei, Yu; Tang, Wei; Fu, Xinyu; Gandikota, Srinivas; Noori, Atif; Brand, Adam; Yoshida, Naomi; Thean, Aaron; Horiguchi, Naoto

    2013-04-01

    This work reports on aggressively scaled replacement metal gate, high-k last devices (RMG-HKL), exploring several options for effective work function (EWF) engineering, and targeting logic high-performance and low-power applications. Tight low-threshold voltage (VT) distributions for scaled NMOS devices are obtained by controlled TiN/TiAl-alloying, either by using RF-physical vapor deposition (RF-PVD) or atomic layer deposition (ALD) for TiN growth. The first technique allows optimization of the TiAl/TiN thicknesses at the bottom of gate trenches while maximizing the space to be filled with a low-resistance metal; using ALD minimizes the occurrence of preferential paths, at gate sidewalls, for Al diffusion into the high-k dielectric, reducing gate leakage (JG). For multi-gate fin field-effect transistors (FinFETs) which require smaller EWF shifts from mid-gap for low-VT: 1) conformal, lower-JG ALD-TiN/TaSiAl; and 2) Al-rich ALD-TiN by controlled Al diffusion from the fill-metal are demonstrated to be promising candidates. Comparable bias temperature instability (BTI), improved noise behavior, and slightly reduced equivalent oxide thickness (EOT) are measured on Al-rich EWF-metal stacks.

  3. 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).

  4. HIGH-k GATE DIELECTRIC: AMORPHOUS Ta/La2O3 FILMS GROWN ON Si AT LOW PRESSURE

    NASA Astrophysics Data System (ADS)

    Bahari, Ali; Khorshidi, Zahra

    2014-09-01

    In the present study, Ta/La2O3 films (La2O3 doped with Ta2O5) as a gate dielectric were prepared using a sol-gel method at low pressure. Ta/La2O3 film has some hopeful properties as a gate dielectric of logic device. The structure and morphology of Ta/La2O3 films were studied using X-ray diffraction (XRD), atomic force microscopy (AFM) and scanning electron microscopy (SEM). Electrical properties of films were performed using capacitance-voltage (C-V) and current density-voltage (J-V) measurements. The optical bandgap of samples was studied by UV-visible optical absorbance measurement. The optical bandgap, Eopt, is determined from the absorbance spectra. The obtained results show that Ta/La2O3 film as a good gate dielectric has amorphous structure, good thermal stability, high dielectric constant (≈ 25), low leakage current and wide bandgap (≈ 4.7 eV).

  5. Comparative study of CNT, silicon nanowire and fullerene embedded multilayer high-k gate dielectric MOS memory devices

    NASA Astrophysics Data System (ADS)

    Sengupta, Amretashis; Sarkar, Chandan Kumar; Requejo, Felix G.

    2011-10-01

    Here, we present a comparative theoretical study on stacked (multilayer) gate dielectric MOS memory devices, having a metallic/semiconducting carbon nanotube (CNT), silicon nanowire (Si NW) and fullerene (C60) embedded nitride layer acting as a floating gate. Two types of devices, one with HfO2-SiO2 stack (stack-1) and the other with La2O3-SiO2 stack (stack-2) as the tunnel oxide were compared. We evaluated the effective barrier height, the dielectric constant and the effective electron mobility in the composite gate dielectric with the Maxwell-Garnett effective medium theory. Thereafter applying the WKB approximation, we simulated the Fowler-Nordheim (F-N) tunnelling/writing current and the direct tunnelling/leakage current in these devices. We evaluated the I-V characteristics, the charge decay and also the impact of CNT/Si NW aspect ratio and the volume fraction on the effective barrier height and the write voltage, respectively. We also simulated the write time, retention time and the erase time of these MOS devices. Based on the simulation results, it was concluded that the metallic CNT embedded stack-1 device offered the best performance in terms of higher F-N tunnelling current, lower direct tunnelling current and lesser write voltage and write time compared with the other devices. In case of direct tunnelling leakage and retention time it was found that the met CNT embedded stack-2 device showed better characteristics. For erasing, however, the C60 embedded stack-1 device showed the smallest erase time. When compared with earlier reports, it was seen that CNT, C60 and Si NW embedded devices all performed better than nanocrystalline Si embedded MOS non-volatile memories.

  6. Simulation of Leakage Current in Si/Ge/Si Quantum Dot Floating Gate MOSFET Using High-K Material as Tunnel Oxide

    NASA Astrophysics Data System (ADS)

    Aji, Adha Sukma; Nugraha, Mohamad Insan; Yudhistira; Rahayu, Fitria; Darma, Yudi

    2011-12-01

    Leakage current in nano-scale MOSFET has been calculated using variety of tunnel oxides. Firstly, this paper evaluates the leakage current in MOSFET devices when using SiO2 as tunnel oxide. When the thickness of tunnel oxide decreases into 1,4 nm, the leakage current will raise and cause power dissipation about 40 percent. Leakage current can be reduced by using high-K materials as tunnel oxides. Thicker high-K materials as tunnel oxides are easier to fabricate than SiO2 tunnel oxides with the thickness down to 1,4 nm. In term of Equivalent Oxide Thickness (EOT), using high-K materials for tunnel oxides could give the better performance as 1,4nm SiO2 which is also more simple in the fabrication. Here, we also evaluates the leakage current as the function of temperature, channel length, and oxide thickness. Computational result shows that using HfO2 to replace SiO2 as tunnel oxides can make leakage current decrease up to seven times. For practically use, HfO2 were suiTable as tunnel oxide in memory devices, particularly in quantum dot (QD) floating gate memory. In this case we use heterostructure QD consisting Si/Ge/Si as electronic storage node. The results demonstrated that the memory operation using HfO2 as tunnel oxide has a better performance rather than SiO2.

  7. 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.

  8. Reactive pulsed laser deposition of high-k silicon dioxide and silicon oxynitride thin films for gate-dielectric applications

    NASA Astrophysics Data System (ADS)

    Desbiens, E.; Dolbec, R.; El Khakani, M. A.

    2002-05-01

    We have successfully developed two reactive pulsed laser deposition (PLD) processes for the growth of high-k SiO2 and SiOxNy thin films. At a KrF laser intensity of 3×108 W/cm2, both SiO2 and SiOxNy films have been deposited by ablating a silicon target in a reactive gas atmosphere (O2 and O2/N2 mixture, respectively) on both Si (100) and Pt-coated Si substrates. Two key issues are presented here, namely (i) the effect of the deposition temperature (Td in the 20-450 °C range) and (ii) the effect of the N incorporation (in the 0.3-20 at. % concentration range) on the microstructure and electrical properties of PLD SiO2 and SiOxNy thin films, respectively. For the PLD-SiO2 films, 300 °C has been identified as the optimal deposition temperature that yields stoichiometric ([O]/[Si]~1.9), hydrogen-free films with a low local disorder, a highly dense microstructure and a dielectric constant (k) higher than that quoted for thermally grown SiO2. On the other hand, the PLD SiOxNy films containing 20 at. % of N have exhibited a dielectric constant as high as ~7. A rather good agreement is obtained between the k values deduced from the Poole-Frenkel emission (PFE) model and those obtained from direct impedance measurements, confirming thereby that the PFE remains the predominant conduction mechanism in the PLD SiOxNy films.

  9. 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.

  10. 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.

  11. Effects of gate stack structural and process defectivity on high-k dielectric dependence of NBTI reliability in 32 nm technology node PMOSFETs.

    PubMed

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

    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.

  12. 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

  13. 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

  14. 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

    2016-05-25

    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.

  15. 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.

  16. 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.

  17. 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.

  18. Impact of nitrogen concentration on the performance of LaAlO3(1-y/2)Ny films for high-k gate dielectric applications

    NASA Astrophysics Data System (ADS)

    Shi, G. H.; Lu, X. B.; Kong, X. K.; Liu, Z. G.

    2005-02-01

    A series of LaAlO3(1-y/2)Ny (LAON) films with different nitrogen concentrations have been prepared by pulsed laser deposition on Pt-coated silicon substrates and directly on hydrogen terminated Si (100) substrates using LaAlO3(1-y/2)Ny ceramic targets with y = 0, 0.2, 0.4, 0.8 and 1, respectively. All the films as deposited at a substrate temperature of 600°C and in 20 Pa nitrogen ambient have amorphous structures. Their crystallization temperatures are not less than 845°C. For ease of comparison, all the films are deposited under the same deposition conditions and all the films deposited on hydrogen terminated silicon (100) substrates have the same physical thickness of 9 nm. The dielectric constant of the materials as well as the equivalent oxide thickness (EOT) and the leakage current density of the Pt/LAON/Si structures as functions of nitrogen concentration of the films were studied systematically and determined. It is found that with a dielectric constant of 33, an EOT of 2 nm and a leakage current density of 11.5 mA cm-2 at 1 V, the LAON films with y = 0.4 exhibited optimal properties for high-k gate dielectric applications. The reasons for the excellent performance of the films with this nitrogen concentration were discussed.

  19. Dual Metal/High-k Gate-Last Complementary Metal-Oxide-Semiconductor Field-Effect Transistor with SiBN Film and Characteristic Behavior In Sub-1-nm Equivalent Oxide Thickness

    NASA Astrophysics Data System (ADS)

    Kikuchi, Yoshiaki; Wakabayashi, Hitoshi; Tsukamoto, Masanori; Nagashima, Naoki

    2011-08-01

    For the first time, dual metal/high-k gate-last complementary metal-oxide-semiconductor field-effect transistors (CMOSFETs) with low-dielectric-constant-material offset spacers and several gate oxide thicknesses were fabricated to improve CMOSFETs characteristics. Improvements of 23 aF/µm in parasitic capacitances were confirmed with a low-dielectric-constant material, and drive current improvements were also achieved with a thin gate oxide. The drive currents at 100 nA/µm off leakages in n-type metal-oxide-semiconductor (NMOS) were improved from 830 to 950 µA/µm and that in p-type metal-oxide-semiconductor (PMOS) were from 405 to 450 µA/µm with a reduction in gate oxide thickness. The thin gate oxide in PMOS was thinner than that in NMOS and the gate leakage was increased. However the gate leakage did not affect the off leakage below a gate length of about 44 nm. On the basis of this result, in these gate-last CMOSFETs, it is concluded that the transistors have potential for further reduction of the equivalent oxide thickness without an increase in off leakages at short gate lengths for high off leakage CMOSFETs. For low off leakage CMOSFETs, the optimization of wet process condition is needed to prevent the reduction of the 2 nm HfO2 thickness in PMOS during a wet process.

  20. 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.

  1. Low-Frequency Noise of Strained and Non-Strained n-Channel Tri-Gate FinFETs With Different Gate Dielectrics

    NASA Astrophysics Data System (ADS)

    Lukyanchikova, N.; Garbar, N.; Kudina, V.; Smolanka, A.; Simoen, E.; Claeys, C.

    2009-04-01

    The influence of different front gate Hf-based high-k dielectrics (HfSiON/SiO2 and HfO2/SiO2) on the shape of the low-frequency noise spectra for n-channel tri-gate FinFETs processed in standard silicon-on-insulator (SOI) substrates, and global Strained Si Directly On Insulator (sSOI) wafers with/without Selective Epitaxial Grown (SEG) source and drain regions is studied. For different process splits the concentration distributions of slow traps over the thickness of the gate dielectric are estimated and it is shown that these distributions depend on the dielectric type.

  2. 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).

  3. Physical and electrical properties of induced high-k ZrHfO crystallization with ZrN cap by high power impulse magnetron sputtering for metal-gate metal-insulator-semiconductor structures

    NASA Astrophysics Data System (ADS)

    Tsai, Jung-Ruey; Juan, Pi-Chun; Lin, Cheng-Li; Lin, Guo-Cheng

    2017-01-01

    Metal-gate TiN/ZrN/ZrHfO/p-Si metal-insulator-semiconductor (MIS) structures have been fabricated in this work. The physical and electrical properties were characterized. The crystallization of high-k ZrHfO thin-film is induced by high power impulse magnetron sputtering (HIPIMS) during the deposition of ZrN capping layer. The binding energies and depth profiles were investigated by X-ray photoelectron spectroscopy (XPS). It is found that Zr and Hf out-diffusion from high-k dielectric in samples with HIPIMS is lesser than those in samples with the conventional DC magnetron sputtering (DCMS). The dielectric constant which strongly relates to the tetragonal phase becomes higher and the flatband voltage shift shows smaller by using the HIPIMS method than by the conventional DCMS. The cation and anion vacancies have been investigated by the defect reaction model.

  4. Impacts of Ti on electrical properties of Ge metal-oxide-semiconductor capacitors with ultrathin high- k LaTiON gate dielectric

    NASA Astrophysics Data System (ADS)

    Xu, H. X.; Xu, J. P.; Li, C. X.; Chan, C. L.; Lai, P. T.

    2010-06-01

    Ge Metal-Oxide-Semiconductor (MOS) capacitors with LaON gate dielectric incorporating different Ti contents are fabricated and their electrical properties are measured and compared. It is found that Ti incorporation can increase the dielectric permittivity, and the higher the Ti content, the larger is the permittivity. However, the interfacial and gate-leakage properties become poorer as the Ti content increases. Therefore, optimization of Ti content is important in order to obtain a good trade-off among the electrical properties of the device. For the studied range of the Ti/La2O3 ratio, a suitable Ti/La2O3 ratio of 14.7% results in a high relative permittivity of 24.6, low interface-state density of 3.1×1011 eV-1 cm-2, and relatively low gate-leakage current density of 2.0×10-3 A cm-2 at a gate voltage of 1 V.

  5. 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.

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

    SciTech Connect

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

    2013-08-28

    Metal-gate MIS structures with and without ZrN capping layer on high-k Y{sub 2}O{sub 3}:Zr/Y{sub 2}O{sub 3} 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 ΔV{sub FB} for samples with ZrN layer. In contrast, an excess of Ti outdiffusion will produce the interstitial defects in high-k films without ZrN capping.

  7. 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.

  8. Memory and negative-resistance effects in a strained metal-gate high-k n-type field-effect-transistor from 375 K down to 77 K

    NASA Astrophysics Data System (ADS)

    Gutiérrez-D, E. A.; Vega-G, V. H.; García-R, P. J.; Huerta-G, O. V.

    2016-12-01

    We introduce an experimental alternative way of looking into the charging and discharging mechanism inside a high-k stacked oxide of a metal-gate strained n-type Field-Effect-Transistor (nFET). This alternative way reproduces a memory and negative resistance effect by biasing the nFET device in a non-conventional way. This is achieved by forward-biasing the drain-bulk junction and by setting the gate electrode in a high-impedance mode. The produced negative resistance effect (NRE) has a controllable peak-to-valley current ratio (PVCR) that goes from about 3.0 up to a value of 5.5 at room temperature. The PVCR increases up to 8.35 at T = 225 K and reduces to 2.84 at T = 375 K in a linear trend. The memory effect is observed when the drain-bulk junction voltage is swept from low to high values and back from high to low values. From low to high forward drain-bulk bias the NRE shows up and vanishes when coming back from high to low forward drain-bulk bias. The NRE and memory effects are attributed to a coupled-gate oxide charging/discharging mechanism with an induced bipolar transistor action in the channel of the FET.

  9. 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.

  10. Interface engineering and reliability characteristics of hafnium dioxide with poly silicon gate and dual metal (ruthenium-tantalum alloy, ruthenium) gate electrode for beyond 65 nm technology

    NASA Astrophysics Data System (ADS)

    Kim, Young-Hee

    Chip density and performance improvements have been driven by aggressive scaling of semiconductor devices. In both logic and memory applications, SiO 2 gate dielectrics has reached its physical limit, direct tunneling resulting from scaling down of dielectrics thickness. Therefore high-k dielectrics have attracted a great deal of attention from industries as the replacement of conventional SiO2 gate dielectrics. So far, lots of candidate materials have been evaluated and Hf-based high-k dielectrics were chosen to the promising materials for gate dielectrics. However, lots of issues were identified and more thorough researches were carried out on Hf-based high-k dielectrics. For instances, mobility degradation, charge trapping, crystallization, Fermi level pinning, interface engineering, and reliability studies. In this research, reliability study of HfO2 were explored with poly gate and dual metal (Ru-Ta alloy, Ru) gate electrode as well as interface engineering. Hard breakdown and soft breakdown were compared and Weibull slope of soft breakdown was smaller than that of hard breakdown, which led to a potential high-k scaling issue. Dynamic reliability has been studied and the combination of trapping and detrapping contributed the enhancement of lifetime projection. Polarity dependence was shown that substrate injection might reduce lifetime projection as well as it increased soft breakdown behavior. Interface tunneling mechanism was suggested with dual metal gate technology. Soft breakdown (l st breakdown) was mainly due to one layer breakdown of bi-layer structure. Low weibull slope was in part attributed to low barrier height of HfO 2 compared to interface layer. Interface layer engineering was thoroughly studied in terms of mobility, swing, and short channel effect using deep sub-micron MOSFET devices. In fact, Hf-based high-k dielectrics could be scaled down to below EOT of ˜10A and it successfully achieved the competitive performance goals. However, it is

  11. 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.

  12. Surface and Interface Chemistry for Gate Stacks on Silicon

    NASA Astrophysics Data System (ADS)

    Frank, M. M.; Chabal, Y. J.

    This chapter addresses the fundamental silicon surface science associated with the continued progress of nanoelectronics along the path prescribed by Moore's law. Focus is on hydrogen passivation layers and on ultrathin oxide films encountered during silicon cleaning and gate stack formation in the fabrication of metal-oxide-semiconductor field-effect transistors (MOSFETs). Three main topics are addressed. (i) First, the current practices and understanding of silicon cleaning in aqueous solutions are reviewed, including oxidizing chemistries and cleans leading to a hydrogen passivation layer. The dependence of the final surface termination and morphology/roughness on reactant choice and pH and the influence of impurities such as dissolved oxygen or metal ions are discussed. (ii) Next, the stability of hydrogen-terminated silicon in oxidizing liquid and gas phase environments is considered. In particular, the remarkable stability of hydrogen-terminated silicon surface in pure water vapor is discussed in the context of atomic layer deposition (ALD) of high-permittivity (high-k) gate dielectrics where water is often used as an oxygen precursor. Evidence is also provided for co-operative action between oxygen and water vapor that accelerates surface oxidation in humid air. (iii) Finally, the fabrication of hafnium-, zirconium- and aluminum-based high-k gate stacks is described, focusing on the continued importance of the silicon/silicon oxide interface. This includes a review of silicon surface preparation by wet or gas phase processing and its impact on high-k nucleation during ALD growth, and the consideration of gate stack capacitance and carrier mobility. In conclusion, two issues are highlighted: the impact of oxygen vacancies on the electrical characteristics of high-k MOS devices, and the way alloyed metal ions (such as Al in Hf-based gate stacks) in contact with the interfacial silicon oxide layer can be used to control flatband and threshold voltages.

  13. Improved electrical properties of Ge metal-oxide-semiconductor capacitors with high-k HfO2 gate dielectric by using La2O3 interlayer sputtered with/without N2 ambient

    NASA Astrophysics Data System (ADS)

    Xu, H. X.; Xu, J. P.; Li, C. X.; Lai, P. T.

    2010-07-01

    The electrical properties of n-Ge metal-oxide-semiconductor (MOS) capacitors with HfO2/LaON or HfO2/La2O3 stacked gate dielectric (LaON or La2O3 as interlayer) are investigated. It is found that better electrical performances, including lower interface-state density, smaller gate leakage current, smaller capacitance equivalent thickness, larger k value, and negligible C-V frequency dispersion, can be achieved for the MOS device with LaON interlayer. The involved mechanism lies in that the LaON interlayer can effectively block the interdiffusions of Ge, O, and Hf, thus suppressing the growth of unstable GeOx interlayer and improving the dielectric/Ge interface quality.

  14. 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.

  15. Determination of Energy Band Alignment in Ultrathin Hf-based Oxide/Pt System

    NASA Astrophysics Data System (ADS)

    Ohta, A.; Murakami, H.; Higashi, S.; Miyazaki, S.

    2013-03-01

    Effect of incorporating a third element into HfO2 on the electronic structures has been studied by high resolution x-ray photoelectron spectroscopy (XPS). Hf-IIIa (La, Y, Gd, and Dy) oxide and Hf-Ti oxide films were deposited on a Pt layer by metal organic chemical vapor deposition (MOCVD) and co-sputtering and followed by post-deposition annealing in O2 ambience at 500°C. The energy bandgap (Eg) of these Hf-based oxide films was determined by analyzing the energy loss spectra of O 1s photoelectrons in consideration of the overlap with Hf 4s core-line signals. From analyses of the valence band signals and the cut-off energy for photoelectrons, the valence band offset between the Hf based-oxide, and the Pt electrode and the work function value of the Pt layer were evaluated. By combining the oxide bandgap values, the valence band line-ups, and the Pt work function value, the energy band profile of the Hf-based oxide/Pt has been determined.

  16. 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

  17. Charge Trapping Flash Memory With High-k Dielectrics

    NASA Astrophysics Data System (ADS)

    Eun, Dong Seog

    2011-12-01

    High capacity and affordable price of flash memory make portable electronic devices popular, which in turn stimulates the further scaling down effort of the flash memory cells. Indeed the flash memory cells have been scaling down aggressively and face several crucial challenges. As a result, the technology trend is shifting from the floating-gate cell to the charge-trap cell in order to overcome fatal interference problems between cells. There are critical problems in the charge-trap memory cell which will become main-stream in the near future. The first potential problem is related to the memory retention which is degraded by the charge leakage through thin tunnel dielectrics. The second is the reduction of charge-storage capacity in the scaled down SiN trapping layer. The third is the low operation-efficiency resulting from the methods used to solve the first two problems. Using high-k tunnel dielectrics can solve the first problem. The second problem can be overcome by adopting a high-k trapping dielectric. The dielectric constant of the blocking layer must be higher than those of the tunnel dielectric and the trapping dielectric in order to maintain operation efficiency. This dissertation study is focused on adopting high-k dielectrics in all three of the aforementioned layers for figure generations of flash memory technology. For the high-k tunnel dielectric, the MAD Si3N4 and the MAD Al2O3 are used to fabricate the MANNS structure and the MANAS structure. The MANNS structure has the advantage of reducing the erase voltage due to its low barrier height for holes. In addition, the retention characteristic of the MANAS structure is not sensitive to temperature. The reason is that the carrier transport in MAD Al2O3 is dominated by F-N tunneling, which is nearly independent of temperature. Adopting TiOx as the trapping dielectric forms the MATAS structure. Although the charge capacity of TiOx is not very high, the operating voltage can be reduced to less than 10V

  18. 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.

  19. 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

  20. 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

  1. 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.

  2. Driving force of oxygen-ion migration across high-k/SiO2 interface

    NASA Astrophysics Data System (ADS)

    Kunugi, Ryota; Nakagawa, Nobuhiro; Watanabe, Takanobu

    2017-03-01

    We clarified the mechanism of oxygen (O‑)-ion migration at a high-k/SiO2 interface, which is a possible origin of the flat-band voltage shift in metal/high-k gate stacks. The oxygen density difference accommodation model was reproduced by a molecular dynamics simulation of an Al2O3/SiO2 structure, in which O‑ ions migrate from the higher oxygen density side to the lower one. We determined that the driving force of the O‑-ion migration is the short-range repulsion between ionic cores. The repulsive force is greater in materials with a higher oxygen density, pushing O‑ ions to the lower oxygen density side.

  3. 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.

  4. Ab-initio simulations on initial growth steps of high-K oxides on silicon

    NASA Astrophysics Data System (ADS)

    Bloechl, Peter E.

    2003-03-01

    One of the most acute challenges of semiconductor industry is the introduction of new so-called high-K gate oxides. Conventional SiO2 based gate oxides need to be replaced in order to avoid quantum mechanical leakage currents through ultrathin oxide layers. State of the art electronic structure calculations and ab-initio molecular dynamics simulations of the deposition of metals onto silicon and the formation of oxides have been performed. Atomic structure, chemical binding and electronic structure have been analyzed for a wide range of different adsorption structures of Zr, Hf, and Sr on silicon. Silicide formation and the step-wise formation of the oxides have been investigated. Particular emphasis will be given to the formation of the interface between SrTiO3 and silicon (001).

  5. Surface preparation for ALD of High-k dielectrics on indium gallium arsenide

    NASA Astrophysics Data System (ADS)

    Melitz, Wilhelm

    The key for a successful gate-first process is when subsequent processing steps cannot degrade the semiconductor, the dielectric, or the oxide-semiconductor interfaces. For silicon, the only commercial ALD high-k fabrication process, which avoids processing induced damage, is a replacement gate process (a type of gate-last process). While preparing silicon for gate-last processing is straightforward, the key to a gate-last process for III-V semiconductors is the order and cleanliness of the III-V channel prior to dielectric deposition. Aggressive oxide thickness reduction (equivalent oxide thickness, or EOT, scaling) is needed to fabricate small gate length devices with small subthreshold swings. Furthermore, aggressive EOT scaling requires a very high uniform ALD nucleation density, with no pinholes due to surface contaminants. The key barrier to solving a very practical problem is a surface chemistry challenge: develop a chemical process which removes nearly all air induced defects and contaminants and leaves the III-V surface flat and electrically active for high nucleation density ALD gate oxide deposition, which unpins the Fermi level. The following study uses scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS) to observe the removal of the oxide layer and restoration of the clean InGaAs surface reconstruction with atomic hydrogen cleaning, allowing for a gate-last or replacement-gate process. Along with surface cleaning STM and STS was used to characterize the initial passivation of InGaAs surfaces via ALD of trimethyl aluminum (TMA). The substrate temperature and initial surface reconstruction was critical to forming an unpinned passivation layer with a high nucleation density. A method was developed to use Kelvin probe force microscopy (KPFM) as a tool for insightful feedback on the electrostatics of scaled MOSFET devices. KPFM is a unique technique for providing two-dimensional potential profiles inside a working device. A

  6. 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

  7. 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

  8. 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

  9. 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

  10. Atomic layer deposition of high-k dielectrics on single-walled carbon nanotubes: a Raman study.

    PubMed

    Liyanage, Luckshitha Suriyasena; Cott, Daire J; Delabie, Annelies; Van Elshocht, Sven; Bao, Zhenan; Wong, H-S Philip

    2013-06-21

    Single-wall carbon nanotubes (SWCNTs) have great potential to become the channel material for future high-speed transistor technology. However, to realize a carbon nanotube field effect transistor (CNTFET) with excellent gate control, the high-k dielectrics between the CNT and the metal gate must have superb electrical properties and extremely high uniformity. Thus it is essential to understand the interactions between high-k materials and the SWCNTs to effectively control the transistor characteristics. In this study, we investigate the effects of atomic layer deposited (ALD) high-k dielectrics (Al2O3 and HfO2) on SWCNTs using Raman spectroscopy. We subjected the SWCNTs to various ALD cycles and studied the nucleation and growth of ALD dielectrics at defect sites using scanning electron microscopy and transmission electron microscopy images. We analyzed these samples using Raman spectroscopy and x-ray photoelectron spectroscopy. The Raman peak shifts of the G-peak and the 2D (G') peaks suggest doping and stress induced effects on the CNTs by the surrounding high-k oxide environment. Trends in the G-peak FWHM and G/D-peak ratios were identified and compared between Al2O3 and HfO2. We confirmed the ALD-deposited HfO2 is polycrystalline using x-ray diffraction and analyzed dielectric-CNT bonding states using XPS measurements. This study provides insights on the effects of ALD high-k materials on SWCNTs for future high-speed transistor applications.

  11. Atomic layer deposition of high-k dielectrics on single-walled carbon nanotubes: a Raman study

    NASA Astrophysics Data System (ADS)

    Suriyasena Liyanage, Luckshitha; Cott, Daire J.; Delabie, Annelies; Van Elshocht, Sven; Bao, Zhenan; Wong, H.-S. Philip

    2013-06-01

    Single-wall carbon nanotubes (SWCNTs) have great potential to become the channel material for future high-speed transistor technology. However, to realize a carbon nanotube field effect transistor (CNTFET) with excellent gate control, the high-k dielectrics between the CNT and the metal gate must have superb electrical properties and extremely high uniformity. Thus it is essential to understand the interactions between high-k materials and the SWCNTs to effectively control the transistor characteristics. In this study, we investigate the effects of atomic layer deposited (ALD) high-k dielectrics (Al2O3 and HfO2) on SWCNTs using Raman spectroscopy. We subjected the SWCNTs to various ALD cycles and studied the nucleation and growth of ALD dielectrics at defect sites using scanning electron microscopy and transmission electron microscopy images. We analyzed these samples using Raman spectroscopy and x-ray photoelectron spectroscopy. The Raman peak shifts of the G-peak and the 2D (G‧) peaks suggest doping and stress induced effects on the CNTs by the surrounding high-k oxide environment. Trends in the G-peak FWHM and G/D-peak ratios were identified and compared between Al2O3 and HfO2. We confirmed the ALD-deposited HfO2 is polycrystalline using x-ray diffraction and analyzed dielectric-CNT bonding states using XPS measurements. This study provides insights on the effects of ALD high-k materials on SWCNTs for future high-speed transistor applications.

  12. 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

  13. 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

  14. Investigation of 6T SRAM memory circuit using high-k dielectrics based nano scale junctionless transistor

    NASA Astrophysics Data System (ADS)

    Charles Pravin, J.; Nirmal, D.; Prajoon, P.; Mohan Kumar, N.; Ajayan, J.

    2017-04-01

    In this paper the Dual Metal Surround Gate Junctionless Transistor (DMSGJLT) has been implemented with various high-k dielectric. The leakage current in the device is analysed in detail by obtaining the band structure for different high-k dielectric material. It is noticed that with increasing dielectric constant the device provides more resistance for the direct tunnelling of electron in off state. The gate oxide capacitance also shows 0.1 μF improvement with Hafnium Oxide (HfO2) than Silicon Oxide (SiO2). This paved the way for a better memory application when high-k dielectric is used. The Six Transistor (6T) Static Random Access Memory (SRAM) circuit implemented shows 41.4% improvement in read noise margin for HfO2 than SiO2. It also shows 37.49% improvement in write noise margin and 30.16% improvement in hold noise margin for HfO2 than SiO2.

  15. Thermally stable yttrium-scandium oxide high-k dielectrics deposited by a solution process

    NASA Astrophysics Data System (ADS)

    Hu, Wenbing; Frost, Bradley; Peterson, Rebecca L.

    2016-03-01

    We investigated the thermal stability of electrical properties in ternary alloy (Y x Sc1-x )2O3 high-k oxides as a function of yttrium fraction, x. The yttrium-scandium oxide dielectric films are deposited using a facile ink-based process. The oxides have a stoichiometry-dependent relative dielectric constant of 26.0 to 7.7 at 100 kHz, low leakage current density of 10-8 A·cm-2, high breakdown field of 4 MVṡcm-1, and interface trap density of 1012 cm-2·eV-1 with silicon. Compared with binary oxides, ternary alloys exhibit less frequency dispersion of the dielectric constant and a higher crystallization temperature. After crystallization is induced through a 900 °C anneal, ternary (Y0.6Sc0.4)2O3 films maintain their low leakage current and high breakdown field. In contrast, the electrical performance of the binary oxides significantly degrades following the same treatment. The solution-processed ternary oxide dielectrics demonstrated here may be used as high-k gate insulators in complementary metal-oxide semiconductor (CMOS) technologies, in novel electronic material systems and devices, and in printed, flexible thin film electronics, and as passivation layers for high power devices. These oxides may also be used as insulators in fabrication process flows that require a high thermal budget.

  16. High-k dielectric Al2O3 nanowire and nanoplate field effect sensors for improved pH sensing

    PubMed Central

    Reddy, Bobby; Dorvel, Brian R.; Go, Jonghyun; Nair, Pradeep R.; Elibol, Oguz H.; Credo, Grace M.; Daniels, Jonathan S.; Chow, Edmond K. C.; Su, Xing; Varma, Madoo; Alam, Muhammad A.

    2011-01-01

    Over the last decade, field-effect transistors (FETs) with nanoscale dimensions have emerged as possible label-free biological and chemical sensors capable of highly sensitive detection of various entities and processes. While significant progress has been made towards improving their sensitivity, much is yet to be explored in the study of various critical parameters, such as the choice of a sensing dielectric, the choice of applied front and back gate biases, the design of the device dimensions, and many others. In this work, we present a process to fabricate nanowire and nanoplate FETs with Al2O3 gate dielectrics and we compare these devices with FETs with SiO2 gate dielectrics. The use of a high-k dielectric such as Al2O3 allows for the physical thickness of the gate dielectric to be thicker without losing sensitivity to charge, which then reduces leakage currents and results in devices that are highly robust in fluid. This optimized process results in devices stable for up to 8 h in fluidic environments. Using pH sensing as a benchmark, we show the importance of optimizing the device bias, particularly the back gate bias which modulates the effective channel thickness. We also demonstrate that devices with Al2O3 gate dielectrics exhibit superior sensitivity to pH when compared to devices with SiO2 gate dielectrics. Finally, we show that when the effective electrical silicon channel thickness is on the order of the Debye length, device response to pH is virtually independent of device width. These silicon FET sensors could become integral components of future silicon based Lab on Chip systems. PMID:21203849

  17. Low on-resistance diamond field effect transistor with high-k ZrO2 as dielectric

    PubMed Central

    Liu, Jiangwei; Liao, Meiyong; Imura, Masataka; Tanaka, Akihiro; Iwai, Hideo; Koide, Yasuo

    2014-01-01

    Although several high-k insulators have been deposited on the diamond for metal-insulator-semiconductor field effect transistors (MISFETs) fabrication, the k values and current output are still not fully satisfactory. Here, we present a high-k ZrO2 layer on the diamond for the MISFETs. The k value for ZrO2 is determined by capacitance-voltage characteristic to be 15.4. The leakage current density is smaller than 4.8 × 10−5 A·cm−2 for the gate voltage ranging from −4.0 to 2.0 V. The low on-resistance MISFET is obtained by eliminating source/drain-channel interspaces, which shows a large current output and a high extrinsic transconductance. The high-performance diamond MISFET fabrication will push forward the development of power devices. PMID:25242175

  18. Alternative materials for next-generation transistors: High-k/germanium-based MOSFET

    NASA Astrophysics Data System (ADS)

    Hsueh, Chein-Lan

    Electronic devices that make up 99% of the computer processor and memory market are based on silicon (semiconductor) and silicon dioxide (insulator) technology. Unfortunately the key transistor gate stack structure within the "traditional" technology has reached an intrinsic physical scaling limit; the ultrathin gate oxide, already at 1nm thickness, cannot be made thinner without resulting in an intolerably high leakage current and reduced drive current. This limitation can be avoided by replacing the thin gate dielectric with a thicker film of an alternative material with a permittivity higher than that of SiO2, an accomplishing that has been realized in production just as this thesis goes to press. To further increase device performance, replacing the Si semiconductor with germanium as an alternative channel material is an attractive option for its high mobility and narrow band gap. However, the lack of a stable insulating oxide with high quality electrical properties prevents the fabrication of competitive Ge-based metal oxide semiconductor field effect transistors (MOSFETs). This dissertation reports the study of potential future-generation transistors with high-k dielectrics (HfO2 and Al2O3) on Ge substrates. A brief review of current research and development is first given followed by an introduction of the thin film characterization techniques used in this work. Various cleaning treatments as well as surface passivation methods using wet chemistry have been investigated on Ge substrates. Next, thin high-k dielectric films of HfO2 and Al2O3 have been deposited on Ge using atomic layer deposition (ALD). ALD permits films to be grown with monolayer control and excellent film conformality. Physical, chemical and electrical characterization has been performed on the multilayer film structures. Optimization of the film growth has been developed and we have demonstrated high quality with Au/HfO2/Ge nMOS devices. Capacitance-voltage electrical measurements show that

  19. Nonadditivity in moments ofinertia of high-K multiquasiparticle bands

    NASA Astrophysics Data System (ADS)

    Zhang, Zhen-Hua; Wu, Xi; Lei, Yi-An; Zeng, Jin-Yan

    2008-09-01

    The experimental high-K 2- and 3-quasiparticle bands of well deformed rare-earth nuclei are analyzed. It is found that there exists significant nonadditivity in moments of inertia (MOIs) for these bands. The microscopic mechanism of the rotational bands is investigated by the particle number conserving (PNC) method in the frame of cranked shell model with pairing, in which the blocking effects are taken care of exactly. The experimental rotational frequency dependence of these bands is well reproduced in PNC calculations. The nonadditivity in MOIs originates from the destructive interference between Pauli blocking effects. Supported by National Natural Science Foundation of China (10675006, 10675007, 10435010)

  20. 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.

  1. 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.

  2. Identical high- K three-quasiparticle rotational bands

    NASA Astrophysics Data System (ADS)

    Kaur, Harjeet; Singh, Pardeep

    2016-12-01

    A comprehensive study of high- K three-quasiparticle rotational bands in odd- A nuclei indicates the similarity in γ -ray energies and dynamic moment of inertia Im^{(2)} . The extent of the identicality between the rotational bands is evaluated by using the energy factor method. For nuclei pairs exhibiting identical bands, the average relative change in the dynamic moment of inertia Im^{(2)} is also determined. The identical behaviour shown by these bands is attributed to the interplay of nuclear structure parameters: deformation and the pairing correlations. Also, experimental trend of the I(hbar) vs. hbar ω (MeV) plot for these nuclei pairs is shown to be in agreement with Tilted-Axis Cranking (TAC) model calculations.

  3. 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.

  4. 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.

  5. Improved integration of ultra-thin high-k dielectrics in few-layer MoS2 FET by remote forming gas plasma pretreatment

    NASA Astrophysics Data System (ADS)

    Wang, Xiao; Zhang, Tian-Bao; Yang, Wen; Zhu, Hao; Chen, Lin; Sun, Qing-Qing; Zhang, David Wei

    2017-01-01

    The effective and high-quality integration of high-k dielectrics on two-dimensional (2D) crystals is essential to the device structure engineering and performance improvement of field-effect transistor (FET) based on the 2D semiconductors. We report a 2D MoS2 transistor with ultra-thin Al2O3 top-gate dielectric (6.1 nm) and extremely low leakage current. Remote forming gas plasma pretreatment was carried out prior to the atomic layer deposition, providing nucleation sites with the physically adsorbed ions on the MoS2 surface. The top gate MoS2 FET exhibited excellent electrical performance, including high on/off current ratio over 109, subthreshold swing of 85 mV/decade and field-effect mobility of 45.03 cm2/V s. Top gate leakage current less than 0.08 pA/μm2 at 4 MV/cm has been obtained, which is the smallest compared with the reported top-gated MoS2 transistors. Such an optimized integration of high-k dielectric in 2D semiconductor FET with enhanced performance is very attractive, and it paves the way towards the realization of more advanced 2D nanoelectronic devices and integrated circuits.

  6. Gate-all-around technology: Taking advantage of ballistic transport?

    NASA Astrophysics Data System (ADS)

    Huguenin, J. L.; Bidal, G.; Denorme, S.; Fleury, D.; Loubet, N.; Pouydebasque, A.; Perreau, P.; Leverd, F.; Barnola, S.; Beneyton, R.; Orlando, B.; Gouraud, P.; Salvetat, T.; Clement, L.; Monfray, S.; Ghibaudo, G.; Boeuf, F.; Skotnicki, T.

    2010-09-01

    This work presents an experimental study in order to evaluate the quality of transport in the most advanced state-of-the-art gate-all-around devices in term of performances. Experiments have been done on silicon channel devices with metal/high-k gate all-round stack at aggressive dimensions ( L × W × TSi = 25nm × 20 nm × 10nm). We deeply investigated the mobility and the limiting velocity in order to evaluate the possible occurrence of ballisticity. Interest of the gate-all-around in terms of effective current and parasitic capacitance has then been studied in the scope of elementary circuit perspectives.

  7. Interfacial reaction and electrical properties of HfO2 film gate dielectric prepared by pulsed laser deposition in nitrogen: role of rapid thermal annealing and gate electrode.

    PubMed

    Wang, Yi; Wang, Hao; Ye, Cong; Zhang, Jun; Wang, Hanbin; Jiang, Yong

    2011-10-01

    The high-k dielectric HfO(2) thin films were deposited by pulsed laser deposition in nitrogen atmosphere. Rapid thermal annealing effect on film surface roughness, structure and electrical properties of HfO(2) film was investigated. The mechanism of interfacial reaction and the annealing atmosphere effect on the interfacial layer thickness were discussed. The sample annealed in nitrogen shows an amorphous dominated structure and the lowest leakage current density. Capacitors with high-k HfO(2) film as gate dielectric were fabricated, using Pt, Au, and Ti as the top gate electrode whereas Pt constitutes the bottom side electrode. At the gate injection case, the Pt- and Au-gated metal oxide semiconductor devices present a lower leakage current than that of the Ti-gated device, as well as similar leakage current conduction mechanism and interfacial properties at the metal/HfO(2) interface, because of their close work function and chemical properties.

  8. 49 CFR 234.255 - Gate arm and gate mechanism.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 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....

  9. 49 CFR 234.255 - Gate arm and gate mechanism.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 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....

  10. 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...

  11. 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....

  12. 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...

  13. Analytical drain current formulation for gate dielectric engineered dual material gate-gate all around-tunneling field effect transistor

    NASA Astrophysics Data System (ADS)

    Madan, Jaya; Gupta, R. S.; Chaujar, Rishu

    2015-09-01

    In this work, an analytical drain current model for gate dielectric engineered (hetero dielectric)-dual material gate-gate all around tunnel field effect transistor (HD-DMG-GAA-TFET) has been developed. Parabolic approximation has been used to solve the two-dimensional (2D) Poisson equation with appropriate boundary conditions and continuity equations to evaluate analytical expressions for surface potential, electric field, tunneling barrier width and drain current. Further, the analog performance of the device is studied for three high-k dielectrics (Si3N4, HfO2, and ZrO2), and it has been investigated that the problem of lower ION, can be overcome by using the hetero-gate architecture. Moreover, the impact of scaling the gate oxide thickness and bias variations has also been studied. The HD-DMG-GAA-TFET shows an enhanced ION of the order of 10-4 A. The effectiveness of the proposed model is validated by comparing it with ATLAS device simulations.

  14. 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

  15. Correlation of bandgap reduction with inversion response in (Si)GeSn/high-k/metal stacks.

    PubMed

    Schulte-Braucks, Christian; Narimani, Keyvan; Glass, Stefan; von den Driesch, Nils; Hartmann, Jean-Michel; Ikonic, Zoran; Afanas'ev, Valeri V; Zhao, Qing-Tai; Mantl, Siegfried; Buca, Dan

    2017-02-21

    The bandgap tunability of (Si)GeSn group IV semiconductors opens a new era in Si-technology. Depending on the Si/Sn contents, direct and indirect bandgaps in the range of 0.4 eV to 0.8 eV can be obtained, offering a broad spectrum of both photonic and low power electronic applications. In this work, we systematically studied capacitance-voltage characteristics of high-k/metal gate stacks formed on GeSn and SiGeSn alloys with Sn-contents ranging from 0 to 14 at.% and Si-contents from 0 to 10 at.% particularly focusing on the minority carrier inversion response. A clear correlation between the Sn-induced shrinkage of the bandgap energy and enhanced minority carrier response was confirmed using temperature and frequency dependent capacitance voltage-measurements, in good agreement with k.p theory predictions and photoluminescence measurements of the analyzed epilayers as reported earlier. The enhanced minority generation rate for higher Sn-contents can be firmly linked to the bandgap reduction in the GeSn epilayer without significant influence of substrate/interface effects. It thus offers a unique possibility to analyze intrinsic defects in (Si)GeSn epilayers. The extracted dominant defect level for minority carrier inversion lies approximately 0.4 eV above the valence band edge in the studied Sn-content range (0 to12.5 at.%). This finding is of critical importance since it shows that the presence of Sn by itself does not impair the minority carrier lifetime. Therefore, the continuous improvement of (Si)GeSn material quality should yield longer non-radiative recombination times which are required for the fabrication of efficient light detectors and to obtain room temperature lasing action.

  16. Properties of high k gate dielectric gadolinium oxide deposited on Si (1 0 0) by dual ion beam deposition (DIBD)

    NASA Astrophysics Data System (ADS)

    Zhou, Jian-Ping; Chai, Chun-Lin; Yang, Shao-Yan; Liu, Zhi-Kai; Song, Shu-Lin; Li, Yan-Li; Chen, Nuo-Fu

    2004-09-01

    Gadolinium oxide thin films have been prepared on silicon (1 0 0) substrates with a low-energy dual ion-beam epitaxial technique. Substrate temperature was an important factor to affect the crystal structures and textures in an ion energy range of 100-500 eV. The films had a monoclinic Gd2O3 structure with preferred orientation (4 bar 0 2) at low substrate temperatures. When the substrate temperature was increased, the orientation turned to (2 0 2), and finally, the cubic structure appeared at the substrate temperature of 700 °C, which disagreed with the previous report because of the ion energy. The AES studies found that Gadolinium oxide shared Gd2O3 structures, although there were a lot of oxygen deficiencies in the films, and the XPS results confirmed this. AFM was also used to investigate the surface images of the samples. Finally, the electrical properties were presented.

  17. 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.

  18. 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

  19. 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

  20. 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

  1. Investigation of an anomalous hump in gate current after negative-bias temperature-instability in HfO2/metal gate p-channel metal-oxide-semiconductor field-effect transistors

    NASA Astrophysics Data System (ADS)

    Ho, Szu-Han; Chang, Ting-Chang; Wu, Chi-Wei; Lo, Wen-Hung; Chen, Ching-En; Tsai, Jyun-Yu; Liu, Guan-Ru; Chen, Hua-Mao; Lu, Ying-Shin; Wang, Bin-Wei; Tseng, Tseung-Yuen; Cheng, Osbert; Huang, Cheng-Tung; Sze, Simon M.

    2013-01-01

    This Letter investigates a hump in gate current after negative-bias temperature-instability (NBTI) in HfO2/metal gate p-channel metal-oxide-semiconductor field-effect transistors. Measuring gate current at initial through body floating and source/drain floating shows that hole current flows from source/drain. The fitting of gate current (Ig)-gate voltage (Vg) characteristic curves demonstrates that the Frenkel-Poole mechanism dominates the conduction. Next, by fitting the gate current after NBTI, in the order of Frenkel-Poole then tunneling, the Frenkel-Poole mechanism can be confirmed. These phenomena can be attributed to hole trapping in high-k bulk and the electric field formula Ehigh-k ɛhigh-k = Q + Esio2ɛsio2.

  2. Analysis of an anomalous hump in gate current after dynamic negative bias stress in HfxZr1-xO2/metal gate p-channel metal-oxide-semiconductor field-effect transistors

    NASA Astrophysics Data System (ADS)

    Ho, Szu-Han; Chang, Ting-Chang; Wu, Chi-Wei; Lo, Wen-Hung; Chen, Ching-En; Tsai, Jyun-Yu; Luo, Hung-Ping; Tseng, Tseung-Yuen; Cheng, Osbert; Huang, Cheng-Tung; Sze, Simon M.

    2012-07-01

    This letter investigates a hump in gate current after dynamic negative bias stress (NBS) in HfxZr1-xO2/metal gate p-channel metal-oxide-semiconductor field-effect transistors. By measuring gate current under initial through body floating and source/drain floating, it shows that hole current flows from source/drain. The fitting of gate current-gate voltage characteristic curve demonstrates that Frenkel-Poole mechanism dominates the conduction. Next, by fitting the gate current after dynamic NBS, in the order of Frenkel-Poole then tunneling, the Frenkel-Poole mechanism can be confirmed. These phenomena can be attributed to hole trapping in high-k bulk and the electric field formula Ehigh-k ɛhigh-k = Q + Esio2ɛsio2.

  3. 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''.

  4. 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.

  5. 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.

  6. 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.

  7. Range gated imaging experiments using gated intensifiers

    SciTech Connect

    McDonald, T.E. Jr.; Yates, G.J.; Cverna, F.H.; Gallegos, R.A.; Jaramillo, S.A.; Numkena, D.M.; Payton, J.; Pena-Abeyta, C.R.

    1999-03-01

    A variety of range gated imaging experiments using high-speed gated/shuttered proximity focused microchannel plate image intensifiers (MCPII) are reported. Range gated imaging experiments were conducted in water for detection of submerged mines in controlled turbidity tank test and in sea water for the Naval Coastal Sea Command/US Marine Corps. Field experiments have been conducted consisting of kilometer range imaging of resolution targets and military vehicles in atmosphere at Eglin Air Force Base for the US Air Force, and similar imaging experiments, but in smoke environment, at Redstone Arsenal for the US Army Aviation and Missile Command (AMCOM). Wavelength of the illuminating laser was 532 nm with pulse width ranging from 6 to 12 ns and comparable gate widths. These tests have shown depth resolution in the tens of centimeters range from time phasing reflected LADAR images with MCPII shutter opening.

  8. Tantalum oxide thin films for high-k dielectric applications: Crystallization, anisotropy and three dimensional imaging

    NASA Astrophysics Data System (ADS)

    Min, Kyunghoon

    2004-12-01

    High dielectric constant (high-k) materials have been drawing much attention for applications such as gate oxides for transistors and dynamic random access memory (DRAM) capacitors. Tantalum pentoxide (Ta2O5) is a possible replacement because of its relatively high dielectric constant and process compatibility. The microstructure of Ta2O5 thin films, deposited on Si substrates by atomic layer deposition, was investigated primarily using transmission electron microscopy (TEM). The kinetics of the crystallization and evolution of a complicated subgrain structure were studied by in-situ TEM heating experiments carried out at nominal temperatures of 790°C, 820°C and 850°C. It was found that the crystallization behavior could be modeled by a standard kinetic approach, using the Avrami equation, and differences from conventional bulk behavior are discussed. The growth and overall crystallization activation energies extracted from the in-situ TEM results were 4.2 eV and 6.3 eV, respectively. The tantalum oxide films used in this study were found to have two predominant crystallographic orientations. In order to evaluate the possible anisotropic properties of the two types of grains, micro-capacitors were fabricated on each type using a combination of a focused ion beam machine (FIB) and the TEM. Plan-view TEM samples were prepared to identify and locate grain orientations followed by electron beam assisted chemical vapor deposition of a Pt top electrode using the local deposition capability of the FIB. Electrical measurement of the micro-capacitors was carried out using a micromanipulator inside the FIB. The dielectric properties of the two types of grains were directly compared from the measurements. A further application of FIB combined with TEM allows novel specimen preparation for electron tomography. Accordingly, we can address the three dimensional imaging of Ta2O5 thin films deposited on hemi-spherical grain silicon (HSG) structures. The post-shaped sample

  9. Configurations and decay hindrances of high-K states in 180Hf

    NASA Astrophysics Data System (ADS)

    Tandel, S. K.; Chowdhury, P.; Kondev, F. G.; Janssens, R. V. F.; Khoo, T. L.; Carpenter, M. P.; Lauritsen, T.; Lister, C. J.; Seweryniak, D.; Zhu, S.; Deacon, A.; Freeman, S. J.; Hammond, N. J.; Jones, G. D.; Moore, E. F.; Smith, J. F.

    2016-12-01

    Multi-quasiparticle high-K states, several of which are isomeric, were observed in 180Hf with the Gammasphere array. Lifetimes in the ns-μ s range were determined using centroid-shift and decay measurements within a μ s coincidence time window. The configurations of high-K states involve two and four quasiparticles, with states up to Kπ=(18-) established. High-K excitations are found to be progressively more favored with increasing excitation energy. The K quantum number is quite robust up to the highest spins observed, as evidenced by the large values of the reduced hindrance for isomeric decays. Rotational bands built on three high-K states are identified, and the measured branching ratios in these sequences enable the assignment of underlying configurations. Multi-quasiparticle calculations using the Lipkin-Nogami approach for pairing, with blocking included, reproduce the observed high-K energies quite well.

  10. Optical Logic Gates

    NASA Technical Reports Server (NTRS)

    Du Fresne, E. R.; Dowler, W. L.

    1985-01-01

    Logic gates for light signals constructed from combinations of prisms, polarizing plates, and quarterwave plates. Optical logic gate performs elementary logic operation on light signals received along two optical fibers. Whether gate performs OR function or exclusive-OR function depends on orientation of analyzer. Nonbinary truth tables also obtained by rotating polarizer or analyzer to other positions or inserting other quarter-wave plates.

  11. 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

  12. 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

  13. 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

  14. 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.

  15. 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.

  16. CCD gate definition process

    NASA Astrophysics Data System (ADS)

    Bluzer

    1986-02-01

    The present invention utilizes a double masking step in a CCD gate definition process to eliminate the re-entrant oxide by using a thin film layer other than photoresist to define the polysilicon gates used by defining the thin film layer with a double masking process before any of the polysilicon gate layer is etched. It is one object of the present invention, therefore, to provide an improved process for CCD gate definition. It is another object of the invention to provide an improved CCD gate definition process wherein a profiled oxide layer is produced over a polysilicon layer without re-entrant oxide regions. It is another object of the invention to provide an improved CCD gate definition process wherein a thin film layer is utilized to define the polysilicon gate layers. It is another object of the invention to provide an improved CCD gate definition process wherein the thin film layer is defined by a double masking process before any polysilicon layer is etched.

  17. 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.

  18. Detection of high k turbulence using two dimensional phase contrast imaging on LHD

    SciTech Connect

    Michael, C. A.; Tanaka, K.; Akiyama, T.; Kawahata, K.; Vyacheslavov, L. N.; Sanin, A.; Kharchev, N. K.; Okajima, S.

    2008-10-15

    High k turbulence, up to 30 cm{sup -1}, can be measured using the two dimensional CO2 laser phase contrast imaging system on LHD. Recent hardware improvements and experimental results are presented. Precise control over the lens positions in the detection system is necessary because of the short depth of focus for high k modes. Remote controllable motors to move optical elements were installed, which, combined with measurements of the response to ultrasound injection, allowed experimental verification and shot-to-shot adjustment of the object plane. Strong high k signals are observed within the first 100-200 ms after the initial electron cyclotron heating (ECH) breakdown, in agreement with gyrotron scattering. During later times in the discharge, the entire k spectrum shifts to lower values (although the total amplitude does not change significantly), and the weaker high k signals are obscured by leakage of low k components at low frequency, and detector noise, at high frequency.

  19. 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.

  20. 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.

  1. Technology and characterization of Thin-Film Transistors (TFTs) with a-IGZO semiconductor and high-k dielectric layer

    NASA Astrophysics Data System (ADS)

    Mroczyński, R.; Wachnicki, Ł.; Gierałtowska, S.

    2016-12-01

    In this work, we present the design of the technology and fabrication of TFTs with amorphous IGZO semiconductor and high-k gate dielectric layer in the form of hafnium oxide (HfOx). In the course of this work, the IGZO fabrication was optimized by means of Taguchi orthogonal tables approach in order to obtain an active semiconductor with reasonable high concentration of charge carriers, low roughness and relatively high mobility. The obtained Thin-Film Transistors can be characterized by very good electrical parameters, i.e., the effective mobility (μeff ≍ 12.8 cm2V-1s-1) significantly higher than that for a-Si TFTs (μeff ≍ 1 cm2V-1s-1). However, the value of sub-threshold swing (i.e., 640 mV/dec) points that the interfacial properties of IGZO/HfOx stack is characterized by high value of interface states density (Dit) which, in turn, demands further optimization for future applications of the demonstrated TFT structures.

  2. 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

  3. 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

  4. Optical XOR gate

    SciTech Connect

    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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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)

  10. CFTR Gating I

    PubMed Central

    Bompadre, Silvia G.; Ai, Tomohiko; Cho, Jeong Han; Wang, Xiaohui; Sohma, Yoshiro; Li, Min; Hwang, Tzyh-Chang

    2005-01-01

    The CFTR chloride channel is activated by phosphorylation of serine residues in the regulatory (R) domain and then gated by ATP binding and hydrolysis at the nucleotide binding domains (NBDs). Studies of the ATP-dependent gating process in excised inside-out patches are very often hampered by channel rundown partly caused by membrane-associated phosphatases. Since the severed ΔR-CFTR, whose R domain is completely removed, can bypass the phosphorylation-dependent regulation, this mutant channel might be a useful tool to explore the gating mechanisms of CFTR. To this end, we investigated the regulation and gating of the ΔR-CFTR expressed in Chinese hamster ovary cells. In the cell-attached mode, basal ΔR-CFTR currents were always obtained in the absence of cAMP agonists. Application of cAMP agonists or PMA, a PKC activator, failed to affect the activity, indicating that the activity of ΔR-CFTR channels is indeed phosphorylation independent. Consistent with this conclusion, in excised inside-out patches, application of the catalytic subunit of PKA did not affect ATP-induced currents. Similarities of ATP-dependent gating between wild type and ΔR-CFTR make this phosphorylation-independent mutant a useful system to explore more extensively the gating mechanisms of CFTR. Using the ΔR-CFTR construct, we studied the inhibitory effect of ADP on CFTR gating. The Ki for ADP increases as the [ATP] is increased, suggesting a competitive mechanism of inhibition. Single channel kinetic analysis reveals a new closed state in the presence of ADP, consistent with a kinetic mechanism by which ADP binds at the same site as ATP for channel opening. Moreover, we found that the open time of the channel is shortened by as much as 54% in the presence of ADP. This unexpected result suggests another ADP binding site that modulates channel closing. PMID:15767295

  11. DNA logic gates.

    PubMed

    Okamoto, Akimitsu; Tanaka, Kazuo; Saito, Isao

    2004-08-04

    A conceptually new logic gate based on DNA has been devised. Methoxybenzodeazaadenine ((MD)A), an artificial nucleobase which we recently developed for efficient hole transport through DNA, formed stable base pairs with T and C. However, a reasonable hole-transport efficiency was observed in the reaction for the duplex containing an (MD)A/T base pair, whereas the hole transport was strongly suppressed in the reaction using a duplex where the base opposite (MD)A was replaced by C. The influence of complementary pyrimidines on the efficiency of hole transport through (MD)A was quite contrary to the selectivity observed for hole transport through G. The orthogonality of the modulation of these hole-transport properties by complementary pyrimidine bases is promising for the design of a new molecular logic gate. The logic gate system was executed by hole transport through short DNA duplexes, which consisted of the "logic gate strand", containing hole-transporting nucleobases, and the "input strand", containing pyrimidines which modulate the hole-transport efficiency of logic bases. A logic gate strand containing multiple (MD)A bases in series provided the basis for a sharp AND logic action. On the other hand, for OR logic and combinational logic, conversion of Boolean expressions to standard sum-of-product (SOP) expressions was indispensable. Three logic gate strands were designed for OR logic according to each product term in the standard SOP expression of OR logic. The hole-transport efficiency observed for the mixed sample of logic gate strands exhibited an OR logic behavior. This approach is generally applicable to the design of other complicated combinational logic circuits such as the full-adder.

  12. Hetero-epitaxial growth of the cubic single crystalline HfO 2 film as high k materials by pulsed laser ablation

    NASA Astrophysics Data System (ADS)

    Zhang, Xinqiang; Tu, Hailing; Wang, Xiaona; Xiong, Yuhua; Yang, Mengmeng; Wang, Lei; Du, Jun

    2010-10-01

    We report a hetero-epitaxial growth of cubic single crystalline HfO 2 film on Si substrates as high k materials by pulse laser ablation (PLA) at 820 °C. To eliminate the interfacial defects, the HfO 2 film has then been annealed at 900 °C for 5 min in N 2. Reflection high-energy electron diffraction (RHEED) results indicate orientation of the HfO 2 film on Si substrates corresponding to (∥( and [∥[. An interface layer has been revealed by high-resolution transmission electron microscope (HRTEM). Through capacitance-voltage ( C- V) and current-voltage ( I- V), it has been obtained that the leakage current of the HfO 2 gate insulator with dielectric constant of 26 is 5×10 -6 A/cm 2 at -1 V.

  13. Synchronous pulsing plasma utilization in dummy poly gate removal process

    NASA Astrophysics Data System (ADS)

    Huang, Ruixuan; Meng, Xiao-Ying; Han, Qiu-Hua; Zhang, Hai-Yang

    2015-03-01

    When CMOS technology reaches 28/20nm node and beyond, several new schemes are implemented such as High K metal gate (HKMG) which can enhance the device performance and has better control of device current leakage. Dummy poly gate removal (DPGR) process is introduced for HKMG, and works as a key process to control the work function of metal gate and threshold voltage (Vt) shift. In dry etch technology, conventional continuous wave (CW) plasma process has been widely used, however, it may not be capable for some challenging process in 28nm node and beyond. In DPGR process for HKMG scheme, CW scheme may result in plasma damage of gate oxide/capping layer for its inherent high electron temperature (Te) and ion energy while synchronous pulsing scheme is capable to simultaneously pulse both source and bias power, which could achieve lower Te, independent control of ion and radical flux, well control the loading of polymer deposition on dense/ isolate features. It's the first attempt to utilize synchronous pulsing plasma in DPGR process. Experiment results indicate that synchronous pulsing could provide less silicon recess under thin gate oxide which is induced by the plasma oxidation. Furthermore, the loading of HK capping layer loss between long channel and short channel can be well controlled which plays a key role on transistor performance, such as leakage and threshold voltage shift. Additionally, it has been found that synchronous pulsing could distinctly improve ILD loss when compared with CW, which is helpful to broaden the whole process window.

  14. 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.

  15. Effects of gate-last and gate-first process on deep submicron inversion-mode InGaAs n-channel metal-oxide-semiconductor field effect transistors

    NASA Astrophysics Data System (ADS)

    Gu, J. J.; Wu, Y. Q.; Ye, P. D.

    2011-03-01

    Recently, encouraging progress has been made on surface-channel inversion-mode In-rich InGaAs NMOSFETs with superior drive current, high transconductance and minuscule gate leakage, using atomic layer deposited (ALD) high-k dielectrics. Although gate-last process is favorable for high-k/III-V integration, high-speed logic devices require a self-aligned gate-first process for reducing the parasitic resistance and overlap capacitance. On the other hand, a gate-first process usually requires higher thermal budget and may degrade the III-V device performance. In this paper, we systematically investigate the thermal budget of gate-last and gate-first process for deep-submicron InGaAs MOSFETs. We conclude that the thermal instability of (NH4)2S as the pretreatment before ALD gate dielectric formation leads to the potential failure of enhancement-mode operation and deteriorates interface quality in the gate-first process. We thus report on the detailed study of scaling metrics of deep-submicron self-aligned InGaAs MOSFET without sulfur passivation, featuring optimized threshold voltage and negligible off-state degradation.

  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. 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.

  18. 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

  19. 2. CANNON GATES. DETAIL OF NORTHWEST GATE STONE WALL TO ...

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

    2. CANNON GATES. DETAIL OF NORTHWEST GATE STONE WALL TO LEFT IS A REMNANT OF THE ORIGINAL FACILITY BOUNDARY FENCE. IT IS CONSTRUCTED IN BLUE PUDDING STONE. - Picatinny Arsenal, State Route 15 near I-80, Dover, Morris County, NJ

  20. Modulation of NCC activity by low and high K(+) intake: insights into the signaling pathways involved.

    PubMed

    Castañeda-Bueno, María; Cervantes-Perez, Luz Graciela; Rojas-Vega, Lorena; Arroyo-Garza, Isidora; Vázquez, Norma; Moreno, Erika; Gamba, Gerardo

    2014-06-15

    Modulation of Na(+)-Cl(-) cotransporter (NCC) activity is essential to adjust K(+) excretion in the face of changes in dietary K(+) intake. We used previously characterized genetic mouse models to assess the role of Ste20-related proline-alanine-rich kinase (SPAK) and with-no-lysine kinase (WNK)4 in the modulation of NCC by K(+) diets. SPAK knockin and WNK4 knockout mice were placed on normal-, low-, or high-K(+)-citrate diets for 4 days. The low-K(+) diet decreased and high-K(+) diet increased plasma aldosterone levels, but both diets were associated with increased phosphorylation of NCC (phospho-NCC, Thr(44)/Thr(48)/Thr(53)) and phosphorylation of SPAK/oxidative stress responsive kinase 1 (phospho-SPAK/OSR1, Ser(383)/Ser(325)). The effect of the low-K(+) diet on SPAK phosphorylation persisted in WNK4 knockout and SPAK knockin mice, whereas the effects of ANG II on NCC and SPAK were lost in both mouse colonies. This suggests that for NCC activation by ANG II, integrity of the WNK4/SPAK pathway is required, whereas for the low-K(+) diet, SPAK phosphorylation occurred despite the absence of WNK4, suggesting the involvement of another WNK (WNK1 or WNK3). Additionally, because NCC activation also occurred in SPAK knockin mice, it is possible that loss of SPAK was compensated by OSR1. The positive effect of the high-K(+) diet was observed when the accompanying anion was citrate, whereas the high-KCl diet reduced NCC phosphorylation. However, the effect of the high-K(+)-citrate diet was aldosterone dependent, and neither metabolic alkalosis induced by bicarbonate, nor citrate administration in the absence of K(+) increased NCC phosphorylation, suggesting that it was not due to citrate-induced metabolic alkalosis. Thus, the accompanying anion might modulate the NCC response to the high-K(+) diet.

  1. Modulation of NCC activity by low and high K+ intake: insights into the signaling pathways involved

    PubMed Central

    Castañeda-Bueno, María; Cervantes-Perez, Luz Graciela; Rojas-Vega, Lorena; Arroyo-Garza, Isidora; Vázquez, Norma; Moreno, Erika

    2014-01-01

    Modulation of Na+-Cl− cotransporter (NCC) activity is essential to adjust K+ excretion in the face of changes in dietary K+ intake. We used previously characterized genetic mouse models to assess the role of Ste20-related proline-alanine-rich kinase (SPAK) and with-no-lysine kinase (WNK)4 in the modulation of NCC by K+ diets. SPAK knockin and WNK4 knockout mice were placed on normal-, low-, or high-K+-citrate diets for 4 days. The low-K+ diet decreased and high-K+ diet increased plasma aldosterone levels, but both diets were associated with increased phosphorylation of NCC (phospho-NCC, Thr44/Thr48/Thr53) and phosphorylation of SPAK/oxidative stress responsive kinase 1 (phospho-SPAK/OSR1, Ser383/Ser325). The effect of the low-K+ diet on SPAK phosphorylation persisted in WNK4 knockout and SPAK knockin mice, whereas the effects of ANG II on NCC and SPAK were lost in both mouse colonies. This suggests that for NCC activation by ANG II, integrity of the WNK4/SPAK pathway is required, whereas for the low-K+ diet, SPAK phosphorylation occurred despite the absence of WNK4, suggesting the involvement of another WNK (WNK1 or WNK3). Additionally, because NCC activation also occurred in SPAK knockin mice, it is possible that loss of SPAK was compensated by OSR1. The positive effect of the high-K+ diet was observed when the accompanying anion was citrate, whereas the high-KCl diet reduced NCC phosphorylation. However, the effect of the high-K+-citrate diet was aldosterone dependent, and neither metabolic alkalosis induced by bicarbonate, nor citrate administration in the absence of K+ increased NCC phosphorylation, suggesting that it was not due to citrate-induced metabolic alkalosis. Thus, the accompanying anion might modulate the NCC response to the high-K+ diet. PMID:24761002

  2. 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.

  3. 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.

  4. 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

  5. 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

  6. A threshold voltage model of short-channel fully-depleted recessed-source/drain (Re-S/D) SOI MOSFETs with high-k dielectric

    NASA Astrophysics Data System (ADS)

    Gopi Krishna, Saramekala; Sarvesh, Dubey; Pramod, Kumar Tiwari

    2015-10-01

    In this paper, a surface potential based threshold voltage model of fully-depleted (FD) recessed-source/drain (Re-S/D) silicon-on-insulator (SOI) metal-oxide semiconductor field-effect transistor (MOSFET) is presented while considering the effects of high-k gate-dielectric material induced fringing-field. The two-dimensional (2D) Poisson’s equation is solved in a channel region in order to obtain the surface potential under the assumption of the parabolic potential profile in the transverse direction of the channel with appropriate boundary conditions. The accuracy of the model is verified by comparing the model’s results with the 2D simulation results from ATLAS over a wide range of channel lengths and other parameters, including the dielectric constant of gate-dielectric material. The author, Pramod Kumar Tiwari, was supported by the Science and Engineering Research Board (SERB), Department of Science and Technology, Ministry of Human Resource and Development, Government of India under Young Scientist Research (Grant No. SB/FTP/ETA-415/2012).

  7. 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…

  8. 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.

  9. High-performance SEGISFET pH Sensor using the structure of double-gate a-IGZO TFTs with engineered gate oxides

    NASA Astrophysics Data System (ADS)

    Pyo, Ju-Young; Cho, Won-Ju

    2017-03-01

    In this paper, we propose a high-performance separative extended gate ion-sensitive field-effect transistor (SEGISFET) that consists of a tin dioxide (SnO2) SEG sensing part and a double-gate structure amorphous indium gallium zinc oxide (a-IGZO) thin-film transistor (TFT) with tantalum pentoxide/silicon dioxide (Ta2O5/SiO2)-engineered top-gate oxide. To increase sensitivity, we maximized the capacitive coupling ratio by applying high-k dielectric at the top-gate oxide layer. As an engineered top-gate oxide, a stack of 25 nm-thick Ta2O5 and 10 nm-thick SiO2 layers was found to simultaneously satisfy a small equivalent oxide thickness (∼17.14 nm), a low leakage current, and a stable interfacial property. The threshold-voltage instability, which is a fundamental issue in a-IGZO TFTs, was improved by low-temperature post-deposition annealing (∼87 °C) using microwave irradiation. The double-gate structure a-IGZO TFTs with engineered top-gate oxide exhibited high mobility, small subthreshold swing, high drive current, and larger on/off current ratio. The a-IGZO SEGISFETs with a dual-gate sensing mode showed a pH sensitivity of 649.04 mV pH‑1, which is far beyond the Nernst limit. The non-ideal behavior of ISFETs, hysteresis, and drift effect also improved. These results show that the double-gate structure a-IGZO TFTs with engineered top-gate oxide can be a good candidate for cheap and disposable SEGISFET sensors.

  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. Si-compatible candidates for high-K dielectrics with the Pbnm perovskite structure

    SciTech Connect

    Coh, Sinisa; Heeg, Tassilo; Haeni, Jeffery; Biegalski, Michael D; Letteri, James; Bernhagen, M; Reiche, Paul; O'brien, Kevin; Uecker, Rinhold; Trolier-McKinstry, Susan; Schlom, Darrell; Vanderbilt, David

    2010-01-01

    We analyze both experimentally (where possible) and theoretically from first-principles the dielectric tensor components and crystal structure of five classes of Pbnm perovskites. All of these materials are believed to be stable on silicon and are therefore promising candidates for high-K dielectrics. We also analyze the structure of these materials with various simple models, decompose the lattice contribution to the dielectric tensor into force constant matrix eigenmode contributions, explore a peculiar correlation between structural and dielectric anisotropies in these compounds and give phonon frequencies and infrared activities of those modes that are infrared-active. We find that CaZrO3, SrZrO3, LaHoO3, and LaYO3 are among the most promising candidates for high-K dielectrics among the compounds we considered.

  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. 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.

  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. Gate Last Indium-Gallium-Arsenide MOSFETs with Regrown Source-Drain Regions and ALD Dielectrics

    NASA Astrophysics Data System (ADS)

    Carter, Andrew Daniel

    III-V-based MOSFETs have the potential to exceed the performance of silicon-based MOSFETs due to the semiconductor's small electron effective mass. Modern silicon-based MOSFETs with 22 nm gate lengths utilize high-k gate insulators and non-planar device geometries to optimize device performance. III-V HEMT technology has achieved similar gate lengths, but large source-drain access resistances and the lack of high-quality gate insulators prevent further device performance scaling. Sub-22 nm gate length III-V MOSFETs require metal-semiconductor contact resistivity to be less than 1 ohm-micron squared, gate insulators with less than 1 nm effective oxide thickness, and semiconductor-insulator interface trap densities less than 2E12 per square centimeter per electron volt. This dissertation presents InGaAs-based III-V MOSFET process flows and device results to assess their use in VLSI circuits. Previous III-V MOSFET results focused on long (>100 nm) gate lengths and ion implantation for source-drain region formation. Scaling III-V MOSFETs to shorter gate lengths requires source-drain regions that have low sheet resistance, high mobile charge densities, and low metal-semiconductor contact resistance. MBE- and MOCVD-based raised epitaxial source-drain regrowth meet these requirements. MBE InAs source-drain regrowth samples have shown 0.5 to 2 ohm-micron squared metal semiconductor contact resistivities. MOCVD InGaAs source-drain regrowth samples have shown < 100 ohm-micron single-sided access resistance to InGaAs MOSFETs. Gate insulators on III-V materials require large conduction band offsets to the channel, high dielectric permittivities, and low semiconductor-insulator interface trap densities. An in-situ hydrogen plasma / trimethylaluminum treatment has been developed to lower the gate semiconductor-insulator interface trap density. This treatment, done immediately before gate insulator deposition, has been shown to lower MOS capacitor interface trap densities by more

  16. 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.

  17. 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

  18. Hysteresis-Free Nanosecond Pulsed Electrical Characterization of Top-Gated Graphene Transistors

    NASA Astrophysics Data System (ADS)

    Carrion, Enrique A.; Serov, Andrey Y.; Islam, Sharnali; Behnam, Ashkan; Malik, Akshay; Xiong, Feng; Bianchi, Massimiliano; Sordan, Roman; Pop, Eric

    2014-05-01

    We measure top-gated graphene field effect transistors (GFETs) with nanosecond-range pulsed gate and drain voltages. Due to high-k dielectric or graphene imperfections, the drain current decreases ~10% over time scales of ~10 us, consistent with charge trapping mechanisms. Pulsed operation leads to hysteresis-free I-V characteristics, which are studied with pulses as short as 75 ns and 150 ns at the drain and gate, respectively. The pulsed operation enables reliable extraction of GFET intrinsic transconductance and mobility values independent of sweep direction, which are up to a factor of two higher than those obtained from simple DC characterization. We also observe drain-bias-induced charge trapping effects at lateral fields greater than 0.1 V/um. In addition, using modeling and capacitance-voltage measurements we extract charge trap densities up to 10^12 1/cm^2 in the top gate dielectric (here Al2O3). Our study illustrates important time- and field-dependent imperfections of top-gated GFETs with high-k dielectrics, which must be carefully considered for future developments of this technology

  19. 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.

  20. Nanocomposites of polyimide and mixed oxide nanoparticles for high performance nanohybrid gate dielectrics in flexible thin film transistors

    NASA Astrophysics Data System (ADS)

    Kim, Ju Hyun; Hwang, Byeong-Ung; Kim, Do-Il; Kim, Jin Soo; Seol, Young Gug; Kim, Tae Woong; Lee, Nae-Eung

    2017-01-01

    Organic gate dielectrics in thin film transistors (TFTs) for flexible display have advantages of high flexibility yet have the disadvantage of low dielectric constant (low-k). To supplement low-k characteristics of organic gate dielectrics, an organic/inorganic nanocomposite insulator loaded with high-k inorganic oxide nanoparticles (NPs) has been investigated but high loading of high-k NPs in polymer matrix is essential. Herein, compositing of over-coated polyimide (PI) on self-assembled (SA) layer of mixed HfO2 and ZrO2 NPs as inorganic fillers was used to make dielectric constant higher and leakage characteristics lower. A flexible TFT with lower the threshold voltage and high current on/off ratio could be fabricated by using the hybrid gate dielectric structure of the nanocomposite with SA layer of mixed NPs on ultrathin atomic-layer deposited Al2O3.

  1. Impact of gate geometry on ionic liquid gated ionotronic systems

    NASA Astrophysics Data System (ADS)

    Wong, A. T.; Noh, J. H.; Pudasaini, P. R.; Wolf, B.; Balke, N.; Herklotz, A.; Sharma, Y.; Haglund, A. V.; Dai, S.; Mandrus, D.; Rack, P. D.; Ward, T. Z.

    2017-04-01

    Ionic liquid electrolytes are gaining widespread application as a gate dielectric used to control ion transport in functional materials. This letter systematically examines the important influence that device geometry in standard "side gate" 3-terminal geometries plays in device performance of a well-known oxygen ion conductor. We show that the most influential component of device design is the ratio between the area of the gate electrode and the active channel, while the spacing between these components and their individual shapes has a negligible contribution. These findings provide much needed guidance in device design intended for ionotronic gating with ionic liquids.

  2. Multibit gates for quantum computing.

    PubMed

    Wang, X; Sørensen, A; Mølmer, K

    2001-04-23

    We present a general technique to implement products of many qubit operators communicating via a joint harmonic oscillator degree of freedom in a quantum computer. By conditional displacements and rotations we can implement Hamiltonians which are trigonometric functions of qubit operators. With such operators we can effectively implement higher order gates such as Toffoli gates and C(n)-NOT gates, and we show that the entire Grover search algorithm can be implemented in a direct way.

  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. 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.

  5. 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.

  6. Analysis of Interface Charge Densities for High-k Dielectric Materials based Metal Oxide Semiconductor Devices

    NASA Astrophysics Data System (ADS)

    Maity, N. P.; Thakur, R. R.; Maity, Reshmi; Thapa, R. K.; Baishya, S.

    2016-10-01

    In this paper, the interface charge densities (Dit) are studied and analyzed for ultra thin dielectric metal oxide semiconductor (MOS) devices using different high-k dielectric materials such as Al2O3, ZrO2 and HfO2. The Dit have been calculated by a new approach using conductance method and it indicates that by reducing the thickness of the oxide, the Dit increases and similar increase is also found by replacing SiO2 with high-k. For the same oxide thickness, SiO2 has the lowest Dit and found to be the order of 1011cm-2eV-1. Linear increase in Dit has been observed as the dielectric constant of the oxide increases. The Dit is found to be in good agreement with published fabrication results at p-type doping level of 1×1017cm-3. Numerical calculations and solutions are performed by MATLAB and device simulation is done by ATLAS.

  7. Crosslinkable high k polymer dielectrics for low voltage organic field-effect transistor memories (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Wu, Hung-Chin; Hung, Chih-Chien; Chiu, Yu-Cheng; Tung, Shih-Huang; Chen, Wen-Chang

    2016-09-01

    High Performance organic field-effect transistor (OFET) memory devices were successfully prepared using new dielectric materials, poly(N-(hydroxymethyl)acrylamide-co-5 -(9-(5-(diethylamino)pentyl)-2-(4-vinylphenyl)-9H-fluorene (P(NMA-co-F6NSt)), which contained chemical cross-linkable segment (NMA) and hole trapping building block (F6NSt). The high k characteristics of P(NMA-co-F6NSt)) led to a low voltage operation, a small power consumption, and a good digital information storage capacity. Such P(NMA-co-F6NSt) dielectrics in OFET memories with variant NMA/F6NSt molar ratios (100/0 (P1), 95/5 (P2), 80/20 (P3), and 67/33 (P4)) showed excellent insulating properties and good charge storage performance under a low operating voltage below ±5V, due to the tightly network structures after crosslinking and well-dispersed trapping cites (i.e. fluorene moieties). P3-based memory device, in particular, exhibited largest memory window of 4.13 V among the studied polymers, and possessed stable data retention stability over 104 s with a high on/off current ratio (i.e. 104) and good endurance characteristics of more than 200 write-read-write-erase (WRER) cycles. The above results suggested that a high-performance OFET memory device could be facilely achieved using the novel synthesized high-k copolymers.

  8. Energy band alignment of high-k oxide heterostructures at MoS2/Al2O3 and MoS2/ZrO2 interfaces

    NASA Astrophysics Data System (ADS)

    Pradhan, Sangram K.; Xiao, Bo; Pradhan, Aswini K.

    2016-09-01

    Substrate-induced electron energy band alignments of ultrathin molybdenum disulfide (MoS2) films are investigated using photoemission spectroscopy. Thin layer MoS2/Al2O3 and MoS2/ZrO2 interfaces show valence band offset (VBO) values of 3.21 eV and 2.77 eV, respectively. The corresponding conduction-band offset (CBO) values are 3.63 eV and 1.27 eV. Similarly, the calculated VBO and CBO values for an ultrathin layer of MoS2/SiO2 are estimated to be 4.25 and 2.91 eV, respectively. However, a very thick layer of MoS2 on Al2O3 and ZrO2 layers increases the CBO and VBO values by 0.31 eV and 0.2 eV, respectively, due to the shifting of the Mo 4dz2 band toward the Fermi level. The atomic force microscopy images show that the films are atomically smooth and favor the formation of a high-quality interface between the substrate and the film. The investigated luminescence spectra reveal that the MoS2 films show very strong interactions with different high-k surfaces, whereas the Raman spectrum is only weakly influenced by the different dielectric substrates. This interesting finding encourages the application of high-k oxide insulators as gate materials in MoS2-based complementary metal-oxide semiconductors and other electronic devices.

  9. 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.

  10. 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.

  11. 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.

  12. Impact and Origin of Interface States in MOS Capacitor with Monolayer MoS2 and HfO2 High-k Dielectric

    NASA Astrophysics Data System (ADS)

    Xia, Pengkun; Feng, Xuewei; Ng, Rui Jie; Wang, Shijie; Chi, Dongzhi; Li, Cequn; He, Zhubing; Liu, Xinke; Ang, Kah-Wee

    2017-01-01

    Two-dimensional layered semiconductors such as molybdenum disulfide (MoS2) at the quantum limit are promising material for nanoelectronics and optoelectronics applications. Understanding the interface properties between the atomically thin MoS2 channel and gate dielectric is fundamentally important for enhancing the carrier transport properties. Here, we investigate the frequency dispersion mechanism in a metal-oxide-semiconductor capacitor (MOSCAP) with a monolayer MoS2 and an ultra-thin HfO2 high-k gate dielectric. We show that the existence of sulfur vacancies at the MoS2-HfO2 interface is responsible for the generation of interface states with a density (Dit) reaching ~7.03 × 1011 cm-2 eV-1. This is evidenced by a deficit S:Mo ratio of ~1.96 using X-ray photoelectron spectroscopy (XPS) analysis, which deviates from its ideal stoichiometric value. First-principles calculations within the density-functional theory framework further confirms the presence of trap states due to sulfur deficiency, which exist within the MoS2 bandgap. This corroborates to a voltage-dependent frequency dispersion of ~11.5% at weak accumulation which decreases monotonically to ~9.0% at strong accumulation as the Fermi level moves away from the mid-gap trap states. Further reduction in Dit could be achieved by thermally diffusing S atoms to the MoS2-HfO2 interface to annihilate the vacancies. This work provides an insight into the interface properties for enabling the development of MoS2 devices with carrier transport enhancement.

  13. Impact and Origin of Interface States in MOS Capacitor with Monolayer MoS2 and HfO2 High-k Dielectric

    PubMed Central

    Xia, Pengkun; Feng, Xuewei; Ng, Rui Jie; Wang, Shijie; Chi, Dongzhi; Li, Cequn; He, Zhubing; Liu, Xinke; Ang, Kah-Wee

    2017-01-01

    Two-dimensional layered semiconductors such as molybdenum disulfide (MoS2) at the quantum limit are promising material for nanoelectronics and optoelectronics applications. Understanding the interface properties between the atomically thin MoS2 channel and gate dielectric is fundamentally important for enhancing the carrier transport properties. Here, we investigate the frequency dispersion mechanism in a metal-oxide-semiconductor capacitor (MOSCAP) with a monolayer MoS2 and an ultra-thin HfO2 high-k gate dielectric. We show that the existence of sulfur vacancies at the MoS2-HfO2 interface is responsible for the generation of interface states with a density (Dit) reaching ~7.03 × 1011 cm−2 eV−1. This is evidenced by a deficit S:Mo ratio of ~1.96 using X-ray photoelectron spectroscopy (XPS) analysis, which deviates from its ideal stoichiometric value. First-principles calculations within the density-functional theory framework further confirms the presence of trap states due to sulfur deficiency, which exist within the MoS2 bandgap. This corroborates to a voltage-dependent frequency dispersion of ~11.5% at weak accumulation which decreases monotonically to ~9.0% at strong accumulation as the Fermi level moves away from the mid-gap trap states. Further reduction in Dit could be achieved by thermally diffusing S atoms to the MoS2-HfO2 interface to annihilate the vacancies. This work provides an insight into the interface properties for enabling the development of MoS2 devices with carrier transport enhancement. PMID:28084434

  14. 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…

  15. 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.

  16. Cooperative gating between ion channels.

    PubMed

    Choi, Kee-Hyun

    2014-01-01

    Cooperative gating between ion channels, i.e. the gating of one channel directly coupled to the gating of neighboring channels, has been observed in diverse channel types at the single-channel level. Positively coupled gating could enhance channel-mediated signaling while negative coupling may effectively reduce channel gating noise. Indeed, the physiological significance of cooperative channel gating in signal transduction has been recognized in several in vivo studies. Moreover, coupled gating of ion channels was reported to be associated with some human disease states. In this review, physiological roles for channel cooperativity and channel clustering observed in vitro and in vivo are introduced, and stimulation-induced channel clustering and direct channel cross linking are suggested as the physical mechanisms of channel assembly. Along with physical clustering, several molecular mechanisms proposed as the molecular basis for functional coupling of neighboring channels are covered: permeant ions as a channel coupling mediator, concerted channel activation through the membrane, and allosteric mechanisms. Also, single-channel analysis methods for cooperative gating such as the binomial analysis, the variance analysis, the conditional dwell time density analysis, and the maximum likelihood fitting analysis are reviewed and discussed.

  17. Maintaining K(+) balance on the low-Na(+), high-K(+) diet.

    PubMed

    Cornelius, Ryan J; Wang, Bangchen; Wang-France, Jun; Sansom, Steven C

    2016-04-01

    A low-Na(+), high-K(+) diet (LNaHK) is considered a healthier alternative to the "Western" high-Na(+) diet. Because the mechanism for K(+) secretion involves Na(+) reabsorptive exchange for secreted K(+) in the distal nephron, it is not understood how K(+) is eliminated with such low Na(+) intake. Animals on a LNaHK diet produce an alkaline load, high urinary flows, and markedly elevated plasma ANG II and aldosterone levels to maintain their K(+) balance. Recent studies have revealed a potential mechanism involving the actions of alkalosis, urinary flow, elevated ANG II, and aldosterone on two types of K(+) channels, renal outer medullary K(+) and large-conductance K(+) channels, located in principal and intercalated cells. Here, we review these recent advances.

  18. 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.

  19. 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.

  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. 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

  2. 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.

  3. Impact of gate geometry on ionic liquid gated ionotronic systems

    DOE PAGES

    Wong, Anthony T.; Noh, Joo Hyon; Pudasaini, Pushpa Raj; ...

    2017-01-23

    Ionic liquid electrolytes are gaining widespread application as a gate dielectric used to control ion transport in functional materials. This letter systematically examines the important influence that device geometry in standard “side gate” 3-terminal geometries plays in device performance of a well-known oxygen ion conductor. We show that the most influential component of device design is the ratio between the area of the gate electrode and the active channel, while the spacing between these components and their individual shapes has a negligible contribution. Finally, these findings provide much needed guidance in device design intended for ionotronic gating with ionic liquids.

  4. 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).

  5. Nitride passivation of the interface between high-k dielectrics and SiGe

    SciTech Connect

    Sardashti, Kasra; Hu, Kai-Ting; Tang, Kechao; McIntyre, Paul; Madisetti, Shailesh; Oktyabrsky, Serge; Siddiqui, Shariq; Sahu, Bhagawan; Yoshida, Naomi; Kachian, Jessica; Dong, Lin; Fruhberger, Bernd; Kummel, Andrew C.

    2016-01-04

    In-situ direct ammonia (NH{sub 3}) plasma nitridation has been used to passivate the Al{sub 2}O{sub 3}/SiGe interfaces with Si nitride and oxynitride. X-ray photoelectron spectroscopy of the buried Al{sub 2}O{sub 3}/SiGe interface shows that NH{sub 3} plasma pre-treatment should be performed at high temperatures (300 °C) to fully prevent Ge nitride and oxynitride formation at the interface and Ge out-diffusion into the oxide. C-V and I-V spectroscopy results show a lower density of interface traps and smaller gate leakage for samples with plasma nitridation at 300 °C.

  6. Unified model for physics-based modelling of a new device architecture: triple material gate oxide stack epitaxial channel profile (TRIMGAS Epi) MOSFET

    NASA Astrophysics Data System (ADS)

    Goel, Kirti; Saxena, Manoj; Gupta, Mridula; Gupta, R. S.

    2007-04-01

    A new device architecture triple material gate oxide stack (TRIMGAS) epitaxial channel (Epi) MOSFET for reduced short channel effects (SCEs) at short gate lengths is proposed. The structure has a gate electrode consisting of three different materials, an oxide stack having high-K material on top of an SiO2 layer and an epitaxial channel profile. A two-dimensional analytical threshold voltage and drain current model has been presented. An analysis of subthreshold slope and I-V characteristics has been done for the first time including all regions of operation. The model proposed is capable of modelling various other MOSFET structures: (a) dual material gate stack (DUMGAS), (b) single material gate stack (SIMGAS), (c) straddle-gate/EJ/side-gate MOSFET oxide stack, (d) dual/hetero material gate (DMG/HMG), (e) single material gate (SMG) and (f) triple material gate (TMG), all with and without an epitaxial channel profile. A 2D device simulator, ATLAS, is used over a wide range of parameters and bias conditions to validate the analytical results.

  7. 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

  8. Robust Soldier Crab Ball Gate

    NASA Astrophysics Data System (ADS)

    Gunji, Yukio-Pegio; Nishiyama, Yuta; Adamatzky, Andrew

    2011-09-01

    Based on the field observation of soldier crabs, we previously proposed a model for a swarm of soldier crabs. Here, we describe the interaction of coherent swarms in the simulation model, which is implemented in a logical gate. Because a swarm is generated by inherent perturbation, a swarm can be generated and maintained under highly perturbed conditions. Thus, the model reveals a robust logical gate rather than stable one. In addition, we show that the logical gate of swarms is also implemented by real soldier crabs (Mictyris guinotae).

  9. Superconducting gates with fluxon logics

    NASA Astrophysics Data System (ADS)

    Nacak, H.; Kusmartsev, F. V.

    2010-10-01

    We have developed several logic gates (OR, XOR, AND and NAND) made of superconducting Josephson junctions. The gates based of the flux cloning phenomenon and high speed of fluxons moving in Josephson junctions of different shapes. In a contrast with previous design the gates operates extremely fast since fluxons are moving with the speed close to the speed of light. We have demonstrated their operations and indicated several ways to made a more complicated logic elements which have at the same time a compact form.

  10. Commentary on WHO GATE Initiative.

    PubMed

    Cooper, Rory A

    2017-01-01

    Assistive technology is essential to people with spinal cord injuries (SCI) for living and participating in their communities. However, many people with SCI do not have access to adequate assistive technology and qualified services. The World Health Organization (WHO) is addressing this need through the Global Cooperation on Assistive Technology (GATE). The GATE initiative is focused on improving access to high-quality affordable AT world-wide. GATE working to meet the AT sector needs in response to the call by WHO to increase access to essential, high-quality, safe, effective and affordable medical devices, which is one of the six WHO leadership priorities.

  11. High-k Scattering Receiver Mixer Performance for NSTX-U

    NASA Astrophysics Data System (ADS)

    Barchfeld, Robert; Riemenschneider, Paul; Domier, Calvin; Luhmann, Neville; Ren, Yang; Kaita, Robert

    2016-10-01

    The High-k Scattering system detects primarily electron-scale turbulence k θ spectra for studying electron thermal transport in NSTX-U. A 100 mW, 693 GHz probe beam passes through plasma, and scattered power is detected by a 4-pixel quasi optical, mixer array. Remotely controlled receiving optics allows the scattering volume to be located from core to edge with a k θ span of 7 to 40 cm-1. The receiver array features 4 RF diagonal input horns, where the electric field polarization is aligned along the diagonal of a square cross section horn, at 30 mm channel spacing. The local oscillator is provided by a 14.4 GHz source followed by a x48 multiplier chain, giving an intermediate frequency of 1 GHz. The receiver optics receive 4 discreet scattering angles simultaneously, and then focus the signals as 4 parallel signals to their respective horns. A combination of a steerable probe beam, and translating receiver, allows for upward or downward scattering which together can provide information about 2D turbulence wavenumber spectrum. IF signals are digitized and stored for later computer analysis. The performance of the receiver mixers is discussed, along with optical design features to enhance the tuning and performance of the mixers. Work supported in part by U.S. DOE Grant DE-FG02-99ER54518 and DE-AC02-09CH1146.

  12. 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.

  13. 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.

  14. Tb2O3 thin films: An alternative candidate for high-k dielectric applications

    NASA Astrophysics Data System (ADS)

    Gray, Nathan W.; Prestgard, Megan C.; Tiwari, Ashutosh

    2014-12-01

    We are reporting the growth and structural, optical, and dielectric properties of Tb2O3, a relatively unexplored high-k dielectric material. A pulsed-laser deposition technique was used to grow Tb2O3 thin-films on four different substrates: Si(100), SrTiO3(100), LaAlO3(100), and MgO(100). High-resolution X-ray diffraction and transmission electron microscopy results confirmed that film growth in an oxygen-rich (10-1 Torr) environment yields nearly single-crystal C-phase films, while a low-oxygen (10-6 Torr) environment growth results in the formation of monoclinic polycrystalline B-phase films. Optical transmission measurements showed that the bandgap of Tb2O3 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 Tb2O3 films, respectively.

  15. 49 CFR 234.223 - Gate arm.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Gate arm. 234.223 Section 234.223 Transportation... Maintenance Standards § 234.223 Gate arm. Each gate arm, when in the downward position, shall extend across... clearly viewed by approaching highway users. Each gate arm shall start its downward motion not less...

  16. 49 CFR 234.223 - Gate arm.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 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...

  17. 49 CFR 234.223 - Gate arm.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 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...

  18. 49 CFR 234.223 - Gate arm.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Gate arm. 234.223 Section 234.223 Transportation... Maintenance Standards § 234.223 Gate arm. Each gate arm, when in the downward position, shall extend across... clearly viewed by approaching highway users. Each gate arm shall start its downward motion not less...

  19. 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...

  20. 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…

  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. Phloridzin inhibits high K+-induced contraction via the inhibition of sodium: glucose cotransporter 1 in rat ileum

    PubMed Central

    KANDA, Hidenori; KANEDA, Takeharu; KAWAGUCHI, Akira; SASAKI, Noriyasu; TAJIMA, Tsuyoshi; URAKAWA, Norimoto; SHIMIZU, Kazumasa; SUZUKI, Hiroetsu

    2017-01-01

    Recent studies have shown that phloridzin, an inhibitor of sodium–glucose cotransporter (SGLT), strongly decreases high K+-induced contraction in phasic muscle, such as tenia coli, but slightly affects tonic muscle, such as trachea . In this study, we examined the inhibitory mechanism of phloridzin on high K+-induced muscle contraction in rat ileum, a phasic muscle. Phloridzin inhibited the high K+-induced contraction in the ileum and the aorta, and the relaxing effect of phloridzin at 1 mM in the ileum was approximately five-fold more potent than that in the aorta. The expression of SGLT1 mRNA in the ileum was higher than that of the aorta. Phloridzin significantly inhibited NADH/NAD ratio and phosphocreatine (PCr) content in the ileum; however, application of pyruvate recovered the inhibition of contraction and PCr content, but had no effect on ratio of NADH/NAD. High K+ increased 2-(N (7-nitrobenz-2-oxa-1,3-diazol-4-yl) amino)-2-deoxyglucose (2-NBDG) uptake in ileal smooth muscle cells, and phloridzin inhibited the increase in a concentration-dependent manner. These results suggest that phloridzin inhibits high K+-induced contraction because of the inhibition of energy metabolism via the inhibition of SGLT1. PMID:28190822

  4. 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.

  5. Surface and interfacial chemistry of high-k dielectric and interconnect materials on silicon

    NASA Astrophysics Data System (ADS)

    Kirsch, Paul Daniel

    Surfaces and interfaces play a critical role in the manufacture and function of silicon based integrated circuits. It is therefore reasonable to study the chemistries at these surfaces and interfaces to improve existing processes and to develop new ones. Model barium strontium titanate high-k dielectric systems have been deposited on ultrathin silicon oxynitride in ultrahigh vacuum. The resulting nanostructures are characterized with secondary ion mass spectroscopy (SIMS) and X-ray photoelectron spectroscopy (XPS). An interfacial reaction between Ba and Sr atoms and SiOxNy was found to create silicates, BaSixOy or SrSi xOy. Inclusion of N in the interfacial oxide decreased silicate formation in both Ba and Sr systems. Furthermore, inclusion of N in the interfacial oxide decreased the penetration of Ba and Sr containing species, such as silicides and silicates. Sputter deposited HfO2 was studied on nitrided and unnitrided Si(100) surfaces. XPS and SIMS were used to verify the presence of interfacial HfSixOy and estimate its relative amount on both nitrided and unnitrided samples. More HfSixOy formed without the SiNx interfacial layer. These interfacial chemistry results are then used to explain the electrical measurements obtained from metal oxide semiconductor (MOS) capacitors. MOS capacitors with interfacial SiNx exhibit reduced leakage current and increased capacitance. Lastly, surface science techniques were used to develop a processing technique for reducing thin films of copper (II) and copper (I) oxide to copper. Deuterium atoms (D*) and methyl radicals (CH3*) were shown to reduce Cu 2+ and/or Cu1+ to Cu0 within 30 min at a surface temperature of 400 K under a flux of 1 x 1015 atoms/cm2s. Temperature programmed desorption experiments suggest that oxygen leaves the surface as D2O and CO2 for the D* and CH3* treated surfaces, respectively.

  6. 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

  7. 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

  8. Prospectively gated cardiac computed tomography.

    PubMed

    Moore, S C; Judy, P F; Garnic, J D; Kambic, G X; Bonk, F; Cochran, G; Margosian, P; McCroskey, W; Foote, F

    1983-01-01

    A fourth-generation scanner has been modified to perform prospectively gated cardiac computed tomography (CT). A computer program monitors the electrocardiogram (ECG) and predicts when to initiate the next scan in a gated series in order to acquire all projection data for a desired phase of the heart cycle. The system has been tested with dogs and has produced cross-sectional images of all phases of the cardiac cycle. Eight to ten scans per series were sufficient to obtain reproducible images of each transverse section in the end-diastolic and end-systolic phases. The radiation dose to the skin was approximately 1.4 cGy per scan. The prospectively gated system is more than twice as efficient as a retrospectively gated system in obtaining complete angular projection data for a 10% heart cycle window. A temporal smoothing technique to suppress reconstruction artifacts due to sorting inconsistent projection data was developed and evaluated. Image noise was reduced by averaging together any overlapping projection data. Prospectively gated cardiac CT has also been used to demonstrate that the error in attenuation measured with a single nongated CT scan through the heart can be as large as 50-60 CT numbers outside the heart in the lung field.

  9. High-k dielectrics based field plate edge termination engineering in 4H-SiC Schottky diode

    NASA Astrophysics Data System (ADS)

    Shankar, Bhawani; Gupta, Sanjeev K.; Taube, William R.; Akhtar, J.

    2016-12-01

    This paper develops a deep insight into the behaviour of high-k dielectric-based field plate on Ni/4H-SiC Schottky diode. It tries to explain the mechanism by which high-k materials outperform silicon dioxide, when used under the field plate. Phenomena like modulation of field enhancement factor, reshaping of equipotential contours and expansion of depletion region while maintaining fixed depletion ratio (length/width = 2.3) helps to understand the electrical behaviour of high-k dielectric-based field plate. High-k materials relaxed the equipotential contours under the field plate edge which resulted in electric field reduction up to 88% and significant drop from 6.6 to 2.2 in field enhancement factor at device edges. The study considers the field plate of different dielectrics (SiO2, Si3N4, Al203, HfO2) and in each case, analytically explores the optimisation of field plate parameters (overlap length and dielectric thickness, dielectric constant). All the investigations have been done using numerical simulations on calibrated setup.

  10. Electrostatic Gating of Ultrathin Films

    NASA Astrophysics Data System (ADS)

    Goldman, A. M.

    2014-07-01

    Electrostatic gating of ultrathin films can be used to modify electronic and magnetic properties of materials by effecting controlled alterations of carrier concentration while, in principle, not changing the level of disorder. As such, electrostatic gating can facilitate the development of novel devices and can serve as a means of exploring the fundamental properties of materials in a manner far simpler than is possible with the conventional approach of chemical doping. The entire phase diagram of a compound can be traversed by changing the gate voltage. In this review, we survey results involving conventional field effect devices as well as more recent progress, which has involved structures that rely on electrochemical configurations such as electric double-layer transistors. We emphasize progress involving thin films of oxide materials such as high-temperature superconductors, magnetic oxides, and oxides that undergo metal-insulator transitions.

  11. Ionic thermoelectric gating organic transistors

    PubMed Central

    Zhao, Dan; Fabiano, Simone; Berggren, Magnus; Crispin, Xavier

    2017-01-01

    Temperature is one of the most important environmental stimuli to record and amplify. While traditional thermoelectric materials are attractive for temperature/heat flow sensing applications, their sensitivity is limited by their low Seebeck coefficient (∼100 μV K−1). Here we take advantage of the large ionic thermoelectric Seebeck coefficient found in polymer electrolytes (∼10,000 μV K−1) to introduce the concept of ionic thermoelectric gating a low-voltage organic transistor. The temperature sensing amplification of such ionic thermoelectric-gated devices is thousands of times superior to that of a single thermoelectric leg in traditional thermopiles. This suggests that ionic thermoelectric sensors offer a way to go beyond the limitations of traditional thermopiles and pyroelectric detectors. These findings pave the way for new infrared-gated electronic circuits with potential applications in photonics, thermography and electronic-skins. PMID:28139738

  12. Ionic thermoelectric gating organic transistors

    NASA Astrophysics Data System (ADS)

    Zhao, Dan; Fabiano, Simone; Berggren, Magnus; Crispin, Xavier

    2017-01-01

    Temperature is one of the most important environmental stimuli to record and amplify. While traditional thermoelectric materials are attractive for temperature/heat flow sensing applications, their sensitivity is limited by their low Seebeck coefficient (~100 μV K-1). Here we take advantage of the large ionic thermoelectric Seebeck coefficient found in polymer electrolytes (~10,000 μV K-1) to introduce the concept of ionic thermoelectric gating a low-voltage organic transistor. The temperature sensing amplification of such ionic thermoelectric-gated devices is thousands of times superior to that of a single thermoelectric leg in traditional thermopiles. This suggests that ionic thermoelectric sensors offer a way to go beyond the limitations of traditional thermopiles and pyroelectric detectors. These findings pave the way for new infrared-gated electronic circuits with potential applications in photonics, thermography and electronic-skins.

  13. 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

  14. Localizing a gate in CFTR

    PubMed Central

    Gao, Xiaolong; Hwang, Tzyh-Chang

    2015-01-01

    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

  15. 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.

  16. Reading Gate Positions with a Smartphone

    NASA Astrophysics Data System (ADS)

    van Overloop, Peter-Jules; Hut, Rolf

    2015-04-01

    Worldwide many flow gates are built in water networks in order to direct water to appropriate locations. Most of these gates are adjusted manually by field operators of water management organizations and it is often centrally not known what the new position of the gate is. This makes centralized management of the entire water network difficult. One of the reasons why the measurement of the gate position is usually not executed, is that for certain gates it is not easy to do such a reading. Tilting weirs or radial gates are examples where operators need special equipment (measuring rod and long level) to determine the position and it could even be a risky procedure. Another issue is that once the measurement is done, the value is jotted down in a notebook and later, at the office, entered in a computer system. So the entire monitoring procedure is not real-time and prone to human errors. A new way of monitoring gate positions is introduced. It consists of a level that is attached to the gate and an app with which a picture can be taken from the level. Using dedicated pattern recognition algorithms, the gate position can be read by using the angle of the level versus reference points on the gate, the radius of that gate and the absolute level of the joint around which the gate turn. The method uses gps-localization of the smartphone to store the gate position in the right location in the central database.

  17. 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.

  18. 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

  19. Radial gate evaluation: Olympus Dam, Colorado

    SciTech Connect

    1997-06-01

    The report presents a structural analysis of the radial gates of Olympus Dam in eastern Colorado. Five 20-foot wide by 17-foot high radial gates are used to control flow through the spillway at Olympus Dam. The spillway gates were designed in 1947. The gate arm assemblies consist of two separate wide flange beams, with a single brace between the arms. The arms pivot about a 4.0-inch diameter pin and bronze graphite-insert bushing. The pin is cantilevered from the pier anchor girder. The radial gates are supported by a pin bearing on a pier anchor birder bolted to the end of the concrete pier. The gates are operated by two-part wire rope 15,000-pound capacity hoise. Stoplog slots upstream of the radial gates are provided in the concrete piers. Selected drawings of the gates and hoists are located in appendix A.

  20. 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

  1. 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.

  2. 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…

  3. Talking with Microsoft's Bill Gates.

    ERIC Educational Resources Information Center

    EDUCOM Review, 1994

    1994-01-01

    Presents the transcript of an interview with William Gates, chairman of Microsoft Corporation. Topics discussed include continued support from the information technology industry for higher education; experiences with recent college graduates in the industry; new technologies developing in the near future; alliances in the computer industry; and…

  4. 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.

  5. GATED PORES IN THE FERRITIN PROTEIN NANOCAGE

    PubMed Central

    Theil, Elizabeth C.; Liu, Xiaofeng S.; Tosha, Takehiko

    2008-01-01

    Synopsis and pictogram: Gated pores in the ferritin family of protein nanocages, illustrated in the pictogram, control transfer of ferrous iron into and out of the cages by regulating contact between hydrated ferric oxide mineral inside the protein cage, and reductants such as FMNH2 on the outside. The structural and functional homology between the gated ion channel proteins in inaccessible membranes and gated ferritin pores in the stable, water soluble nanoprotein, make studies of ferritin pores models for gated pores in many ion channel proteins. Properties of ferritin gated pores, which control rates of FMNH2 reduction of ferric iron in hydrated oxide minerals inside the protein nanocage, are discussed in terms of the conserved pore gate residues (arginine 72-apspartate 122 and leucine 110-leucine 134), of pore sensitivity to heat at temperatures 30 °C below that of the nanocage itself, and of pore sensitivity to physiological changes in urea (1–10 mM). Conditions which alter ferritin pore structure/function in solution, coupled with the high evolutionary conservation of the pore gates, suggest the presence of molecular regulators in vivo that recognize the pore gates and hold them either closed or open, depending on biological iron need. The apparent homology between ferrous ion transport through gated pores in the ferritin nanocage and ion transport through gated pores in ion channel proteins embedded in cell membranes, make studies of water soluble ferritin and the pore gating folding/unfolding a useful model for other gated pores. PMID:19262678

  6. Quantum Circuit Synthesis using a New Quantum Logic Gate Library of NCV Quantum Gates

    NASA Astrophysics Data System (ADS)

    Li, Zhiqiang; Chen, Sai; Song, Xiaoyu; Perkowski, Marek; Chen, Hanwu; Zhu, Wei

    2017-04-01

    Since Controlled-Square-Root-of-NOT (CV, CV‡) gates are not permutative quantum gates, many existing methods cannot effectively synthesize optimal 3-qubit circuits directly using the NOT, CNOT, Controlled-Square-Root-of-NOT quantum gate library (NCV), and the key of effective methods is the mapping of NCV gates to four-valued quantum gates. Firstly, we use NCV gates to create the new quantum logic gate library, which can be directly used to get the solutions with smaller quantum costs efficiently. Further, we present a novel generic method which quickly and directly constructs this new optimal quantum logic gate library using CNOT and Controlled-Square-Root-of-NOT gates. Finally, we present several encouraging experiments using these new permutative gates, and give a careful analysis of the method, which introduces a new idea to quantum circuit synthesis.

  7. Quantum Circuit Synthesis using a New Quantum Logic Gate Library of NCV Quantum Gates

    NASA Astrophysics Data System (ADS)

    Li, Zhiqiang; Chen, Sai; Song, Xiaoyu; Perkowski, Marek; Chen, Hanwu; Zhu, Wei

    2016-12-01

    Since Controlled-Square-Root-of-NOT (CV, CV‡) gates are not permutative quantum gates, many existing methods cannot effectively synthesize optimal 3-qubit circuits directly using the NOT, CNOT, Controlled-Square-Root-of-NOT quantum gate library (NCV), and the key of effective methods is the mapping of NCV gates to four-valued quantum gates. Firstly, we use NCV gates to create the new quantum logic gate library, which can be directly used to get the solutions with smaller quantum costs efficiently. Further, we present a novel generic method which quickly and directly constructs this new optimal quantum logic gate library using CNOT and Controlled-Square-Root-of-NOT gates. Finally, we present several encouraging experiments using these new permutative gates, and give a careful analysis of the method, which introduces a new idea to quantum circuit synthesis.

  8. 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.

  9. Top gate ZnO-Al2O3 thin film transistors fabricated using a chemical bath deposition technique

    NASA Astrophysics Data System (ADS)

    Gogoi, Paragjyoti; Saikia, Rajib; Changmai, Sanjib

    2015-04-01

    ZnO thin films were prepared by a simple chemical bath deposition technique using an inorganic solution mixture of ZnCl2 and NH3 on glass substrates and then were used as the active material in thin film transistors (TFTs). The TFTs were fabricated in a top gate coplanar electrode structure with high-k Al2O3 as the gate insulator and Al as the source, drain and gate electrodes. The TFTs were annealed in air at 500 °C for 1 h. The TFTs with a 50 μm channel length exhibited a high field-effect mobility of 0.45 cm2/(V·s) and a low threshold voltage of 1.8 V. The sub-threshold swing and drain current ON-OFF ratio were found to be 0.6 V/dec and 106, respectively.

  10. Optimization of side gate length and side gate voltage for sub-100-nm double-gate MOSFET

    NASA Astrophysics Data System (ADS)

    Kim, Jae-hong; Kim, Geun-ho; Ko, Suk-woong; Jung, Hak-kee

    2002-11-01

    In this paper, we have investigated double gate (DG) MOSFET structure, which has main gate (MG) and two side gates (SG). We know that optimum side gate voltage for each side gate length is about 2V in the main gate 50nm. Also, we know that optimum side gate length for each main gate length is 70nm above. DG MOSFET shows a small threshold voltage (Vth) roll-off. From the I-V characteristics, we obtained IDsat=510μA/μm at VMG=VDS=1.5V and VSG=3.0V for DG MOSFET with the main gate length of 50nm and the side gate length of 70nm. The subthreshold slope is 86mV/decade, transconductance is 111μA/V and DIBL (Drain Induced Barrier Lowering) is 51.3mV. Then, we have investigated the advantage of this structure for the application to multi-input NAND gate logic. Also, we have presented that TCAD simulator is suitable for device simulation.

  11. 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.

  12. 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.

  13. RGB-NIR active gated imaging

    NASA Astrophysics Data System (ADS)

    Spooren, Nick; Geelen, Bert; Tack, Klaas; Lambrechts, Andy; Jayapala, Murali; Ginat, Ran; David, Yaara; Levi, Eyal; Grauer, Yoav

    2016-10-01

    This paper presents multispectral active gated imaging in relation to the transportation and security fields. Active gated imaging is based on a fast gated camera and pulsed illuminator, synchronized in the time domain to provide range based images. We have developed a multispectral pattern deposited on a gated CMOS Image Sensor (CIS) with a pulsed Near Infrared VCSEL module. This paper will cover the component-level description of the multispectral gated CIS including the camera and illuminator units. Furthermore, the design considerations and characterization results of the spectral filters are presented together with a newly developed image processing method.

  14. Quantum computing gates via optimal control

    NASA Astrophysics Data System (ADS)

    Atia, Yosi; Elias, Yuval; Mor, Tal; Weinstein, Yossi

    2014-10-01

    We demonstrate the use of optimal control to design two entropy-manipulating quantum gates which are more complex than the corresponding, commonly used, gates, such as CNOT and Toffoli (CCNOT): A two-qubit gate called polarization exchange (PE) and a three-qubit gate called polarization compression (COMP) were designed using GRAPE, an optimal control algorithm. Both gates were designed for a three-spin system. Our design provided efficient and robust nuclear magnetic resonance (NMR) radio frequency (RF) pulses for 13C2-trichloroethylene (TCE), our chosen three-spin system. We then experimentally applied these two quantum gates onto TCE at the NMR lab. Such design of these gates and others could be relevant for near-future applications of quantum computing devices.

  15. Unifying Gate Synthesis and Magic State Distillation

    NASA Astrophysics Data System (ADS)

    Campbell, Earl T.; Howard, Mark

    2017-02-01

    The leading paradigm for performing a computation on quantum memories can be encapsulated as distill-then-synthesize. Initially, one performs several rounds of distillation to create high-fidelity magic states that provide one good T gate, an essential quantum logic gate. Subsequently, gate synthesis intersperses many T gates with Clifford gates to realize a desired circuit. We introduce a unified framework that implements one round of distillation and multiquibit gate synthesis in a single step. Typically, our method uses the same number of T gates as conventional synthesis but with the added benefit of quadratic error suppression. Because of this, one less round of magic state distillation needs to be performed, leading to significant resource savings.

  16. 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.

  17. 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.

  18. 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.

  19. Cyclic networks of quantum gates

    NASA Astrophysics Data System (ADS)

    Cabauy, Peter

    In this thesis we first give an introduction to the basic aspects of quantum computation followed by an analysis of networks of quantum logic gates where the qubit lines are loops (cyclic). Thus far, investigations into cyclic networks of quantum logic gates have not been examined (as far as we know) by the quantum information community. In our investigations of cyclic quantum networks we have studied simple, one and two qubit systems. The analysis includes: classifying networks into groups, the dynamics of the qubits in a cyclic quantum network, and the perturbation effects of an external qubit acting on a cyclic quantum network. The analysis will be followed by a discussion on quantum algorithms and quantum information processing with cyclic quantum networks, a novel implementation of a cyclic network quantum memory and a discussion of quantum sensors via cyclic quantum networks.

  20. 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.

  1. 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

  2. Hydrophobic gating in ion channels.

    PubMed

    Aryal, Prafulla; Sansom, Mark S P; Tucker, Stephen J

    2015-01-16

    Biological ion channels are nanoscale transmembrane pores. When water and ions are enclosed within the narrow confines of a sub-nanometer hydrophobic pore, they exhibit behavior not evident from macroscopic descriptions. At this nanoscopic level, the unfavorable interaction between the lining of a hydrophobic pore and water may lead to stochastic liquid-vapor transitions. These transient vapor states are "dewetted", i.e. effectively devoid of water molecules within all or part of the pore, thus leading to an energetic barrier to ion conduction. This process, termed "hydrophobic gating", was first observed in molecular dynamics simulations of model nanopores, where the principles underlying hydrophobic gating (i.e., changes in diameter, polarity, or transmembrane voltage) have now been extensively validated. Computational, structural, and functional studies now indicate that biological ion channels may also exploit hydrophobic gating to regulate ion flow within their pores. Here we review the evidence for this process and propose that this unusual behavior of water represents an increasingly important element in understanding the relationship between ion channel structure and function.

  3. Gating of two pore domain potassium channels.

    PubMed

    Mathie, Alistair; Al-Moubarak, Ehab; Veale, Emma L

    2010-09-01

    Two-pore-domain potassium (K2P) channels are responsible for background leak currents which regulate the membrane potential and excitability of many cell types. Their activity is modulated by a variety of chemical and physical stimuli which act to increase or decrease the open probability of individual K2P channels. Crystallographic data and homology modelling suggest that all K(+) channels possess a highly conserved structure for ion selectivity and gating mechanisms. Like other K(+) channels, K2P channels are thought to have two primary conserved gating mechanisms: an inactivation (or C-type) gate at the selectivity filter close to the extracellular side of the channel and an activation gate at the intracellular entrance to the channel involving key, identified, hinge glycine residues. Zinc and hydrogen ions regulate Drosophila KCNK0 and mammalian TASK channels, respectively, by interacting with the inactivation gate of these channels. In contrast, the voltage dependence of TASK3 channels is mediated through its activation gate. For KCNK0 it has been shown that the gates display positive cooperativity. It is of much interest to determine whether other K2P regulatory compounds interact with either the activation gate or the inactivation gate to alter channel activity or, indeed, whether additional regulatory gating pathways exist.

  4. Gating of two pore domain potassium channels

    PubMed Central

    Mathie, Alistair; Al-Moubarak, Ehab; Veale, Emma L

    2010-01-01

    Two-pore-domain potassium (K2P) channels are responsible for background leak currents which regulate the membrane potential and excitability of many cell types. Their activity is modulated by a variety of chemical and physical stimuli which act to increase or decrease the open probability of individual K2P channels. Crystallographic data and homology modelling suggest that all K+ channels possess a highly conserved structure for ion selectivity and gating mechanisms. Like other K+ channels, K2P channels are thought to have two primary conserved gating mechanisms: an inactivation (or C-type) gate at the selectivity filter close to the extracellular side of the channel and an activation gate at the intracellular entrance to the channel involving key, identified, hinge glycine residues. Zinc and hydrogen ions regulate Drosophila KCNK0 and mammalian TASK channels, respectively, by interacting with the inactivation gate of these channels. In contrast, the voltage dependence of TASK3 channels is mediated through its activation gate. For KCNK0 it has been shown that the gates display positive cooperativity. It is of much interest to determine whether other K2P regulatory compounds interact with either the activation gate or the inactivation gate to alter channel activity or, indeed, whether additional regulatory gating pathways exist. PMID:20566661

  5. 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.

  6. Device Performance and Reliability Improvements of AlGaN/GaN/Si MOSFET Using Defect-Free Gate Recess and Laser Annealing

    DTIC Science & Technology

    2012-07-18

    1 Annual Report for AOARD Grant FA2386-11-1-4077 “Device Performance and Reliability Improvements of AlGaN/GaN/ Si MOSFET Using Defect- Free Gate...transistors (MOS-HEMTs or MOS-HFETs) by incorporating a high-dielectric constant (high-k) oxide layer between the semiconductor and the gate metal.5,6 This...concentrations when compared to various other wet chemical treatments,11 with only HCl seen to produce a marginally more oxide free surface.12 Previous

  7. 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.

  8. 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.

  9. Hafnium zirconate gate dielectric for advanced gate stack applications

    NASA Astrophysics Data System (ADS)

    Hegde, R. I.; Triyoso, D. H.; Samavedam, S. B.; White, B. E.

    2007-04-01

    We report on the development of a hafnium zirconate (HfZrO4) alloy gate dielectric for advanced gate stack applications. The HfZrO4 and hafnium dioxide (HfO2) films were formed by atomic layer deposition using metal halides and heavy water as precursors. The HfZrO4 material properties were examined and compared with those of HfO2 by a wide variety of analytical methods. The dielectric properties, device performance, and reliability of HfZrO4 were investigated by fabricating HfZrO4/tantalum carbide (TaxCy) metal-oxide-semiconductor field effect transistor. The HfZrO4 dielectric film has smaller band gap, smaller and more uniform grains, less charge traps, and more uniform film quality than HfO2. The HfZrO4 dielectric films exhibited good thermal stability with silicon. Compared to HfO2, the HfZrO4 gate dielectric showed lower capacitance equivalent thickness value, higher transconductance, less charge trapping, higher drive current, lower threshold voltage (Vt), reduced capacitance-voltage (C-V ) hysteresis, lower interface state density, superior wafer level thickness uniformity, and longer positive bias temperature instability lifetime. Incorporation of zirconium dioxide (ZrO2) into HfO2 enhances the dielectric constant (k ) of the resulting HfZrO4 which is associated with structural phase transformation from mainly monoclinic to tetragonal. The tetragonal phase increases the k value of HfZrO4 dielectric to a large value as predicted. The improved device characteristics are attributed to less oxygen vacancy in the fine grained microstructure of HfZrO4 films.

  10. Comparative studies of AlGaN/GaN MOS-HEMTs with stacked gate dielectrics by the mixed thin film growth method

    NASA Astrophysics Data System (ADS)

    Chou, Bo-Yi; Hsu, Wei-Chou; Lee, Ching-Sung; Liu, Han-Yin; Ho, Chiu-Sheng

    2013-07-01

    This paper reports Al0.27Ga0.73N/GaN metal-oxide-semiconductor high electron mobility transistors (MOS-HEMTs) with stacked Al2O3/HfO2 gate dielectrics by using hydrogen peroxideoxidation/sputtering techniques. The Al2O3 employed as a gate dielectric and surface passivation layer effectively suppresses the gate leakage current, improves RF drain current collapse and exhibits good thermal stability. Moreover, by stacking the good insulating high-k HfO2 dielectric further suppresses the gate leakage, enhances the dielectric breakdown field and power-added efficiency, and decreases the equivalent oxide thickness. The present MOS-HEMT design has demonstrated superior improvements of 10.1% (16.4%) in the maximum drain-source current (IDS, max), 11.4% (22.5%) in the gate voltage swing and 12.5%/14.4% (21.9%/22.3%) in the two-terminal gate-drain breakdown/turn-on voltages (BVGD/VON), and the present design also demonstrates the lowest gate leakage current and best thermal stability characteristics as compared to two reference MOS-HEMTs with a single Al2O3/(HfO2) dielectric layer of the same physical thickness.

  11. Experimental superposition of orders of quantum gates.

    PubMed

    Procopio, Lorenzo M; Moqanaki, Amir; Araújo, Mateus; Costa, Fabio; Alonso Calafell, Irati; Dowd, Emma G; Hamel, Deny R; Rozema, Lee A; Brukner, Časlav; Walther, Philip

    2015-08-07

    Quantum computers achieve a speed-up by placing quantum bits (qubits) in superpositions of different states. However, it has recently been appreciated that quantum mechanics also allows one to 'superimpose different operations'. Furthermore, it has been shown that using a qubit to coherently control the gate order allows one to accomplish a task--determining if two gates commute or anti-commute--with fewer gate uses than any known quantum algorithm. Here we experimentally demonstrate this advantage, in a photonic context, using a second qubit to control the order in which two gates are applied to a first qubit. We create the required superposition of gate orders by using additional degrees of freedom of the photons encoding our qubits. The new resource we exploit can be interpreted as a superposition of causal orders, and could allow quantum algorithms to be implemented with an efficiency unlikely to be achieved on a fixed-gate-order quantum computer.

  12. 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

  13. Experimental superposition of orders of quantum gates

    PubMed Central

    Procopio, Lorenzo M.; Moqanaki, Amir; Araújo, Mateus; Costa, Fabio; Alonso Calafell, Irati; Dowd, Emma G.; Hamel, Deny R.; Rozema, Lee A.; Brukner, Časlav; Walther, Philip

    2015-01-01

    Quantum computers achieve a speed-up by placing quantum bits (qubits) in superpositions of different states. However, it has recently been appreciated that quantum mechanics also allows one to ‘superimpose different operations'. Furthermore, it has been shown that using a qubit to coherently control the gate order allows one to accomplish a task—determining if two gates commute or anti-commute—with fewer gate uses than any known quantum algorithm. Here we experimentally demonstrate this advantage, in a photonic context, using a second qubit to control the order in which two gates are applied to a first qubit. We create the required superposition of gate orders by using additional degrees of freedom of the photons encoding our qubits. The new resource we exploit can be interpreted as a superposition of causal orders, and could allow quantum algorithms to be implemented with an efficiency unlikely to be achieved on a fixed-gate-order quantum computer. PMID:26250107

  14. Cognitive mechanisms associated with auditory sensory gating.

    PubMed

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

    2016-02-01

    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.

  15. A bistable electromagnetically actuated rotary gate microvalve

    NASA Astrophysics Data System (ADS)

    Luharuka, Rajesh; Hesketh, Peter J.

    2008-03-01

    Two types of rotary gate microvalves are developed for flow modulation in microfluidic systems. These microvalves have been tested for an open flow rate of up to 100 sccm and operate under a differential pressure of 6 psig with flow modulation of up to 100. The microvalve consists of a suspended gate that rotates in the plane of the chip to regulate flow through the orifice. The gate is suspended by a novel fully compliant in-plane rotary bistable micromechanism (IPRBM) that advantageously constrains the gate in all degrees of freedom except for in-plane rotational motion. Multiple inlet/outlet orifices provide flexibility of operating the microvalve in three different flow configurations. The rotary gate microvalve is switched with an external electromagnetic actuator. The suspended gate is made of a soft magnetic material and its electromagnetic actuation is based on the operating principle of a variable-reluctance stepper motor.

  16. 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

  17. High Electron Mobility Ge n-Channel Metal-Insulator-Semiconductor Field-Effect Transistors Fabricated by the Gate-Last Process with the Solid Source Diffusion Technique

    NASA Astrophysics Data System (ADS)

    Maeda, Tatsuro; Morita, Yukinori; Takagi, Shinichi

    2010-06-01

    We fabricate high-k/Ge n-channel metal-insulator-semiconductor field-effect transistors (MISFETs) by the gate-last process with the thermal solid source diffusion to achieve both of high quality source/drain (S/D) and gate stack. The n+/p junction formed by solid source diffusion technique of Sb dopant shows the excellent diode characteristics of ˜1.5×105 on/off ratio between +1 and -1 V and the quite low reverse current density of ˜4.1×10-4 A/cm2 at +1 V after the fabrication of high-k/Ge n-channel MISFETs that enable us to observe well-behaved transistor performances. The extracted electron mobility with the peak of 891 cm2/(V.s) is high enough to be superior to the Si universal electron mobility especially in low Eeff.

  18. 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.

  19. Floating gate transistors as biosensors (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Frisbie, C. Daniel

    2016-11-01

    Electrolyte gated transistors (EGTs) are a sub-class of thin film transistors that are extremely promising for biological sensing applications. These devices employ a solid electrolyte as the gate insulator; the very large capacitance of the electrolyte results in low voltage operation and high transconductance or gain. This talk will describe the fabrication of floating gate EGTs and their use as ricin sensors. The critical performance metrics for EGTs compared with other types of TFTs will also be reviewed.

  20. Bio-fabrication of nanomesh channels of single-walled carbon nanotubes for locally gated field-effect transistors

    NASA Astrophysics Data System (ADS)

    Byeon, Hye-Hyeon; Lee, Woo Chul; Kim, Wonbin; Kim, Seong Keun; Kim, Woong; Yi, Hyunjung

    2017-01-01

    Single-walled carbon nanotubes (SWNTs) are one of the promising electronic components for nanoscale electronic devices such as field-effect transistors (FETs) owing to their excellent device characteristics such as high conductivity, high carrier mobility and mechanical flexibility. Localized gating gemometry of FETs enables individual addressing of active channels and allows for better electrostatics via thinner dielectric layer of high k-value. For localized gating of SWNTs, it becomes critical to define SWNTs of controlled nanostructures and functionality onto desired locations in high precision. Here, we demonstrate that a biologically templated approach in combination of microfabrication processes can successfully produce a nanostructured channels of SWNTs for localized active devices such as local bottom-gated FETs. A large-scale nanostructured network, nanomesh, of SWNTs were assembled in solution using an M13 phage with strong binding affinity toward SWNTs and micrometer-scale nanomesh channels were defined using negative photolithography and plasma-etching processes. The bio-fabrication approach produced local bottom-gated FETs with remarkably controllable nanostructures and successfully enabled semiconducting behavior out of unsorted SWNTs. In addition, the localized gating scheme enhanced the device performances such as operation voltage and I on/I off ratio. We believe that our approach provides a useful and integrative method for fabricating electronic devices out of nanoscale electronic materials for applications in which tunable electrical properties, mechanical flexibility, ambient stability, and chemical stability are of crucial importance.

  1. Molecular beam epitaxy for advanced gate stack materials and processes

    NASA Astrophysics Data System (ADS)

    Locquet, Jean-Pierre

    2005-03-01

    The material requirements for future CMOS generations - as given by the ITRS roadmap - are very challenging. This includes a high K dielectric without a low K interfacial layer, a high mobility channel and the appropriate metal gate. With the help of two projects INVEST and ET4US, we are building up a molecular beam epitaxy (MBE) infrastructure to grow this material set on large area wafers that can be further processed into small scale devices. In the INVEST project, we have developed an MBE system for the growth of complex oxides on semiconductors. The system follows the overall design of a production tool and is equipped with an RF atomic oxygen source, effusion cells, e-beam evaporators and a differential pumping stage. The oxide growth process starts with desorbing the initial surface oxide on the Si wafers in ultra-high vacuum and high temperature to create a clean reconstructed 2x1 surface. Using the atomic oxygen it is possible to oxidize the surface in a well controlled manner at low temperature and to grow very thin and dense SiOx layers, followed by the growth of 2-6 nm amorphous high K dielectrics. The process parameters permit to tune the interface layer from a SiOx rich to a silicide rich interface with a significant impact on the capacitance and the leakage. Initial focus is on developing an optimized growth recipe for high quality amorphous HfO2 and LaHfO3.5 films. This recipe was subsequently used to make wafers for a transistor batch that gave us the first N short channel MBE MOSFET's (100 nm) using an etched gate process flow. Some highlights of the first batch for 3nm HfO2 MOSFET are a high mobility (> 270 cm^2/Vs) with a corresponding low leakage current of 2 mA/cm^2). While there were some process issues for LaHfO3.5, the 3 nm MOSFET showed very low leakage currents below 10-6 A/cm^2. Interestingly all the LaHFO3.5 MOSFETs showed very low threshold voltage instabilities. In collaboration with C. Marchiori, M. Sousa, A.Guiller, H. Siegwart, D

  2. 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

    2016-06-21

    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.

  3. 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

  4. 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…

  5. Picosecond Optoelectronic AND-GATE

    DTIC Science & Technology

    1994-08-01

    SOTA. The bias, gate. and 13 ground probes make contact to their respective bond pads. Fig. 12 Temporal response of the SOTA. 14 Fig. 13 Sheet resistance for...post-annealed, lattice matched LT-GaAs, LT- 18 In0.35GaO. 65 As, LT-In0.53Ga0 .4 7As. The sheet resistance for polycrystalline LT-In0 .35Ga0...65As is also shown. The minimum acceptable values for sheet resistance for detector areas of 50x50 ptm 2 and 8x8 4tm 2 are shown and correspond to a dark

  6. 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.

  7. MIS and MFIS Devices: DyScO3 as a gate-oxide and buffer-layer

    NASA Astrophysics Data System (ADS)

    Melgarejo, R.; Karan, N. K.; Saavedra-Arias, J.; Pradhan, D. K.; Thomas, R.; Katiyar, R. S.

    2008-03-01

    Metal-Ferroelectric-Insulator-Semiconductor (MFIS) structure is of importance in nonvolatile memories, as insulating buffer layer that prevents interdiffusion between the ferroelectric (FE) and the Si substrate. However, insulating layer has some disadvantages viz. generation of depolarization field in FE film and increase of operation voltage. To overcome this, it is important to find a FE with low ɛr (compared to normal FE) and an insulating buffer layer with high ɛr (compared to ɛr = 3.9 of SiO2). High-k materials viz. LaAlO3, SiN, HfO2, HfAlO etc. have been studied as buffer layers in the MFIS structures and as gate-oxide in metal-insulator-silicon (MIS). Recently, a novel gate dielectric material, DyScO3 was considered and studies indicate that crystallization temperature significantly increased and the film on Si remained amorphous even at 1000 C annealing. Considering the requirements on crystallization temperature, ɛr, electrical stability for high-k buffer layers, DyScO3 seems to be very promising for future MFIS device applications. Therefore, the evaluations of MOCVD grown DyScO3 as gate-oxide for MIS and the buffer layers for Bi3.25La0.75Ti3O12 based MFIS structures are presented.

  8. Stimuli-responsive smart gating membranes.

    PubMed

    Liu, Zhuang; Wang, Wei; Xie, Rui; Ju, Xiao-Jie; Chu, Liang-Yin

    2016-02-07

    Membranes are playing paramount roles in the sustainable development of myriad fields such as energy, environmental and resource management, and human health. However, the unalterable pore size and surface properties of traditional porous membranes restrict their efficient applications. The performances of traditional membranes will be weakened upon unavoidable membrane fouling, and they cannot be applied to cases where self-regulated permeability and selectivity are required. Inspired by natural cell membranes with stimuli-responsive channels, artificial stimuli-responsive smart gating membranes are developed by chemically/physically incorporating stimuli-responsive materials as functional gates into traditional porous membranes, to provide advanced functions and enhanced performances for breaking the bottlenecks of traditional membrane technologies. Smart gating membranes, integrating the advantages of traditional porous membrane substrates and smart functional gates, can self-regulate their permeability and selectivity via the flexible adjustment of pore sizes and surface properties based on the "open/close" switch of the smart gates in response to environmental stimuli. This tutorial review summarizes the recent developments in stimuli-responsive smart gating membranes, including the design strategies and the fabrication strategies that are based on the introduction of the stimuli-responsive gates after or during membrane formation, and the positively and negatively responsive gating models of versatile stimuli-responsive smart gating membranes, as well as the advanced applications of smart gating membranes for regulating substance concentration in reactors, controlling the release rate of drugs, separating active molecules based on size or affinity, and the self-cleaning of membrane surfaces. With self-regulated membrane performances, smart gating membranes show great power for use in global sustainable development.

  9. 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

  10. 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

  11. Nanosecond gating properties of proximity focused microchannel plate image intensifiers

    NASA Astrophysics Data System (ADS)

    King, N. S. P.; King, N. S. P.; Yates, G. J.; Jaramillo, S. A.; Noel, B. W.; Detch, J. L., Jr.; Ogle, J. W.

    The optical gating properties of Multichannel plate image intensifiers were characterized. Emphasis was placed on parameters relevant to gating speed and correlations between the applied electrical and resultant optical gates.

  12. A gate drive circuit for gate-turn-off (GTO) devices in series stack.

    SciTech Connect

    Despe, O.

    1999-04-13

    A gate-turn-off (GTO) switch is under development at the Advanced Photon Source as a replacement for a thyratron switch in high power pulsed application. The high voltage in the application requires multiple GTOs connected in series. One component that is critical to the success of GTO operation is the gate drive circuit. The gate drive circuit has to provide fast high-current pulses to the GTO gate for fast turn-on and turn-off. It also has to be able to operate while floating at high voltage. This paper describes a gate drive circuit that meets these requirements.

  13. 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.

  14. 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.

  15. Channel gating pore: a new therapeutic target.

    PubMed

    Kornilov, Polina; Peretz, Asher; Attali, Bernard

    2013-09-01

    Each subunit of voltage-gated cation channels comprises a voltage-sensing domain and a pore region. In a paper recently published in Cell Research, Li et al. showed that the gating charge pathway of the voltage sensor of the KCNQ2 K+ channel can accommodate small opener molecules and offer a new target to treat hyperexcitability disorders.

  16. Using Gates to Enhance Your Paddling Program.

    ERIC Educational Resources Information Center

    Kauffman, Robert B.; Mason, David W.

    1995-01-01

    Describes methods for constructing gates and slalom courses to teach paddling skills to young campers. Describes how the English Gate system, a standardized course, can be used both for instruction and to test camper's paddling skills. Recommends the use of a three-level award system (novice, intermediate, and expert) to recognize camper…

  17. Protected gates for topological quantum field theories

    SciTech Connect

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

    2016-02-15

    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.

  18. 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.

  19. Retaining latch for a water pit gate

    SciTech Connect

    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.

  20. Retaining latch for a water pit gate

    SciTech Connect

    Beale, A.R.

    1996-12-31

    The present invention relates to retaining devices which are used to latch two elements or parts together and, more particularly, to gate latches for use in locking a gate to a wall bracket in a water pit utilized to store or handle hazardous materials. 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.

  1. Retaining latch for a water pit gate

    SciTech Connect

    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.

  2. 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.

  3. 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.

  4. 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.

  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. 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.

  7. Terahertz plasmon amplification in RTD-gated HEMTs with a grating-gate

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

    We analyze amplification of terahertz plasmons in a grating-gate semiconductor hetero-structure. The device consists of a resonant-tunneling-diode gated high-electron-mobility transistor (RTD-gated HEMT), i.e. a HEMT structure with a double-barrier gate stack enabling resonant tunneling from gate to channel. In these devices, the key element enabling substantial power gain is the 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 in previous works, enabling amplification with associated power gain >> 30 dB at room temperature.

  8. Logic gates based on ion transistors.

    PubMed

    Tybrandt, Klas; Forchheimer, Robert; Berggren, Magnus

    2012-05-29

    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.

  9. 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.

  10. Gate-tunable electron interaction in high-κ dielectric films

    PubMed Central

    Kondovych, Svitlana; Luk’yanchuk, Igor; Baturina, Tatyana I.; Vinokur, Valerii M.

    2017-01-01

    The two-dimensional (2D) logarithmic character of Coulomb interaction between charges and the resulting logarithmic confinement is a remarkable inherent property of high dielectric constant (high-κ) thin films with far reaching implications. Most and foremost, this is the charge Berezinskii-Kosterlitz-Thouless transition with the notable manifestation, low-temperature superinsulating topological phase. Here we show that the range of the confinement can be tuned by the external gate electrode and unravel a variety of electrostatic interactions in high-k films. We find that by reducing the distance from the gate to the film, we decrease the spatial range of the 2D long-range logarithmic interaction, changing it to predominantly dipolar or even to exponential one at lateral distances exceeding the dimension of the film-gate separation. Our findings offer a unique laboratory for the in-depth study of topological phase transitions and related phenomena that range from criticality of quantum metal- and superconductor-insulator transitions to the effects of charge-trapping and Coulomb scalability in memory nanodevices. PMID:28218245

  11. Gate-tunable electron interaction in high-κ dielectric films

    NASA Astrophysics Data System (ADS)

    Kondovych, Svitlana; Luk’Yanchuk, Igor; Baturina, Tatyana I.; Vinokur, Valerii M.

    2017-02-01

    The two-dimensional (2D) logarithmic character of Coulomb interaction between charges and the resulting logarithmic confinement is a remarkable inherent property of high dielectric constant (high-κ) thin films with far reaching implications. Most and foremost, this is the charge Berezinskii-Kosterlitz-Thouless transition with the notable manifestation, low-temperature superinsulating topological phase. Here we show that the range of the confinement can be tuned by the external gate electrode and unravel a variety of electrostatic interactions in high-k films. We find that by reducing the distance from the gate to the film, we decrease the spatial range of the 2D long-range logarithmic interaction, changing it to predominantly dipolar or even to exponential one at lateral distances exceeding the dimension of the film-gate separation. Our findings offer a unique laboratory for the in-depth study of topological phase transitions and related phenomena that range from criticality of quantum metal- and superconductor-insulator transitions to the effects of charge-trapping and Coulomb scalability in memory nanodevices.

  12. 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.

  13. 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.

  14. Mechanosensitive gating of Kv channels.

    PubMed

    Morris, Catherine E; Prikryl, Emil A; Joós, Béla

    2015-01-01

    K-selective voltage-gated channels (Kv) are multi-conformation bilayer-embedded proteins whose mechanosensitive (MS) Popen(V) implies that at least one conformational transition requires the restructuring of the channel-bilayer interface. Unlike Morris and colleagues, who attributed MS-Kv responses to a cooperative V-dependent closed-closed expansion↔compaction transition near the open state, Mackinnon and colleagues invoke expansion during a V-independent closed↔open transition. With increasing membrane tension, they suggest, the closed↔open equilibrium constant, L, can increase >100-fold, thereby taking steady-state Popen from 0→1; "exquisite sensitivity to small…mechanical perturbations", they state, makes a Kv "as much a mechanosensitive…as…a voltage-dependent channel". Devised to explain successive gK(V) curves in excised patches where tension spontaneously increased until lysis, their L-based model falters in part because of an overlooked IK feature; with recovery from slow inactivation factored in, their g(V) datasets are fully explained by the earlier model (a MS V-dependent closed-closed transition, invariant L≥4). An L-based MS-Kv predicts neither known Kv time courses nor the distinctive MS responses of Kv-ILT. It predicts Kv densities (hence gating charge per V-sensor) several-fold different from established values. If opening depended on elevated tension (L-based model), standard gK(V) operation would be compromised by animal cells' membrane flaccidity. A MS V-dependent transition is, by contrast, unproblematic on all counts. Since these issues bear directly on recent findings that mechanically-modulated Kv channels subtly tune pain-related excitability in peripheral mechanoreceptor neurons we undertook excitability modeling (evoked action potentials). Kvs with MS V-dependent closed-closed transitions produce nuanced mechanically-modulated excitability whereas an L-based MS-Kv yields extreme, possibly excessive (physiologically

  15. 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.

  16. Gated escaping of ligand out of protein

    NASA Astrophysics Data System (ADS)

    Sheu, Sheh-Yi; Yang, Dah-Yen

    2000-01-01

    We construct a new gating model and develop a new theory to study the escaping process of a ligand out of a spherical cavity with a puncture (or gate) on the surface. The gate undulation can be regulated by any time-dependent function and the motion of the ligand inside the spherical cavity is mapped into a two-dimensional entropy potential surface. Hence the driving force of our model is entropy only. For a static gate, the escaping process corresponds to climbing a two-dimensional entropy barrier. When the gate open angle is small, the escaping rate is proportional to the square of the opening angle. The prefactor of the escaping rate constant depends on the curvature of the entropy potential surface. For coherent gating, the survival time depends not only on the gate undulation frequency but also on how the initial state is defined. On the escaping from protein, our escaping rate shows it is qualitatively consistent with the experimental result of ligand recombination in myoglobin.

  17. Range gating experiments through a scattering media

    SciTech Connect

    Payton, J.; Cverna, F.; Gallegos, R.; McDonald, T.; Numkena, D.; Obst, A.; Pena-Abeyta, C.; Yates, G.

    1998-12-31

    This paper discusses range-gated imaging experiments performed recently at Redstone Arsenal in Huntsville, Alabama. Range gating is an imaging technique that uses a pulsed laser and gated camera to image objects at specific ranges. The technique can be used for imaging through scattering media such as dense smoke or fog. Range gating uses the fact that light travels at 3 x 10{sup 8} m/s. Knowing the speed of light the authors can calculate the time it will take the laser light to travel a known distance, then gate open a Micro Channel Plate Image Intensifier (MCPII) at the time the reflected light returns from the target. In the Redstone experiment the gate width on the MCPII was set to equal the laser pulse width ({approximately} 8 ns) for the highest signal to noise ratio. The gate allows the light reflected form the target and a small portion of the light reflected from the smoke in the vicinity of the target to be imaged. They obtained good results in light and medium smoke but the laser they were used did not have sufficient intensity to penetrate the thickest smoke. They did not diverge the laser beam to cover the entire target in order to maintain a high flux that would achieve better penetration through the smoke. They were able to image an Armored Personnel Carrier (APC) through light and medium smoke but they were not able to image the APC through heavy smoke. The experiment and results are presented.

  18. 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.

  19. Adaptive quantum gate-set tomography

    NASA Astrophysics Data System (ADS)

    Blume-Kohout, Robin

    2013-03-01

    Quantum information hardware needs to be characterized and calibrated. This is the job of quantum state and process tomography, but standard tomographic methods have an Achilles heel: to characterize an unknown process, they rely on a set of absolutely calibrated measurements. But many technologies (e.g., solid-state qubits) admit only a single native measurement basis, and other bases are measured using unitary control. So tomography becomes circular - tomographic protocols are using gates to calibrate themselves! Gate-set tomography confronts this problem head-on and resolves it by treating gates relationally. We abandon all assumptions about what a given gate operation does, and characterize entire universal gate sets from the ground up using only the observed statistics of an [unknown] 2-outcome measurement after various strings of [unknown] gate operations. The accuracy and reliability of the resulting estimate depends critically on which gate strings are used, and benefits greatly from adaptivity. Sandia National Labs is a multiprogram laboratory operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Dept. of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000

  20. 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.

  1. A quantum Fredkin gate (Conference Presentation)

    NASA Astrophysics Data System (ADS)

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

    2016-10-01

    One of the greatest challenges in modern science is the realisation of quantum computers which, as their scale increases, will allow enhanced performance of tasks across many areas of quantum information processing. Quantum logic gates play a vital role in realising these applications by carrying out the elementary operations on the qubits; a key aim is minimising the resources needed to build these gates into useful circuits. While the salient features of a quantum computer have been shown in proof-of-principle experiments, e.g., single- and two-qubit gates, difficulties in scaling quantum systems to encode and manipulate multiple qubits has hindered demonstrations of more complex operations. This is exemplified by the classical Fredkin (or controlled-SWAP) gate [1] for which, despite many theoretical proposals [2,3] relying on concatenating multiple two-qubit gates, a quantum analogue has yet to be realised. Here, by directly adding control to a two-qubit SWAP unitary [4], we use photonic qubit logic to report the first experimental demonstration of a quantum Fredkin gate [5]. Our scheme uses linear optics and improves on the overall probability of success by an order of magnitude over previous proposals [2,3]. This optical approach allows us to add control an arbitrary black-box unitary which is otherwise forbidden in the standard circuit model [6]. Additionally, the action of our gate exhibits quantum coherence allowing the generation of the highest fidelity three-photon GHZ states to date. The quantum Fredkin gate has many applications in quantum computing, quantum measurements [7] and cryptography [8,9]. Using our scheme, we apply the Fredkin gate to the task of direct measurements of the purity and state overlap of a quantum system [7] without recourse to quantum state tomography.

  2. 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.

  3. Cellular mechanisms involved in iso-osmotic high K+ solutions-induced contraction of the estrogen-primed rat myometrium.

    PubMed

    Trujillo, M M; Ausina, P; Savineau, J P; Marthan, R; Strippoli, G; Advenier, C; Pinto, F M; Candenas, M L

    2000-01-01

    The aim of the present study was to investigate the mechanisms involved in the contraction evoked by iso-osmotic high K+ solutions in the estrogen-primed rat uterus. In Ca2+-containing solution, iso-osmotic addition of KCl (30, 60 or 90 mM K+) induced a rapid, phasic contraction followed by a prolonged sustained plateau (tonic component) of smaller amplitude. The KCl (60 mM)-induced contraction was unaffected by tetrodotoxin (3 microM), omega-conotoxin MVIIC (1 microM), GF 109203X (1 microM) or calphostin C (3 microM) but was markedly reduced by tissue treatment with neomycin (1 mM), mepacrine (10 microM) or U-73122 (10 microM). Nifedipine (0.01-0.1 microM) was significantly more effective as an inhibitor of the tonic component than of the phasic component. After 60 min incubation in Ca2+-free solution containing 3 mM EGTA, iso-osmotic KCl did not cause any increase in tension but potentiated contractions evoked by oxytocin (1 microM), sodium orthovanadate (160 micrM) or okadaic acid (20 microM) in these experimental conditions. In freshly dispersed myometrial cells maintained in Ca2+-containing solution and loaded with indo 1, iso-osmotic KCl (60 mM) caused a biphasic increase in the intracellular Ca2+ concentration ([Ca2+]i). In cells superfused for 60 min in Ca2+-free solution containing EGTA (1 mM), KCl did not increase [Ca2+]i. In Ca2+-containing solution, KCl (60 mM) produced a 76.0 +/- 16.2% increase in total [3H]inositol phosphates above basal levels and increased the intracellular levels of free arachidonic acid. These results suggest that, in the estrogen-primed rat uterus, iso-osmotic high K+ solutions, in addition to their well known effect on Ca2+ influx, activate other cellular processes leading to an increase in the Ca2+ sensitivity of the contractile machinery by a mechanism independent of extracellular Ca2+.

  4. Doppler backscattering for spherical tokamaks and measurement of high-k density fluctuation wavenumber spectrum in MAST

    NASA Astrophysics Data System (ADS)

    Hillesheim, J. C.; Crocker, N. A.; Peebles, W. A.; Meyer, H.; Meakins, A.; Field, A. R.; Dunai, D.; Carr, M.; Hawkes, N.; the MAST Team

    2015-07-01

    The high-k (7≲ {{k}\\bot}{ρi}≲ 11 ) wavenumber spectrum of density fluctuations has been measured for the first time in MAST (Lloyd et al 2003 Nucl. Fusion 43 1665). This was accomplished with the first implementation of Doppler backscattering (DBS) for core measurements in a spherical tokamak. DBS has become a well-established and versatile diagnostic technique for the measurement of intermediate- k ({{k}\\bot}{ρi}˜ 1 , and higher) density fluctuations and flows in magnetically confined fusion experiments. Previous implementations of DBS for core measurements have been in standard, large aspect ratio tokamaks. A novel implementation with two-dimensional (2D) steering was necessary to enable DBS measurements in MAST, where the large variation of the magnetic field pitch angle presents a challenge. We report on the scattering considerations and ray tracing calculations used to optimize the design and present data demonstrating measurement capabilities. Initial results confirm the applicability of the design and implementation approaches, showing the strong dependence of scattering alignment on the toroidal launch angle and demonstrating that DBS is sensitive to the local magnetic field pitch angle. We also present comparisons of DBS plasma velocity measurements with charge exchange recombination and beam emission spectroscopy measurements, which show reasonable agreement over most of the minor radius, but imply large poloidal flows approaching the magnetic axis in a discharge with an internal transport barrier. The 2D steering is shown to enable high-k measurements with DBS, at {{k}\\bot}>20 cm-1 ({{k}\\bot}{ρi}>10 ) for launch frequencies less than 75 GHz; this capability is used to measure the wavenumber spectrum of turbulence and we find \\mid n≤ft({{k}\\bot}\\right){{\\mid}2}\\propto k\\bot-4.7+/- 0.2 for {{k}\\bot}{ρi}≈ 7 -11, which is similar to the expectation for the turbulent kinetic cascade of \\mid n≤ft({{k}\\bot}\\right){{\\mid}2}\\propto

  5. Gate-assisted turn-off thyristor

    NASA Technical Reports Server (NTRS)

    Lowry, L. R.; Page, D. J.; Schlegel, E. S.

    1978-01-01

    1,000-volt, 200-ampere gate-assisted turn-off thyristor has been developed for power circuits requiring high efficiency, small size, and low weight. Design features include shunted cathode for high dV/dt capability. Cathode in interdigitated with dynamic gate for fast, low-loss switching. Operating frequency exceeds 20 kHz with overall energy dissipation of less that 12 mJ per pulse for typical 20-microsecond half-sine waveform. Device has turn-on time of 2 microseconds and turn-off time as short as 3 microseconds with only 2 amperes of gate drive.

  6. Quantum gates and their coexisting geometric phases

    SciTech Connect

    Wu Lianao; Bishop, C. Allen; Byrd, Mark S.

    2011-08-15

    Geometric phases arise naturally in a variety of quantum systems with observable consequences. They also arise in quantum computations when dressed states are used in gating operations. Here we show how they arise in these gating operations and how one may take advantage of the dressed states producing them. Specifically, we show that for a given, but arbitrary Hamiltonian, and at an arbitrary time {tau}, there always exists a set of dressed states such that a given gate operation can be performed by the Hamiltonian up to a phase {phi}. The phase is a sum of a dynamical phase and a geometric phase. We illustrate the dressed phase for several systems.

  7. GADL: A gate array description language

    NASA Astrophysics Data System (ADS)

    Lippens, P. E. R.; Slenter, A. G. J.

    1987-01-01

    A way to map digital networks onto gate array images is described. A language to describe gate array images, design rules for the wiring, and arbitrary specified macros from image dependent libraries is defined. A data base is generated by compiling the description of a gate array family in terms of the above items. Place and route software is automatically conditioned to implement arbitrary specifications of a digital system in terms of a netlist. The performance of the system is demonstrated for various practical situations.

  8. 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.

  9. Diagonal gates in the Clifford hierarchy

    NASA Astrophysics Data System (ADS)

    Cui, Shawn X.; Gottesman, Daniel; Krishna, Anirudh

    2017-01-01

    The Clifford hierarchy is a set of gates that appears in the theory of fault-tolerant quantum computation, but its precise structure remains elusive. We give a complete characterization of the diagonal gates in the Clifford hierarchy for prime-dimensional qudits. They turn out to be pmth roots of unity raised to polynomial functions of the basis state to which they are applied, and we determine which level of the Clifford hierarchy a given gate sits in based on m and the degree of the polynomial.

  10. The gating of the CFTR channel.

    PubMed

    Moran, Oscar

    2017-01-01

    Cystic fibrosis transmembrane conductance regulator (CFTR) is an anion channel expressed in the apical membrane of epithelia. Mutations in the CFTR gene are the cause of cystsic fibrosis. CFTR is the only ABC-protein that constitutes an ion channel pore forming subunit. CFTR gating is regulated in complex manner as phosphorylation is mandatory for channel activity and gating is directly regulated by binding of ATP to specific intracellular sites on the CFTR protein. This review covers our current understanding on the gating mechanism in CFTR and illustrates the relevance of alteration of these mechanisms in the onset of cystic fibrosis.

  11. 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.

  12. Swelling, NEM, and A23187 activate Cl(-)-dependent K+ transport in high-K+ sheep red cells

    SciTech Connect

    Fujise, H.; Lauf, P.K.

    1987-02-01

    In low K+ (LK) sheep red cells a significant fraction of the total ouabain-resistant (OR) K+ flux is inhibited when Cl- is replaced by other anions of the Hofmeister series except Br- (Cl(-)-dependent K+ flux). In contrast, high K+ (HK) sheep red cells in isosmotic media did not possess any significant OR Cl(-)-dependent K+ flux when Cl- was replaced by NO/sub 3/- or I-. However, exposure to hyposmotic solutions, treatment with the sulfhydryl (SH) group reagent N-ethylmaleimide (NEM) or with the bivalent metal ion (Me2+) ionophore A23187 in absence of external Me2+ caused a significant activation of Cl(-)-dependent K+ transport as measured with Rb+ as K+ congener. There was no Cl(-)-dependent Rb+ flux in A23187-treated cells when Mn2+, Mg2+, and Ca2+ were present at 1 mM concentrations, suggesting that cellular accumulation of these Me2+ is inhibitory. Similar to LK red cells, HK red cells failed to respond to A23187 when pretreated with NEM supporting the hypothesis proposed recently of a common mechanism of Cl(-)-dependent K+ transport activation. The magnitudes of the Cl(-)-dependent Rb+ fluxes in HK cells were much smaller than those elicited by identical treatments in LK red cells, and the effect of all interventions was not due to the presence of reticulocytes known to possess Cl(-)-dependent K+ transport.

  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. Assignment of the Perfluoropropionic Acid-Formic Acid Complex and the Difficulties of Including High K_a Transitions.

    NASA Astrophysics Data System (ADS)

    Obenchain, Daniel A.; Lin, Wei; Novick, Stewart E.; Cooke, S. A.

    2016-06-01

    We recently began an investigation into the perfluoropropionic acid\\cdotsformic acid complex using broadband microwave spectroscopy. This study aims to examine the possible double proton transfer between the two interacting carboxcyclic acid groups. The spectrum presented as a doubled set of lines, with spacing between transitions of < 1 MHz. Transitions appeared to be a-type, R branch transitions for an asymmetric top. Assignment of all K_a=1,0 transitions yields decent fits to a standard rotational Hamiltonian. Treatment of the doubling as either a two state system (presumably with a double proton transfer) or as two distinct, but nearly identical conformations of the complex produce fits of similar quality. Including higher K_a transitions for the a-type, R-branch lines greatly increases the error of these fits. A previous study involving the trifluoroacetic acid\\cdotsformic acid complex published observed similar high K_a transitions, but did not include them in the published fit. We hope to shed more light on this conundrum. Similarities to other double-well potential minimum systems will be discussed. Martinache, L.; Kresa, W.; Wegener, M.;, Vonmont, U.; and Bauder, A. Chem. Phys. 148 (1990) 129-140.

  15. Preliminary Investigation of High-K Materials -Tio2 Doped Ta2o5 Films by Remote Plasma Ald

    NASA Astrophysics Data System (ADS)

    Fang, Q.; Hodson, C.; Liu, M.; Fang, Z. W.; Potter, R.; Gunn, R.

    (TiO2)x(Ta2O5)1-x (x is up to 0.45) films deposited by a remote plasma atomic layer deposition (ALD) are reported in this work. The growth rates of the ALD films measured by ellipsometer are in a range of 0.8 - 1.06 Å/cycle at a deposition temperature of 300°C, depending on Ti/(Ti+Ta) ratio. In order to evaluate the high-k materials of Ti-doped Ta2O5 films, EDX and AES were used for determining the composition of the films. The thickness and optical properties of the films were measured by a spectral ellipsometer and CV-measurement was applied for testing the electrical property of the film. Furthermore, the effects of thermal annealing and in-situ O2-oxidation on thickness, refractive index and electrical property of (TiO2)x(Ta2O5)1-x films are also discussed.

  16. Polaron-electron assisted giant dielectric dispersion in SrZrO3 high-k dielectric

    NASA Astrophysics Data System (ADS)

    Borkar, Hitesh; Barvat, Arun; Pal, Prabir; Shukla, A. K.; Pulikkotil, J. J.; Kumar, Ashok

    2016-06-01

    The SrZrO3 is a well known high-k dielectric constant (˜22) and high optical bandgap (˜5.8 eV) material and one of the potential candidates for future generation nanoelectronic logic elements (8 nm node technology) beyond silicon. Its dielectric behavior is fairly robust and frequency independent till 470 K; however, it suffers a strong small-polaron based electronic phase transition (Te) linking 650 to 750 K. The impedance spectroscopy measurements revealed the presence of conducting grains and grain boundaries at elevated temperature which provide energetic mobile charge carriers with activation energy in the range of 0.7 to 1.2 eV supporting the oxygen ions and proton conduction. X-ray photoemission spectroscopy measurements suggest the presence of weak non-stoichiometric O2- anions and hydroxyl species bound to different sites at the surface and bulk. These thermally activated charge carriers at elevated temperature significantly contribute to the polaronic based dielectric anomaly and conductivity. Our dielectric anomaly supports pseudo phase transition due to high degree of change in ZrO6 octahedral angle in the temperature range of 650-750 K, where electron density and phonon vibration affect the dielectric and conductivity properties.

  17. Selective wet etch of a TaN metal gate with an amorphous-silicon hard mask

    NASA Astrophysics Data System (ADS)

    Yongliang, Li; Qiuxia, Xu

    2010-11-01

    The appropriate wet etch process for the selective removal of TaN on the HfSiON dielectric with an amorphous-silicon (a-Si) hardmask is presented. SC1 (NH4OH: H2O2: H2O), which can achieve reasonable etch rates for metal gates and very high selectivity to high-k dielectrics and hardmask materials, is chosen as the TaN etchant. Compared with the photoresist mask and the tetraethyl orthosilicate (TEOS) hardmask, the a-Si hardmask is a better choice to achieve selective removal of TaN on the HfSiON dielectric because it is impervious to the SC1 etchant and can be readily etched with NH4OH solution without attacking the TaN and the HfSiON film. In addition, the surface of the HfSiON dielectric is smooth after the wet etching of the TaN metal gate and a-Si hardmask removal, which could prevent device performance degradation. Therefore, the wet etching of TaN with the a-Si hardmask can be applied to dual metal gate integration for the selective removal of the first TaN metal gate deposition.

  18. Mechanosensitive Gating of Kv Channels

    PubMed Central

    Morris, Catherine E.; Prikryl, Emil A.; Joós, Béla

    2015-01-01

    K-selective voltage-gated channels (Kv) are multi-conformation bilayer-embedded proteins whose mechanosensitive (MS) Popen(V) implies that at least one conformational transition requires the restructuring of the channel-bilayer interface. Unlike Morris and colleagues, who attributed MS-Kv responses to a cooperative V-dependent closed-closed expansion↔compaction transition near the open state, Mackinnon and colleagues invoke expansion during a V-independent closed↔open transition. With increasing membrane tension, they suggest, the closed↔open equilibrium constant, L, can increase >100-fold, thereby taking steady-state Popen from 0→1; “exquisite sensitivity to small…mechanical perturbations”, they state, makes a Kv “as much a mechanosensitive…as…a voltage-dependent channel”. Devised to explain successive gK(V) curves in excised patches where tension spontaneously increased until lysis, their L-based model falters in part because of an overlooked IK feature; with recovery from slow inactivation factored in, their g(V) datasets are fully explained by the earlier model (a MS V-dependent closed-closed transition, invariant L≥4). An L-based MS-Kv predicts neither known Kv time courses nor the distinctive MS responses of Kv-ILT. It predicts Kv densities (hence gating charge per V-sensor) several-fold different from established values. If opening depended on elevated tension (L-based model), standard gK(V) operation would be compromised by animal cells’ membrane flaccidity. A MS V-dependent transition is, by contrast, unproblematic on all counts. Since these issues bear directly on recent findings that mechanically-modulated Kv channels subtly tune pain-related excitability in peripheral mechanoreceptor neurons we undertook excitability modeling (evoked action potentials). Kvs with MS V-dependent closed-closed transitions produce nuanced mechanically-modulated excitability whereas an L-based MS-Kv yields extreme, possibly excessive

  19. 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

  20. 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.

  1. 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

  2. Mechanical gating of a mechanochemical reaction cascade

    NASA Astrophysics Data System (ADS)

    Wang, Junpeng; Kouznetsova, Tatiana B.; Boulatov, Roman; Craig, Stephen L.

    2016-11-01

    Covalent polymer mechanochemistry offers promising opportunities for the control and engineering of reactivity. To date, covalent mechanochemistry has largely been limited to individual reactions, but it also presents potential for intricate reaction systems and feedback loops. Here we report a molecular architecture, in which a cyclobutane mechanophore functions as a gate to regulate the activation of a second mechanophore, dichlorocyclopropane, resulting in a mechanochemical cascade reaction. Single-molecule force spectroscopy, pulsed ultrasonication experiments and DFT-level calculations support gating and indicate that extra force of >0.5 nN needs to be applied to a polymer of gated gDCC than of free gDCC for the mechanochemical isomerization gDCC to proceed at equal rate. The gating concept provides a mechanism by which to regulate stress-responsive behaviours, such as load-strengthening and mechanochromism, in future materials designs.

  3. Funding announcements from federal government, Gates Foundation.

    PubMed

    Garmaise, David

    2007-05-01

    In two separate announcements, in December 2006 and February 2007, the federal government allocated new funding for HIV/AIDS. The latter announcement was accompanied by a pledge from the Gates Foundation.

  4. Current profiles in gated graphene ribbons

    NASA Astrophysics Data System (ADS)

    Cresti, Alessandro; Grosso, Giuseppe; Pastori Parravicini, Giuseppe

    2008-03-01

    We simulate stationary current distribution in graphene ribbons in the presence of top gate potentials, by means of the nonequilibrium Keldysh-Green's function formalism within a tight-binding model. In the absence of magnetic fields and in the presence of a model potential barrier, we observe the Klein paradox, where electrons turn into holes in the gated region and again into electrons beyond it. We establish a connection between the band structure at the corner points of the Brillouin zone and Klein paradox, and give a pictorial description of conductive channels. In the presence of high magnetic fields, transport currents are chiral and flow along the edges of the ribbon. The intensity and sign of the potential barrier with respect to the Fermi energy influence the nature (electron/hole) of the carriers inside the gated region and determine the edge involved in the transport process. We demonstrate that manipulation of currents in the ribbon can be obtained by external gates.

  5. 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

  6. Mechanical gating of a mechanochemical reaction cascade

    PubMed Central

    Wang, Junpeng; Kouznetsova, Tatiana B.; Boulatov, Roman; Craig, Stephen L.

    2016-01-01

    Covalent polymer mechanochemistry offers promising opportunities for the control and engineering of reactivity. To date, covalent mechanochemistry has largely been limited to individual reactions, but it also presents potential for intricate reaction systems and feedback loops. Here we report a molecular architecture, in which a cyclobutane mechanophore functions as a gate to regulate the activation of a second mechanophore, dichlorocyclopropane, resulting in a mechanochemical cascade reaction. Single-molecule force spectroscopy, pulsed ultrasonication experiments and DFT-level calculations support gating and indicate that extra force of >0.5 nN needs to be applied to a polymer of gated gDCC than of free gDCC for the mechanochemical isomerization gDCC to proceed at equal rate. The gating concept provides a mechanism by which to regulate stress-responsive behaviours, such as load-strengthening and mechanochromism, in future materials designs. PMID:27848956

  7. Greening the Golden Gate National Recreation Area

    EPA Pesticide Factsheets

    The Golden Gate National Recreation Area was recognized a 2016 Federal Green Challenge Award for making significant strides to reduce its carbon footprint with the goal of becoming a carbon neutral park.

  8. 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.

  9. 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.

  10. 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

  11. The effect of pregabalin on sensorimotor gating in 'low' gating humans and mice.

    PubMed

    Acheson, Dean T; Stein, Murray B; Paulus, Martin P; Geyer, Mark A; Risbrough, Victoria B

    2012-09-01

    Pregabalin, an anticonvulsant and anxiolytic compound that binds to α2-δ auxiliary subunit Types 1 and 2 of voltage-gated calcium channels, has been shown to reduce excitatory neurotransmission partially through modulation of glutamatergic signaling. Prepulse inhibition (PPI) of startle is an operational measure of sensorimotor gating impacted by disruption of the glutamatergic system and is reduced in schizophrenia patients. Dysregulation of the glutamatergic system has also been implicated in the pathophysiology of schizophrenia. Here we tested the hypothesis that pregabalin may ameliorate PPI in a model of deficient gating in humans and mice. In study 1, 14 healthy human subjects participated in a within subjects, cross-over study with placebo, 50 mg or 200 mg pregabalin treatment prior to undergoing a PPI task. In study 2, 24 C57BL/6 mice underwent a similar procedure with vehicle, 30 and 100 mg/kg dose treatments. In both studies, subjects were assigned to a "Low" or "High" gating group using a median split procedure based on their PPI performance during placebo/vehicle. Drug effects were then examined across these groups. In humans, pregabalin treatment significantly increased PPI performance in the "low gating" group. In mice, pregabalin treatment significantly increased PPI in the low gating group but reduced PPI in the high gating group. Across species, pregabalin treatment improves PPI in subjects with low gating. These data support further exploration of pregabalin as a potential treatment for disorders characterized by sensorimotor gating deficits and glutamatergic hypersignaling, such as schizophrenia.

  12. Deletion of cytosolic gating ring decreases gate and voltage sensor coupling in BK channels.

    PubMed

    Zhang, Guohui; Geng, Yanyan; Jin, Yakang; Shi, Jingyi; McFarland, Kelli; Magleby, Karl L; Salkoff, Lawrence; Cui, Jianmin

    2017-03-06

    Large conductance Ca(2+)-activated K(+) channels (BK channels) gate open in response to both membrane voltage and intracellular Ca(2+) The channel is formed by a central pore-gate domain (PGD), which spans the membrane, plus transmembrane voltage sensors and a cytoplasmic gating ring that acts as a Ca(2+) sensor. How these voltage and Ca(2+) sensors influence the common activation gate, and interact with each other, is unclear. A previous study showed that a BK channel core lacking the entire cytoplasmic gating ring (Core-MT) was devoid of Ca(2+) activation but retained voltage sensitivity (Budelli et al. 2013. Proc. Natl. Acad. Sci. USA http://dx.doi.org/10.1073/pnas.1313433110). In this study, we measure voltage sensor activation and pore opening in this Core-MT channel over a wide range of voltages. We record gating currents and find that voltage sensor activation in this truncated channel is similar to WT but that the coupling between voltage sensor activation and gating of the pore is reduced. These results suggest that the gating ring, in addition to being the Ca(2+) sensor, enhances the effective coupling between voltage sensors and the PGD. We also find that removal of the gating ring alters modulation of the channels by the BK channel's β1 and β2 subunits.

  13. Electron transporting water-gated thin film transistors

    NASA Astrophysics Data System (ADS)

    Al Naim, Abdullah; Grell, Martin

    2012-10-01

    We demonstrate an electron-transporting water-gated thin film transistor, using thermally converted precursor-route zinc-oxide (ZnO) intrinsic semiconductors with hexamethyldisilazene (HMDS) hydrophobic surface modification. Water gated HMDS-ZnO thin film transistors (TFT) display low threshold and high electron mobility. ZnO films constitute an attractive alternative to organic semiconductors for TFT transducers in sensor applications for waterborne analytes. Despite the use of an electrolyte as gate medium, the gate geometry (shape of gate electrode and distance between gate electrode and TFT channel) is relevant for optimum performance of water-gated TFTs.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Hysteresis in voltage-gated channels.

    PubMed

    Villalba-Galea, Carlos A

    2016-09-30

    Ion channels constitute a superfamily of membrane proteins found in all living creatures. Their activity allows fast translocation of ions across the plasma membrane down the ion's transmembrane electrochemical gradient, resulting in a difference in electrical potential across the plasma membrane, known as the membrane potential. A group within this superfamily, namely voltage-gated channels, displays activity that is sensitive to the membrane potential. The activity of voltage-gated channels is controlled by the membrane potential, while the membrane potential is changed by these channels' activity. This interplay produces variations in the membrane potential that have evolved into electrical signals in many organisms. These signals are essential for numerous biological processes, including neuronal activity, insulin release, muscle contraction, fertilization and many others. In recent years, the activity of the voltage-gated channels has been observed not to follow a simple relationship with the membrane potential. Instead, it has been shown that the activity of voltage-gated channel displays hysteresis. In fact, a growing number of evidence have demonstrated that the voltage dependence of channel activity is dynamically modulated by activity itself. In spite of the great impact that this property can have on electrical signaling, hysteresis in voltage-gated channels is often overlooked. Addressing this issue, this review provides examples of voltage-gated ion channels displaying hysteretic behavior. Further, this review will discuss how Dynamic Voltage Dependence in voltage-gated channels can have a physiological role in electrical signaling. Furthermore, this review will elaborate on the current thoughts on the mechanism underlying hysteresis in voltage-gated channels.

  20. 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.

  1. Fast phase gates with trapped ions

    NASA Astrophysics Data System (ADS)

    Palmero, M.; Martínez-Garaot, S.; Leibfried, D.; Wineland, D. J.; Muga, J. G.

    2017-02-01

    We implement faster-than-adiabatic two-qubit phase gates using smooth state-dependent forces. The forces are designed to leave no final motional excitation, independently of the initial motional state in the harmonic small-oscillations limit. They are simple, explicit functions of time and the desired logical phase of the gate, and are based on quadratic invariants of motion and Lewis-Riesenfeld phases of the normal modes.

  2. 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.

  3. Modulation of CFTR gating by permeant ions

    PubMed Central

    Yeh, Han-I; Yeh, Jiunn-Tyng

    2015-01-01

    Cystic fibrosis transmembrane conductance regulator (CFTR) is unique among ion channels in that after its phosphorylation by protein kinase A (PKA), its ATP-dependent gating violates microscopic reversibility caused by the intimate involvement of ATP hydrolysis in controlling channel closure. Recent studies suggest a gating model featuring an energetic coupling between opening and closing of the gate in CFTR’s transmembrane domains and association and dissociation of its two nucleotide-binding domains (NBDs). We found that permeant ions such as nitrate can increase the open probability (Po) of wild-type (WT) CFTR by increasing the opening rate and decreasing the closing rate. Nearly identical effects were seen with a construct in which activity does not require phosphorylation of the regulatory domain, indicating that nitrate primarily affects ATP-dependent gating steps rather than PKA-dependent phosphorylation. Surprisingly, the effects of nitrate on CFTR gating are remarkably similar to those of VX-770 (N-(2,4-Di-tert-butyl-5-hydroxyphenyl)-4-oxo-1,4-dihydroquinoline-3-carboxamide), a potent CFTR potentiator used in clinics. These include effects on single-channel kinetics of WT CFTR, deceleration of the nonhydrolytic closing rate, and potentiation of the Po of the disease-associated mutant G551D. In addition, both VX-770 and nitrate increased the activity of a CFTR construct lacking NBD2 (ΔNBD2), indicating that these gating effects are independent of NBD dimerization. Nonetheless, whereas VX-770 is equally effective when applied from either side of the membrane, nitrate potentiates gating mainly from the cytoplasmic side, implicating a common mechanism for gating modulation mediated through two separate sites of action. PMID:25512598

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Solution-processed high-k magnesium oxide dielectrics for low-voltage oxide thin-film transistors

    NASA Astrophysics Data System (ADS)

    Jiang, Guixia; Liu, Ao; Liu, Guoxia; Zhu, Chundan; Meng, You; Shin, Byoungchul; Fortunato, Elvira; Martins, Rodrigo; Shan, Fukai

    2016-10-01

    Solution-processed metal-oxide thin films with high dielectric constants (k) have been extensively studied for low-cost and high-performance thin-film transistors (TFTs). In this report, MgO dielectric films were fabricated using the spin-coating method. The MgO dielectric films annealed at various temperatures (300, 400, 500, and 600 °C) were characterized by using thermogravimetric analysis, optical spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and atomic-force microscopy. The electrical measurements indicate that the insulating properties of MgO thin films are improved with an increase in annealing temperature. In order to clarify the potential application of MgO thin films as gate dielectrics in TFTs, solution-derived In2O3 channel layers were separately fabricated on various MgO dielectric layers. The optimized In2O3/MgO TFT exhibited an electron mobility of 5.48 cm2/V s, an on/off current ratio of 107, and a subthreshold swing of 0.33 V/dec at a low operation voltage of 6 V. This work represents a great step toward the development of portable and low-power consumption electronics.

  9. Controlling E. coli adhesion on high-k dielectric bioceramics films using poly(amino acid) multilayers.

    PubMed

    Lawrence, Neil J; Wells-Kingsbury, Jamie M; Ihrig, Marcella M; Fangman, Teresa E; Namavar, Fereydoon; Cheung, Chin Li

    2012-03-06

    The influence of high-k dielectric bioceramics with poly(amino acid) multilayer coatings on the adhesion behavior of Escherichia coli (E. coli) was studied by evaluating the density of bacteria coverage on the surfaces of these materials. A biofilm forming K-12 strain (PHL628), a wild-type strain (JM109), and an engineered strain (XL1-Blue) of E. coli were examined for their adherence to zirconium oxide (ZrO(2)) and tantalum oxide (Ta(2)O(5)) surfaces functionalized with single and multiple layers of poly(amino acid) polyelectrolytes made by the layer-by-layer (LBL) deposition. Two poly(amino acids), poly(l-arginine) (PARG) and poly(l-aspartic acid) (PASP), were chosen for the functionalization schemes. All three strains were found to grow and preferentially adhere to bare bioceramic film surfaces over bare glass slides. The bioceramic and glass surfaces functionalized with positively charged poly(amino acid) top layers were observed to enhance the adhesion of these bacteria by up to 4-fold in terms of bacteria surface coverage. Minimal bacteria coverage was detected on surfaces functionalized with negatively charged poly(amino acid) top layers. The effect of different poly(amino acid) coatings to promote or minimize bacterial adhesion was observed to be drastically enhanced with the bioceramic substrates than with glass. Such observed enhancements were postulated to be attributed to the formation of higher density of poly(amino acids) coatings enabled by the high dielectric strength (k) of these bioceramics. The multilayer poly(amino acid) functionalization scheme was successfully applied to utilize this finding for micropatterning E. coli on bioceramic thin films.

  10. Thermal behavior of the microstructure and the electrical properties of magnetron-sputtered high-k titanium silicate thin films

    NASA Astrophysics Data System (ADS)

    Brassard, D.; El Khakani, M. A.

    2008-06-01

    We report on the high-temperature stability of high-dielectric-constant (high-k) titanium silicate (Ti0.5Si0.5O2) thin films deposited by means of a magnetron sputtering process. We have investigated the effect of substrate deposition temperature Td (in the 20-600°C range) and postdeposition annealing temperature Ta (in the 200-800°C range) on the electrical, microstructural, and optical properties of the films. The Ti-silicate films grown at room temperature were found to exhibit a combination of excellent electrical properties, including a k-value of 16.5, a leakage current as low as 3nA at 1MV/cm, and a dissipation factor tan(δ )<0.01. On the other hand, when the processing temperature (Td or Ta) is ⩾300°C, the leakage current of the films is found to degrade progressively. The x-ray diffraction, Raman spectroscopy, and transmission electron microscopy characterizations have shown that the Ti-silicate films exhibit an amorphous microstructure up to a temperature of about 600°C. For higher temperatures, (i.e., Td of 600°C or a Ta⩾700°C) some anatase TiO2 nanocrystallites (in the 1.5-5nm size range) formation is evidenced. This TiO2 nanocrystallite precipitation results from a thermally induced phase segregation of TiO2-rich and SiO2-rich environments, which is shown to be initiated at rather low processing temperatures. This progressive phase segregation, which leads to the precipitation of a low band gap and leaky TiO2-rich phase in the films, is believed to be at the origin of the observed degradation of the leakage current of the Ti-silicate films with increasing temperatures (Td or Ta).

  11. Electrical properties of HfO2 high- k thin-film MOS capacitors for advanced CMOS technology

    NASA Astrophysics Data System (ADS)

    Khairnar, A. G.; Patil, L. S.; Salunke, R. S.; Mahajan, A. M.

    2015-11-01

    We deposited the hafnium dioxide (HfO2) thin films on p-Si (100) substrates. The thin films were deposited with deposition time variations, viz 2, 4, 7 and 20 min using RF-sputtering technique. The thickness and refractive index of the films were measured using spectroscopic ellipsometer. The thicknesses of the films were measured to be 13.7, 21.9, 35.38 and 92.2 nm and refractive indices of 1.90, 1.93, 1.99 and 1.99, respectively, of the films deposited for 2, 4, 7 and 20 min deposition time. The crystal structures of the deposited HfO2 thin films were determined using XRD spectra and showed the monoclinic structure, confirmed with the ICDD card no 34-0104. Aluminum metallization was carried to form the Al/HfO2/ p-Si MOS structures by using thermal evaporation system with electrode area of 12.56 × 10-4 cm2. Capacitance voltage and current voltage measurements were taken to know electrical behavior of these fabricated MOS structures. The electrical parameters such as dielectric constant, flat-band shift and interface trap density determined through CV measurement were 7.99, 0.11 V and 6.94 × 1011 eV-1 cm-2, respectively. The low leakage current density was obtained from IV measurement of fabricated MOS structure at 1.5 V is 4.85 × 10-10 Acm-2. Aforesaid properties explored the suitability of the fabricated HfO2 high- k-based MOS capacitors for advanced CMOS technology.

  12. 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.

  13. Tunnel FET with non-uniform gate capacitance for improved device and circuit level performance

    NASA Astrophysics Data System (ADS)

    Alper, C.; De Michielis, L.; Dağtekin, N.; Lattanzio, L.; Bouvet, D.; Ionescu, A. M.

    2013-06-01

    We report the significant improvement obtained by a non-uniform gate capacitance made by appropriate combination of high-k and low-k regions over the tunneling and the channel regions of a heterostucture TFET (called HKLKTFET). In addition to significantly enhanced ION and subthreshold swing, we find that this structure offers great improvements for the dynamic switching energy (66% saving) and propagation delay (˜3× fast operation) compared to a heterostructure TFET (HeTFET) due to the reduction of the Miller effect. We compare and benchmark the proposed device against a 65 nm low stand-by power (LSTP) CMOS technology, and we show that at a supply voltage of VDD = 0.4 V, TFETs can have smaller propagation delays compared to CMOS operating in the subthreshold region. Higher cut-off frequency (˜3×) and bandwidth for analog applications is observed in circuit-level simulations.

  14. Controlled Logic Gates-Switch Gate and Fredkin Gate Based on Enzyme-Biocatalyzed Reactions Realized in Flow Cells.

    PubMed

    Fratto, Brian E; Katz, Evgeny

    2016-04-04

    Controlled logic gates, where the logic operations on the Data inputs are performed in the way determined by the Control signal, were designed in a chemical fashion. Specifically, the systems where the Data output signals directed to various output channels depending on the logic value of the Control input signal have been designed based on enzyme biocatalyzed reactions performed in a multi-cell flow system. In the Switch gate one Data signal was directed to one of two possible output channels depending on the logic value of the Control input signal. In the reversible Fredkin gate the routing of two Data signals between two output channels is controlled by the third Control signal. The flow devices were created using a network of flow cells, each modified with one enzyme that biocatalyzed one chemical reaction. The enzymatic cascade was realized by moving the solution from one reacting cell to another which were organized in a specific network. The modular design of the enzyme-based systems realized in the flow device allowed easy reconfiguration of the logic system, thus allowing simple extension of the logic operation from the 2-input/3-output channels in the Switch gate to the 3-input/3-output channels in the Fredkin gate. Further increase of the system complexity for realization of various logic processes is feasible with the use of the flow cell modular design.

  15. 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.

  16. Gallium arsenide processing for gate array logic

    NASA Astrophysics Data System (ADS)

    Cole, Eric D.

    1989-09-01

    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.

  17. Effect of interlayer trapping and detrapping on the determination of interface state densities on high-k dielectric stacks

    NASA Astrophysics Data System (ADS)

    Castán, H.; Dueñas, S.; García, H.; Gómez, A.; Bailón, L.; Toledano-Luque, M.; del Prado, A.; Mártil, I.; González-Díaz, G.

    2010-06-01

    The influence of the silicon nitride blocking layer thickness on the interface state densities (Dit) of HfO2/SiNx:H gate-stacks on n-type silicon have been analyzed. The blocking layer consisted of 3 to 7 nm thick silicon nitride films directly grown on the silicon substrates by electron-cyclotron-resonance assisted chemical-vapor-deposition. Afterwards, 12 nm thick hafnium oxide films were deposited by high-pressure reactive sputtering. Interface state densities were determined by deep-level transient spectroscopy (DLTS) and by the high and low frequency capacitance-voltage (HLCV) method. The HLCV measurements provide interface trap densities in the range of 1011 cm-2 eV-1 for all the samples. However, a significant increase in about two orders of magnitude was obtained by DLTS for the thinnest silicon nitride barrier layers. In this work we probe that this increase is an artifact due to the effect of traps located at the internal interface existing between the HfO2 and SiNx:H films. Because charge trapping and discharging are tunneling assisted, these traps are more easily charged or discharged as lower the distance from this interface to the substrate, that is, as thinner the SiNx:H blocking layer. The trapping/detrapping mechanisms increase the amplitude of the capacitance transient and, in consequence, the DLTS signal that have contributions not only from the insulator/substrate interface states but also from the HfO2/SiNx:H interlayer traps.

  18. 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.

  19. Comparative band alignment of plasma-enhanced atomic layer deposited high-k dielectrics on gallium nitride

    NASA Astrophysics Data System (ADS)

    Yang, Jialing; Eller, Brianna S.; Zhu, Chiyu; England, Chris; Nemanich, Robert J.

    2012-09-01

    Al2O3 films, HfO2 films, and HfO2/Al2O3 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 H2/N2 plasma at 650 °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 °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 °C. The valence band and conduction band offsets (VBOs and CBOs) of the Al2O3/GaN and HfO2/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 Al2O3 layer was investigated as an interfacial passivation layer (IPL), which, as results suggest, may lead to improved stability, performance, and reliability of HfO2/IPL/GaN structures. The VBOs were ˜0.1 and 1.3 eV, while the deduced CBOs were 0.6 and 1.1 eV for HfO2 with respect to Al2O3 and GaN, respectively.

  20. Noisy signaling through promoter logic gates

    NASA Astrophysics Data System (ADS)

    Gerstung, Moritz; Timmer, Jens; Fleck, Christian

    2009-01-01

    We study the influence of noisy transcription factor signals on cis-regulatory promoter elements. These elements process the probability of binary binding events analogous to computer logic gates. At equilibrium, this probability is given by the so-called input function. We show that transcription factor noise causes deviations from the equilibrium value due to the nonlinearity of the input function. For a single binding site, the correction is always negative resulting in an occupancy below the mean-field level. Yet for more complex promoters it depends on the correlation of the transcription factor signals and the geometry of the input function. We present explicit solutions for the basic types of AND and OR gates. The correction size varies among these different types of gates and signal types, mainly being larger in AND gates and for correlated fluctuations. In all cases we find excellent agreement between the analytical results and numerical simulations. We also study the E. coli Lac operon as an example of an AND NOR gate. We present a consistent mathematical method that allows one to separate different sources of noise and quantifies their effect on promoter occupation. A surprising result of our analysis is that Poissonian molecular fluctuations, in contrast to external fluctuations, do no contribute to the correction.

  1. Ion-dependent gating of kainate receptors.

    PubMed

    Bowie, Derek

    2010-01-01

    Ligand-gated ion channels are an important class of signalling protein that depend on small chemical neurotransmitters such as acetylcholine, l-glutamate, glycine and gamma-aminobutyrate for activation. Although numerous in number, neurotransmitter substances have always been thought to drive the receptor complex into the open state in much the same way and not rely substantially on other factors. However, recent work on kainate-type (KAR) ionotropic glutamate receptors (iGluRs) has identified an exception to this rule. Here, the activation process fails to occur unless external monovalent anions and cations are present. This absolute requirement of ions singles out KARs from all other ligand-gated ion channels, including closely related AMPA- and NMDA-type iGluR family members. The uniqueness of ion-dependent gating has earmarked this feature of KARs as a putative target for the development of selective ligands; a prospect all the more compelling with the recent elucidation of distinct anion and cation binding pockets. Despite these advances, much remains to be resolved. For example, it is still not clear how ion effects on KARs impacts glutamatergic transmission. I conclude by speculating that further analysis of ion-dependent gating may provide clues into how functionally diverse iGluRs families emerged by evolution. Consequently, ion-dependent gating of KARs looks set to continue to be a subject of topical inquiry well into the future.

  2. Hydraulics characteristics of tipping sediment flushing gate.

    PubMed

    Bong, C H J; Lau, T L; Ab Ghani, A

    2013-01-01

    This paper highlights a preliminary study on the potential of a tipping flush gate to be used in an open storm drain to remove sediment. The investigation was carried out by using a plasboard model of the tipping flush gate installed in a rectangular flume. A steady flow experiment was carried out to determine the discharge coefficients and also the outflow relationship of the tipping flush gate. The velocity produced by the gate at various distances downstream of the gate during flushing operation was measured using a flowmeter and the velocity at all the points was higher than the recommended self-cleansing design available in the literature. A preliminary experiment on the efficiency of flushing was conducted using uniform sediment with d50 sizes of 0.81, 1.53 and 4.78 mm. Results generally showed that the number of flushes required to totally remove the sediment from the initial position by a distance of 1 m increased by an average of 1.50 times as the sediment deposit bed thickness doubled. An equation relating the number of flushes required to totally remove the sediment bed for 1 m with the sediment bed deposit thickness was also developed for the current study.

  3. 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.

  4. Transversal Clifford gates on folded surface codes

    SciTech Connect

    Moussa, Jonathan E.

    2016-10-12

    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. Lastly, the specific application of these codes to universal quantum computation based on qubit fusion is also discussed.

  5. Transversal Clifford gates on folded surface codes

    DOE PAGES

    Moussa, Jonathan E.

    2016-10-12

    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 surfacemore » 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. Lastly, the specific application of these codes to universal quantum computation based on qubit fusion is also discussed.« less

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. Coupling between Voltage Sensors and Activation Gate in Voltage-gated K+ Channels

    PubMed Central

    Lu, Zhe; Klem, Angela M.; Ramu, Yajamana

    2002-01-01

    Current through voltage-gated K+ channels underlies the action potential encoding the electrical signal in excitable cells. The four subunits of a voltage-gated K+ channel each have six transmembrane segments (S1–S6), whereas some other K+ channels, such as eukaryotic inward rectifier K+ channels and the prokaryotic KcsA channel, have only two transmembrane segments (M1 and M2). A voltage-gated K+ channel is formed by an ion-pore module (S5–S6, equivalent to M1–M2) and the surrounding voltage-sensing modules. The S4 segments are the primary voltage sensors while the intracellular activation gate is located near the COOH-terminal end of S6, although the coupling mechanism between them remains unknown. In the present study, we found that two short, complementary sequences in voltage-gated K+ channels are essential for coupling the voltage sensors to the intracellular activation gate. One sequence is the so called S4–S5 linker distal to the voltage-sensing S4, while the other is around the COOH-terminal end of S6, a region containing the actual gate-forming residues. PMID:12407078

  13. Lipid-dependent gating of a voltage-gated potassium channel

    PubMed Central

    Zheng, Hui; Liu, Weiran; Anderson, Lingyan Y.; Jiang, Qiu-Xing

    2011-01-01

    Recent studies hypothesized that phospholipids stabilize two voltage-sensing arginine residues of certain voltage-gated potassium channels in activated conformations. It remains unclear how lipids directly affect these channels. Here, by examining the conformations of the KvAP in different lipids, we showed that without voltage change, the voltage-sensor domains switched from the activated to the resting state when their surrounding lipids were changed from phospholipids to nonphospholipids. Such lipid-determined conformational change was coupled to the ion-conducting pore, suggesting that parallel to voltage gating, the channel is gated by its annular lipids. Our measurements recognized that the energetic cost of lipid-dependent gating approaches that of voltage gating, but kinetically it appears much slower. Our data support that a channel and its surrounding lipids together constitute a functional unit, and natural nonphospholipids such as cholesterol should exert strong effects on voltage-gated channels. Our first observation of lipid-dependent gating may have general implications to other membrane proteins. PMID:21427721

  14. Ultralow turnoff loss dual-gate SOI LIGBT with trench gate barrier and carrier stored layer

    NASA Astrophysics Data System (ADS)

    He, Yi-Tao; Qiao, Ming; Zhang, Bo

    2016-12-01

    A novel ultralow turnoff loss dual-gate silicon-on-insulator (SOI) lateral insulated gate bipolar transistor (LIGBT) is proposed. The proposed SOI LIGBT features an extra trench gate inserted between the p-well and n-drift, and an n-type carrier stored (CS) layer beneath the p-well. In the on-state, the extra trench gate acts as a barrier, which increases the carrier density at the cathode side of n-drift region, resulting in a decrease of the on-state voltage drop (Von). In the off-state, due to the uniform carrier distribution and the assisted depletion effect induced by the extra trench gate, large number of carriers can be removed at the initial turnoff process, contributing to a low turnoff loss (Eoff). Moreover, owing to the dual-gate field plates and CS layer, the carrier density beneath the p-well can greatly increase, which further improves the tradeoff between Eoff and Von. Simulation results show that Eoff of the proposed SOI LIGBT can decrease by 77% compared with the conventional trench gate SOI LIGBT at the same Von of 1.1 V. Project supported by the National Natural Science Foundation of China (Grant Nos. 61376080 and 61674027) and the Natural Science Foundation of Guangdong Province, China (Grant Nos. 2014A030313736 and 2016A030311022).

  15. Broadening of Distribution of Trap States in PbS Quantum Dot Field-Effect Transistors with High-k Dielectrics

    PubMed Central

    2017-01-01

    We perform a quantitative analysis of the trap density of states (trap DOS) in PbS quantum dot field-effect transistors (QD-FETs), which utilize several polymer gate insulators with a wide range of dielectric constants. With increasing gate dielectric constant, we observe increasing trap DOS close to the lowest unoccupied molecular orbital (LUMO) of the QDs. In addition, this increase is also consistently followed by broadening of the trap DOS. We rationalize that the increase and broadening of the spectral trap distribution originate from dipolar disorder as well as polaronic interactions, which are appearing at strong dielectric polarization. Interestingly, the increased polaron-induced traps do not show any negative effect on the charge carrier mobility in our QD devices at the highest applied gate voltage, giving the possibility to fabricate efficient low-voltage QD devices without suppressing carrier transport. PMID:28084725

  16. Broadening of Distribution of Trap States in PbS Quantum Dot Field-Effect Transistors with High-k Dielectrics.

    PubMed

    Nugraha, Mohamad I; Häusermann, Roger; Watanabe, Shun; Matsui, Hiroyuki; Sytnyk, Mykhailo; Heiss, Wolfgang; Takeya, Jun; Loi, Maria A

    2017-02-08

    We perform a quantitative analysis of the trap density of states (trap DOS) in PbS quantum dot field-effect transistors (QD-FETs), which utilize several polymer gate insulators with a wide range of dielectric constants. With increasing gate dielectric constant, we observe increasing trap DOS close to the lowest unoccupied molecular orbital (LUMO) of the QDs. In addition, this increase is also consistently followed by broadening of the trap DOS. We rationalize that the increase and broadening of the spectral trap distribution originate from dipolar disorder as well as polaronic interactions, which are appearing at strong dielectric polarization. Interestingly, the increased polaron-induced traps do not show any negative effect on the charge carrier mobility in our QD devices at the highest applied gate voltage, giving the possibility to fabricate efficient low-voltage QD devices without suppressing carrier transport.

  17. Optimizing the fast Rydberg quantum gate

    SciTech Connect

    Safronova, M.S.; Williams, Carl J.; Clark, Charles W.

    2003-04-01

    The fast phase gate scheme, in which the qubits are atoms confined in sites of an optical lattice, and gate operations are mediated by excitation of Rydberg states, was proposed by Jaksch et al. [Phys. Rev. Lett. 85, 2208 (2000)]. A potential source of decoherence in this system derives from motional heating, which occurs if the ground and Rydberg states of the atom move in different optical lattice potentials. We propose to minimize this effect by choosing the lattice photon frequency {omega}, so that the ground and Rydberg states have the same frequency-dependent polarizability {alpha}({omega}). The results are presented for the case of Rb.

  18. 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.

  19. Fidelity of adiabatic holonomic quantum gates

    NASA Astrophysics Data System (ADS)

    Malinovsky, Vladimir; Rudin, Sergey

    2016-05-01

    During last few years non-Abelian geometric phases are attracting increasing interest due to possible experimental applications in quantum computation. Here we discuss universal set of holonomic quantum gates using the geometric phase that the qubit wave function acquires after a cyclic evolution. The proposed scheme utilizes ultrafast pulses and provides a possibility to substantially suppress transient population of the ancillary states. Fidelity of the holonomic quantum gates in the presence of dephasing and dissipation is discussed. Example of electron spin qubit system in the InGaN/GaN, GaN/AlN quantum dot is considered in details.

  20. 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.

  1. 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.

  2. 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.

  3. Gate dependent electronic Raman scattering in graphene

    NASA Astrophysics Data System (ADS)

    Riccardi, E.; Méasson, M.-A.; Kazayous, M.; Sacuto, A.; Gallais, Y.; Spectroscopy Of Quasi-Particles (Squap) Team

    We report the direct observation of polarization resolved electronic Raman scattering in a gated monolayer graphene device. The evolution of the electronic Raman scattering spectra with gate voltage and its polarization dependence are in full agreement with theoretical expectations for non-resonant Raman processes involving interband electron-hole excitations across the Dirac cone. We further show that the spectral dependence of the electronic Raman scattering signal can be simply described by the dynamical polarizability of graphene in the long wavelength limit. The possibility to directly observe Dirac fermion excitations in graphene opens the way to promising Raman investigations of electronic properties of graphene and other 2D materials.

  4. Gate dependent electronic Raman scattering in graphene

    NASA Astrophysics Data System (ADS)

    Riccardi, E.; Méasson, M.-A.; Kazayous, M.; Sacuto, A.; Gallais, Y.; Spectroscopy Of Quasi-Particles (Squap) Team

    We report the direct observation of polarization resolved electronic Raman scattering in a gated monolayer graphene device. The evolution of the electronic Raman scattering spectra with gate voltage and its polarization dependence are in full agreement with theoretical expectations for non-resonant Raman processes involving interband electron-hole excitations across the Dirac cone [1]. We further show that the spectral dependence of the electronic Raman scattering signal can be simply described by the dynamical polarizability of graphene in the long wavelength limit [2]. The possibility to directly observe Dirac fermion excitations in graphene opens the way to promising Raman investigations of electronic properties of graphene and other 2D materials.

  5. Ultrafast quantum gates in circuit QED.

    PubMed

    Romero, G; Ballester, D; Wang, Y M; Scarani, V; Solano, E

    2012-03-23

    We present a method to implement ultrafast two-qubit gates valid for the ultrastrong coupling and deep strong coupling regimes of light-matter interaction, considering state-of-the-art circuit quantum electrodynamics technology. Our proposal includes a suitable qubit architecture and is based on a four-step sequential displacement of the intracavity field, operating at a time proportional to the inverse of the resonator frequency. Through ab initio calculations, we show that these quantum gates can be performed at subnanosecond time scales while keeping a fidelity above 99%.

  6. Gate-Controlled WSe2 Transistors Using a Buried Triple-Gate Structure

    NASA Astrophysics Data System (ADS)

    Müller, M. R.; Salazar, R.; Fathipour, S.; Xu, H.; Kallis, K.; Künzelmann, U.; Seabaugh, A.; Appenzeller, J.; Knoch, J.

    2016-11-01

    In the present paper, we show tungsten diselenide (WSe2) devices that can be tuned to operate as n-type and p-type field-effect transistors (FETs) as well as band-to-band tunnel transistors on the same flake. Source, channel, and drain areas of the WSe2 flake are adjusted, using buried triple-gate substrates with three independently controllable gates. The device characteristics found in the tunnel transistor configuration are determined by the particular geometry of the buried triple-gate structure, consistent with a simple estimation of the expected off-state behavior.

  7. Determination of prospective displacement-based gate threshold for respiratory-gated radiation delivery from retrospective phase-based gate threshold selected at 4D CT simulation

    SciTech Connect

    Vedam, S.; Archambault, L.; Starkschall, G.; Mohan, R.; Beddar, S.

    2007-11-15

    Four-dimensional (4D) computed tomography (CT) imaging has found increasing importance in the localization of tumor and surrounding normal structures throughout the respiratory cycle. Based on such tumor motion information, it is possible to identify the appropriate phase interval for respiratory gated treatment planning and delivery. Such a gating phase interval is determined retrospectively based on tumor motion from internal tumor displacement. However, respiratory-gated treatment is delivered prospectively based on motion determined predominantly from an external monitor. Therefore, the simulation gate threshold determined from the retrospective phase interval selected for gating at 4D CT simulation may not correspond to the delivery gate threshold that is determined from the prospective external monitor displacement at treatment delivery. The purpose of the present work is to establish a relationship between the thresholds for respiratory gating determined at CT simulation and treatment delivery, respectively. One hundred fifty external respiratory motion traces, from 90 patients, with and without audio-visual biofeedback, are analyzed. Two respiratory phase intervals, 40%-60% and 30%-70%, are chosen for respiratory gating from the 4D CT-derived tumor motion trajectory. From residual tumor displacements within each such gating phase interval, a simulation gate threshold is defined based on (a) the average and (b) the maximum respiratory displacement within the phase interval. The duty cycle for prospective gated delivery is estimated from the proportion of external monitor displacement data points within both the selected phase interval and the simulation gate threshold. The delivery gate threshold is then determined iteratively to match the above determined duty cycle. The magnitude of the difference between such gate thresholds determined at simulation and treatment delivery is quantified in each case. Phantom motion tests yielded coincidence of simulation

  8. 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

  9. 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

  10. 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

  11. 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

  12. Improved Classical Simulation of Quantum Circuits Dominated by Clifford Gates.

    PubMed

    Bravyi, Sergey; Gosset, David

    2016-06-24

    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.

  13. 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

  14. Washington Water Power Spokane River Upper Falls Hydroelectric Development, Gates ...

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

    Washington Water Power Spokane River Upper Falls Hydroelectric Development, Gates & Gate-Lifting Mechanisms, Spokane River, approximately 0.5 mile northeast of intersection of Spokane Falls Boulevard & Post Street, Spokane, Spokane County, WA

  15. Micromachined mold-type double-gated metal field emitters

    NASA Astrophysics Data System (ADS)

    Lee, Yongjae; Kang, Seokho; Chun, Kukjin

    1997-12-01

    Electron field emitters with double gates were fabricated using micromachining technology and the effect of the electric potential of the focusing gate (or second gate) was experimentally evaluated. The molybdenum field emission tip was made by filling a cusplike mold formed when a conformal film was deposited on the hole-trench that had been patterned on stacked metals and dielectric layers. The hole-trench was patterned by electron beam lithography and reactive ion etching. Each field emitter has a 0960-1317/7/4/009/img1 diameter extraction gate (or first gate) and a 0960-1317/7/4/009/img2 diameter focusing gate (or second gate). To make a path for the emitted electrons, silicon bulk was etched anisotropically in KOH and EDP (ethylene-diamine pyrocatechol) solution successively. The I - V characteristics and anode current change due to the focusing gate potential were measured.

  16. 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

  17. 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

  18. 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

  19. 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

  20. 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

  1. 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

  2. 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

  3. 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

  4. 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

  5. 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

  6. 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

  7. 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

  8. 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

  9. 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

  10. 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

  11. 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

  12. 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

  13. 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

  14. Corticostriatal output gating during selection from working memory.

    PubMed

    Chatham, Christopher H; Frank, Michael J; Badre, David

    2014-02-19

    Convergent evidence suggests that corticostriatal interactions act as a gate to select the input to working memory (WM). However, not all information in WM is relevant for behavior simultaneously. For this reason, a second "output gate" might advantageously govern which contents of WM influence behavior. Here, we test whether frontostriatal circuits previously implicated in input gating also support output gating during selection from WM. fMRI of a hierarchical rule task with dissociable input and output gating demands demonstrated greater lateral prefrontal cortex (PFC) recruitment and frontostriatal connectivity during output gating. Moreover, PFC and striatum correlated with distinct behavioral profiles. Whereas PFC recruitment correlated with mean efficiency of selection from WM, striatal recruitment and frontostriatal interactions correlated with its reliability, as though such dynamics stochastically gate WM's output. These results support the output gating hypothesis, suggesting that contextual representations in PFC influence striatum to select which information in WM drives responding.

  15. Reliability study of refractory gate gallium arsenide MESFETS

    NASA Technical Reports Server (NTRS)

    Yin, J. C. W.; Portnoy, W. M.

    1981-01-01

    Refractory gate MESFET's were fabricated as an alternative to aluminum gate devices, which have been found to be unreliable as RF power amplifiers. In order to determine the reliability of the new structures, statistics of failure and information about mechanisms of failure in refractory gate MESFET's are given. Test transistors were stressed under conditions of high temperature and forward gate current to enhance failure. Results of work at 150 C and 275 C are reported.

  16. Learning robust pulses for generating universal quantum gates

    NASA Astrophysics Data System (ADS)

    Dong, Daoyi; Wu, Chengzhi; Chen, Chunlin; Qi, Bo; Petersen, Ian R.; Nori, Franco

    2016-10-01

    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.

  17. 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

  18. Intracellular calcium oscillations in strongly metastatic human breast and prostate cancer cells: control by voltage-gated sodium channel activity.

    PubMed

    Rizaner, Nahit; Onkal, Rustem; Fraser, Scott P; Pristerá, Alessandro; Okuse, Kenji; Djamgoz, Mustafa B A

    2016-10-01

    The possible association of intracellular Ca(2+) with metastasis in human cancer cells is poorly understood. We have studied Ca(2+) signaling in human prostate and breast cancer cell lines of strongly versus weakly metastatic potential in a comparative approach. Intracellular free Ca(2+) was measured using a membrane-permeant fluorescent Ca(2+)-indicator dye (Fluo-4 AM) and confocal microscopy. Spontaneous Ca(2+) oscillations were observed in a proportion of strongly metastatic human prostate and breast cancer cells (PC-3M and MDA-MB-231, respectively). In contrast, no such oscillations were observed in weakly/non metastatic LNCaP and MCF-7 cells, although a rise in the resting Ca(2+) level could be induced by applying a high-K(+) solution. Various parameters of the oscillations depended on extracellular Ca(2+) and voltage-gated Na(+) channel activity. Treatment with either tetrodotoxin (a general blocker of voltage-gated Na(+) channels) or ranolazine (a blocker of the persistent component of the channel current) suppressed the Ca(2+) oscillations. It is concluded that the functional voltage-gated Na(+) channel expression in strongly metastatic cancer cells makes a significant contribution to generation of oscillatory intracellular Ca(2+) activity. Possible mechanisms and consequences of the Ca(2+) oscillations are discussed.

  19. 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.

  20. Protected gates for topological quantum field theories

    NASA Astrophysics Data System (ADS)

    Koenig, Robert

    2015-03-01

    We give restrictions on the locality-preserving unitary automorphisms U, which are protected gates, for topologically ordered systems. For arbitrary anyon models, we show that such unitaries only generate a finite group, and hence do not provide universality. For abelian anyon models, we find that the logical action of U is contained in a proper subgroup of the generalized Clifford group. In the case D(?2), which describes Kitaev's toric code, this represents a tightening of statement previously obtained within the stabilizer framework (PRL 110:170503). For non-abelian models, we find that such automorphisms are very limited: for example, there is no non-trivial gate for Fibonacci anyons. For Ising anyons, protected gates are elements of the Pauli group. These results are derived by relating such automorphisms to symmetries of the underlying anyon model: protected gates realize automorphisms of the Verlinde algebra. We additionally use the compatibility with basis changes to characterize the logical action. This is joint work with M. Beverland, F. Pastawski, J. Preskill and S. Sijher.

  1. 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).

  2. 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…

  3. 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…

  4. 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.

  5. Penumbras of Care beyond the Schoolhouse Gate.

    ERIC Educational Resources Information Center

    Hagenau, W. Paul

    1980-01-01

    Examines the responsibility of care owed to students by the school when the student is off the school premises. Concludes that prudent administrators must never presume that students automatically shed the protective mantle of the school's duty of care when they leave the schoolhouse gate. (Author/IRT)

  6. Capacitance modeling of gate material engineered cylindrical/surrounded gate MOSFETs for sensor applications

    NASA Astrophysics Data System (ADS)

    Verma, Jay Hind Kumar; Pratap, Yogesh; Haldar, Subhasis; Gupta, R. S.; Gupta, Mridula

    2015-12-01

    This paper presents charge based analytical drain current and capacitance model of material engineered Cylindrical/Surrounded Gate (CGT/SGT) MOSFET with nanogap cavity region for sensor applications. Material engineered i.e. dual material gate provides improvement in Short Channel Effects (SCEs) and cylindrical shape nanogap cavity region is used for sensing of biomolecule strength. The material engineered CGT/SGT MOSFET sensor electrically detect the targeted biomolecules of different strength by change in drain current and gate capacitance. Analysis has been carried out by using unified charge control based model derived from Poisson's equation. It is shown that sensitivity of changing biomolecules strength is more in gate capacitance than the drain current. The results so obtained are in good agreement with the 3D simulated data which validate the model.

  7. 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

  8. 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

  9. 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... unloading shaft conveyances....

  10. 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... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Personnel Hoisting Shafts § 56.19100 Shaft landing gates. Shaft landings shall be equipped with substantial safety gates...

  11. 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...

  12. 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...

  13. 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...

  14. 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...

  15. Rapidly Reconfigurable All-Optical Universal Logic Gates

    SciTech Connect

    Goddard, L L; Kallman, J S; Bond, T C

    2006-06-21

    We present designs and simulations for a highly cascadable, rapidly reconfigurable, all-optical, universal logic gate. We will discuss the gate's expected performance, e.g. speed, fanout, and contrast ratio, as a function of the device layout and biasing conditions. The gate is a three terminal on-chip device that consists of: (1) the input optical port, (2) the gate selection port, and (3) the output optical port. The device can be built monolithically using a standard multiple quantum well graded index separate confinement heterostructure laser configuration. The gate can be rapidly and repeatedly reprogrammed to perform any of the basic digital logic operations by using an appropriate analog electrical or optical signal at the gate selection port. Specifically, the same gate can be selected to execute one of the 2 basic unary operations (NOT or COPY), or one of the 6 binary operations (OR, XOR, AND, NOR, XNOR, or NAND), or one of the many logic operations involving more than two inputs. The speed of the gate for logic operations as well as for reprogramming the function of the gate is primarily limited to the small signal modulation speed of a laser, which can be on the order of tens of GHz. The reprogrammable nature of the universal gate offers maximum flexibility and interchangeability for the end user since the entire application of a photonic integrated circuit built from cascaded universal logic gates can be changed simply by adjusting the gate selection port signals.

  16. 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...

  17. High-fidelity gates in quantum dot spin qubits

    PubMed Central

    Koh, Teck Seng; Coppersmith, S. N.; Friesen, Mark

    2013-01-01

    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 ϵ, 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 that is universal for different types of gates. Next, we identify physical constraints on the control parameters; this yields an upper bound that is specific to the qubit-gate combination. We show that similar gate fidelities 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. PMID:24255105

  18. Hafnium dioxide gate dielectrics, metal gate electrodes, and phenomena occurring at their interfaces

    NASA Astrophysics Data System (ADS)

    Schaeffer, James Kenyon, III

    As metal-oxide-semiconductor field-effect transistor (MOSFET) gate lengths scale down below 45 nm, the gate oxide thickness approaches 1 nm equivalent oxide thickness. At this thickness, conventional silicon dioxide (SiO 2) gate dielectrics suffer from excessive gate leakage. Higher permittivity dielectrics are required to counter the increase in gate leakage. Hafnium dioxide (HfO2) has emerged as a promising dielectric candidate. HfO2 films deposited using metal organic chemical vapor deposition are being studied to determine the impact of process and annealing conditions on the physical and electrical properties of the gate dielectric. This study indicates that deposition and annealing temperatures influence the microstructure, density, impurity concentration, chemical environment of the impurities, and band-gap of the HfO2 dielectric. Correlations of the electrical and physical properties of the films indicate that impurities in the form of segregated carbon clusters, and low HfO2 density are detrimental to the leakage properties of the gate dielectric. Additionally, as the HfO2 thickness scales, the additional series capacitance due to poly-silicon depletion plays a larger roll in reducing the total gate capacitance. To solve this problem, high performance bulk MOSFETs will require dual metal gate electrodes possessing work functions near the silicon band edges for optimized drive current. This investigation evaluates TiN, Ta-Si-N, Ti-Al-N, WN, TaN, TaSi, Ir and IrO2 electrodes as candidate electrodes on HfO2 dielectrics. The metal-dielectric compatibility was studied by annealing the gate stacks at different temperatures. The physical stability and effective work functions of metal electrodes on HfO2 are discussed. Finally, Fermi level pinning of the metal is a barrier to identifying materials with appropriate threshold voltages. The contributions to the Fermi level pinning of platinum electrodes on HfO2 gate dielectrics are investigated by examining the

  19. Gating current harmonics. III. Dynamic transients and steady states with intact sodium inactivation gating.

    PubMed Central

    Fohlmeister, J F; Adelman, W J

    1986-01-01

    Internally perfused squid giant axons with intact sodium inactivation gating were prepared for gating current experiments. Gating current records were obtained in sinusoidally driven dynamic steady states and as dynamic transients as functions of the mean membrane potential and the frequency of the command sinusoid. Controls were obtained after internal protease treatment of the axons that fully removed inactivation. The nonlinear analysis consisted of determining and interpreting the harmonic content in the current records. The results indicate the presence of three kinetic processes, two of which are associated with activation gating (the so-called primary and secondary processes), and the third with inactivation gating. The dynamic steady state data show that inactivation gating does not contribute a component to the gating current, and has no direct voltage-dependence of its own. Rather, the inactivation kinetics appear to be coupled to the primary activation kinetics, and the coupling mechanism appears to be one of reciprocal steric hindrance between two molecular components. The mechanism allows the channel to become inactivated without first entering the conducting state, and will do so in about 40 percent of depolarizing voltage-clamp steps to 0 mV. The derived model kinetics further indicate that the conducting state may flicker between open and closed with the lifetime of either state being 10 microseconds. Dynamic transients generated by the model kinetics (i.e., the behavior of the harmonic components as a function of time after an instantaneous change in the mean membrane potential from a holding potential of -80 mV) match the experimental dynamic transients in all details. These transients have a duration of 7-10 ms (depending on the level of depolarization), and are the result of the developing inactivation following the discontinuous voltage change. A detailed hypothetical molecular model of the channel and gating machinery is presented. PMID

  20. Allosteric gating mechanism underlies the flexible gating of KCNQ1 potassium channels.

    PubMed

    Osteen, Jeremiah D; Barro-Soria, Rene; Robey, Seth; Sampson, Kevin J; Kass, Robert S; Larsson, H Peter

    2012-05-01

    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.

  1. Gating motions in voltage-gated potassium channels revealed by coarse-grained molecular dynamics simulations.

    PubMed

    Treptow, Werner; Marrink, Siewert-J; Tarek, Mounir

    2008-03-20

    Voltage-gated potassium (Kv) channels are ubiquitous transmembrane proteins involved in electric signaling of excitable tissues. A fundamental property of these channels is the ability to open or close in response to changes in the membrane potential. To date, their structure-based activation mechanism remains unclear, and there is a large controversy on how these gates function at the molecular level, in particular, how movements of the voltage sensor domain are coupled to channel gating. So far, all mechanisms proposed for this coupling are based on the crystal structure of the open voltage-gated Kv1.2 channel and structural models of the closed form based on electrophysiology experiments. Here, we use coarse-grain (CG) molecular dynamics simulations that allow conformational changes from the open to the closed form of the channel (embedded in its membrane environment) to be followed. Despite the low specificity of the CG force field, the obtained closed structure satisfies several experimental constraints. The overall results suggest a gating mechanism in which a lateral displacement the S4-S5 linker leads to a closing of the gate. Only a small up-down movement of the S4 helices is noticed. Additionally, the study suggests a peculiar upward motion of the intracellular tetramerization domain of the channel, hence providing a molecular view on how this domain may further regulate conduction in Kv channels.

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. 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.

  7. From surface to volume plasmons in hyperbolic metamaterials: General existence conditions for bulk high-k waves in metal-dielectric and graphene-dielectric multilayers

    NASA Astrophysics Data System (ADS)

    Zhukovsky, Sergei V.; Andryieuski, Andrei; Sipe, J. E.; Lavrinenko, Andrei V.

    2014-10-01

    We theoretically investigate general existence conditions for broadband bulk large-wave-vector (high-k) propagating waves (such as volume plasmon polaritons in hyperbolic metamaterials) in subwavelength periodic multilayer structures. Describing the elementary excitation in the unit cell of the structure by a generalized resonance pole of a reflection coefficient and using Bloch's theorem, we derive analytical expressions for the band of large-wave-vector propagating solutions. We apply our formalism to determine the high-k band existence in two important cases: the well-known metal-dielectric and recently introduced graphene-dielectric stacks. We confirm that short-range surface plasmons in thin metal layers can give rise to hyperbolic metamaterial properties and demonstrate that long-range surface plasmons cannot. We also show that graphene-dielectric multilayers tend to support high-k waves and explore the range of parameteres for which this is possible, confirming the prospects of using graphene for materials with hyperbolic dispersion. The approach is applicable to a large variety of structures, such as continuous or structured microwave, terahertz, and optical metamaterials.

  8. Mechanism of cell swelling of HeLa cells in an isosmotic Na(+)-free, high-K+ medium: study on the K+ transport pathways.

    PubMed

    Kaku, M; Ikehara, T; Yamaguchi, H

    1992-06-01

    The K+ content and the free Ca2+ concentration ([Ca2+]c) in HeLa cells began to increase after a latent period following medium change to an isosmotic Na(+)-free, high-K+ medium in the presence of 10-100 microM ouabain. These increases were accompanied by cell swelling, and stimulated by the addition of 1 microM ionomycin, whereas treatment with 1 mM quinine significantly inhibited the net K+ uptake. [Ca2+]c was slightly decreased, but the K+ uptake was unaffected in the Ca(2+)-free, high-K+ medium. However, when [Ca2+]c was extremely reduced by preloading 5 microM BAPTA-AM, the K+ uptake decreased to a level attained in the presence of quinine. Addition of DIDS and substitution with NO3- or SCN- for medium Cl- inhibited the K+ uptake to similar extents, and their effects were less strong than that of quinine. Substitution of medium Cl- with an impermeable anion gluconate completely inhibited the K+ uptake. Therefore, we conclude that cell swelling in the high-K+ medium is associated with K+ uptake mediated in greater part by quinine-sensitive and in smaller part by -insensitive pathway. The former pathway depends on cellular Ca2+ and its major component is Cl(-)-dependent, whereas the latter is independent of the Ca2+ and unselective for anions.

  9. Free-exciton states in crystalline GaTe

    NASA Astrophysics Data System (ADS)

    Wan, J. Z.; Brebner, J. L.; Leonelli, R.

    1995-12-01

    Polarized properties of both the singlet and triplet ground exciton states in the photoluminescence and transmission spectra of crystalline GaTe are explained based on the possible symmetry properties of the energy band edge of GaTe. Some experimental results about excited exciton states in GaTe are presented and discussed. The energy positions of exciton series in GaTe follow the three-dimensional direct allowed Wannier exciton formula just as in the the other III-VI layered compounds of GaSe and InSe. The nonthermalized, ``hot'' nature of excitons inside GaTe under higher optical excitation intensities is also discussed.

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. 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

  15. Optimized pulse shapes for a resonator-induced phase gate

    NASA Astrophysics Data System (ADS)

    Cross, Andrew W.; Gambetta, Jay M.

    2015-03-01

    The resonator-induced phase gate is a multiqubit controlled-phase gate for fixed-frequency superconducting qubits. Through off-resonant driving of a bus resonator, statically coupled qubits acquire a state-dependent phase. However, photon loss leads to dephasing during the gate, and any residual entanglement between the resonator and qubits after the gate leads to decoherence. Here we consider how to shape the drive pulse to minimize these unwanted effects. First, we review how the gate's entangling and dephasing rates depend on the system parameters and validate closed-form solutions against direct numerical solution of a master equation. Next, we propose spline pulse shapes that reduce residual qubit-bus entanglement, are robust to imprecise knowledge of the resonator shift, and can be shortened by using higher-degree polynomials. Finally, we present a procedure that optimizes over the subspace of pulses that leave the resonator unpopulated. This finds shaped drive pulses that further reduce the gate duration. Assuming realistic parameters, we exhibit shaped pulses that have the potential to realize ˜212 ns spline pulse gates and ˜120 ns optimized gates with ˜6 ×10-4 average gate infidelity. These examples do not represent fundamental limits of the gate and, in principle, even shorter gates may be achievable.

  16. Quasi-specific access of the potassium channel inactivation gate.

    PubMed

    Venkataraman, Gaurav; Srikumar, Deepa; Holmgren, Miguel

    2014-06-09

    Many voltage-gated potassium channels open in response to membrane depolarization and then inactivate within milliseconds. Neurons use these channels to tune their excitability. In Shaker K(+) channels, inactivation is caused by the cytoplasmic amino terminus, termed the inactivation gate. Despite having four such gates, inactivation is caused by the movement of a single gate into a position that occludes ion permeation. The pathway that this single inactivation gate takes into its inactivating position remains unknown. Here we show that a single gate threads through the intracellular entryway of its own subunit, but the tip of the gate has sufficient freedom to interact with all four subunits deep in the pore, and does so with equal probability. This pathway demonstrates that flexibility afforded by the inactivation peptide segment at the tip of the N-terminus is used to mediate function.

  17. Local Ambipolar Graphene Field Effect Transistors via Metal Side Gates

    NASA Astrophysics Data System (ADS)

    Tian, Jifa; Jauregui, Luis; Lopez, Gabriel; Cao, Helin; Chen, Yong

    2010-03-01

    We fabricated local graphene field effect transistors (FET) based on metal side gates. The characteristic ambipolar field effect of graphene device was observed by sweeping only the voltage of a local metal side gate. The local charge neutrality point of the side-gate graphene FET can be tuned in a large voltage range from positive to negative by a second side gate. Furthermore, we observed that the field effect due to the side gate can be appreciably weakened by electrically grounding the back gate compared to floating the back gate. The experimental results can be well explained by electrostatic simulation using COMSOL. Our technique offers a simple method for local tuning of charge density of graphene nanodevices while avoiding coating graphene surface with dielectrics, which may cause contamination and degradation of graphene.

  18. Nonadiabatic holonomic gates realized by a single-shot implementation

    NASA Astrophysics Data System (ADS)

    Xu, G. F.; Liu, C. L.; Zhao, P. Z.; Tong, D. M.

    2015-11-01

    Nonadiabatic holonomic quantum computation has received increasing attention due to its robustness against control errors. However, all the previous schemes have to use at least two sequentially implemented gates to realize a general one-qubit gate. In this paper we put forward a scheme by which one can directly realize an arbitrary holonomic one-qubit gate with a single-shot implementation, avoiding the extra work of combining two gates into one. Based on a three-level model driven by laser pulses, we show that any single-qubit holonomic gate can be realized by varying the detuning, amplitude, and phase of lasers. Our scheme is compatible with previously proposed nonadiabatic holonomic two-qubit gates, combining with which the arbitrary holonomic one-qubit gates can play universal nonadiabatic holonomic quantum computation. We also investigate the effects of some unavoidable realistic errors on our scheme.

  19. Petrogenesis of high-K metagranites in the Kerala Khondalite Belt, southern India: a possible magmatic-arc link between India, Sri Lanka, and Madagascar

    NASA Astrophysics Data System (ADS)

    Sreejith, C.; Ravindra Kumar, G. R.

    2013-01-01

    The Proterozoic Kerala Khondalite Belt (KKB), southern India preserves a distinct high-grade terrain that is interpreted to have been situated adjacent to Madagascar and Sri Lanka during Gondwana assembly. As such, it has become a major focus for testing models of supercontinent amalgamation and dispersal. The lithounits of KKB have remarkable petrological similarities to the Highland Complex (HC) of Sri Lanka and south-central Madagascar. However, there is no well-constrained petrogenetic model for the KKB that fits explicitly within a supercontinent reconstruction model. We present here results from our on-going studies on the origin and evolution of K-rich (potassic, where K2O/Na2O > 1) gneisses of KKB in relation to Proterozoic supercontinent events. Our results show, in a major departure from earlier metasedimentary origin, that potassic gneisses are metamorphosed granitoids. The metagranitoid samples display high K2O contents and low Al2O3/(FeO + MgO + TiO2) values. They are moderate to strongly peraluminous (ASI values ranging from 1.05 to 1.47) rocks showing mineralogical, petrological, and geochemical characteristics distinctive of the high-K calc-alkaline suites. Typical of igneous suites, the high-K metagranites show minor variation in chemical compositions with most oxides showing negative correlation with SiO2. Geochemistry illustrates distinctive features of arc-related magmas with LILE (K, Rb, and Th) and LREE enriched patterns and considerable depletion of HSFE (Nb, Zr, and Ti). The high-K metagranites are further characterized by strong negative anomalies of Eu (Eu/Eu* = 0.10-0.44) and Sr, suggesting melting in plagioclase stability field and retention of plagioclase in the residual phase. Petrogenetic discrimination for granitoids, using major and trace elements demonstrates that the high-K metagranites of the KKB formed by partial melting of igneous source in lower- to middle-crust levels. Overall the geochemical features are supportive of origin

  20. Investigation of light doping and hetero gate dielectric carbon nanotube tunneling field-effect transistor for improved device and circuit-level performance

    NASA Astrophysics Data System (ADS)

    Wang, Wei; Sun, Yuan; Wang, Huan; Xu, Hongsong; Xu, Min; Jiang, Sitao; Yue, Gongshu

    2016-03-01

    We perform a comparative study (both for device and circuit simulations) of three carbon nanotube tunneling field-effect transistor (CNT-TFET) designs: high-K gate dielectric TFETs (HK-TFETs), hetero gate dielectric TFETs (HTFETs) and a novel CNT-TFET-based combination of light doping and hetero gate dielectric TFETs (LD-HTFETs). At device level, the effects of channel and gate dielectric engineering on the switching and high-frequency characteristics for CNT-TFET have been theoretically investigated using a quantum kinetic model. This model is based on two-dimensional non-equilibrium Green’s functions solved self-consistently with Poisson’s equations. It is revealed that the proposed LD-HTFET structure can significantly reduce leakage current, enhance control ability of the gate on the channel, improve the switching speed, and is more suitable for use in low-power, high-frequency circuits. At circuit level, using HSPICE with look-up table-based Verilog-A models, the performance and reliability of CNT-TFET logic gate circuits is evaluated on the basis of power consumption, average delay, stability, energy consumption and power-delay product (PDP). Simulation results indicate that, compared to a traditional CNT-TFET-based circuit, the one based on LD-HTFET has a significantly better performance (static noise margin, energy, delay, PDP). It is also observed that our proposed design exhibits better robustness under different operational conditions by considering power supply voltage and temperature variations. Our results may be useful for designing and optimizing CNTFET devices and circuits.

  1. Site-Directed Spin Labeling Reveals Pentameric Ligand-Gated Ion Channel Gating Motions

    PubMed Central

    Dellisanti, Cosma D.; Ghosh, Borna; Hanson, Susan M.; Raspanti, James M.; Grant, Valerie A.; Diarra, Gaoussou M.; Schuh, Abby M.; Satyshur, Kenneth; Klug, Candice S.; Czajkowski, Cynthia

    2013-01-01

    Pentameric ligand-gated ion channels (pLGICs) are neurotransmitter-activated receptors that mediate fast synaptic transmission. In pLGICs, binding of agonist to the extracellular domain triggers a structural rearrangement that leads to the opening of an ion-conducting pore in the transmembrane domain and, in the continued presence of neurotransmitter, the channels desensitize (close). The flexible loops in each subunit that connect the extracellular binding domain (loops 2, 7, and 9) to the transmembrane channel domain (M2–M3 loop) are essential for coupling ligand binding to channel gating. Comparing the crystal structures of two bacterial pLGIC homologues, ELIC and the proton-activated GLIC, suggests channel gating is associated with rearrangements in these loops, but whether these motions accurately predict the motions in functional lipid-embedded pLGICs is unknown. Here, using site-directed spin labeling (SDSL) electron paramagnetic resonance (EPR) spectroscopy and functional GLIC channels reconstituted into liposomes, we examined if, and how far, the loops at the ECD/TMD gating interface move during proton-dependent gating transitions from the resting to desensitized state. Loop 9 moves ∼9 Å inward toward the channel lumen in response to proton-induced desensitization. Loop 9 motions were not observed when GLIC was in detergent micelles, suggesting detergent solubilization traps the protein in a nonactivatable state and lipids are required for functional gating transitions. Proton-induced desensitization immobilizes loop 2 with little change in position. Proton-induced motion of the M2–M3 loop was not observed, suggesting its conformation is nearly identical in closed and desensitized states. Our experimentally derived distance measurements of spin-labeled GLIC suggest ELIC is not a good model for the functional resting state of GLIC, and that the crystal structure of GLIC does not correspond to a desensitized state. These findings advance our

  2. Gate Set Tomography on two qubits

    NASA Astrophysics Data System (ADS)

    Nielsen, Erik; Blume-Kohout, Robin; Gamble, John; Rudinger, Kenneth

    Gate set tomography (GST) is a method for characterizing quantum gates that does not require pre-calibrated operations, and has been used to both certify and improve the operation of single qubits. We analyze the performance of GST applied to a simulated two-qubit system, and show that Heisenberg scaling is achieved in this case. We present a GST analysis of preliminary two-qubit experimental data, and draw comparisons with the simulated data case. Finally, we will discuss recent theoretical developments that have improved the efficiency of GST estimation procedures, and which are particularly beneficial when characterizing two qubit systems. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under Contract DE-AC04-94AL85000.

  3. Philosophy of voltage-gated proton channels

    PubMed Central

    DeCoursey, Thomas E.; Hosler, Jonathan

    2014-01-01

    In this review, voltage-gated proton channels are considered from a mainly teleological perspective. Why do proton channels exist? What good are they? Why did they go to such lengths to develop several unique hallmark properties such as extreme selectivity and ΔpH-dependent gating? Why is their current so minuscule? How do they manage to be so selective? What is the basis for our belief that they conduct H+ and not OH–? Why do they exist in many species as dimers when the monomeric form seems to work quite well? It is hoped that pondering these questions will provide an introduction to these channels and a way to logically organize their peculiar properties as well as to understand how they are able to carry out some of their better-established biological functions. PMID:24352668

  4. Method for voltage-gated protein fractionation

    DOEpatents

    Hatch, Anson [Tracy, CA; Singh, Anup K [Danville, CA

    2012-04-24

    We report unique findings on the voltage dependence of protein exclusion from the pores of nanoporous polymer exclusion membranes. The pores are small enough that proteins are excluded from passage with low applied electric fields, but increasing the field enables proteins to pass through. The requisite field necessary for a change in exclusion is protein-specific with a correlation to protein size. The field-dependence of exclusion is important to consider for preconcentration applications. The ability to selectively gate proteins at exclusion membranes is also a promising means for manipulating and characterizing proteins. We show that field-gated exclusion can be used to selectively remove proteins from a mixture, or to selectively trap protein at one exclusion membrane in a series.

  5. SWNT array resonant gate MOS transistor.

    PubMed

    Arun, A; Campidelli, S; Filoramo, A; Derycke, V; Salet, P; Ionescu, A M; Goffman, M F

    2011-02-04

    We show that thin horizontal arrays of single wall carbon nanotubes (SWNTs) suspended above the channel of silicon MOSFETs can be used as vibrating gate electrodes. This new class of nano-electromechanical system (NEMS) combines the unique mechanical and electronic properties of SWNTs with an integrated silicon-based motion detection. Its electrical response exhibits a clear signature of the mechanical resonance of SWNT arrays (120-150 MHz) showing that these thin horizontal arrays behave as a cohesive, rigid and elastic body membrane with a Young's modulus in the order of 1-10 GPa and ultra-low mass. The resonant frequency can be tuned by the gate voltage and its dependence is well understood within the continuum mechanics framework.

  6. Water-gel for gating graphene transistors.

    PubMed

    Kim, Beom Joon; Um, Soong Ho; Song, Woo Chul; Kim, Yong Ho; Kang, Moon Sung; Cho, Jeong Ho

    2014-05-14

    Water, the primary electrolyte in biology, attracts significant interest as an electrolyte-type dielectric material for transistors compatible with biological systems. Unfortunately, the fluidic nature and low ionic conductivity of water prevents its practical usage in such applications. Here, we describe the development of a solid state, megahertz-operating, water-based gate dielectric system for operating graphene transistors. The new electrolyte systems were prepared by dissolving metal-substituted DNA polyelectrolytes into water. The addition of these biocompatible polyelectrolytes induced hydrogelation to provide solid-state integrity to the system. They also enhanced the ionic conductivities of the electrolytes, which in turn led to the quick formation of an electric double layer at the graphene/electrolyte interface that is beneficial for modulating currents in graphene transistors at high frequencies. At the optimized conditions, the Na-DNA water-gel-gated flexible transistors and inverters were operated at frequencies above 1 MHz and 100 kHz, respectively.

  7. Structure of molten Ga-Te eutectic

    SciTech Connect

    Dutchak, Ya.I.; Mudryi, S.I.; Kozyrenko, V.N.

    1988-02-01

    We have made an x-ray study of the Ga-Te eutectic liquid. The phase diagram shows a series of compounds as well as immiscibility regions for two liquid phases and the eutectic. The compounds GaTe and Ga/sub 2/Te/sub 3/ melt congruently. The phase diagram is complicated, and the phase state varies substantially with the component ratio. The liquid eutectic (87 at. % Te) was examined with a high-temperature diffractometer intended particularly for liquids; Cu K..cap alpha.. radiation was used, which was monochromatized with LiF. An integral Fourier transformation was used to calculate the radial distributions for the atoms and the density; the first were used to derive the most likely shortest interatomic distances, while the second gave the mean coordination numbers.

  8. Surface conduction in encapsulated topological gated structures

    NASA Astrophysics Data System (ADS)

    Deshko, Yury; Korzhovska, Inna; Zhao, Lukas; Arefe, Ghidewon; Konczykowski, Marcin; Krusin-Elbaum, Lia

    2015-03-01

    In three-dimensional (3D) topological insulators (TIs), the surface Dirac fermions intermix with the conducting bulk, thereby complicating access to the low-energy surface charge transport or magnetic response. The subsurface 2D states of bulk origin are vulnerable to bandbending due to surface adatoms, a band modification thought to be responsible for the `ageing' effect. To minimize this effect, we have developed an inert environment mechanical exfoliation technique to fabricate transistor-like gated structures in which prototypical binary TIs as well as ultra-low bulk carrier density ternaries (such as Bi2Te2Se) were encapsulated by thin h-BN layers, with electrical contacts made using exfoliated graphene. The effects of electrostatic tuning by the gate bias voltage on surface conductivity as a function of thickness of the TI layers and the variation with disorder will be presented. Supported by NSF-DMR-1312483, and DOD-W911NF-13-1-0159.

  9. DIFMOS - A floating-gate electrically erasable nonvolatile semiconductor memory technology. [Dual Injector Floating-gate MOS

    NASA Technical Reports Server (NTRS)

    Gosney, W. M.

    1977-01-01

    Electrically alterable read-only memories (EAROM's) or reprogrammable read-only memories (RPROM's) can be fabricated using a single-level metal-gate p-channel MOS technology with all conventional processing steps. Given the acronym DIFMOS for dual-injector floating-gate MOS, this technology utilizes the floating-gate technique for nonvolatile storage of data. Avalanche injection of hot electrons through gate oxide from a special injector diode in each bit is used to charge the floating gates. A second injector structure included in each bit permits discharge of the floating gate by avalanche injection of holes through gate oxide. The overall design of the DIFMOS bit is dictated by the physical considerations required for each of the avalanche injector types. The end result is a circuit technology which can provide fully decoded bit-erasable EAROM-type circuits using conventional manufacturing techniques.

  10. Cortical Gating of Oropharyngeal Sensory Stimuli

    PubMed Central

    Wheeler-Hegland, Karen; Pitts, Teresa; Davenport, Paul W.

    2010-01-01

    Somatosensory evoked potentials provide a measure of cortical neuronal activation in response to various types of sensory stimuli. In order to prevent flooding of the cortex with redundant information various sensory stimuli are gated cortically such that response to stimulus 2 (S2) is significantly reduced in amplitude compared to stimulus 1 (S1). Upper airway protective mechanisms, such as swallowing and cough, are dependent on sensory input for triggering and modifying their motor output. Thus, it was hypothesized that central neural gating would be absent for paired-air puff stimuli applied to the oropharynx. Twenty-three healthy adults (18–35 years) served as research participants. Pharyngeal sensory evoked potentials (PSEPs) were measured via 32-electrode cap (10–20 system) connected to SynAmps2 Neuroscan EEG System. Paired-pulse air puffs were delivered with an inter-stimulus interval of 500 ms to the oropharynx using a thin polyethylene tube connected to a flexible laryngoscope. Data were analyzed using descriptive statistics and a repeated measures analysis of variance. There were no significant differences found for the amplitudes S1 and S2 for any of the four component PSEP peaks. Mean gating ratios were above 0.90 for each peak. Results supports our hypothesis that sensory central neural gating would be absent for component PSEP peaks with paired-pulse stimuli delivered to the oropharynx. This may be related to the need for constant sensory monitoring necessary for adequate airway protection associated with swallowing and coughing. PMID:21423402

  11. Advantages of gated silicon single photon detectors

    NASA Astrophysics Data System (ADS)

    Legré, Matthieu; Lunghi, Tommaso; Stucki, Damien; Zbinden, Hugo

    2013-05-01

    We present gated silicon single photon detectors based on two commercially available avalanche photodiodes (APDs) and one customised APD from ID Quantique SA. This customised APD is used in a commercially available device called id110. A brief comparison of the two commercial APDs is presented. Then, the charge persistence effect of all of those detectors that occurs just after a strong illumination is shown and discussed.

  12. Cluster computing software for GATE simulations.

    PubMed

    De Beenhouwer, Jan; Staelens, Steven; Kruecker, Dirk; Ferrer, Ludovic; D'Asseler, Yves; Lemahieu, Ignace; Rannou, Fernando R

    2007-06-01

    Geometry and tracking (GEANT4) is a Monte Carlo package designed for high energy physics experiments. It is used as the basis layer for Monte Carlo simulations of nuclear medicine acquisition systems in GEANT4 Application for Tomographic Emission (GATE). GATE allows the user to realistically model experiments using accurate physics models and time synchronization for detector movement through a script language contained in a macro file. The downside of this high accuracy is long computation time. This paper describes a platform independent computing approach for running GATE simulations on a cluster of computers in order to reduce the overall simulation time. Our software automatically creates fully resolved, nonparametrized macros accompanied with an on-the-fly generated cluster specific submit file used to launch the simulations. The scalability of GATE simulations on a cluster is investigated for two imaging modalities, positron emission tomography (PET) and single photon emission computed tomography (SPECT). Due to a higher sensitivity, PET simulations are characterized by relatively high data output rates that create rather large output files. SPECT simulations, on the other hand, have lower data output rates but require a long collimator setup time. Both of these characteristics hamper scalability as a function of the number of CPUs. The scalability of PET simulations is improved here by the development of a fast output merger. The scalability of SPECT simulations is improved by greatly reducing the collimator setup time. Accordingly, these two new developments result in higher scalability for both PET and SPECT simulations and reduce the computation time to more practical values.

  13. Voltage Gated Ion Channel Function: Gating, Conduction, and the Role of Water and Protons

    PubMed Central

    Kariev, Alisher M.; Green, Michael E.

    2012-01-01

    Ion channels, which are found in every biological cell, regulate the concentration of electrolytes, and are responsible for multiple biological functions, including in particular the propagation of nerve impulses. The channels with the latter function are gated (opened) by a voltage signal, which allows Na+ into the cell and K+ out. These channels have several positively charged amino acids on a transmembrane domain of their voltage sensor, and it is generally considered, based primarily on two lines of experimental evidence, that these charges move with respect to the membrane to open the channel. At least three forms of motion, with greatly differing extents and mechanisms of motion, have been proposed. There is a “gating current”, a capacitative current preceding the channel opening, that corresponds to several charges (for one class of channel typically 12–13) crossing the membrane field, which may not require protein physically crossing a large fraction of the membrane. The coupling to the opening of the channel would in these models depend on the motion. The conduction itself is usually assumed to require the “gate” of the channel to be pulled apart to allow ions to enter as a section of the protein partially crosses the membrane, and a selectivity filter at the opposite end of the channel determines the ion which is allowed to pass through. We will here primarily consider K+ channels, although Na+ channels are similar. We propose that the mechanism of gating differs from that which is generally accepted, in that the positively charged residues need not move (there may be some motion, but not as gating current). Instead, protons may constitute the gating current, causing the gate to open; opening consists of only increasing the diameter at the gate from approximately 6 Å to approximately 12 Å. We propose in addition that the gate oscillates rather than simply opens, and the ion experiences a barrier to its motion across the channel that is tuned

  14. Engineering integrated photonics for heralded quantum gates

    NASA Astrophysics Data System (ADS)

    Meany, Thomas; Biggerstaff, Devon N.; Broome, Matthew A.; Fedrizzi, Alessandro; Delanty, Michael; Steel, M. J.; Gilchrist, Alexei; Marshall, Graham D.; White, Andrew G.; Withford, Michael J.

    2016-06-01

    Scaling up linear-optics quantum computing will require multi-photon gates which are compact, phase-stable, exhibit excellent quantum interference, and have success heralded by the detection of ancillary photons. We investigate the design, fabrication and characterisation of the optimal known gate scheme which meets these requirements: the Knill controlled-Z gate, implemented in integrated laser-written waveguide arrays. We show device performance to be less sensitive to phase variations in the circuit than to small deviations in the coupler reflectivity, which are expected given the tolerance values of the fabrication method. The mode fidelity is also shown to be less sensitive to reflectivity and phase errors than the process fidelity. Our best device achieves a fidelity of 0.931 ± 0.001 with the ideal 4 × 4 unitary circuit and a process fidelity of 0.680 ± 0.005 with the ideal computational-basis process.

  15. Gated Luminescence Imaging of Silicon Nanoparticles.

    PubMed

    Joo, Jinmyoung; Liu, Xiangyou; Kotamraju, Venkata Ramana; Ruoslahti, Erkki; Nam, Yoonkey; Sailor, Michael J

    2015-06-23

    The luminescence lifetime of nanocrystalline silicon is typically on the order of microseconds, significantly longer than the nanosecond lifetimes exhibited by fluorescent molecules naturally present in cells and tissues. Time-gated imaging, where the image is acquired at a time after termination of an excitation pulse, allows discrimination of a silicon nanoparticle probe from these endogenous signals. Because of the microsecond time scale for silicon emission, time-gated imaging is relatively simple to implement for this biocompatible and nontoxic probe. Here a time-gated system with ∼10 ns resolution is described, using an intensified CCD camera and pulsed LED or laser excitation sources. The method is demonstrated by tracking the fate of mesoporous silicon nanoparticles containing the tumor-targeting peptide iRGD, administered by retro-orbital injection into live mice. Imaging of such systemically administered nanoparticles in vivo is particularly challenging because of the low concentration of probe in the targeted tissues and relatively high background signals from tissue autofluorescence. Contrast improvements of >100-fold (relative to steady-state imaging) is demonstrated in the targeted tissues.

  16. Flux-gate magnetometer for Mars exploration

    NASA Astrophysics Data System (ADS)

    Zhao, Hua; Zhu, G. W.; Yu, P.; Wang, J. D.; Yu, M. F.; Li, L.; Sun, Y. Q.; Chen, S. W.; Liao, H. Z.; Zhou, B.; Feng, Y. Y.

    2008-10-01

    A micro-satellite, Yinghuo-1, would be launched with Russian spacecraft, Phobos-Grunt in October, 2009 to investigate the space environment around Mars. YH-1 and Phobos-Grunt forms a two-point measurement configuration in the Martian space environment. YH-1 and Phobos-Grunt are equipped with similar magnetic field and plasma detecting payload on two spacecraft would give some coordinated exploration around Mars. YH-1 would orbit Mars with periapsis of 800 km above the Martian surface, and apoapsis about 80000km to the center of Mars. The orbit inclination is in the range of 0~7° to the Martian equator. A flux-gate type magnetometer, with two tri-axial sensors, is developed for YH-1 spacecraft. Two sensors are mounted on one-side of the deployable solar panel with a radial separation about 45cm to function as a gradiometer to minimize the affects of platform remanence. The dynamic range of the magnetometer is +/-256nT with a 16-bit ADC converter, and the noise level is better than 0.01nT/√Hz, to measure three-component magnetic field from DC to 10Hz. Flux-gate magnetometer would work together with the Plasma Package onboard of YH-1 to investigate the Martian bow shock, magnetosheath, magnetic pileup region (MPR). A detail description of the flux-gate magnetometer is presented in this paper, with test and calibration results.

  17. Gate manipulation of DNA capture into nanopores.

    PubMed

    He, Yuhui; Tsutsui, Makusu; Fan, Chun; Taniguchi, Masateru; Kawai, Tomoji

    2011-10-25

    Understanding biophysics governing DNA capture into a nanopore and establishing a manipulation system for the capture process are essential for nanopore-based genome sequencing. In this work, the functionality of extended electric field and electroosmotic flow (EOF) during the capture stage and their dependence on gate voltage, U(G), are investigated. We demonstrate that while both the electric field and EOF within a cis chamber make long-distance contributions to DNA capture around the pore mouth, the former effect is always capturing, while the latter causes trapping or blocking of the molecule depending on the magnitude of the gate voltage, U(G): an anionic EOF induced by high U(G) is capable of doubling the DNA trapping speed and thus the absorption radius in the cis chamber, whereas a cationic EOF by low U(G) would substantially offset the trapping effort by the electric field and even totally block DNA entrance into the pore. Based on the analysis, a gate regulation is proposed with the objective of achieving a high DNA capture rate while maintaining a low error rate.

  18. Gate-Tunable Conducting Oxide Metasurfaces.

    PubMed

    Huang, Yao-Wei; Lee, Ho Wai Howard; Sokhoyan, Ruzan; Pala, Ragip A; Thyagarajan, Krishnan; Han, Seunghoon; Tsai, Din Ping; Atwater, Harry A

    2016-09-14

    Metasurfaces composed of planar arrays of subwavelength artificial structures show promise for extraordinary light manipulation. They have yielded novel ultrathin optical components such as flat lenses, wave plates, holographic surfaces, and orbital angular momentum manipulation and detection over a broad range of the electromagnetic spectrum. However, the optical properties of metasurfaces developed to date do not allow for versatile tunability of reflected or transmitted wave amplitude and phase after their fabrication, thus limiting their use in a wide range of applications. Here, we experimentally demonstrate a gate-tunable metasurface that enables dynamic electrical control of the phase and amplitude of the plane wave reflected from the metasurface. Tunability arises from field-effect modulation of the complex refractive index of conducting oxide layers incorporated into metasurface antenna elements which are configured in reflectarray geometry. We measure a phase shift of 180° and ∼30% change in the reflectance by applying 2.5 V gate bias. Additionally, we demonstrate modulation at frequencies exceeding 10 MHz and electrical switching of ±1 order diffracted beams by electrical control over subgroups of metasurface elements, a basic requirement for electrically tunable beam-steering phased array metasurfaces. In principle, electrically gated phase and amplitude control allows for electrical addressability of individual metasurface elements and opens the path to applications in ultrathin optical components for imaging and sensing technologies, such as reconfigurable beam steering devices, dynamic holograms, tunable ultrathin lenses, nanoprojectors, and nanoscale spatial light modulators.

  19. Engineering integrated photonics for heralded quantum gates.

    PubMed

    Meany, Thomas; Biggerstaff, Devon N; Broome, Matthew A; Fedrizzi, Alessandro; Delanty, Michael; Steel, M J; Gilchrist, Alexei; Marshall, Graham D; White, Andrew G; Withford, Michael J

    2016-06-10

    Scaling up linear-optics quantum computing will require multi-photon gates which are compact, phase-stable, exhibit excellent quantum interference, and have success heralded by the detection of ancillary photons. We investigate the design, fabrication and characterisation of the optimal known gate scheme which meets these requirements: the Knill controlled-Z gate, implemented in integrated laser-written waveguide arrays. We show device performance to be less sensitive to phase variations in the circuit than to small deviations in the coupler reflectivity, which are expected given the tolerance values of the fabrication method. The mode fidelity is also shown to be less sensitive to reflectivity and phase errors than the process fidelity. Our best device achieves a fidelity of 0.931 ± 0.001 with the ideal 4 × 4 unitary circuit and a process fidelity of 0.680 ± 0.005 with the ideal computational-basis process.

  20. Voltage-gated proton channels: what' next?

    PubMed Central

    DeCoursey, Thomas E

    2008-01-01

    This review is an attempt to identify and place in context some of the many questions about voltage-gated proton channels that remain unsolved. As the gene was identified only 2 years ago, the situation is very different than in fields where the gene has been known for decades. For the proton channel, most of the obvious and less obvious structure–function questions are still wide open. Remarkably, the proton channel protein strongly resembles the voltage-sensing domain of many voltage-gated ion channels, and thus offers a novel approach to study gating mechanisms. Another surprise is that the proton channel appears to function as a dimer, with two separate conduction pathways. A number of significant biological questions remain in dispute, unanswered, or in some cases, not yet asked. This latter deficit is ascribable to the intrinsic difficulty in evaluating the importance of one component in a complex system, and in addition, to the lack, until recently, of a means of performing an unambiguous lesion experiment, that is, of selectively eliminating the molecule in question. We still lack a potent, selective pharmacological inhibitor, but the identification of the gene has allowed the development of powerful new tools including proton channel antibodies, siRNA and knockout mice. PMID:18801839