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Sample records for gaas bipolar transistor

  1. Fabrication and high temperature characteristics of ion-implanted GaAs bipolar transistors and ring-oscillators

    NASA Technical Reports Server (NTRS)

    Doerbeck, F. H.; Yuan, H. T.; Mclevige, W. V.

    1981-01-01

    Ion implantation techniques that permit the reproducible fabrication of bipolar GaAs integrated circuits are studied. A 15 stage ring oscillator and discrete transistor were characterized between 25 and 400 C. The current gain of the transistor was found to increase slightly with temperature. The diode leakage currents increase with an activation energy of approximately 1 eV and dominate the transistor leakage current 1 sub CEO above 200 C. Present devices fail catastrophically at about 400 C because of Au-metallization.

  2. An analytical study of current-voltage characteristics and breakdown performance of GaInP /GaAs composite collector double heterojunction bipolar transistor

    NASA Astrophysics Data System (ADS)

    Goh, Y. L.; Ong, D. S.; Yow, H. K.

    2004-10-01

    An analytical model taking into account the nonlocal dead-space effects is developed to study the dc characteristics and avalanche multiplication of GaInP /GaAs double heterojunction bipolar transistor (DHBT) incorporating composite collector designs. The dependence of the turn-on characteristics and the multiplication onset of the HBT on the device composite layer thickness and doping densities are investigated. In this paper, optimum combinations of composite parameters are presented to obtain zero spike effect in the base-collector heterojunction conduction band and to improve output breakdown voltages. The model is then applied to the GaInP /GaAs DHBT with AlGaAs in the composite collector, which is found to have good I-V characteristics and high operating voltage range before the onset of avalanche multiplication.

  3. GaInP /GaAs double heterojunction bipolar transistor with GaAs /Al0.11Ga0.89As/GaInP composite collector

    NASA Astrophysics Data System (ADS)

    Poh, Z. S.; Yow, H. K.; Houston, P. A.; Krysa, A. B.; Ong, D. S.

    2006-07-01

    GaInP /GaAs/GaInP double heterojunction bipolar transistor (DHBT) with an Al0.11Ga0.89As layer within lowly doped GaAs-GaInP composite collector was characterized. In comparison to an abrupt GaInP /GaAs/GaInP DHBT with saturation voltages in excess of 20V, current gains of 25 at high biases, and breakdown voltages in the range of 22V, the DHBT incorporating GaAs -Al0.11Ga0.89As-GaInP composite collector has demonstrated lower saturation voltages of less than 6V and high current gains of 50 without compromising the breakdown voltages of the GaInP collector. Al0.11Ga0.89As layer can thus provide an alternative design to effectively minimize the potential spike effects at the GaAs /GaInP heterojunction.

  4. A new bipolar transistor - GAT

    NASA Astrophysics Data System (ADS)

    Kondo, H.; Yukimoto, Y.

    1980-02-01

    A new bipolar transistor named Gate Associated Transistor (GAT) was proposed and the operating mechanisms were verified. The structure of the GAT has a unique base region consisting of an FET merged into the base of a standard bipolar transistor. The operating mechanisms and characteristics of the GAT were investigated and compared with those of standard power transistors. The most outstanding feature of the GAT was a large area for safe operation.

  5. High power gain switched laser diodes using a novel compact picosecond switch based on a GaAs bipolar junction transistor structure for pumping

    NASA Astrophysics Data System (ADS)

    Vainshtein, Sergey; Kostamovaara, Juha

    2006-04-01

    A number of up-to-date applications, including advanced optical radars with high single-shot resolution, precise 3 D imaging, laser tomography, time imaging spectroscopy, etc., require low-cost, compact, reliable sources enabling the generation of high-power (1-100 W) single optical pulses in the picosecond range. The well-known technique of using the gain-switching operation mode of laser diodes to generate single picosecond pulses in the mW range fails to generate high-power single picosecond pulses because of a lack of high-current switches operating in the picosecond range. We report here on the achieving of optical pulses of 45W / 70ps, or alternatively 5W / 40ps, with gain-switched commercial quantum well (QW) laser diodes having emitting areas of 250 × 200 μm and 75 × 2 μm, respectively. This was made possible by the use of a novel high-current avalanche switch based on a GaAs bipolar junction transistor (BJT) structure with a switching time (<200ps) comparable to the lasing delay. (The extremely fast transient in this switch is caused by the generation and spread of a comb of powerfully avalanching Gunn domains of ultra-high amplitude in the transistor structure.) A simulation code developed earlier but modified and carefully verified here allowed detailed comparison of the experimental and simulated laser responses and the transient spectrum.

  6. Ion bipolar junction transistors

    PubMed Central

    Tybrandt, Klas; Larsson, Karin C.; Richter-Dahlfors, Agneta; Berggren, Magnus

    2010-01-01

    Dynamic control of chemical microenvironments is essential for continued development in numerous fields of life sciences. Such control could be achieved with active chemical circuits for delivery of ions and biomolecules. As the basis for such circuitry, we report a solid-state ion bipolar junction transistor (IBJT) based on conducting polymers and thin films of anion- and cation-selective membranes. The IBJT is the ionic analogue to the conventional semiconductor BJT and is manufactured using standard microfabrication techniques. Transistor characteristics along with a model describing the principle of operation, in which an anionic base current amplifies a cationic collector current, are presented. By employing the IBJT as a bioelectronic circuit element for delivery of the neurotransmitter acetylcholine, its efficacy in modulating neuronal cell signaling is demonstrated. PMID:20479274

  7. Npn double heterostructure bipolar transistor with ingaasn base region

    DOEpatents

    Chang, Ping-Chih; Baca, Albert G.; Li, Nein-Yi; Hou, Hong Q.; Ashby, Carol I. H.

    2004-07-20

    An NPN double heterostructure bipolar transistor (DHBT) is disclosed with a base region comprising a layer of p-type-doped indium gallium arsenide nitride (InGaAsN) sandwiched between n-type-doped collector and emitter regions. The use of InGaAsN for the base region lowers the transistor turn-on voltage, V.sub.on, thereby reducing power dissipation within the device. The NPN transistor, which has applications for forming low-power electronic circuitry, is formed on a gallium arsenide (GaAs) substrate and can be fabricated at commercial GaAs foundries. Methods for fabricating the NPN transistor are also disclosed.

  8. TILBW Bipolar Power Switching Transistor

    NASA Astrophysics Data System (ADS)

    Silard, Andrei P.; Nani, Gabriel

    1989-03-01

    The work reports the development of TILBW (Two Interdigitation Levels with heavily-doped Base Wells) bipolar power switching transistors, which combine the main advantages of both TIL and GAT devices. The TILBW transistors exhibit the following many-fold advantages in comparison with identical, yet conventional devices of the same class (identical area and case) processed simultaneously: a reduction of the turn-on time by a factor of ˜ 20; a two-fold reduction of the fall time tf; an ˜ 18-percent increase of VCEO(SUS); an ˜ 23-percent increase of VCBO; an enhanced RBSOA.

  9. Vertical Bipolar Charge Plasma Transistor with Buried Metal Layer

    PubMed Central

    Nadda, Kanika; Kumar, M. Jagadesh

    2015-01-01

    A self-aligned vertical Bipolar Charge Plasma Transistor (V-BCPT) with a buried metal layer between undoped silicon and buried oxide of the silicon-on-insulator substrate, is reported in this paper. Using two-dimensional device simulation, the electrical performance of the proposed device is evaluated in detail. Our simulation results demonstrate that the V-BCPT not only has very high current gain but also exhibits high BVCEO · fT product making it highly suitable for mixed signal high speed circuits. The proposed device structure is also suitable for realizing doping-less bipolar charge plasma transistor using compound semiconductors such as GaAs, SiC with low thermal budgets. The device is also immune to non-ideal current crowding effects cropping up at high current densities. PMID:25597295

  10. Voltage regulator for battery power source. [using a bipolar transistor

    NASA Technical Reports Server (NTRS)

    Black, J. M. (Inventor)

    1979-01-01

    A bipolar transistor in series with the battery as the control element also in series with a zener diode and a resistor is used to maintain a predetermined voltage until the battery voltage decays to very nearly the predetermined voltage. A field effect transistor between the base of the bipolar transistor and a junction between the zener diode and resistor regulates base current of the bipolar transistor, thereby regulating the conductivity of the bipolar transistor for control of the output voltage.

  11. Bipolar effects in unipolar junctionless transistors

    NASA Astrophysics Data System (ADS)

    Parihar, Mukta Singh; Ghosh, Dipankar; Armstrong, G. Alastair; Yu, Ran; Razavi, Pedram; Kranti, Abhinav

    2012-08-01

    In this work, we analyze hysteresis and bipolar effects in unipolar junctionless transistors. A change in subthreshold drain current by 5 orders of magnitude is demonstrated at a drain voltage of 2.25 V in silicon junctionless transistor. Contrary to the conventional theory, increasing gate oxide thickness results in (i) a reduction of subthreshold slope (S-slope) and (ii) an increase in drain current, due to bipolar effects. The high sensitivity to film thickness in junctionless devices will be most crucial factor in achieving steep transition from ON to OFF state.

  12. Magnetoamplification in a bipolar magnetic junction transistor.

    PubMed

    Rangaraju, N; Peters, J A; Wessels, B W

    2010-09-10

    We have demonstrated the first bipolar magnetic junction transistor using a dilute magnetic semiconductor. For an InMnAs p-n-p transistor magnetoamplification is observed at room temperature. The observed magnetoamplification is attributed to the magnetoresistance of the magnetic semiconductor InMnAs heterojunction. The magnetic field dependence of the transistor characteristics confirm that the magnetoamplification results from the junction magnetoresistance. To describe the experimentally observed transistor characteristics, we propose a modified Ebers-Moll model that includes a series magnetoresistance attributed to spin-selective conduction. The capability of magnetic field control of the amplification in an all-semiconductor transistor at room temperature potentially enables the creation of new computer logic architecture where the spin of the carriers is utilized.

  13. Bipolar-FET combinational power transistors for power conversion applications

    NASA Technical Reports Server (NTRS)

    Chen, D. Y.; Chin, S. A.

    1984-01-01

    Four bipolar-FET (field-effect transistor) combinational transistor configurations are compared from the application point of view. The configurations included are FET-Darlington (cascade), emitter-open switch (cascode), parallel configuration, and FET-gated bipolar transistors (FGT).

  14. Polyphosphonium-based ion bipolar junction transistors

    PubMed Central

    Gabrielsson, Erik O.; Berggren, Magnus

    2014-01-01

    Advancements in the field of electronics during the past few decades have inspired the use of transistors in a diversity of research fields, including biology and medicine. However, signals in living organisms are not only carried by electrons but also through fluxes of ions and biomolecules. Thus, in order to implement the transistor functionality to control biological signals, devices that can modulate currents of ions and biomolecules, i.e., ionic transistors and diodes, are needed. One successful approach for modulation of ionic currents is to use oppositely charged ion-selective membranes to form so called ion bipolar junction transistors (IBJTs). Unfortunately, overall IBJT device performance has been hindered due to the typical low mobility of ions, large geometries of the ion bipolar junction materials, and the possibility of electric field enhanced (EFE) water dissociation in the junction. Here, we introduce a novel polyphosphonium-based anion-selective material into npn-type IBJTs. The new material does not show EFE water dissociation and therefore allows for a reduction of junction length down to 2 μm, which significantly improves the switching performance of the ion transistor to 2 s. The presented improvement in speed as well the simplified design will be useful for future development of advanced iontronic circuits employing IBJTs, for example, addressable drug-delivery devices. PMID:25553192

  15. Polyphosphonium-based ion bipolar junction transistors.

    PubMed

    Gabrielsson, Erik O; Tybrandt, Klas; Berggren, Magnus

    2014-11-01

    Advancements in the field of electronics during the past few decades have inspired the use of transistors in a diversity of research fields, including biology and medicine. However, signals in living organisms are not only carried by electrons but also through fluxes of ions and biomolecules. Thus, in order to implement the transistor functionality to control biological signals, devices that can modulate currents of ions and biomolecules, i.e., ionic transistors and diodes, are needed. One successful approach for modulation of ionic currents is to use oppositely charged ion-selective membranes to form so called ion bipolar junction transistors (IBJTs). Unfortunately, overall IBJT device performance has been hindered due to the typical low mobility of ions, large geometries of the ion bipolar junction materials, and the possibility of electric field enhanced (EFE) water dissociation in the junction. Here, we introduce a novel polyphosphonium-based anion-selective material into npn-type IBJTs. The new material does not show EFE water dissociation and therefore allows for a reduction of junction length down to 2 μm, which significantly improves the switching performance of the ion transistor to 2 s. The presented improvement in speed as well the simplified design will be useful for future development of advanced iontronic circuits employing IBJTs, for example, addressable drug-delivery devices. PMID:25553192

  16. Mathematical modeling of the characteristics of bipolar heterojunction transistors

    SciTech Connect

    Butakova, N.G.; Valiev, K.A.; Zubov, A.V.; Orlikovskii, A.A.

    1986-03-01

    The authors review the known methods of modeling bipolar heterojunction transistors (BHT) and illustrate that none of the available models is sufficiently universal. The authors develop a semi-empirical model which is valid for a wide number of heterojunctions, such as InSb-Ge, GaSb-Ge, CdS-Ge, GaAs-Ge, ZnSe-Ge, GaAs-Si, ZnSe-GaAs, etc., plus three-component compounds such as Als/bu z/Ga/sub 1-z/ As - GaAs. The assumptions underlying the model were confirmed experimentally in the cases when the heterojunction is formed by compounds of the group A/sub III/B/sub V/ with a common anion, such as CdTe-CdHgTe.

  17. Dose Rate Effects in Linear Bipolar Transistors

    NASA Technical Reports Server (NTRS)

    Johnston, Allan; Swimm, Randall; Harris, R. D.; Thorbourn, Dennis

    2011-01-01

    Dose rate effects are examined in linear bipolar transistors at high and low dose rates. At high dose rates, approximately 50% of the damage anneals at room temperature, even though these devices exhibit enhanced damage at low dose rate. The unexpected recovery of a significant fraction of the damage after tests at high dose rate requires changes in existing test standards. Tests at low temperature with a one-second radiation pulse width show that damage continues to increase for more than 3000 seconds afterward, consistent with predictions of the CTRW model for oxides with a thickness of 700 nm.

  18. Perpendicular transport in superlattice bipolar transistors (SBT)

    NASA Astrophysics Data System (ADS)

    Sibille, A.; Palmier, J. F.; Minot, C.; Harmand, J. C.; Dubon-Chevallier, C.

    Diffusion-limited electron transport in superlattices is studied by gain measurements on heterojunction bipolar transistors with a {GaAs}/{GaAlAs} superlattice base. In the case of thin barriers, Bloch conduction is observed, while hopping between localized levels prevails for large barriers. A transition occurs between these two regimes, localization being achieved when the energy broadening induced by the electron-phonon coupling added to the disorder due to imperfect growth is of the order of the miniband width. This interpretation is supported by temperature dependence measurements of the perpendicular mobilities in relation with theoretical calculations of these mobilities.

  19. Noise modeling of microwave heterojunction bipolar transistors

    NASA Astrophysics Data System (ADS)

    Escotte, Laurent; Roux, Jean-Phillippe; Plana, Robert; Graffeuil, Jacques; Gruhle, Andreas

    1995-05-01

    Analytical expressions of microwave heterojunction bipolar transistors minimum noise figure and noise parameter are reported in this paper. These expressions are derived from a noise model including nonideal junctions, emitter and base resistances and have been compared with measured data obtained on a Si/SiGe HBT. An agreement between theoretical and experimental data was observed up to 20 GHz for several bias conditions. The limits of the model or the range of validity of the proposed equations have been also examined with the help of an appropriate CAD software. The analysis of the influence of parasitic elements on noise parameters has shown a strong influence of the extrinsic base collector capacitance at microwave frequencies.

  20. 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.

  1. Free electron gas primary thermometer: The bipolar junction transistor

    SciTech Connect

    Mimila-Arroyo, J.

    2013-11-04

    The temperature of a bipolar transistor is extracted probing its carrier energy distribution through its collector current, obtained under appropriate polarization conditions, following a rigorous mathematical method. The obtained temperature is independent of the transistor physical properties as current gain, structure (Homo-junction or hetero-junction), and geometrical parameters, resulting to be a primary thermometer. This proposition has been tested using off the shelf silicon transistors at thermal equilibrium with water at its triple point, the transistor temperature values obtained involve an uncertainty of a few milli-Kelvin. This proposition has been successfully tested in the temperature range of 77–450 K.

  2. Observation of negative differential transconductance in tunneling emitter bipolar transistors

    NASA Astrophysics Data System (ADS)

    van Veenhuizen, Marc J.; Locatelli, Nicolas; Moodera, Jagadeesh; Chang, Joonyeon

    2009-08-01

    We report on measurement of negative differential transconductance (NDTC) of iron (Fe)/magnesium-oxide (MgO)/silicon tunneling emitter NPN bipolar transistors. Device simulations reveal that the NDTC is a consequence of an inversion layer at the tunneling-oxide/P-silicon interface for low base voltages. Electrons travel laterally through the inversion layer into the base and give rise to an increase in collector current. The NDTC results from the recombination of those electrons at the interface between emitter and base contact which is dependent on the base voltage. For larger base voltages, the inversion layer disappears marking the onset of normal bipolar transistor behavior.

  3. Heterojunction bipolar transistor technology for data acquisition and communication

    NASA Technical Reports Server (NTRS)

    Wang, C.; Chang, M.; Beccue, S.; Nubling, R.; Zampardi, P.; Sheng, N.; Pierson, R.

    1992-01-01

    Heterojunction Bipolar Transistor (HBT) technology has emerged as one of the most promising technologies for ultrahigh-speed integrated circuits. HBT circuits for digital and analog applications, data conversion, and power amplification have been realized, with speed performance well above 20 GHz. At Rockwell, a baseline AlGaAs/GaAs HBT technology has been established in a manufacturing facility. This paper describes the HBT technology, transistor characteristics, and HBT circuits for data acquisition and communication.

  4. Surface treatment effect on temperature-dependent properties of InGaP /GaAs heterobipolar transistors

    NASA Astrophysics Data System (ADS)

    Chen, Tzu-Pin; Fu, Ssu-I.; Liu, Wen-Chau; Cheng, Shiou-Ying; Tsai, Jung-Hui; Guo, Der-Feng; Lour, Wen-Shiung

    2007-02-01

    Specific treatments of the base surface of InGaP /GaAs heterojunction bipolar transistors are studied experimentally. The dual treatment method, based on the combination of ledge and sulfur passivation, shows better temperature-dependent characteristics including higher dc gain, lower saturation voltage, lower base-emitter junction turn on voltage, lower leakage current, lower collector and base current ideality factors nC and nB, and wider collector current operating regimes over the measured temperature range (300-400K). Therefore, the dual surface treatment method provides promise for high-performance electronic applications.

  5. A gallium phosphide high-temperature bipolar junction transistor

    NASA Technical Reports Server (NTRS)

    Zipperian, T. E.; Dawson, L. R.; Chaffin, R. J.

    1981-01-01

    Preliminary results are reported on the development of a high temperature (350 C) gallium phosphide bipolar junction transistor (BJT) for geothermal and other energy applications. This four-layer p(+)n(-)pp(+) structure was formed by liquid phase epitaxy using a supercooling technique to insure uniform nucleation of the thin layers. Magnesium was used as the p-type dopant to avoid excessive out-diffusion into the lightly doped base. By appropriate choice of electrodes, the device may also be driven as an n-channel junction field-effect transistor. The initial design suffers from a series resistance problem which limits the transistor's usefulness at high temperatures.

  6. Toward complementary ionic circuits: the npn ion bipolar junction transistor.

    PubMed

    Tybrandt, Klas; Gabrielsson, Erik O; Berggren, Magnus

    2011-07-01

    Many biomolecules are charged and may therefore be transported with ionic currents. As a step toward addressable ionic delivery circuits, we report on the development of a npn ion bipolar junction transistor (npn-IBJT) as an active control element of anionic currents in general, and specifically, demonstrate actively modulated delivery of the neurotransmitter glutamic acid. The functional materials of this transistor are ion exchange layers and conjugated polymers. The npn-IBJT shows stable transistor characteristics over extensive time of operation and ion current switch times below 10 s. Our results promise complementary chemical circuits similar to the electronic equivalence, which has proven invaluable in conventional electronic applications. PMID:21598973

  7. Demonstration and properties of a planar heterojunction bipolar transistor with lateral current flow

    NASA Astrophysics Data System (ADS)

    Thornton, Robert L.; Mosby, William J.; Chung, Harlan F.

    1989-10-01

    The authors present fabrication techniques and device performance for a novel transistor structure, the lateral heterojunction bipolar transistor. The lateral heterojunctions are formed by impurity-induced disordering of a GaAs base layer sandwiched between two AlGaAs layers. These transistor structures exhibit current gains of 14 for base widths of 0.74 micron. Transistor action in this device occurs parallel to the surface of the device structure. The active base region of the structure is completely submerged, resulting in a reduction of surface recombination as a mechanism for gain reduction in the device. Impurity-induced disordering is used to widen the bandgap of the alloy in the emitter and collector, resulting in an improvement of the emitter injection efficiency. Since the device is based entirely on a surface diffusion process, the device is completely planar and has no steps involving etching of the III-V alloy material. These advantages lead this device to be considered as a candidate for optoelectronic integration applications. The transistor device functions as a buried heterostructure laser, with a threshold current as low as 6 mA for a 1.4-micron stripe.

  8. Experiments with Charge Indicator Based on Bipolar Transistors

    ERIC Educational Resources Information Center

    Dvorak, Leos; Planinsic, Gorazd

    2012-01-01

    A simple charge indicator with bipolar transistors described recently enables us to perform a number of experiments suitable for high-school physics. Several such experiments are presented and discussed in this paper as well as some features of the indicator important for its use in schools, namely its sensitivity and robustness, i.e. the…

  9. Bipolar Transistors Can Detect Charge in Electrostatic Experiments

    ERIC Educational Resources Information Center

    Dvorak, L.

    2012-01-01

    A simple charge indicator with bipolar transistors is described that can be used in various electrostatic experiments. Its behaviour enables us to elucidate links between 'static electricity' and electric currents. In addition it allows us to relate the sign of static charges to the sign of the terminals of an ordinary battery. (Contains 7 figures…

  10. Early effect of SiGe heterojunction bipolar transistors

    NASA Astrophysics Data System (ADS)

    Xu, Xiao-Bo; Zhang, He-Ming; Hu, Hui-Yong; Qu, Jiang-Tao

    2012-06-01

    The standard Early voltage of the SGP model is generalized for SiGe NPN heterojunction bipolar transistors (HBTs). A new compact formulation of the Early voltage compatible with the SGP model is presented. The impact of the Ge profile on Early effect is shown and validated by experiments. The model can be applied to the SGP model for circuit simulation.

  11. Computer simulation of the scaled power bipolar SHF transistor structures

    NASA Astrophysics Data System (ADS)

    Nelayev, V. V.; Efremov, V. A.; Snitovsky, Yu. P.

    2007-04-01

    New advanced technology for creation of the npn power silicon bipolar SHF transistor structure is proposed. Preferences of the advanced technology in comparison with standard technology are demonstrated. Simulation of both technology flows was performed with emphasis on scaling of the discussed device structure.

  12. InP Heterojunction Bipolar Transistor Amplifiers to 255 GHz

    NASA Technical Reports Server (NTRS)

    Radisic, Vesna; Sawdai, Donald; Scott, Dennis; Deal, William; Dang, Linh; Li, Danny; Cavus, Abdullah; To, Richard; Lai, Richard

    2009-01-01

    Two single-stage InP heterojunction bipolar transistor (HBT) amplifiers operate at 184 and 255 GHz, using Northrop Grumman Corporation s InP HBT MMIC (monolithic microwave integrated circuit) technology. At the time of this reporting, these are reported to be the highest HBT amplifiers ever created. The purpose of the amplifier design is to evaluate the technology capability for high-frequency designs and verify the model for future development work.

  13. Doping To Reduce Base Resistances Of Bipolar Transistors

    NASA Technical Reports Server (NTRS)

    Lin, True-Lon

    1991-01-01

    Modified doping profile proposed to reduce base resistance of bipolar transistors. A p/p+ base-doping profile reduces base resistance without reducing current gain. Proposed low/high base-doping profile realized by such low-temperature deposition techniques as molecular-beam epitaxy, ultra-high-vacuum chemical-vapor deposition, and limited-reaction epitaxy. Produces desired doping profiles without excessive diffusion of dopant.

  14. Dead-space corrected GaInP/GaAs composite collector double heterojunction bipolar transistors

    NASA Astrophysics Data System (ADS)

    Poh, Z. S.; Yow, H. K.; Ong, D. S.; Houston, P. A.; Krysa, A. B.

    2007-04-01

    GaInP/GaAs/GaInP double heterojunction bipolar transistors incorporating dead-space corrected composite collectors were investigated experimentally. The optimized DHBT with a 10-nm lowly doped GaAs spacer and a 5-nm highly doped GaInP spacer has extended the operating range of the collector-emitter voltage, VCE, by maximizing the collector-emitter voltage at the onset of the multiplication, VCE ,onset, to 20 V, while minimizing the saturation voltage, VCE ,sat (<1 V), and maintaining the nominal breakdown voltage, BVCEO, of the GaInP collector at 25 V. The design incorporating an Al0.11Ga0.89As spacer rather than a GaInP spacer within the lowly doped GaAs-GaInP composite collector demonstrated similar breakdown behavior.

  15. Minority carrier properties of carbon-doped GaInAsN bipolar transistors

    NASA Astrophysics Data System (ADS)

    Welser, R. E.; Setzko, R. S.; Stevens, K. S.; Rehder, E. M.; Lutz, C. R.; Hill, D. S.; Zampardi, P. J.

    2004-08-01

    We have developed an InGaP/GaInAsN/GaAs double heterojunction bipolar transistor technology that substantially improves upon existing GaAs-based HBTs. Band-gap engineering with dilute nitride GaInAsN alloys is utilized to enhance a variety of key device characteristics, including lower operating voltages, improved temperature stability and increased RF performance. Furthermore, GaInAsN-based HBTs are fully compatible with existing high-volume MOVPE and IC fabrication processes. While poor lifetimes have limited the applicability of dilute nitride materials in photovoltaic applications, we achieve minority carrier characteristics that approach those of conventional GaAs HBTs. We have found that a combination of growth algorithm optimization and compositional grading are critical for improving minority carrier properties in GaInAsN. In this work, we characterize the impact of both carbon and nitrogen doping on minority carrier lifetimes in GaInAsN base layers. Minority carrier lifetimes are extracted from direct measurements on bipolar transistor device structures. Specifically, lifetime is derived from the DC current gain, or bgr, taken in the bias regime dominated by neutral base recombination. Lifetimes extracted using this technique are observed to be inversely proportional to both carbon and nitrogen doping. As with conventional C-doped GaAs HBTs, current soaking (i.e. burn-in) is found to have a significant impact on GaInAsN HBTs. While we can replicate poor as-grown lifetimes consistent with those reported in photovoltaic dilute nitride materials, our best material to date exhibits nearly 30 × higher lifetime after current soaking.

  16. AlGaAs/InGaAsN/GaAs PnP double heterojunction bipolar transistor

    SciTech Connect

    Chang, P.C.; Baca, A.G.; Li, N.Y.; Sharps, P.R.; Hou, H.Q.; Laroche, J.R.; Ren, F.

    2000-01-04

    The authors demonstrated a functional PnP double heterojunction bipolar transistor (DHBT) using AlGaAs, InGaAsN, and GaAs. The band alignment between InGaAsN and GaAs has a large {triangle}E{sub c} and negligible {triangle}E{sub v}, this unique characteristic is very suitable for PnP DHBT applications. The metalorganic vapor phase epitaxy (MOCVD) grown Al{sub 0.3}Ga{sub 0.7}As/In{sub 0.03}Ga{sub 0.97}As{sub 0.99}N{sub 0.01}/GaAs PnP DHBT is lattice matched to GaAs and has a peak current gain of 25. Because of the smaller bandgap (E{sub g}=1.20eV) of In{sub 0.03}Ga{sub 0.97}As{sub 0.99}N{sub 0.01} used for the base layer, this device has a low V{sub ON} of 0.79 V, which is 0.25 V lower than in a comparable Pnp AlGaAs/GaAs HBT. And because GaAs is used for the collector, its BV{sub CEO} is 12 V, consistent with BV{sub CEO} of AlGaAs/GaAs HBTs.

  17. Correlated noise in bipolar transistors: Model implementation issues

    NASA Astrophysics Data System (ADS)

    Huszka, Zoltan; Chakravorty, Anjan

    2015-12-01

    A new orthogonalization scheme is suggested for implementing correlated noise of bipolar transistors. The scheme provides a necessary condition on the non-quasi-static (NQS) models that can be used to obtain an implementation-suitable correlated noise model. One of the solutions presented here corresponds to a single node realization not reported so far. The gm -factor is introduced in the noise analysis explaining the deviations of a former noise model from device simulations. The model is extended to include the collector space-charge-region induced noise by retaining the simplicity of the realization and preserving the model parameter count.

  18. Current dependence of base-collector capacitance of bipolar transistors

    NASA Astrophysics Data System (ADS)

    Liu, William; Harris, James S.

    1992-08-01

    We present analytical expressions for the base-collector capacitance of bipolar transistors in three operating conditions as the collector current density is continuously increased until the collector is fully depleted. A simple model is also presented to calculate this capacitance after base pushout occurs. The critical current densities separating each operating condition are discussed. The capacitance as a function of current density is calculated for various base-collector biases, collector thicknesses and collector dopings. The calculated results of this simple base-collector capacitance model are in close agreement with SEDAN simulation results. In addition, these results are shown to agree with published experimental work.

  19. Single-event burnout of power bipolar junction transistors

    SciTech Connect

    Titus, J.L. ); Johnson, G.H.; Schrimpf, R.D.; Galloway, K.F. . Dept. of Electrical and Computer Engineering)

    1991-12-01

    Experimental evidence of single-event burnout of power bipolar junctions transistors (BJTs) is reported for the first time. Several commercial power BJTs were characterized in a simulated cosmic ray environment using mono-energetic ions at the tandem Van de Graaff accelerator facility at Brookhaven National Laboratory. Most of the device types exposed to this simulated environment exhibited burnout behavior. In this paper the experimental technique, data, and results are presented, while a qualitative model is used to help explain those results and trends observed in this experiment.

  20. Inversion-mode GaAs wave-shaped field-effect transistor on GaAs (100) substrate

    SciTech Connect

    Zhang, Jingyun; Si, Mengwei; Wu, Heng; Ye, Peide D.; Lou, Xiabing; Gordon, Roy G.; Shao, Jiayi; Manfra, Michael J.

    2015-02-16

    Inversion-mode GaAs wave-shaped metal-oxide-semiconductor field-effect transistors (WaveFETs) are demonstrated using atomic-layer epitaxy of La{sub 2}O{sub 3} as gate dielectric on (111)A nano-facets formed on a GaAs (100) substrate. The wave-shaped nano-facets, which are desirable for the device on-state and off-state performance, are realized by lithographic patterning and anisotropic wet etching with optimized geometry. A well-behaved 1 μm gate length GaAs WaveFET shows a maximum drain current of 64 mA/mm, a subthreshold swing of 135 mV/dec, and an I{sub ON}/I{sub OFF} ratio of greater than 10{sup 7}.

  1. The effects of gamma irradiation on neutron displacement sensitivity of lateral PNP bipolar transistors

    NASA Astrophysics Data System (ADS)

    Wang, Chenhui; Chen, Wei; Liu, Yan; Jin, Xiaoming; Yang, Shanchao; Qi, Chao

    2016-09-01

    The effects of gamma irradiation on neutron displacement sensitivity of four types of lateral PNP bipolar transistors (LPNPs) with different neutral base widths, emitter widths and the doping concentrations of the epitaxial base region are studied. The physical mechanisms of the effects are explored by defect analysis using deep level transient spectroscopy (DLTS) techniques and numerical simulations of recombination process in the base region of the lateral PNP bipolar transistors, and are verified by the experiments on gate-controlled lateral PNP bipolar transistors (GCLPNPs) manufactured in the identical commercial bipolar process with different gate bias voltage. The results indicate that gamma irradiation increases neutron displacement damage sensitivity of lateral PNP bipolar transistors and the mechanism of this phenomenon is that positive charge induced by gamma irradiation enhances the recombination process in the defects induced by neutrons in the base region, leading to larger recombination component of base current and greater gain degradation.

  2. Radiation effects on junction field-effect transistors (JFETS), MOSFETs, and bipolar transistors, as related to SSC circuit design

    SciTech Connect

    Kennedy, E.J. Oak Ridge National Lab., TN ); Alley, G.T.; Britton, C.L. Jr. ); Skubic, P.L. ); Gray, B.; Wu, A. )

    1990-01-01

    Some results of radiation effects on selected junction field-effect transistors, MOS field-effect transistors, and bipolar junction transistors are presented. The evaluations include dc parameters, as well as capacitive variations and noise evaluations. The tests are made at the low current and voltage levels (in particular, at currents {le}1 mA) that are essential for the low-power regimes required by SSC circuitry. Detailed noise data are presented both before and after 5-Mrad (gamma) total-dose exposure. SPICE radiation models for three high-frequency bipolar processes are compared for a typical charge-sensitive preamplifier.

  3. Bipolar transistor degradation under dynamic hot carrier stress

    NASA Astrophysics Data System (ADS)

    Horiuchi, Tadahiko; David Burnett, J.; Hu, Chenming

    1995-04-01

    Hot carrier induced bipolar transistor degradation under dynamic stress is studied. The model, ΔIB ∝ ( IR1.8t) 0.5, established from d.c. emitter-base reverse bias stress measurements is found to be still valid under pulse stress down to 20 ns pulse width, where ΔIB is drift of base current, IR is reverse emitter-base current under stress and t is stress time. Although partial degradation recovery is observed under d.c. emitter-base forward bias, ΔIB from alternating reverse-forward stress representative BiCMOS circuit operation agrees with the ΔIB model with no significant recovery effect. This is explained by a higher degradation rate after recovery of previous damage. An experimental basis of BiCMOS circuit reliability testing simulation is thus provided.

  4. Hardening measures for bipolar transistors against microwave-induced damage

    NASA Astrophysics Data System (ADS)

    Chai, Chang-Chun; Ma, Zhen-Yang; Ren, Xing-Rong; Yang, Yin-Tang; Zhao, Ying-Bo; Yu, Xin-Hai

    2013-06-01

    In the present paper we study the influences of the bias voltage and the external components on the damage progress of a bipolar transistor induced by high-power microwaves. The mechanism is presented by analyzing the variation in the internal distribution of the temperature in the device. The findings show that the device becomes less vulnerable to damage with an increase in bias voltage. Both the series diode at the base and the relatively low series resistance at the emitter, Re, can obviously prolong the burnout time of the device. However, Re will aid damage to the device when the value is sufficiently high due to the fact that the highest hot spot shifts from the base-emitter junction to the base region. Moreover, the series resistance at the base Rb will weaken the capability of the device to withstand microwave damage.

  5. Development of gallium nitride-based PNP heterojunction bipolar transistors

    NASA Astrophysics Data System (ADS)

    Green, Daniel S.

    GaN-based electronics have progressed mightily in the last 15 years. The primary focus of this development has been the AlGaN/GaN heterostructure FET, with the commercialization of this device in progress. Bipolar transistors however offer a few key potential advantages over the FET device, including the primary advantage of normally off operation. Additionally, the pnp heterostructure bipolar transistor (HBT) in particular offers more attractive base performance relative to the npn HBT. The pnp HBT also serves as an excellent test vehicle for the several material parameters of p-Gan that remain poor defined. However, implementation of the pnp HBT has been limited by the difficulty contacting p-GaN collector material. This work was designed to demonstrate and understand the pnp HBT. The research served as both an engineering challenge as well as an investigation of physical parameters governing the transport in the device. In order to remedy the poor collector contact available with buried p-GaN, a transformation diode HBT structure was introduced that added an n-type subcollector the HBT structure. This allowed for good collector contact at the cost of introducing an offset voltage to the HBT performance due to the turn-on voltage of the transformation diode under normal operation. The first transformation diode HBT in GaN was successful demonstrated. In order to improve the transformation diode performance, successive design iterations were performed to isolate the performance limiting elements. Device designs were implemented to mitigate saturated hole velocity, as well as to decrease base transit time through aggressive base scaling and compositional grading. Physical simulations and modelling of device non-idealities were used to understand actual device performance. Hole lifetime and saturated hole velocity were identified as primary contributors to lower than expected performance device performance. Successive device iterations yielded HBT performance of

  6. Neutron effects on the electrical and switching characteristics of NPN bipolar power transistors

    NASA Technical Reports Server (NTRS)

    Frasca, Albert J.; Schwarze, Gene E.

    1988-01-01

    The use of nuclear reactors to generate electrical power for future space missions will require the electrical components used in the power conditioning, control, and transmission subsystem to operate in the associated radiation environments. An initial assessment of neutron irradiation on the electrical and switching characteristics of commercial high power NPN bipolar transistors was investigated. The results clearly show the detrimental effects caused by neutron irradiation on the electrical and switching characteristics of the NPN bipolar power transistor.

  7. Electric field perturbation due to impurities in GaAs through single electron transistor

    NASA Astrophysics Data System (ADS)

    Abdalla, S.

    2009-11-01

    The present work shows the presence of inevitable impurities in the semi-insulating GaAs domains when one is developing a single electron transistor (SET) and alters the quantization mechanism of single electron tunneling through the island. It is also indicated that these impurities decrease the amount of energy required to change the number of electrons on the island, which leads to a drastic reduction of SET quality. A theoretical model has been presented for elucidating the I- V characteristics of GaAs nano-crystals. It is found that this proposed model fits well the experimental data.

  8. Optimisation of trench isolated bipolar transistors on SOI substrates by 3D electro-thermal simulations

    NASA Astrophysics Data System (ADS)

    Nigrin, S.; Armstrong, G. A.; Kranti, A.

    2007-09-01

    This paper provides a comprehensive analysis of thermal resistance of trench isolated bipolar transistors on SOI substrates based on 3D electro-thermal simulations calibrated to experimental data. The impact of emitter length, width, spacing and number of emitter fingers on thermal resistance is analysed in detail. The results are used to design and optimise transistors with minimum thermal resistance and minimum transistor area.

  9. Molecular beam epitaxy of gallium arsenide antimonide-based ultra-high-speed double heterojunction bipolar transistors and light emitting transistors

    NASA Astrophysics Data System (ADS)

    Wu, Bing-Ruey

    In this work, GaAsSb-based double heterojunction bipolar transistors (DHBTs) and light emitting transistors (LETs) are grown using gas source molecular beam epitaxy (GSMBE). High-speed GaAs0.5Sb0.5/InP DHBTs are developed through the exercise of GSMBE growth optimization, device fabrication, and characterization. By adjusting the growth temperature and V/III flux ratio, the optimal conditions for growing GaAs0.5Sb0.5 base are found to be at high growth temperature and low V/III ratio. The switching sequence is also optimized so that the Sb segregation effect is minimized. By using GaAs0.5Sb0.5-In0.2Ga0.8As 0.7Sb0.3 compositional grading in the base of the GaAsSb/InP DHBT, a significant improvement of fT from 380 GHz to 500 GHz was achieved compared to a uniform GaAs0.5Sb 0.5 DHBT, while maintaining a high breakdown voltage BVCEO ˜ 4V. The cutoff frequency---breakdown voltage product, fT·BVCEO, of over 2000 GHz-V, is the record value for DHBTs of any material system. Incorporating graded InAs-InGaAs emitter contact layer is also shown to effectively reduce the total emitter resistance, further improving the DHBT high speed performance. LET characteristics with quantum wells (QWs) inserted into the base region of GaAsSb/InP DHBTs are also investigated and the preliminary results are presented. An LET with a tensile strained InGaAsSb/GaAs0.65Sb 0.35 DQW in the base was designed and achieved the emission wavelength of ˜1.6 mum, despite of its low light output intensity. The potential and limitation of realizing a transistor laser with an emission wavelength of 1.55 mum using GaAsSb/InP material system will be discussed.

  10. Low-temperature characteristics of the current gain of GaN/InGaN double-heterojunction bipolar transistors

    NASA Astrophysics Data System (ADS)

    Nishikawa, Atsushi; Kumakura, Kazuhide; Kasu, Makoto; Makimoto, Toshiki

    2009-05-01

    We investigated the temperature dependence of the current gain of npn-type GaN/InGaN double-heterojunction bipolar transistors (DHBTs) in the low-temperature region. The current gain increased with decrease in device temperature due to the reduction of the recombination current in the p-type base layer. The current gain reached as high as 5000 at 40 K, which is the highest among nitride-based HBTs. For conventional HBTs made of InP or GaAs, the current gain decreased with decreasing device temperature. However, no reduction of the current gain was observed in this study, suggesting that the minority carrier mobility in the p-type InGaN base layer has negative temperature dependence, presumably because the ionized impurity scattering is relatively unaffected owing to the carrier freezeout and the high activation energy of Mg in the p-InGaN base layer.

  11. Radiation induced deep level defects in bipolar junction transistors under various bias conditions

    NASA Astrophysics Data System (ADS)

    Liu, Chaoming; Yang, Jianqun; Li, Xingji; Ma, Guoliang; Xiao, Liyi; Bollmann, Joachim

    2015-12-01

    Bipolar junction transistor (BJT) is sensitive to ionization and displacement radiation effects in space. In this paper, 35 MeV Si ions were used as irradiation source to research the radiation damage on NPN and PNP bipolar transistors. The changing of electrical parameters of transistors was in situ measured with increasing irradiation fluence of 35 MeV Si ions. Using deep level transient spectroscopy (DLTS), defects in the bipolar junction transistors under various bias conditions are measured after irradiation. Based on the in situ electrical measurement and DLTS spectra, it is clearly that the bias conditions can affect the concentration of deep level defects, and the radiation damage induced by heavy ions.

  12. Neutron Radiation Effect On 2N2222 And NTE 123 NPN Silicon Bipolar Junction Transistors

    NASA Astrophysics Data System (ADS)

    Oo, Myo Min; Rashid, N. K. A. Md; Karim, J. Abdul; Zin, M. R. Mohamed; Hasbullah, N. F.

    2013-12-01

    This paper examines neutron radiation with PTS (Pneumatic Transfer System) effect on silicon NPN bipolar junction transistors (2N2222 and NTE 123) and analysis of the transistors in terms of electrical characterization such as current gain after neutron radiation. The key parameters are measured with Keithley 4200SCS. Experiment results show that the current gain degradation of the transistors is very sensitive to neutron radiation. The neutron radiation can cause displacement damage in the bulk layer of the transistor structure. The current degradation is believed to be governed by increasing recombination current between the base and emitter depletion region.

  13. Single-hole transistor in p-type GaAs /AlGaAs heterostructures

    NASA Astrophysics Data System (ADS)

    Grbić, Boris; Leturcq, Renaud; Ensslin, Klaus; Reuter, Dirk; Wieck, Andreas D.

    2005-12-01

    A single-hole transistor is patterned in a p-type, C-doped GaAs /AlGaAs heterostructure by scanning probe oxidation lithography. Clear Coulomb blockade resonances have been observed at Thole=300mK. A charging energy of ˜1.5meV is extracted from Coulomb diamond measurements, in agreement with the lithographic dimensions of the dot. The absence of excited states in Coulomb diamond measurements, as well as the temperature dependence of Coulomb peak heights indicate that the dot is in the multilevel transport regime. Fluctuations in peak spacings larger than the estimated mean single-particle level spacing are observed.

  14. 300 Degree C GaN/AlGaN Heterojunction Bipolar Transistor

    SciTech Connect

    Abernathy, C.R.; Baca, A.G.; Cho, H.; Chow, P.P.; Han, J.; Hichman, R.A.; Jung, K.B.; Kopf, R.F.; La Roche, J.R.; Pearton, S.J.; Ren, F.; Shul, R.J.; Van Hove, J.M.; Wilson, R.G.

    1998-10-14

    A GaN/AIGaN heterojunction bipolar transistor has been fabricated using C12/Ar dry etching for mesa formation. As the hole concentration increases due to more efficient ionization of the Mg acceptors at elevated temperatures (> 250oC), the device shows improved gain. Future efforts which are briefly summarized. should focus on methods for reducing base resistance.

  15. Using Animation to Improve the Students' Academic Achievement on Bipolar Junction Transistor

    ERIC Educational Resources Information Center

    Zoabi, W.; Sabag, N.; Gero, A.

    2012-01-01

    Teaching abstract subjects to students studying towards a degree in electronics practical engineering (a degree between a technician and an engineer) requires didactic tools that enable understanding of issues without using advanced mathematics and physics. One basic issue is the BJT (Bipolar Junction Transistor) that requires preliminary…

  16. Negative Differential Transconductance in Silicon Quantum Well MOSFET/Bipolar Hybrid Transistors

    NASA Astrophysics Data System (ADS)

    Naquin, Clint; Lee, Mark; Edwards, Hal; Chatterjee, Tathagata; Mathur, Guru; Maggio, Ken; Univ of Texas, Dallas/Texas Instruments Collaboration

    2015-03-01

    Introducing explicit quantum transport into Si transistors in a manner amenable to industrial fabrication has proven challenging. Hybrid field-effect / bipolar Si transistors fabricated on an industrial 45 nm process line are shown to demonstrate explicit quantum transport signatures. These transistors incorporate a lateral ion implantation-defined quantum well (QW) whose potential depth is controlled by a gate voltage (VG). Quantum transport in the form of negative differential transconductance (NDTC) is observed to temperatures >200 K. The NDTC is tied to a non-monotonic dependence of bipolar current gain on VG that reduces drain-source current through the QW. These devices establish the feasibility of exploiting quantum transport to transform the performance horizons of Si devices fabricated in an industrially scalable manner. Supported by Semiconductor Research Council Task Number 1836.145.

  17. Transferred substrate heterojunction bipolar transistors for submillimeter wave applications

    NASA Technical Reports Server (NTRS)

    Fung, A.; Samoska, L.; Siegel, P.; Rodwell, M.; Urteaga, M.; Paidi, V.

    2003-01-01

    We present ongoing work towards the development of submillimeter wave transistors with goals of realizing advanced high frequency amplifiers, voltage controlled oscillators, active multipliers, and traditional high-speed digital circuits.

  18. A high-voltage optoelectronic GaAs static induction transistor

    SciTech Connect

    Hadizad, P.; Hur, J.H.; Zhao, H.; Kaviani, K.; Gundersen, M.A. ); Fetterman, H.R. )

    1993-04-01

    Experimental realization of an optically activated, high-voltage GaAs static induction transistor (SIT) is reported. In the forward blocking state, the breakdown voltage of the device was [approximately]200 V, while in the conduction state, on-state current densities exceeding 150 A/cm[sup 2] were obtained. In the floating-gate configuration (gate open), the specific on-resistance of the device was [approximately]50 m[Omega] [center dot] cm[sup 2]. Optical modulation of the device was achieved using a compact semiconductor laser array as the triggering source, In this mode, a gate-coupled RC network was implemented, resulting in an average switching energy gain (load energy/optical energy) of [approximately]30. This mode of operation is applicable to series-coupled devices for pulsed switching at higher power levels.

  19. Emitter space charge layer transit time in bipolar junction transistors

    NASA Astrophysics Data System (ADS)

    Rustagi, S. C.; Chattopadhyaya, S. K.

    1981-04-01

    The charge defined emitter space charge layer transit times of double diffused transistors have been calculated using a regional approach, and compared with the corresponding base transit times. The results obtained for emitter space-charge layer transit times have been discussed with reference to the capacitance analysis of Morgan and Smit (1960) for graded p-n junctions.

  20. Bipolar Junction Transistors in Two-Dimensional WSe2 with Large Current and Photocurrent Gains.

    PubMed

    Agnihotri, Pratik; Dhakras, Prathamesh; Lee, Ji Ung

    2016-07-13

    In the development of semiconductor devices, the bipolar junction transistor (BJT) features prominently as being the first solid state transistor that helped to usher in the digital revolution. For any new semiconductor, therefore, the fabrication and characterization of the BJT are important for both technological importance and historical significance. Here, we demonstrate a BJT device in exfoliated TMD semiconductor WSe2. We use buried gates to electrostatically create doped regions with back-to-back p-n junctions. We demonstrate two central characteristics of a bipolar device: current gain when operated as a BJT and a photocurrent gain when operated as a phototransistor. We demonstrate a current gain of 1000 and photocurrent gain of 40 and describe features that enhance these properties due to the doping technique that we employ. PMID:27336742

  1. Unified planar process for fabricating heterojunction bipolar transistors and buried-heterostructure lasers utilizing impurity-induced disordering

    SciTech Connect

    Thornton, R.L.; Mosby, W.J.; Chung, H.F.

    1988-12-26

    We describe results on a novel geometry of heterojunction bipolar transistor that has been realized by impurity-induced disordering. This structure is fabricated by a method that is compatible with techniques for the fabrication of low threshold current buried-heterostructure lasers. We have demonstrated this compatibility by fabricating a hybrid laser/transistor structure that operates as a laser with a threshold current of 6 mA at room temperature, and as a transistor with a current gain of 5.

  2. Unified planar process for fabricating heterojunction bipolar transistors and buried-heterostructure lasers utilizing impurity-induced disordering

    NASA Astrophysics Data System (ADS)

    Thornton, R. L.; Mosby, W. J.; Chung, H. F.

    1988-12-01

    We describe results on a novel geometry of heterojunction bipolar transistor that has been realized by impurity-induced disordering. This structure is fabricated by a method that is compatible with techniques for the fabrication of low threshold current buried-heterostructure lasers. We have demonstrated this compatibility by fabricating a hybrid laser/transistor structure that operates as a laser with a threshold current of 6 mA at room temperature, and as a transistor with a current gain of 5.

  3. On the AlGaInP-bulk and AlGaInP/GaAs-superlattice confinement effects for heterostructure-emitter bipolar transistors

    SciTech Connect

    Tsai, Jung-Hui

    2015-02-09

    The confinement effect and electrical characteristics of heterostructure-emitter bipolar transistors with an AlGaInP bulk-confinement layer and an AlGaInP/GaAs superlattice-confinement layer are first demonstrated and compared by experimentally results. In the two devices, the relatively large valence band discontinuity at AlGaInP/GaAs heterojunction provides excellent confinement effect for holes to enhance current gain. As to the AlGaInP/GaAs superlattice-confinement device, part of thermionic-emission electrons will be trapped in the GaAs quantum wells of the superlattice. This will result in lower collector current and current gain as compared with the bulk-confinement device. Nevertheless, the superlattice-confinement device exhibits a larger current-gain cutoff frequency, which can be attributed that the tunneling behavior is included in the carrier transportation and transporting time across the emitter region could be substantially reduced.

  4. Experimental Analysis of Proton-Induced Displacement and Ionization Damage Using Gate-Controlled Lateral PNP Bipolar Transistors

    NASA Technical Reports Server (NTRS)

    Ball, D. R.; Schrimpf, R. D.; Barnaby, H. J.

    2006-01-01

    The electrical characteristics of proton-irradiated bipolar transistors are affected by ionization damage to the insulating oxide and displacement damage to the semiconductor bulk. While both types of damage degrade the transistor, it is important to understand the mechanisms individually and to be able to analyze them separately. In this paper, a method for analyzing the effects of ionization and displacement damage using gate-controlled lateral PNP bipolar junction transistors is described. This technique allows the effects of oxide charge, surface recombination velocity, and bulk traps to be measured independently.

  5. Ionizing/displacement synergistic effects induced by gamma and neutron irradiation in gate-controlled lateral PNP bipolar transistors

    NASA Astrophysics Data System (ADS)

    Wang, Chenhui; Chen, Wei; Yao, Zhibin; Jin, Xiaoming; Liu, Yan; Yang, Shanchao; Wang, Zhikuan

    2016-09-01

    A kind of gate-controlled lateral PNP bipolar transistor has been specially designed to do experimental validations and studies on the ionizing/displacement synergistic effects in the lateral PNP bipolar transistor. The individual and mixed irradiation experiments of gamma rays and neutrons are accomplished on the transistors. The common emitter current gain, gate sweep characteristics and sub-threshold sweep characteristics are measured after each exposure. The results indicate that under the sequential irradiation of gamma rays and neutrons, the response of the gate-controlled lateral PNP bipolar transistor does exhibit ionizing/displacement synergistic effects and base current degradation is more severe than the simple artificial sum of those under the individual gamma and neutron irradiation. Enough attention should be paid to this phenomenon in radiation damage evaluation.

  6. Device characteristics of GaAs-based heterojunction bipolar transistors using an InGaAs/GaAsP strain-compensated layer as a base material

    NASA Astrophysics Data System (ADS)

    Wu, Cheng-Hsien; Su, Yan-Kuin; Chang, Shoou-Jinn; Huang, Ying-Sheng; Hsu, Hung-Pin

    2004-07-01

    An InGaAs/GaAsP strain-compensated layer has been proposed as a base material for GaAs-based double heterojunction bipolar transistors (DHBTs). As known, decreasing bandgap energy of the base layer in heterojunction bipolar transistors (HBTs) can result in a smaller turn-on voltage. Using InGaAs as a base material is one possible approach to achieve the aim. However, compressive strain induced by InGaAs diminishes the influence of indium-adding-induced bandgap energy reduction, and thus abates the advantage of turn-on voltage reduction. In this study, a 280 Å GaAs0.81P0.19 layer has been inserted below the In0.054Ga0.946As base layer to compensate the compressive strain induced by the InGaAs base layer. The result shows that the utilization of an InGaAs/GaAsP strain-compensated layer results in a reduction of the turn-on voltage by 20 mV. A turn-on voltage reduction of 190 mV over a conventional HBT with a GaAs base layer is achieved by utilizing the In0.054Ga0.946As/GaAs0.81P0.19 strain-compensated base layer. This particular DHBT has a small offset voltage of 55 mV and a knee voltage of 0.6 V. A peak current gain of 58.98, a unity-current-gain cut-off frequency fT of 22 GHz and a unilateral power gain cut-off frequency fMAX of 25 GHz are also achieved for this particular DHBT.

  7. High-performance K-band GaAs power field-effect transistors prepared by molecular beam epitaxy

    NASA Technical Reports Server (NTRS)

    Saunier, P.; Shih, H. D.

    1983-01-01

    The maturity of the molecular beam epitaxy (MBE) technique for preparing device quality GaAs material for microwave applications is demonstrated by the excellent performance characteristics of K-band GaAs power field-effect transistors (FETs) fabricated on the MBE wafers. An output power of 710 mW with 4.5-dB gain and 17.7 percent power-added efficiency was achieved at 21 GHz with a 1.26-mm gate width pi-gate device. A similar device with a 0.56-mm gate width produced an output power of 320 mW with 5.0-dB gain and 26.6 percent power-added efficiency at 21 GHz. These are the best results yet reported to date for GaAs power FETs operated in the K-band frequency range.

  8. High-performance GaAs metal-insulator-semiconductor field-effect transistors enabled by self-assembled nanodielectrics

    NASA Astrophysics Data System (ADS)

    Lin, H. C.; Ye, P. D.; Xuan, Y.; Lu, G.; Facchetti, A.; Marks, T. J.

    2006-10-01

    High-performance GaAs metal-insulator-semiconductor field-effect-transistors (MISFETs) fabricated with very thin self-assembled organic nanodielectrics (SANDs), deposited from solution at room temperature, are demonstrated. A submicron gate-length depletion-mode n-channel GaAs MISFET with SAND thicknesses ranging from 5.5to16.5nm exhibit a gate leakage current density <10-5A/cm2 at a gate bias smaller than 3V, a maximum drain current of 370mA/mm at a forward gate bias of 2V, and a maximum intrinsic transconductance of 170mS/mm. The importance of appropriate GaAs surface chemistry treatments on SAND/GaAs interface properties is also presented. Application of SANDs to III-V compound semiconductors affords more opportunities to manipulate the complex III-V surface chemistry with broad materials options.

  9. Residual phase noise modeling of amplifiers using silicon bipolar transistors.

    PubMed

    Theodoropoulos, Konstantinos; Everard, Jeremy

    2010-03-01

    In this paper, we describe the modeling of residual 1/f phase noise for Si bipolar amplifiers operating in the linear region. We propose that for Si bipolar amplifiers, the 1/f phase noise is largely caused by the base emitter recombination flicker noise. The up-conversion mechanism is described through linear approximation of the phase variation of the amplifier phase response by the variation of the device parameters (C(b)c, C(be), g(m), r(e)) caused by the recombination 1/f noise. The amplifier phase response describes the device over the whole frequency range of operation for which the influence of the poles and zeros is investigated. It is found that for a common emitter amplifier it is sufficient to only incorporate the effect of the device poles to describe the phase noise behavior over most of its operational frequency range. Simulations predict the measurements of others, including the flattening of the PM noise at frequencies beyond f(3dB), not predicted by previous models.

  10. Investigation and application of neutron damage to bipolar transistors in light water reactor dosimetry

    SciTech Connect

    Roknizadeh, M.

    1987-01-01

    A method of fast neutron metrology and a basis for prediction of changes in performance parameters of semiconductor devices in power plant radiation environments has been established using Cf-252 sources. Three general purpose NPN bipolar transistors (PN2222A, ECG-196, and ECG-184) were chosen as the neutron damage monitors and the change in inverse d.c. current gain before and after irradiation was chosen as the damage parameter for the measurement. The main findings of the investigation were as follows: the change in inverse d.c. current gain for PN2222A transistors was approximately a linear function of the neutron fluence up to 2.0E15 n(1MeV)/cm/sup 2/. The concept of 1-MeV equivalent neutron fluence which characterizes an incident energy-fluence spectrum in terms of the fluence of monoenergetic neutrons at 1 MeV, is in error for application to common transistors in a typical power plant environment. Finally, the normalized damage coefficient which is the ratio of damage to 1-MeV equivalent neutron fluence divided by the measured base transit time of individual transistors, for all three types of transistors is nearly the same with an average value of 1.27E - 7 +/- 15.0% cm/sup 2//m(1 MeV).Sec.

  11. Investigation of deep level defects in copper irradiated bipolar junction transistor

    NASA Astrophysics Data System (ADS)

    Madhu, K. V.; Kumar, Ravi; Ravindra, M.; Damle, R.

    2008-08-01

    Commercial bipolar junction transistor (2N 2219A, npn) irradiated with 150 MeV Cu11+-ions with fluence of the order 1012 ions cm-2, is studied for radiation induced gain degradation and deep level defects. I-V measurements are made to study the gain degradation as a function of ion fluence. The properties such as activation energy, trap concentration and capture cross-section of deep levels are studied by deep level transient spectroscopy (DLTS). Minority carrier trap levels with energies ranging from EC - 0.164 eV to EC - 0.695 eV are observed in the base-collector junction of the transistor. Majority carrier trap levels are also observed with energies ranging from EV + 0.203 eV to EV + 0.526 eV. The irradiated transistor is subjected to isothermal and isochronal annealing. The defects are seen to anneal above 350 °C. The defects generated in the base region of the transistor by displacement damage appear to be responsible for transistor gain degradation.

  12. Reduction method for low-frequency noise of GaAs junction field-effect transistor at a cryogenic temperature

    NASA Astrophysics Data System (ADS)

    Fujiwara, M.; Sasaki, M.; Akiba, M.

    2002-03-01

    A GaAs junction field-effect transistor (JFET) is a promising candidate for low-frequency, low-noise, and low-power cryogenic electronics to read out high-impedance photodetectors. We report on the spectral noise characteristics of a SONY n-type GaAs JFET, operating at the depression mode, at a cryogenic temperature of 4.2 K. If the GaAs JFET is turned on at 4.2 K, a random telegraph signal (RTS) is found to be the dominant noise source at low frequencies. However, the switching rate of RTS can be drastically reduced if the GaAs JFET is heated up to 55 K and cooled down again to 4.2 K while keeping the same drain current flow. We refer to this phenomenon as the thermal cure (TC). With TC, low-frequency noise can be reduced to below 1 μV/Hz1/2 at 1 Hz. The critical temperature for TC is found to be ˜35 K for our GaAs JFET.

  13. Efficient far-infrared thermal bremsstrahlung radiation from a heterojunction bipolar transistor

    SciTech Connect

    Chung, Pei-Kang; Yen, Shun-Tung

    2015-08-28

    We investigate the far-infrared thermal radiation properties of a heterojunction bipolar transistor. The device conveniently provides a high electric field for electrons to heat the lattice and the electron gas in a background with ions embedded. Because of very high effective temperature of the electron gas in the collector, the electron-ion bremsstrahlung makes efficient the thermal radiation in the far-infrared region. The transistor can yield a radiation power of 0.1 mW with the spectral region between 2 and 75 THz and a power conversion efficiency of 6 × 10{sup −4}. Such output contains a power of 20 μW in the low-frequency part (2–20 THz) of the spectrum.

  14. Radiation effects on bipolar junction transistors and integrated circuits produced by different energy Br ions

    NASA Astrophysics Data System (ADS)

    Li, Xingji; Geng, Hongbin; Liu, Chaoming; Zhao, Zhiming; Lan, Mujie; Yang, Dezhuang; He, Shiyu

    2009-12-01

    The radiation responses of the NPN bipolar junction transistors (BJTs) and the TTL bipolar integrated circuits (ICs) have been examined using 20, 40 and 60 MeV Br ions. Key electric parameter was measured and compared after each energy irradiation. Experimental results demonstrate that the degradation in electric parameters caused by the Br ions shows a common feature for the NPN BJTs and TTL ICs, in which the degradation is strengthened with decreasing the Br ions energy. The ionizing dose ( D i) and displacement dose ( D d) as a function of the chip depth in the bipolar devices were calculated using the SRIM code, in order to analyze the radiation effects on the NPN BJTs and the Bipolar ICs. From the experiment and calculation results, it could be deduced that the Br ions mainly cause displacement damage to both the NPN BJTs and the TTL ICs, and the higher the ratio of D d/( D d+D i), the larger the degradation in electric parameters at a given total dose.

  15. Evaluation of Enhanced Low Dose Rate Sensitivity in Discrete Bipolar Junction Transistors

    NASA Technical Reports Server (NTRS)

    Chen, Dakai; Ladbury Raymond; LaBel, Kenneth; Topper, Alyson; Ladbury, Raymond; Triggs, Brian; Kazmakites, Tony

    2012-01-01

    We evaluate the low dose rate sensitivity in several families of discrete bipolar transistors across device parameter, quality assurance level, and irradiation bias configuration. The 2N2222 showed the most significant low dose rate sensitivity, with low dose rate enhancement factor of 3.91 after 100 krad(Si). The 2N2907 also showed critical degradation levels. The devices irradiated at 10 mrad(Si)/s exceeded specifications after 40 and 50 krad(Si) for the 2N2222 and 2N2907 devices, respectively.

  16. Terahertz emission from collapsing field domains during switching of a gallium arsenide bipolar transistor.

    PubMed

    Vainshtein, Sergey; Kostamovaara, Juha; Yuferev, Valentin; Knap, Wojciech; Fatimy, Abdel; Diakonova, Nina

    2007-10-26

    Broadband pulsed THz emission with peak power in the sub-mW range has been observed experimentally during avalanche switching in a gallium arsenide bipolar junction transistor at room temperature, while significantly higher total generated power is predicted in simulations. The emission is attributed to very fast oscillations in the conductivity current across the switching channels, which appear as a result of temporal evolution of the field domains generated in highly dense electron-hole plasma. This plasma is formed in turn by powerful impact ionization in multiple field domains of ultrahigh amplitude.

  17. Large-scale transient sensitivity analysis of a radiation damaged bipolar junction transistor.

    SciTech Connect

    Hoekstra, Robert John; Gay, David M.; Bartlett, Roscoe Ainsworth; Phipps, Eric Todd

    2007-11-01

    Automatic differentiation (AD) is useful in transient sensitivity analysis of a computational simulation of a bipolar junction transistor subject to radiation damage. We used forward-mode AD, implemented in a new Trilinos package called Sacado, to compute analytic derivatives for implicit time integration and forward sensitivity analysis. Sacado addresses element-based simulation codes written in C++ and works well with forward sensitivity analysis as implemented in the Trilinos time-integration package Rythmos. The forward sensitivity calculation is significantly more efficient and robust than finite differencing.

  18. SEMICONDUCTOR DEVICES: A symbolically defined InP double heterojunction bipolar transistor large-signal model

    NASA Astrophysics Data System (ADS)

    Yuxiong, Cao; Zhi, Jin; Ji, Ge; Yongbo, Su; Xinyu, Liu

    2009-12-01

    A self-built accurate and flexible large-signal model based on an analysis of the characteristics of InP double heterojunction bipolar transistors (DHBTs) is implemented as a seven-port symbolically defined device (SDD) in Agilent ADS. The model accounts for most physical phenomena including the self-heating effect, Kirk effect, soft knee effect, base collector capacitance and collector transit time. The validity and the accuracy of the large-signal model are assessed by comparing the simulation with the measurement of DC, multi-bias small signal S parameters for InP DHBTs.

  19. Total dose and dose rate models for bipolar transistors in circuit simulation.

    SciTech Connect

    Campbell, Phillip Montgomery; Wix, Steven D.

    2013-05-01

    The objective of this work is to develop a model for total dose effects in bipolar junction transistors for use in circuit simulation. The components of the model are an electrical model of device performance that includes the effects of trapped charge on device behavior, and a model that calculates the trapped charge densities in a specific device structure as a function of radiation dose and dose rate. Simulations based on this model are found to agree well with measurements on a number of devices for which data are available.

  20. Bias dependence of synergistic radiation effects induced by electrons and protons on silicon bipolar junction transistors

    NASA Astrophysics Data System (ADS)

    Liu, Chaoming; Li, Xingji; Yang, Jianqun; Ma, Guoliang; Xiao, Liyi

    2015-06-01

    Bias dependence on synergistic radiation effects caused by 110 keV electrons and 170 keV protons on the current gain of 3DG130 NPN bipolar junction transistors (BJTs) is studied in this paper. Experimental results indicate that the influence induced by 170 keV protons is always enhancement effect during the sequential irradiation. However, the influence induced by 110 keV electrons on the BJT under various bias cases is different during the sequential irradiation. The transition fluence of 110 keV electrons is dependent on the bias case on the emitter-base junction of BJT.

  1. T-shaped emitter metal heterojunction bipolar transistors for submillimeter wave applications

    NASA Technical Reports Server (NTRS)

    Fung, Andy; Samoska, Lorene; Velebir, Jim; Siege, Peter; Rodwell, Mark; Paidi, Vamsi; Griffth, Zach; Urteaga, Miguel; Malik, Roger

    2004-01-01

    We report on the development of submillimeter wave transistors at JPL. The goal of the effort is to produce advance-reliable high frequency and high power amplifiers, voltage controlled oscillators, active multipliers, and high-speed mixed-signal circuits for space borne applications. The technology in development to achieve this is based on the Indium Phosphide (InP) Heterojunction Bipolar Transistor (HBT). The HBT is well suited for high speed, high power and uniform (across wafer) performance, due to the ability to tailor the material structure that electrons traverse through by well-controlled epitaxial growth methods. InP with its compatible lattice matched alloys such as indium gallium arsenide (InGaAs) and indium aluminium arsenide (InAlAs) provides for high electron velocities and high voltage breakdown capabilities. The epitaxial methods for this material system are fairly mature, however the implementation of high performance and reliable transistors are still under development by many laboratories. Our most recently fabricated, second generation mesa HBTs at JPL have extrapolated current gain cutoff frequency (FJ of 142GHz and power gain cutoff frequency (Fm,) of approximately 160GHz. This represents a 13% and 33% improvement of Ft and F, respectively, compared to the first generation mesa HBTs [l]. Analysis based on the University of California, Santa Barbara (UCSB) device model, RF device characteristics can be significantly improved by reducing base contact resistance and base metal contact width. We will describe our effort towards increasing transistor performance and yield.

  2. Cryogenic Preamplification of a Single-Electron-Transistor using a Silicon-Germanium Heterojunction-Bipolar-Transistor

    SciTech Connect

    Curry, Matthew J.; England, Troy Daniel; Bishop, Nathaniel; Ten Eyck, Gregory A.; Wendt, Joel R.; Pluym, Tammy; Lilly, Michael; Carr, Stephen M; Carroll, Malcolm S.

    2015-05-21

    We examine a silicon-germanium heterojunction bipolar transistor (HBT) for cryogenic pre-amplification of a single electron transistor (SET). The SET current modulates the base current of the HBT directly. The HBT-SET circuit is immersed in liquid helium, and its frequency response from low frequency to several MHz is measured. The current gain and the noise spectrum with the HBT result in a signal-to-noise-ratio (SNR) that is a factor of 10–100 larger than without the HBT at lower frequencies. Furthermore, the transition frequency defined by SNR = 1 has been extended by as much as a factor of 10 compared to without the HBT amplification. The power dissipated by the HBT cryogenic pre-amplifier is approximately 5 nW to 5 μW for the investigated range of operation. We found that the circuit is also operated in a single electron charge read-out configuration in the time-domain as a proof-of-principle demonstration of the amplification approach for single spin read-out.

  3. Cryogenic preamplification of a single-electron-transistor using a silicon-germanium heterojunction-bipolar-transistor

    SciTech Connect

    Curry, M. J.; England, T. D.; Bishop, N. C.; Ten-Eyck, G.; Wendt, J. R.; Pluym, T.; Lilly, M. P.; Carroll, M. S.; Carr, S. M.

    2015-05-18

    We examine a silicon-germanium heterojunction bipolar transistor (HBT) for cryogenic pre-amplification of a single electron transistor (SET). The SET current modulates the base current of the HBT directly. The HBT-SET circuit is immersed in liquid helium, and its frequency response from low frequency to several MHz is measured. The current gain and the noise spectrum with the HBT result in a signal-to-noise-ratio (SNR) that is a factor of 10–100 larger than without the HBT at lower frequencies. The transition frequency defined by SNR = 1 has been extended by as much as a factor of 10 compared to without the HBT amplification. The power dissipated by the HBT cryogenic pre-amplifier is approximately 5 nW to 5 μW for the investigated range of operation. The circuit is also operated in a single electron charge read-out configuration in the time-domain as a proof-of-principle demonstration of the amplification approach for single spin read-out.

  4. Cryogenic Preamplification of a Single-Electron-Transistor using a Silicon-Germanium Heterojunction-Bipolar-Transistor

    DOE PAGESBeta

    Curry, Matthew J.; England, Troy Daniel; Bishop, Nathaniel; Ten Eyck, Gregory A.; Wendt, Joel R.; Pluym, Tammy; Lilly, Michael; Carr, Stephen M; Carroll, Malcolm S.

    2015-05-21

    We examine a silicon-germanium heterojunction bipolar transistor (HBT) for cryogenic pre-amplification of a single electron transistor (SET). The SET current modulates the base current of the HBT directly. The HBT-SET circuit is immersed in liquid helium, and its frequency response from low frequency to several MHz is measured. The current gain and the noise spectrum with the HBT result in a signal-to-noise-ratio (SNR) that is a factor of 10–100 larger than without the HBT at lower frequencies. Furthermore, the transition frequency defined by SNR = 1 has been extended by as much as a factor of 10 compared to withoutmore » the HBT amplification. The power dissipated by the HBT cryogenic pre-amplifier is approximately 5 nW to 5 μW for the investigated range of operation. We found that the circuit is also operated in a single electron charge read-out configuration in the time-domain as a proof-of-principle demonstration of the amplification approach for single spin read-out.« less

  5. Cryogenic preamplification of a single-electron-transistor using a silicon-germanium heterojunction-bipolar-transistor

    NASA Astrophysics Data System (ADS)

    Curry, M. J.; England, T. D.; Bishop, N. C.; Ten-Eyck, G.; Wendt, J. R.; Pluym, T.; Lilly, M. P.; Carr, S. M.; Carroll, M. S.

    2015-05-01

    We examine a silicon-germanium heterojunction bipolar transistor (HBT) for cryogenic pre-amplification of a single electron transistor (SET). The SET current modulates the base current of the HBT directly. The HBT-SET circuit is immersed in liquid helium, and its frequency response from low frequency to several MHz is measured. The current gain and the noise spectrum with the HBT result in a signal-to-noise-ratio (SNR) that is a factor of 10-100 larger than without the HBT at lower frequencies. The transition frequency defined by SNR = 1 has been extended by as much as a factor of 10 compared to without the HBT amplification. The power dissipated by the HBT cryogenic pre-amplifier is approximately 5 nW to 5 μW for the investigated range of operation. The circuit is also operated in a single electron charge read-out configuration in the time-domain as a proof-of-principle demonstration of the amplification approach for single spin read-out.

  6. The influence of a doping profile on the characteristics of an ion-implanted GaAs field-effect transistor with a Schottky barrier

    SciTech Connect

    Shestakov, A. K. Zhuravlev, K. S.

    2011-12-15

    A GaAs field-effect ion-implanted transistor with a Schottky barrier is simulated. The doping profile obtained when doping through an insulator mask is determined and the dependences of the static transistor characteristics on the parameters of the doping profile are calculated and analyzed. The physical processes controlling the transistor characteristics in the case of a variation in the parameters of its doping profile and the coefficient of compensation of the substrate are studied. Based on calculations, the optimal doping-profile parameters ensuring the best characteristics for transistors are predicted.

  7. Urea biosensor based on an extended-base bipolar junction transistor.

    PubMed

    Sun, Tai-Ping; Shieh, Hsiu-Li; Liu, Chun-Lin; Chen, Chung-Yuan

    2014-01-01

    In this study, a urea biosensor was prepared by the immobilization of urease onto the sensitive membrane of an extended-base bipolar junction transistor. The pH variation was used to detect the concentration of urea. The SnO2/ITO glass, fabricated by sputtering SnO2 on the conductive ITO glass, was used as a pH-sensitive membrane, which was connected with a commercial bipolar junction transistor device. The gels, fabricated by the poly vinyl alcohol with pendent styrylpyridinium groups, were used to immobilize the urease. This readout circuit, fabricated in a 0.35-um CMOS 2P4M process, operated at 3.3V supply voltage. This circuit occupied an area of 1.0 mm × 0.9 mm. The dynamic range of the urea biosensor was from 1.4 to 64 mg/dl at the 10 mM phosphate buffer solution and the sensitivity of this range was about 65.8 mV/pUrea. The effect of urea biosensors with different pH values was considered, and the characteristics of urea biosensors based on EBBJT were described. PMID:24211878

  8. Urea biosensor based on an extended-base bipolar junction transistor.

    PubMed

    Sun, Tai-Ping; Shieh, Hsiu-Li; Liu, Chun-Lin; Chen, Chung-Yuan

    2014-01-01

    In this study, a urea biosensor was prepared by the immobilization of urease onto the sensitive membrane of an extended-base bipolar junction transistor. The pH variation was used to detect the concentration of urea. The SnO2/ITO glass, fabricated by sputtering SnO2 on the conductive ITO glass, was used as a pH-sensitive membrane, which was connected with a commercial bipolar junction transistor device. The gels, fabricated by the poly vinyl alcohol with pendent styrylpyridinium groups, were used to immobilize the urease. This readout circuit, fabricated in a 0.35-um CMOS 2P4M process, operated at 3.3V supply voltage. This circuit occupied an area of 1.0 mm × 0.9 mm. The dynamic range of the urea biosensor was from 1.4 to 64 mg/dl at the 10 mM phosphate buffer solution and the sensitivity of this range was about 65.8 mV/pUrea. The effect of urea biosensors with different pH values was considered, and the characteristics of urea biosensors based on EBBJT were described.

  9. Effect of doping and stoichiometric profile on transport in SiGe heterojunction bipolar transistor

    NASA Astrophysics Data System (ADS)

    Halilov, S.

    2016-09-01

    Based on analytical consideration and numerical simulations, it is shown how the mutually adjusted doping and stoichiometric profile results in improved frequency response and current gain in Si1‑x Ge x -based heterojunction bipolar transistor. The closed-form expressions are derived for the dopant distribution within a certain mobility model which is parametrized in terms of the impurity concentration and stoichiometric grading on the same footing. With proper parametrization of the mobility, the method is suitable in both limits of high alloy scattering/low crystal ordering and low alloy scattering/highly ordered stoichiometrically graded structure. The work is corroborated by device simulations of a single-side HBT 30% stoichiometrically graded base, with detailed IV-curve, Gummel and AC analysis. It is shown that the distinct impurity distribution results in a reduced space-charge region, contributes to an effective electric field assisting the diffusion of the minority carriers and results in the saturation current density increased by 50%, the AC gain increased by 90%, the four-fold increase of the DC current gain, and improves the transition frequency from 274 to 358 GHz as compared to the case of the uniformly distributed acceptors. The obtained results may serve as a practical guide in design of highly-graded heterojunction bipolar transistors with efficient frequency response, high gain and enhanced power.

  10. Effect of doping and stoichiometric profile on transport in SiGe heterojunction bipolar transistor

    NASA Astrophysics Data System (ADS)

    Halilov, S.

    2016-09-01

    Based on analytical consideration and numerical simulations, it is shown how the mutually adjusted doping and stoichiometric profile results in improved frequency response and current gain in Si1-x Ge x -based heterojunction bipolar transistor. The closed-form expressions are derived for the dopant distribution within a certain mobility model which is parametrized in terms of the impurity concentration and stoichiometric grading on the same footing. With proper parametrization of the mobility, the method is suitable in both limits of high alloy scattering/low crystal ordering and low alloy scattering/highly ordered stoichiometrically graded structure. The work is corroborated by device simulations of a single-side HBT 30% stoichiometrically graded base, with detailed IV-curve, Gummel and AC analysis. It is shown that the distinct impurity distribution results in a reduced space-charge region, contributes to an effective electric field assisting the diffusion of the minority carriers and results in the saturation current density increased by 50%, the AC gain increased by 90%, the four-fold increase of the DC current gain, and improves the transition frequency from 274 to 358 GHz as compared to the case of the uniformly distributed acceptors. The obtained results may serve as a practical guide in design of highly-graded heterojunction bipolar transistors with efficient frequency response, high gain and enhanced power.

  11. Quasi-ballistic carbon nanotube array transistors with current density exceeding Si and GaAs

    PubMed Central

    Brady, Gerald J.; Way, Austin J.; Safron, Nathaniel S.; Evensen, Harold T.; Gopalan, Padma; Arnold, Michael S.

    2016-01-01

    Carbon nanotubes (CNTs) are tantalizing candidates for semiconductor electronics because of their exceptional charge transport properties and one-dimensional electrostatics. Ballistic transport approaching the quantum conductance limit of 2G0 = 4e2/h has been achieved in field-effect transistors (FETs) containing one CNT. However, constraints in CNT sorting, processing, alignment, and contacts give rise to nonidealities when CNTs are implemented in densely packed parallel arrays such as those needed for technology, resulting in a conductance per CNT far from 2G0. The consequence has been that, whereas CNTs are ultimately expected to yield FETs that are more conductive than conventional semiconductors, CNTs, instead, have underperformed channel materials, such as Si, by sixfold or more. We report quasi-ballistic CNT array FETs at a density of 47 CNTs μm−1, fabricated through a combination of CNT purification, solution-based assembly, and CNT treatment. The conductance is as high as 0.46 G0 per CNT. In parallel, the conductance of the arrays reaches 1.7 mS μm−1, which is seven times higher than the previous state-of-the-art CNT array FETs made by other methods. The saturated on-state current density is as high as 900 μA μm−1 and is similar to or exceeds that of Si FETs when compared at and equivalent gate oxide thickness and at the same off-state current density. The on-state current density exceeds that of GaAs FETs as well. This breakthrough in CNT array performance is a critical advance toward the exploitation of CNTs in logic, high-speed communications, and other semiconductor electronics technologies.

  12. Quasi-ballistic carbon nanotube array transistors with current density exceeding Si and GaAs.

    PubMed

    Brady, Gerald J; Way, Austin J; Safron, Nathaniel S; Evensen, Harold T; Gopalan, Padma; Arnold, Michael S

    2016-09-01

    Carbon nanotubes (CNTs) are tantalizing candidates for semiconductor electronics because of their exceptional charge transport properties and one-dimensional electrostatics. Ballistic transport approaching the quantum conductance limit of 2G 0 = 4e (2)/h has been achieved in field-effect transistors (FETs) containing one CNT. However, constraints in CNT sorting, processing, alignment, and contacts give rise to nonidealities when CNTs are implemented in densely packed parallel arrays such as those needed for technology, resulting in a conductance per CNT far from 2G 0. The consequence has been that, whereas CNTs are ultimately expected to yield FETs that are more conductive than conventional semiconductors, CNTs, instead, have underperformed channel materials, such as Si, by sixfold or more. We report quasi-ballistic CNT array FETs at a density of 47 CNTs μm(-1), fabricated through a combination of CNT purification, solution-based assembly, and CNT treatment. The conductance is as high as 0.46 G 0 per CNT. In parallel, the conductance of the arrays reaches 1.7 mS μm(-1), which is seven times higher than the previous state-of-the-art CNT array FETs made by other methods. The saturated on-state current density is as high as 900 μA μm(-1) and is similar to or exceeds that of Si FETs when compared at and equivalent gate oxide thickness and at the same off-state current density. The on-state current density exceeds that of GaAs FETs as well. This breakthrough in CNT array performance is a critical advance toward the exploitation of CNTs in logic, high-speed communications, and other semiconductor electronics technologies. PMID:27617293

  13. Quasi-ballistic carbon nanotube array transistors with current density exceeding Si and GaAs.

    PubMed

    Brady, Gerald J; Way, Austin J; Safron, Nathaniel S; Evensen, Harold T; Gopalan, Padma; Arnold, Michael S

    2016-09-01

    Carbon nanotubes (CNTs) are tantalizing candidates for semiconductor electronics because of their exceptional charge transport properties and one-dimensional electrostatics. Ballistic transport approaching the quantum conductance limit of 2G 0 = 4e (2)/h has been achieved in field-effect transistors (FETs) containing one CNT. However, constraints in CNT sorting, processing, alignment, and contacts give rise to nonidealities when CNTs are implemented in densely packed parallel arrays such as those needed for technology, resulting in a conductance per CNT far from 2G 0. The consequence has been that, whereas CNTs are ultimately expected to yield FETs that are more conductive than conventional semiconductors, CNTs, instead, have underperformed channel materials, such as Si, by sixfold or more. We report quasi-ballistic CNT array FETs at a density of 47 CNTs μm(-1), fabricated through a combination of CNT purification, solution-based assembly, and CNT treatment. The conductance is as high as 0.46 G 0 per CNT. In parallel, the conductance of the arrays reaches 1.7 mS μm(-1), which is seven times higher than the previous state-of-the-art CNT array FETs made by other methods. The saturated on-state current density is as high as 900 μA μm(-1) and is similar to or exceeds that of Si FETs when compared at and equivalent gate oxide thickness and at the same off-state current density. The on-state current density exceeds that of GaAs FETs as well. This breakthrough in CNT array performance is a critical advance toward the exploitation of CNTs in logic, high-speed communications, and other semiconductor electronics technologies.

  14. Quasi-ballistic carbon nanotube array transistors with current density exceeding Si and GaAs

    PubMed Central

    Brady, Gerald J.; Way, Austin J.; Safron, Nathaniel S.; Evensen, Harold T.; Gopalan, Padma; Arnold, Michael S.

    2016-01-01

    Carbon nanotubes (CNTs) are tantalizing candidates for semiconductor electronics because of their exceptional charge transport properties and one-dimensional electrostatics. Ballistic transport approaching the quantum conductance limit of 2G0 = 4e2/h has been achieved in field-effect transistors (FETs) containing one CNT. However, constraints in CNT sorting, processing, alignment, and contacts give rise to nonidealities when CNTs are implemented in densely packed parallel arrays such as those needed for technology, resulting in a conductance per CNT far from 2G0. The consequence has been that, whereas CNTs are ultimately expected to yield FETs that are more conductive than conventional semiconductors, CNTs, instead, have underperformed channel materials, such as Si, by sixfold or more. We report quasi-ballistic CNT array FETs at a density of 47 CNTs μm−1, fabricated through a combination of CNT purification, solution-based assembly, and CNT treatment. The conductance is as high as 0.46 G0 per CNT. In parallel, the conductance of the arrays reaches 1.7 mS μm−1, which is seven times higher than the previous state-of-the-art CNT array FETs made by other methods. The saturated on-state current density is as high as 900 μA μm−1 and is similar to or exceeds that of Si FETs when compared at and equivalent gate oxide thickness and at the same off-state current density. The on-state current density exceeds that of GaAs FETs as well. This breakthrough in CNT array performance is a critical advance toward the exploitation of CNTs in logic, high-speed communications, and other semiconductor electronics technologies. PMID:27617293

  15. Characterization, Modeling and Fabrication of Aluminum Gallium Arsenide/gallium Arsenide Heterojunction Bipolar Transistors.

    NASA Astrophysics Data System (ADS)

    Ozaydin, Melih

    1995-01-01

    Heterojunction bipolar transistors have found broad applications in recent years as a result of intense research. In order to explore and utilize HBTs for a better performance, the carrier transport phenomenon in HBTs needs to be investigated, and the device parameters optimized. Demand for higher speed and smaller dimensions also requires implementation of new fabrication techniques that will make possible the realization of smaller transistor dimensions. In this thesis we analyze physical characteristics, transport mechanisms, modeling, parameter extraction and electron-beam lithography fabrication techniques for self -aligned heterojunction bipolar transistors. We present a new multi-flux method to analyze the emitter-base heterojunction by self-consistent solution of Schrodinger and Poisson equations. The simulation results show transport characteristics of electrons which differ from those found with the commonly used WKB method. Simulation of electron transport in the base region based on a balance equations approach indicates that tunneling electrons give rise to unique transport characteristics in the base of HBTs. A domain-like density profile is found as a result of ballistic and diffusive transport in different parts of the base region. Bias dependent non-equilibrium behavior is found from the I-V measurements of HBTs, and non-equilibrium transport is shown to be responsible for reduction of the recombination rate. Collector-base space charge region is also investigated and utilization of multi-velocity overshoot is shown to reduce the total collector delay time by 10 percent and improve the breakdown voltage by 70 percent. A semi-two-dimensional model is developed to obtain microwave characteristics, as well as the parameter extraction of transistors. For the parameter extraction procedure, a least-squares technique is used. We also develop a self-aligned process using selective dry-etching for heterojunction transistors. Most of the lithography steps

  16. Performance of electronic switching circuits based on bipolar power transistors at low temperature

    NASA Astrophysics Data System (ADS)

    El-Ghanam, S. M.; Abdel Basit, W.

    2011-03-01

    In this paper, the performance of the bipolar power transistor of the type MJE13007 was evaluated under very low temperature levels. The investigation was carried out to establish a baseline on functionality and to determine suitability of this device for use in space applications under cryogenic temperatures. The static and dynamic electrical characteristics of the proposed transistor were studied at low temperature levels ranging from room level (300 K) down to 100 K. From which, it is clear that, several electrical parameters were affected due to operation on such very low temperature range, e.g. the threshold voltage ( V γ) increasing from 0.62 up to 1.05 V; while the current gain h FE decreases significantly from 26 down to 0.54. Also, the capacitance-voltage relationships ( C- V) of the collector-base and emitter-base junctions were studied at cryogenic temperatures, where a pronounced decrease was observed in the capacitances value due to temperature decrease. For example, at F = 50 kHz; CCB and CBE decreased from 2.33 nF down to 0.07 nF and from 36.2 down to 12 nF, respectively due to decreasing of temperature level from 300 down to 100 K. Finally the study was extended to include the dynamic characteristics and switching properties of the tested high power transistor. The dependency of both the rise and fall times ( t r, t f) on the temperature shows great variations with temperature.

  17. Negative differential transconductance in silicon quantum well metal-oxide-semiconductor field effect/bipolar hybrid transistors

    NASA Astrophysics Data System (ADS)

    Naquin, Clint; Lee, Mark; Edwards, Hal; Mathur, Guru; Chatterjee, Tathagata; Maggio, Ken

    2014-11-01

    Introducing explicit quantum transport into Si transistors in a manner amenable to industrial fabrication has proven challenging. Hybrid field-effect/bipolar Si transistors fabricated on an industrial 45 nm process line are shown to demonstrate explicit quantum transport signatures. These transistors incorporate a lateral ion implantation-defined quantum well (QW) whose potential depth is controlled by a gate voltage (VG). Quantum transport in the form of negative differential transconductance (NDTC) is observed to temperatures >200 K. The NDTC is tied to a non-monotonic dependence of bipolar current gain on VG that reduces drain-source current through the QW. These devices establish the feasibility of exploiting quantum transport to transform the performance horizons of Si devices fabricated in an industrially scalable manner.

  18. Negative differential transconductance in silicon quantum well metal-oxide-semiconductor field effect/bipolar hybrid transistors

    SciTech Connect

    Naquin, Clint; Lee, Mark; Edwards, Hal; Mathur, Guru; Chatterjee, Tathagata; Maggio, Ken

    2014-11-24

    Introducing explicit quantum transport into Si transistors in a manner amenable to industrial fabrication has proven challenging. Hybrid field-effect/bipolar Si transistors fabricated on an industrial 45 nm process line are shown to demonstrate explicit quantum transport signatures. These transistors incorporate a lateral ion implantation-defined quantum well (QW) whose potential depth is controlled by a gate voltage (V{sub G}). Quantum transport in the form of negative differential transconductance (NDTC) is observed to temperatures >200 K. The NDTC is tied to a non-monotonic dependence of bipolar current gain on V{sub G} that reduces drain-source current through the QW. These devices establish the feasibility of exploiting quantum transport to transform the performance horizons of Si devices fabricated in an industrially scalable manner.

  19. Implementation of total dose effects in the bipolar junction transistor Gummel-Poon model

    SciTech Connect

    Montagner, X.; Fouillat, P.; Briand, R.; Touboul, A.; Schrimpf, R.D.; Galloway, K.F.; Calvet, M.C.; Calvel, P.

    1997-12-01

    The effects of total dose on the SPICE model of bipolar junction transistors are investigated. The limitations of the standard Gummel-Poon model for simulating the radiation-induced excess base current are analyzed, and a new model based on an empirical approach is proposed. Four new SPICE rad-parameters are presented, and investigated for different dose rates. The relevant parameters are extracted using a new algorithmic procedure, combining a genetic approach and the standard optimization technique which minimizes the RMS error between measured and simulated excess base current. It is shown that the excess base current is accurately described by the same formula whatever the device type is. An empirical fitting of the rad-parameters as a function of total dose is proposed to use in hardening electronic circuits for space-like environments.

  20. Characterization of InGaP/GaAs Heterojunction Bipolar Transistors with a Heavily Doped Base

    NASA Astrophysics Data System (ADS)

    Oka, Tohru; Ouchi, Kiyoshi; Mochizuki, Kazuhiro

    2001-09-01

    Characteristics of InGaP/GaAs heterojunction bipolar transistors (HBTs) with a heavily doped base are examined at the base doping level NB ranging from 5× 1019 to 5× 1020 cm-3. At NB of less than 3× 1020 cm-3, the current gain is mainly determined by Auger recombination in the intrinsic base region and is inversely proportional to the square of NB. In contrast, the current gain at NB above 3× 1020 cm-3 is significantly decreased. We evaluated the effective barrier height of holes between the emitter and the base by measuring temperature dependence of current gain, and found that the effective hole barrier is reduced as NB increases. This result is explained by the large energy shift of the Fermi level inside the valence band due to heavy doping, causing the increase in the back injection of holes into the emitter, and thus reducing the current gain.

  1. Investigation of InGaP/GaAs double-delta-doped heterojunction bipolar transistor

    NASA Astrophysics Data System (ADS)

    Wang, W.-C.; Cheng, S.-Y.; Chang, W.-L.; Pan, H.-J.; Shie, Y.-H.; Liu, W.-C.

    1998-06-01

    The double-delta-doped heterojunction bipolar transistor 0268-1242/13/6/015/img1 is successfully fabricated with improved current-voltage characteristics by employing the insertion of delta-doped sheets at emitter-base (E-B) and base-collector (B-C) heterojunction. Because of the use of delta-doped sheets, the potential spikes at E-B and B-C heterojunction are suppressed substantially. Thus a higher emitter injection efficiency (current gain) and a lower knee voltage are obtained. From experimental results, it is shown that the studied 0268-1242/13/6/015/img2 device is a good candidate for high-speed and high-power circuit applications.

  2. Analysis of long-term ionizing radiation effects in bipolar transistors

    NASA Technical Reports Server (NTRS)

    Stanley, A. G.; Martin, K. E.

    1978-01-01

    The ionizing radiation effects of electrons on bipolar transistors have been analyzed using the data base from the Voyager project. The data were subjected to statistical analysis, leading to a quantitative characterization of the product and to data on confidence limits which will be useful for circuit design purposes. These newly-developed methods may form the basis for a radiation hardness assurance system. In addition, an attempt was made to identify the causes of the large variations in the sensitivity observed on different product lines. This included a limited construction analysis and a determination of significant design and processes variables, as well as suggested remedies for improving the tolerance of the devices to radiation.

  3. SEMICONDUCTOR DEVICES: Carrier stored trench-gate bipolar transistor with p-floating layer

    NASA Astrophysics Data System (ADS)

    Rongyao, Ma; Zehong, Li; Xin, Hong; Bo, Zhang

    2010-02-01

    A carrier stored trench-gate bipolar transistor (CSTBT) with a p-floating layer (PF-CSTBT) is proposed. Due to the p-floating layer, the thick and highly doped carrier stored layer can be induced, and the conductivity modulation effect will be enhanced near the emitter. The accumulation resistance and the spreading resistance are reduced. The on-state loss will be much lower than in a conventional CSTBT. With the p-floating layer, the distribution of electric fields of the conventional IGBT is reformed, and the breakdown voltage is remarkably improved. The simulation results have shown that the forward voltage drop (VCE-on) of the novel structure is reduced by 20% and 17% respectively, compared with the conventional trench IGBT (TIGBT) and CSTBT under the same conditions. Moreover, an increment of more than 100 V of the breakdown voltage is achieved without sacrificing the SCSOA (short circuit safely operation area) compared with the conventional TIGBT.

  4. Microwave damage susceptibility trend of a bipolar transistor as a function of frequency

    NASA Astrophysics Data System (ADS)

    Ma, Zhen-Yang; Chai, Chang-Chun; Ren, Xing-Rong; Yang, Yin-Tang; Chen, Bin; Song, Kun; Zhao, Ying-Bo

    2012-09-01

    We conduct a theoretical study of the damage susceptibility trend of a typical bipolar transistor induced by a high-power microwave (HPM) as a function of frequency. The dependences of the burnout time and the damage power on the signal frequency are obtained. Studies of the internal damage process and the mechanism of the device are carried out from the variation analysis of the distribution of the electric field, current density, and temperature. The investigation shows that the burnout time linearly depends on the signal frequency. The current density and the electric field at the damage position decrease with increasing frequency. Meanwhile, the temperature elevation occurs in the area between the p-n junction and the n-n+ interface due to the increase of the electric field. Adopting the data analysis software, the relationship between the damage power and frequency is obtained. Moreover, the thickness of the substrate has a significant effect on the burnout time.

  5. Analytical modeling and numerical simulations of the thermal behavior of trench-isolated bipolar transistors

    NASA Astrophysics Data System (ADS)

    Marano, I.; d'Alessandro, V.; Rinaldi, N.

    2009-03-01

    The thermal behavior of trench-isolated bipolar transistors is thoroughly investigated. Fully 3D numerical simulations are performed to analyze the impact of all technological parameters of interest. Based on numerical results, a novel strategy to analytically evaluate the temperature field is proposed, which accounts for the heat propagation through the trench and the nonuniform heat flux distribution over the interface between the silicon box surrounded by trench and the underlying substrate. The resulting model is proved to compare with numerical simulations more favorably than the other approaches available from the literature. As a consequence, it can be employed for an accurate, yet fast evaluation of the thermal resistance of a trench-isolated device as well as of the temperature gradients within the silicon box.

  6. Microwave characterization and modeling of GaAs/AlGaAs heterojunction bipolar transistors

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N.; Romanofsky, Robert R.

    1987-01-01

    The characterization and modeling of a microwave GaAs/AlGaAs heterojunction Bipolar Transistor (HBT) are discussed. The de-embedded scattering parameters are used to derive a small signal lumped element equivalent circuit model using EEsof's Touchstone software package. Each element in the equivalent circuit model is shown to have its origin within the device. The model shows good agreement between the measured and modeled scattering parameters over a wide range of bias currents. Further, the MAG (maximum available power gain) and the h sub 21 (current gain) calculated from the measured data and those predicted by the model are also in good agreement. Consequently, the model should also be capable of predicting the f sub max and the f sub T of other HBTs.

  7. Microwave performance of a self-aligned GaInP/Ga heterojunction bipolar transistor

    SciTech Connect

    Liu, W.; Fan, Shoukong; Henderson, T. ); Davito, D. )

    1993-04-01

    Microwave performance of a self-aligned GaInP/GaAs heterojunction bipolar transistor (HBT) is presented. At an operating current density of 2.08 [times] 10[sup 4] A/cm[sup 2], the measured cutoff frequency is 50 GHz, and the maximum oscillation frequency extrapolated from measured unilateral gain and the maximum available gain are 116 and 81 GHz, respectively, all using 20-dB/decade slopes. To the author's knowledge, these represent the highest reported values of HBT's based on the GaInP/GaAs material system. These results are compared with other reported high-frequency performance of GaInP HBT's. In addition, these results are compared with AlGaAs/GaAs HBT's having a similar device structure.

  8. SiGe:C Heterojunction Bipolar Transistors: From Materials Research to Chip Fabrication

    NASA Astrophysics Data System (ADS)

    Ruecker, H.; Heinemann, B.; Knoll, D.; Ehwald, K.-E.

    Incorporation of substitutional carbon ( ~10^20 cm^-3) into the SiGe region of a heterojunction bipolar transistor (HBT) strongly reduces boron diffusion during device processing. We describe the physical mechanism behind the suppression of B diffusion in C-rich Si and SiGe, and explain how the increased thermal stability of doping profiles in SiGe:C HBTs can be used to improve device performance. Manufacturability of SiGe:C HBTs with transit frequencies of 100 GHz and maximum oscillation frequencies of 130 GHz is demonstrated in a BiCMOS technology capable of fabricating integrated circuits for radio frequencies with high yield.

  9. Design and simulation of oxide and doping engineered lateral bipolar junction transistors for high power applications

    NASA Astrophysics Data System (ADS)

    Loan, Sajad A.; Bashir, Faisal; Akhoon, M. Saqib; Alamoud, Abdulrahman M.

    2016-01-01

    In this paper, we propose new structures of lateral bipolar junction transistor (LBJT) on silicon on insulator (SOI) with improved performance. The proposed devices are lateral bipolar transistors with multi doping zone collector drift region and a thick buried oxide under the collector region. Calibrated simulation studies have revealed that the proposed devices have higher breakdown voltage than the conventional device, that too at higher drift doping concentration. This has resulted in improved tradeoff between the on-resistance and the breakdown voltage of the proposed devices. It has been observed that the proposed device with two collector drift doping zones and a buried oxide thick step results in ∼190% increase in the breakdown voltage than the conventional device. The further increase in the number of collector drift doping zones from two to three has increased the breakdown voltage by 260% than the conventional one. On comparing the proposed devices with the buried oxide double step devices, it has been found that an increase of ∼15-19% in the breakdown voltage is observed in the proposed devices even at higher drift doping concentrations. The use of higher drift doping concentration reduces the on-resistance of the proposed device and thus improves the tradeoff between the breakdown voltage and the on-resistance of the proposed device in comparison to buried oxide double step devices. Further, the use of step doping in the collector drift region has resulted in the reduction of kink effect in the proposed device. Using the mixed mode simulations, the proposed devices have been tested at the circuit level, by designing and simulating inverting amplifiers employing the proposed devices. Both DC and AC analyses of the inverting amplifiers have shown that the proposed devices work well at the circuit level. It has been observed that there is a slight increase in ON delay in the proposed device; however, the OFF delay is more or less same as that of the

  10. Radiative recombination in GaN/InGaN heterojunction bipolar transistors

    SciTech Connect

    Kao, Tsung-Ting; Lee, Yi-Che; Kim, Hee-Jin; Ryou, Jae-Hyun; Kim, Jeomoh; Detchprohm, Theeradetch; Dupuis, Russell D.; Shen, Shyh-Chiang

    2015-12-14

    We report an electroluminescence (EL) study on npn GaN/InGaN heterojunction bipolar transistors (HBTs). Three radiative recombination paths are resolved in the HBTs, corresponding to the band-to-band transition (3.3 eV), conduction-band-to-acceptor-level transition (3.15 eV), and yellow luminescence (YL) with the emission peak at 2.2 eV. We further study possible light emission paths by operating the HBTs under different biasing conditions. The band-to-band and the conduction-band-to-acceptor-level transitions mostly arise from the intrinsic base region, while a defect-related YL band could likely originate from the quasi-neutral base region of a GaN/InGaN HBT. The I{sub B}-dependent EL intensities for these three recombination paths are discussed. The results also show the radiative emission under the forward-active transistor mode operation is more effective than that using a diode-based emitter due to the enhanced excess electron concentration in the base region as increasing the collector current increases.

  11. Simulation of neutron displacement damage in bipolar junction transistors using high-energy heavy ion beams.

    SciTech Connect

    Doyle, Barney Lee; Buller, Daniel L.; Hjalmarson, Harold Paul; Fleming, Robert M; Bielejec, Edward Salvador; Vizkelethy, Gyorgy

    2006-12-01

    Electronic components such as bipolar junction transistors (BJTs) are damaged when they are exposed to radiation and, as a result, their performance can significantly degrade. In certain environments the radiation consists of short, high flux pulses of neutrons. Electronics components have traditionally been tested against short neutron pulses in pulsed nuclear reactors. These reactors are becoming less and less available; many of them were shut down permanently in the past few years. Therefore, new methods using radiation sources other than pulsed nuclear reactors needed to be developed. Neutrons affect semiconductors such as Si by causing atomic displacements of Si atoms. The recoiled Si atom creates a collision cascade which leads to displacements in Si. Since heavy ions create similar cascades in Si we can use them to create similar damage to what neutrons create. This LDRD successfully developed a new technique using easily available particle accelerators to provide an alternative to pulsed nuclear reactors to study the displacement damage and subsequent transient annealing that occurs in various transistor devices and potentially qualify them against radiation effects caused by pulsed neutrons.

  12. Incident particle range dependence of radiation damage in a power bipolar junction transistor

    NASA Astrophysics Data System (ADS)

    Liu, Chao-Ming; Li, Xing-Ji; Geng, Hong-Bin; Rui, Er-Ming; Guo, Li-Xin; Yang, Jian-Qun

    2012-10-01

    The characteristic degradations in silicon NPN bipolar junction transistors (BJTs) of type 3DD155 are examined under the irradiations of 25-MeV carbon (C), 40-MeV silicon (Si), and 40-MeV chlorine (Cl) ions respectively. Different electrical parameters are measured in-situ during the exposure of heavy ions. The experimental data shows that the changes in the reciprocal of the gain variation (Δ(1/β)) of 3DD155 transistors irradiated respectively by 25-MeV C, 40-MeV Si, and 40-MeV Cl ions each present a nonlinear behaviour at a low fluence and a linear response at a high fluence. The Δ(1/β) of 3DD155 BJT irradiated by 25-MeV C ions is greatest at a given fluence, a little smaller when the device is irradiated by 40-MeV Si ions, and smallest in the case of the 40-MeV Cl ions irradiation. The measured and calculated results clearly show that the range of heavy ions in the base region of BJT affects the level of radiation damage.

  13. Annealing effects and DLTS study on NPN silicon bipolar junction transistors irradiated by heavy ions

    NASA Astrophysics Data System (ADS)

    Liu, Chaoming; Li, Xingji; Yang, Jianqun; Rui, Erming

    2014-01-01

    Isochronal anneal sequences have been carried out on 3DG112 silicon NPN bipolar junction transistors (BJTs) irradiated with 20 MeV bromine (Br) heavy ions. The Gummel curve is utilized to characterize the annealing behavior of defects in both the emitter-base depletion region and the neutral base. We find that the base current (IB) decreases with the increasing annealing temperature, while the collector current (IC) remains invariable. The current gain varies slightly, when the annealing temperature (TA) is lower than 400 K, while varies rapidly at TA<450 K, and the current gain of the 3DG112 BJT annealing at 700 K almost restore to that of the pre-radiation transistor. Deep level transient spectroscopy (DLTS) data is used to assign the relative magnitude of each of the important defects. Based on the in situ electrical measurement and DLTS spectra, it is clear that the V2(-/0)+V-P traps are the main contribution to the degradation of current gain after the 20 MeV Br ions irradiation. The V2(-/0)+V-P peak has many of the characteristics expected for the current gain degradation.

  14. Radiative recombination in GaN/InGaN heterojunction bipolar transistors

    NASA Astrophysics Data System (ADS)

    Kao, Tsung-Ting; Lee, Yi-Che; Kim, Hee-Jin; Ryou, Jae-Hyun; Kim, Jeomoh; Detchprohm, Theeradetch; Dupuis, Russell D.; Shen, Shyh-Chiang

    2015-12-01

    We report an electroluminescence (EL) study on npn GaN/InGaN heterojunction bipolar transistors (HBTs). Three radiative recombination paths are resolved in the HBTs, corresponding to the band-to-band transition (3.3 eV), conduction-band-to-acceptor-level transition (3.15 eV), and yellow luminescence (YL) with the emission peak at 2.2 eV. We further study possible light emission paths by operating the HBTs under different biasing conditions. The band-to-band and the conduction-band-to-acceptor-level transitions mostly arise from the intrinsic base region, while a defect-related YL band could likely originate from the quasi-neutral base region of a GaN/InGaN HBT. The IB-dependent EL intensities for these three recombination paths are discussed. The results also show the radiative emission under the forward-active transistor mode operation is more effective than that using a diode-based emitter due to the enhanced excess electron concentration in the base region as increasing the collector current increases.

  15. Neutral base recombination in InP /GaAsSb/InP double-heterostructure bipolar transistors: Suppression of Auger recombination in p+ GaAsSb base layers

    NASA Astrophysics Data System (ADS)

    Bolognesi, C. R.; Liu, H. G.; Tao, N.; Zhang, X.; Bagheri-Najimi, S.; Watkins, S. P.

    2005-06-01

    We report on the tradeoff between current gain β and the base sheet resistance RSH in metalorganic chemical vapor deposition-grown NpN InP /GaAs1-xSbx/InP double-heterojunction bipolar transistors (DHBTs) with heavy base carbon-doping levels resulting in hole concentrations NB ranging from 4×1019 to 12×1019/cm3. In contrast to Ga0.47In0.53As and GaAs-based transistors, which both display gain variations proportional to 1/(NB×WB)2 due to Auger recombination at high doping levels, neutral base recombination in InP /GaAsSb/InP DHBTs is not limited by Auger processes, and the measured current gain is proportional to 1/(NB×WB). We show that GaAs1-xSbx base layers offer a growing lifetime advantage over Ga0.47In0.53As with increasing doping levels. Potential explanations for the observed suppression of Auger recombination in the InP-GaAsSb system are proposed.

  16. Long-Term Reliability of High Speed SiGe/Si Heterojunction Bipolar Transistors

    NASA Technical Reports Server (NTRS)

    Ponchak, George E. (Technical Monitor); Bhattacharya, Pallab

    2003-01-01

    Accelerated lifetime tests were performed on double-mesa structure Si/Si0.7Ge0.3/Si npn heterojunction bipolar transistors, grown by molecular beam epitaxy, in the temperature range of 175C-275C. Both single- and multiple finger transistors were tested. The single-finger transistors (with 5x20 micron sq m emitter area) have DC current gains approximately 40-50 and f(sub T) and f(sub MAX) of up to 22 GHz and 25 GHz, respectively. The multiple finger transistors (1.4 micron finger width, 9 emitter fingers with total emitter area of 403 micron sq m) have similar DC current gain but f(sub T) of 50 GHz. It is found that a gradual degradation in these devices is caused by the recombination enhanced impurity diffusion (REID) of boron atoms from the p-type base region and the associated formation of parasitic energy barriers to electron transport from the emitter to collector layers. This REID has been quantitatively modeled and explained, to the first order of approximation, and the agreement with the measured data is good. The mean time to failure (MTTF) of the devices at room temperature is estimated from the extrapolation of the Arrhenius plots of device lifetime versus reciprocal temperature. The results of the reliability tests offer valuable feedback for SiGe heterostructure design in order to improve the long-term reliability of the devices and circuits made with them. Hot electron induced degradation of the base-emitter junction was also observed during the accelerated lifetime testing. In order to improve the HBT reliability endangered by the hot electrons, deuterium sintered techniques have been proposed. The preliminary results from this study show that a deuterium-sintered HBT is, indeed, more resistant to hot-electron induced base-emitter junction degradation. SiGe/Si based amplifier circuits were also subjected to lifetime testing and we extrapolate MTTF is approximately 1.1_10(exp 6) hours at 125iC junction temperature from the circuit lifetime data.

  17. Analysis of the damage threshold of the GaAs pseudomorphic high electron mobility transistor induced by the electromagnetic pulse

    NASA Astrophysics Data System (ADS)

    Xi, Xiao-Wen; Chai, Chang-Chun; Liu, Yang; Yang, Yin-Tang; Fan, Qing-Yang; Shi, Chun-Lei

    2016-08-01

    An electromagnetic pulse (EMP)-induced damage model based on the internal damage mechanism of the GaAs pseudomorphic high electron mobility transistor (PHEMT) is established in this paper. With this model, the relationships among the damage power, damage energy, pulse width and signal amplitude are investigated. Simulation results show that the pulse width index from the damage power formula obtained here is higher than that from the empirical formula due to the hotspot transferring in the damage process of the device. It is observed that the damage energy is not a constant, which decreases with the signal amplitude increasing, and then changes little when the signal amplitude reaches up to a certain level. Project supported by the National Basic Research Program of China (Grant No. 2014CB339900) and the Open Fund of Key Laboratory of Complex Electromagnetic Environment Science and Technology, China Academy of Engineering Physics (CAEP) (Grant No. 2015-0214.XY.K).

  18. Resonant transmission in the base/collector junction of a bipolar quantum-well resonant-tunneling transistor

    NASA Astrophysics Data System (ADS)

    Seabaugh, A. C.; Kao, Y.-C.; Frensley, W. R.; Randall, J. N.; Reed, M. A.

    1991-12-01

    A new transistor effect is demonstrated in a 120-nm base, bipolar quantum-well, resonant-tunneling transistor (BiQuaRTT). In this BiQuaRTT, a strong, multiple negative differential resistance (NDR) characteristic is obtained at room temperature with high-current gain. The effect is shown to be the consequence of an asymmetric, quantum-well-base heterostructure whose shape is controlled by the base/collector bias. Changes in the quantum-well shape lead to large modulations of the transmission coefficient for quasi-thermalized minority electrons crossing the quantum-well base. In this letter, the transport characteristics of these transistors are described, including also temperature and magnetic field dependence.

  19. Theoretical comparison of Si, Ge, and GaAs ultrathin p-type double-gate metal oxide semiconductor transistors

    NASA Astrophysics Data System (ADS)

    Dib, Elias; Bescond, Marc; Cavassilas, Nicolas; Michelini, Fabienne; Raymond, Laurent; Lannoo, Michel

    2013-08-01

    Based on a self-consistent multi-band quantum transport code including hole-phonon scattering, we compare current characteristics of Si, Ge, and GaAs p-type double-gate transistors. Electronic properties are analyzed as a function of (i) transport orientation, (ii) channel material, and (iii) gate length. We first show that ⟨100⟩-oriented devices offer better characteristics than their ⟨110⟩-counterparts independently of the material choice. Our results also point out that the weaker impact of scattering in Ge produces better electrical performances in long devices, while the moderate tunneling effect makes Si more advantageous in ultimately scaled transistors. Moreover, GaAs-based devices are less advantageous for shorter lengths and do not offer a high enough ON current for longer gate lengths. According to our simulations, the performance switching between Si and Ge occurs for a gate length of 12 nm. The conclusions of the study invite then to consider ⟨100⟩-oriented double-gate devices with Si for gate length shorter than 12 nm and Ge otherwise.

  20. Solution-processible organic-inorganic hybrid bipolar field-effect transistors

    NASA Astrophysics Data System (ADS)

    Chae, Gil Jo; Kim, Kang Dae; Cho, Shinuk; Walker, Bright; Seo, Jung Hwa

    2016-04-01

    Organic-inorganic hybrid bipolar field-effect transistors (HBFETs) comprising a layer of p-type organic poly(3-hexylthiophene) (P3HT) separated from a parallel layer of n-type inorganic zinc oxide (ZnO) were demonstrated by solution processing. In order to achieve balanced hole and electron mobilities, we initially optimized the hole-transporting P3HT channel by the addition of the polar non-solvent acetonitrile (AN) to P3HT solutions in chloroform, which induced a selfassembled nano-fibril morphology and an enhancement of hole mobilities. For the electron channel, a wet-chemically-prepared ZnO layer was optimized by thermal annealing. Unipolar P3HT FET with 5% AN exhibited the highest hole mobility of 7.20 × 10-2 cm2V-1s-1 while the highest electron mobility (3.64 × 10-2 cm2V-1s-1) was observed in unipolar ZnO FETs annealed at 200°C. The organic-inorganic HBFETs consisting of the P3HT layer with 5% AN and ZnO annealed at 200°C exhibited well-balanced hole and electron mobilities of 1.94 × 10-2 cm2V-1s-1 and 1.98 × 10-2 cm2V-1s-1, respectively.

  1. Junction-to-Case Thermal Resistance of a Silicon Carbide Bipolar Junction Transistor Measured

    NASA Technical Reports Server (NTRS)

    Niedra, Janis M.

    2006-01-01

    Junction temperature of a prototype SiC-based bipolar junction transistor (BJT) was estimated by using the base-emitter voltage (V(sub BE)) characteristic for thermometry. The V(sub BE) was measured as a function of the base current (I(sub B)) at selected temperatures (T), all at a fixed collector current (I(sub C)) and under very low duty cycle pulse conditions. Under such conditions, the average temperature of the chip was taken to be the same as that of the temperature-controlled case. At increased duty cycle such as to substantially heat the chip, but same I(sub C) pulse height, the chip temperature was identified by matching the V(sub BE) to the thermometry curves. From the measured average power, the chip-to-case thermal resistance could be estimated, giving a reasonable value. A tentative explanation for an observed bunching with increasing temperature of the calibration curves may relate to an increasing dopant atom ionization. A first-cut analysis, however, does not support this.

  2. Investigation of VLSI Bipolar Transistors Irradiated with Electrons, Ions and Neutrons for Space Application

    NASA Astrophysics Data System (ADS)

    D'Angelo, P.; Fallica, G.; Galbiati, A.; Mangoni, R.; Modica, R.; Pensotti, S.; Rancoita, P. G.

    2006-04-01

    A systematic investigation of radiation effects on a BICMOS technology manufactured by STM has been undertaken. Bipolar transistors were irradiated by neutrons, C, Ar and Kr ions, and recently by electrons. Fast neutrons, as well as other types of particles, produce defects mainly by displacing silicon atoms from their lattice positions to interstitial locations, i.e. generating vacancy-interstitial pairs (the so-called Frenkel pairs). Although imparted doses differ largely, the experimental results indicate that the gain (β) variation is mostly related to the non-ionizing energy-loss (NIEL) deposition for neutrons, ions and electrons. The variation of the inverse of the gain degradation, Δ(1/β), is found to be linearly related (as predicted by the Messenger-Spratt equation for neutron irradiations) to the concentrations of the Frenkel pairs generated independently of the kind of incoming particle. For space applications, this linear dependence on the concentration of Frenkel pairs allows to evaluate the total amount of the gain degradation of VLSI components due to the flux of charged particles during the full life of operation of any pay-load. In fact, the total amount of expected Frenkel pairs can be estimated taking into account the isotopic spectra. It has to be point out that in cosmic rays there is relevant flux of electrons and isotopes up to Ni, which are within the range of particles presently investigated.

  3. Multi-level interconnects for heterojunction bipolar transistor integrated circuit technologies

    SciTech Connect

    Patrizi, G.A.; Lovejoy, M.L.; Schneider, R.P. Jr.; Hou, H.Q.; Enquist, P.M.

    1995-12-31

    Heterojunction bipolar transistors (HBTs) are mesa structures which present difficult planarization problems in integrated circuit fabrication. The authors report a multilevel metal interconnect technology using Benzocyclobutene (BCB) to implement high-speed, low-power photoreceivers based on InGaAs/InP HBTs. Processes for patterning and dry etching BCB to achieve smooth via holes with sloped sidewalls are presented. Excellent planarization of 1.9 {micro}m mesa topographies on InGaAs/InP device structures is demonstrated using scanning electron microscopy (SEM). Additionally, SEM cross sections of both the multi-level metal interconnect via holes and the base emitter via holes required in the HBT IC process are presented. All via holes exhibit sloped sidewalls with slopes of 0.4 {micro}m/{micro}m to 2 {micro}m/{micro}m which are needed to realize a robust interconnect process. Specific contact resistances of the interconnects are found to be less than 6 {times} 10{sup {minus}8} {Omega}cm{sup 2}. Integrated circuits utilizing InGaAs/InP HBTs are fabricated to demonstrate the applicability and compatibility of the multi-level interconnect technology with integrated circuit processing.

  4. A unified electrothermal hot-carrier transport model for silicon bipolar transistor simulations

    NASA Astrophysics Data System (ADS)

    Szeto, Simon; Reif, Rafael

    1989-04-01

    A transport model which consistently takes into account carrier and lattice heating is proposed for silicon bipolar transistor simulations. Unlike earlier nonisothermal and hot-carrier transport formulations, neither the carrier temperatures nor the device (lattice) temperature is required to be uniform. Their spatial dependence is determined from the corresponding energy balance equations. The two previous transport approaches are coupled by a new lattice heat generation model which accounts for mutual energy transfers among the carriers and the lattice through their temperature differences. By applying this model to the heat flow equation, hot-carrier induced lattice heating for a submicron npn structure is simulated. The effect of lattice heating on electron temperature distributions is discussed. Our simulation is also able to predict velocity overshoot and the Kirk effect. To study the problem of device heating, the effects on the lattice temperature due to thermal boundary characteristics and the proximity of heat sinks to the base-collector junction are investigated numerically. Device characteristics are also compared with those obtained from SEDAN.

  5. Heat Removal from Bipolar Transistor by Loop Heat Pipe with Nickel and Copper Porous Structures

    PubMed Central

    Smitka, Martin; Malcho, Milan

    2014-01-01

    Loop heat pipes (LHPs) are used in many branches of industry, mainly for cooling of electrical elements and systems. The loop heat pipe is a vapour-liquid phase-change device that transfers heat from evaporator to condenser. One of the most important parts of the LHP is the porous wick structure. The wick structure provides capillary force to circulate the working fluid. To achieve good thermal performance of LHP, capillary wicks with high permeability and porosity and fine pore radius are expected. The aim of this work was to develop porous structures from copper and nickel powder with different grain sizes. For experiment copper powder with grain size of 50 and 100 μm and nickel powder with grain size of 10 and 25 μm were used. Analysis of these porous structures and LHP design are described in the paper. And the measurements' influences of porous structures in LHP on heat removal from the insulated gate bipolar transistor (IGBT) have been made. PMID:24959622

  6. Cathodoluminescence Microcharacterization of Radiative Recombination Centers in Lifetime-Controlled Insulated Gate Bipolar Transistors

    NASA Astrophysics Data System (ADS)

    Ryuichi Sugie,; Takeshi Mitani,; Masanobu Yoshikawa,; Yoshiharu Iwata,; Ryohei Satoh,

    2010-04-01

    Cross-sectional cathodoluminescence (CL) measurements were applied to the study of electron-irradiated punch-through insulated gate bipolar transistors (IGBTs) to investigate the relationship between radiative recombination centers and electrical characteristics. IGBTs were additionally annealed at temperatures of 200-400 °C for 1 h. As annealing temperature rose, collector-emitter saturation voltage (VCES) decreased and current fall time (tf) increased. The cross-sectional CL measurements showed sharp luminescent peaks at 1018 meV (W or I1), 1040 meV (X or I3), and 790 meV (C) and a broad band at approximately 0.90-1.05 eV. As annealing temperature rose, the intensity of the W line decreased and that of the X line increased, suggesting that small self-interstitial clusters agglomerate and form stable, large self-interstitial clusters reducing the total number of self-interstitial clusters. The C line, which originated from an interstitial oxygen and carbon complex, showed no significant change. We consider that self-interstitial clusters play important roles in the electrical characteristics of lifetime-controlled IGBTs.

  7. Radiation-induced 1/f noise degradation of PNP bipolar junction transistors at different dose rates

    NASA Astrophysics Data System (ADS)

    Qi-Feng, Zhao; Yi-Qi, Zhuang; Jun-Lin, Bao; Wei, Hu

    2016-04-01

    It is found that ionizing-radiation can lead to the base current and the 1/f noise degradations in PNP bipolar junction transistors. In this paper, it is suggested that the surface of the space charge region of the emitter-base junction is the main source of the base surface 1/f noise. A model is developed which identifies the parameters and describes their interactive contributions to the recombination current at the surface of the space charge region. Based on the theory of carrier number fluctuation and the model of surface recombination current, a 1/f noise model is developed. This model suggests that 1/f noise degradations are the result of the accumulation of oxide-trapped charges and interface states. Combining models of ELDRS, this model can explain the reason why the 1/f noise degradation is more severe at a low dose rate than at a high dose rate. The radiations were performed in a Co60 source up to a total dose of 700 Gy(Si). The low dose rate was 0.001 Gy(Si)/s and the high dose rate was 0.1 Gy(Si)/s. The model accords well with the experimental results. Project supported by the National Natural Science Foundation of China (Grant Nos. 61076101 and 61204092).

  8. Understanding the failure mechanisms of microwave bipolar transistors caused by electrostatic discharge

    NASA Astrophysics Data System (ADS)

    Jin, Liu; Yongguang, Chen; Zhiliang, Tan; Jie, Yang; Xijun, Zhang; Zhenxing, Wang

    2011-10-01

    Electrostatic discharge (ESD) phenomena involve both electrical and thermal effects, and a direct electrostatic discharge to an electronic device is one of the most severe threats to component reliability. Therefore, the electrical and thermal stability of multifinger microwave bipolar transistors (BJTs) under ESD conditions has been investigated theoretically and experimentally. 100 samples have been tested for multiple pulses until a failure occurred. Meanwhile, the distributions of electric field, current density and lattice temperature have also been analyzed by use of the two-dimensional device simulation tool Medici. There is a good agreement between the simulated results and failure analysis. In the case of a thermal couple, the avalanche current distribution in the fingers is in general spatially unstable and results in the formation of current crowding effects and crystal defects. The experimental results indicate that a collector-base junction is more sensitive to ESD than an emitter-base junction based on the special device structure. When the ESD level increased to 1.3 kV, the collector-base junction has been burnt out first. The analysis has also demonstrated that ESD failures occur generally by upsetting the breakdown voltage of the dielectric or overheating of the aluminum-silicon eutectic. In addition, fatigue phenomena are observed during ESD testing, with devices that still function after repeated low-intensity ESDs but whose performances have been severely degraded.

  9. Model of radiation-induced gain degradation of NPN bipolar junction transistor at different dose rates

    NASA Astrophysics Data System (ADS)

    Qifeng, Zhao; Yiqi, Zhuang; Junlin, Bao; Wei, Hu

    2015-06-01

    Ionizing-radiation-induced current gain degradation in NPN bipolar junction transistors is due to an increase in base current as a result of recombination at the surface of the device. A model is presented which identifies the physical mechanism responsible for current gain degradation. The increase in surface recombination velocity due to interface states results in an increase in base current. Besides, changing the surface potential along the base surface induced by the oxide-trapped charges can also lead to an increased base current. By combining the production mechanisms of oxide-trapped charges and interface states, this model can explain the fact that the current gain degradation is more severe at a low dose rate than at a high dose rate. The radiations were performed in a Co60 source up to a total dose of 70 krad(Si). The low dose rate was 0.1 rad(Si)/s and the high dose rate was 10 rad(Si)/s. The model accords well with the experimental results. Project supported by the National Natural Science Foundation of China (Nos. 61076101, 61204092).

  10. Working toward high-power GaN/InGaN heterojunction bipolar transistors

    NASA Astrophysics Data System (ADS)

    Shen, Shyh-Chiang; Dupuis, Russell D.; Lochner, Zachery; Lee, Yi-Che; Kao, Tsung-Ting; Zhang, Yun; Kim, Hee-Jin; Ryou, Jae-Hyun

    2013-07-01

    III-nitride (III-N) heterojunction bipolar transistors (HBTs) are a less-explored electronic device technology due to the myriad research issues in material growth, device design and fabrication associated with these devices. For III-N HBTs, npn-GaN/InGaN heterostructures provide the benefits of mitigating the poor base electrical conductivity of p-type GaN and the problematic magnesium incorporation issues. Consequently, InGaN-base III-N HBTs are promising for next-generation high-power RF III-N systems. This paper will describe the current development status of npn GaN/InGaN HBTs grown either on sapphire or free-standing (FS) GaN substrates using optimized metalorganic chemical vapor deposition (MOCVD) and refined HBT processing techniques. Recombination current paths in GaN/InGaN HBTs are studied and small-signal equivalent circuits are developed. The extracted device model indicates that, with further device fabrication technique development, Johnson's figure of merit (JFOM) of GaN/InGaN HBTs can be as high as 5 THz V.

  11. Bipolar-power-transistor-based limiter for high frequency ultrasound imaging systems

    PubMed Central

    Choi, Hojong; Yang, Hao-Chung; Shung, K. Kirk

    2013-01-01

    High performance limiters are described in this paper for applications in high frequency ultrasound imaging systems. Limiters protect the ultrasound receiver from the high voltage (HV) spikes produced by the transmitter. We present a new bipolar power transistor (BPT) configuration and compare its design and performance to a diode limiter used in traditional ultrasound research and one commercially available limiter. Limiter performance depends greatly on the insertion loss (IL), total harmonic distortion (THD) and response time (RT), each of which will be evaluated in all the limiters. The results indicated that, compared with commercial limiter, BPT-based limiter had less IL (–7.7 dB), THD (–74.6 dB) and lower RT (43 ns) at 100MHz. To evaluate the capability of these limiters, they were connected to a 100 MHz single element transducer and a two-way pulse-echo test was performed. It was found that the -6 dB bandwidth and sensitivity of the transducer using BPT-based limiter were better than those of the commercial limiter by 22 % and 140 %, respectively. Compared to the commercial limiter, BPT-based limiter is shown to be capable of minimizing signal attenuation, RT and THD at high frequencies and is thus suited for high frequency ultrasound applications. PMID:24199954

  12. Radiation effects on bipolar junction transistors induced by 25 MeV carbon ions

    NASA Astrophysics Data System (ADS)

    Liu, Chaoming; Li, Xingji; Geng, Hongbin; Zhao, Zhiming; Yang, Dezhuang; He, Shiyu

    2010-12-01

    The characteristic degradation in silicon NPN bipolar junction transistors (BJTs) of 3DG112 type is examined under the irradiation with 25 MeV carbon (C) ions and various bias conditions. Different electrical parameters were measured in-situ during the exposure under each bias condition. From the experimental data, larger variation of base current ( IB) is observed after irradiation at a given value of base-emitter voltage ( VBE), while the collector current is only slightly affected by irradiation at a given VBE. The gain degradation is mostly affected by the behavior of the base current. The change in the reciprocal of current gain (Δ(1/ β)) increases linearly with increasing the C ions fluence. The degradation of the NPN BJTs under various bias conditions during irradiation was studied. Compared to the case where the terminals are grounded, at a given fluence, the change in the reciprocal of current gain varies slightly less when the base-emitter junction is forward biased. On the other hand, there is no distinction for the change in the reciprocal of current gain between the case of reverse-biased base-emitter junction and that of all terminals grounded for the NPN BJTs at a given fluence.

  13. Effect of bias condition on heavy ion radiation in bipolar junction transistors

    NASA Astrophysics Data System (ADS)

    Liu, Chao-Ming; Li, Xing-Ji; Geng, Hong-Bin; Yang, De-Zhuang; He, Shi-Yu

    2012-08-01

    The characteristic degradations in a silicon NPN bipolar junction transistor (BJT) of 3DG142 type are examined under irradiation with 40-MeV chlorine (Cl) ions under forward, grounded, and reverse bias conditions, respectively. Different electrical parameters are in-situ measured during the exposure under each bias condition. From the experimental data, a larger variation of base current (IB) is observed after irradiation at a given value of base-emitter voltage (VBE), while the collector current is slightly affected by irradiation at a given VBE. The gain degradation is affected mostly by the behaviour of the base current. From the experimental data, the variation of current gain in the case of forward bias is much smaller than that in the other conditions. Moreover, for 3DG142 BJT, the current gain degradation in the case of reverse bias is more severe than that in the grounded case at low fluence, while at high fluence, the gain degradation in the reverse bias case becomes smaller than that in the grounded case.

  14. Analysis of generation and annihilation of deep level defects in a silicon-irradiated bipolar junction transistor

    NASA Astrophysics Data System (ADS)

    Madhu, K. V.; Kulkarni, S. R.; Ravindra, M.; Damle, R.

    2007-08-01

    A commercial bipolar junction transistor (2 N 2219 A, npn), irradiated with 120 MeV Si9+ ions with a fluence of the order of 1012 ions cm-2, is studied for radiation-induced gain degradation and deep level defects. I-V measurements are made to study the gain degradation as a function of ion fluence. Properties such as activation energy, trap concentration and capture cross section of deep levels are studied by deep level transient spectroscopy (DLTS). Minority carrier trap energy levels with energies ranging from EC - 0.160 eV to EC - 0.581 eV are observed in the base-collector junction of the transistor. Majority carrier trap levels are also observed with energies ranging from EV + 0.182 eV to EV + 0.401 eV. The identification of the defect type is made on the basis of its finger prints such as activation energy, annealing temperature and capture cross section by comparing with those reported in the literature. New energy levels for the defects A-center, di-vacancy and Si-interstitial are also observed. The irradiated transistor is subjected to isothermal and isochronal annealing. The defects are seen to anneal above 250 °C. The defects generated in the base region of the transistor by displacement damage appear to be responsible for transistor gain degradation.

  15. Ultra-High Voltage 4H-SiC Bi-Directional Insulated Gate Bipolar Transistors

    NASA Astrophysics Data System (ADS)

    Chowdhury, Sauvik

    4H- Silicon Carbide (4H-SiC) is an attractive material for power semiconductor devices due to its large bandgap, high critical electric field and high thermal conductivity compared to Silicon (Si). For ultra-high voltage applications (BV > 10 kV), 4H-SiC Insulated Gate Bipolar Transistors (IGBTs) are favored over unipolar transistors due to lower conduction losses. With improvements in SiC materials and processing technology, promising results have been demonstrated in the area of conventional unidirectional 4H-SiC IGBTs, with breakdown voltage ratings up to 27 kV. This research presents the experimental demonstration of the world's first high voltage bi-directional power transistors in 4H-SiC. Traditionally, four (two IGBTs and two diodes) or two (two reverse blocking IGBTs) semiconductor devices are necessary to yield a bidirectional switch. With a monolithically integrated bidirectional switch as presented here, the number of semiconductor devices is reduced to only one, which results in increased reliability and reduced cost of the overall system. Additionally, by using the unique dual gate operation of BD-IGBTs, switching losses can be reduced to a small fraction of that in conventional IGBTs, resulting in increased efficiency. First, the performance limits of SiC IGBTs are calculated by using analytical methods. The performance benefits of SiC IGBTs over SiC unipolar devices and Si IGBTs are quantified. Numerical simulations are used to optimize the unit cell and edge termination structures for a 15 kV SiC BD-IGBT. The effect of different device parameters on BD-IGBT static and switching performance are quantified. Second, the process technology necessary for the fabrication of high voltage SiC BD-IGBTs is optimized. The effect of different process steps on parameters such as breakdown voltage, carrier lifetime, gate oxide reliability, SiO2-SiC interface charge density is quantified. A carrier lifetime enhancement process has been optimized for lightly doped

  16. Switching Characteristics of a 4H-SiC Based Bipolar Junction Transistor to 200 C

    NASA Technical Reports Server (NTRS)

    Niedra, Janis M.

    2006-01-01

    Static curves and resistive load switching characteristics of a 600 V, 4 A rated, SiC-based NPN bipolar power transistor (BJT) were observed at selected temperatures from room to 200 C. All testing was done in a pulse mode at low duty cycle (approx.0.1 percent). Turn-on was driven by an adjustable base current pulse and turn-off was accelerated by a negative base voltage pulse of 7 V. These base drive signals were implemented by 850 V, gated power pulsers, having rise-times of roughly 10 ns, or less. Base charge sweep-out with a 7 V negative pulse did not produce the large reverse base current pulse seen in a comparably rated Si-based BJT. This may be due to a very low charge storage time. The decay of the collector current was more linear than its exponential-like rise. Switching observations were done at base drive currents (I(sub B)) up to 400 mA and collector currents (I(sub C)) up to 4 A, using a 100 Omega non-inductive load. At I(sub B) = 400 mA and I(sub C) = 4 A, turn-on times typically varied from 80 to 94 ns, over temperatures from 23 to 200 C. As expected, lowering the base drive greatly extended the turn-on time. Similarly, decreasing the load current to I(sub C) = 1 A with I(sub B) = 400 mA produced turn-on times as short as 34 ns. Over the 23 to 200 C range, with I(sub B) = 400 mA and I(sub C) = 4 A, turn-off times were in the range of 72 to 84 ns with the 7 V sweep-out.

  17. Copper-Based OHMIC Contracts for the Si/SiGe Heterojunction Bipolar Transistor Structure

    NASA Technical Reports Server (NTRS)

    Das, Kalyan; Hall, Harvey

    1999-01-01

    Silicon based heterojunction bipolar transistors (HBT) with SiGe base are potentially important devices for high-speed and high-frequency microelectronics. These devices are particularly attractive as they can be fabricated using standard Si processing technology. However, in order to realize the full potential of devices fabricated in this material system, it is essential to be able to form low resistance ohmic contacts using low thermal budget process steps and have full compatibility with VLSI/ULSI processing. Therefore, a study was conducted in order to better understand the contact formation and to develop optimized low resistance contacts to layers with doping densities corresponding to the p-type SiGe base and n-type Si emitter regions of the HBTS. These as-grown doped layers were implanted with BF(sub 2) up to 1 X 10(exp 16)/CM(exp 2) and As up to 5 x 10(exp 15)/CM2, both at 30 keV for the p-type SiGe base and n-type Si emitter layers, respectively, in order to produce a low sheet resistance surface layer. Standard transfer length method (TLM) contact pads on both p and n type layers were deposited using an e-beam evaporated trilayer structure of Ti/CufTi/Al (25)A/1500A/250A/1000A). The TLM pads were delineated by a photoresist lift-off procedure. These contacts in the as-deposited state were ohmic, with specific contact resistances for the highest implant doses of the order of 10(exp -7) ohm-CM2 and lower.

  18. A Logarithmic Response Complementary Metal Oxide Semiconductor Image Sensor with Parasitic P-N-P Bipolar Junction Transistor

    NASA Astrophysics Data System (ADS)

    Lai, Cheng‑Hsiao; Lai, Liang‑Wei; Chiang, Wen‑Jen; King, Ya‑Chin

    2006-04-01

    Logarithmic-response complementary metal oxide semiconductor (CMOS) active pixel sensors provide a desirable attribute of wide dynamic range even with low supply voltages. In this paper, a log-mode pixel with employing parasitic P-N-P bipolar junction transistor (BJT) to amplify photo-current is investigated and optimized. A new log-mode cell with a calibration transistor is proposed to increase the output voltage swing as well as to reduce the fixed pattern noise. The measurement results demonstrate that, the output voltage swing of this new cell is enhanced by 4× and fixed pattern noise (FPN) of a pixel array can be reduced by 10× comparing to that of a conventional log-mode CMOS active pixel sensor.

  19. DLTS Studies of bias dependence of defects in silicon NPN bipolar junction transistor irradiated by heavy ions

    NASA Astrophysics Data System (ADS)

    Liu, Chaoming; Li, Xingji; Geng, Hongbin; Rui, Erming; Yang, Jianqun; Xiao, Liyi

    2012-10-01

    The characteristic degradation in silicon NPN bipolar junction transistors (BJTs) of 3DG130 type is examined under the irradiation with 35 MeV silicon (Si) ions under forward, grounded and reverse bias conditions, respectively. Different electrical parameters were in-situ measured during the exposure under each bias condition. Using deep level transient spectroscopy (DLTS), deep level defects in the base-collector junction of 3DG130 transistors under various bias conditions are measured after irradiation. The activation energy, capture cross section and concentration of observed deep level defects are measured using DLTS technique. Based on the in situ electrical measurement and DLTS spectra, it is clearly that the bias conditions could affect the concentration of deep level defects, and the displacement damage induced by heavy ions.

  20. Composition induced design considerations for InP/Ga xIn 1- xAs heterojunction bipolar transistors

    NASA Astrophysics Data System (ADS)

    Mohammad, S. Noor

    2002-12-01

    Several design principles based on compositional grading and heavy doping of the base region of a heterojunction bipolar transistor (HBT) have been presented. Physical and technological advantages underlying composition induced design criteria of InP/Ga xIn 1- xAs HBTs have been discussed. A number of issues such as superlattice based grading in the base region, base resistance vs base region grading, the emitter-base junction design, tradeoffs between base region grading and the nonuniform doping of the base region, and the surface recombination at the external base region, have been articulated.

  1. Improvement on the dynamical performance of a power bipolar static induction transistor with a buried gate structure

    NASA Astrophysics Data System (ADS)

    Yongshun, Wang; Jingjing, Feng; Chunjuan, Liu; Zaixing, Wang; Caizhen, Zhang; Peng, Chang

    2011-11-01

    The failure of a bipolar static induction transistor (BSIT) often occurs in the transient process between the conducting-state and the blocking-state, so a profound understanding of the physical mechanism of the switching process is of significance for designing and fabricating perfect devices. The dynamical characteristics of the transient process between conducting-state and blocking-state BSITs are represented in detail in this paper. The influences of material, structural and technological parameters on the dynamical performances of BSITs are discussed. The mechanism underlying the transient conversion process is analyzed in depth. The technological approaches are developed to improve the dynamical characteristics of BSITs.

  2. New RAD-Hard STRH3260L6 Bipolar And STRH100N10 Mosfet Power Transistors

    NASA Astrophysics Data System (ADS)

    Camonita, Giuseppe; Pintacuda, Francesco

    2011-10-01

    This article describes two new power discrete components from STMicroelectronics, specifically offered for Space applications. The STRH3260L6 is a double bipolar rad-hard transistor in an SMD package that houses two complementary devices, one NPN and one PNP. The STRH100N10 is an N-channel rad-hard power MOSFET, the first that is ESCC qualified and available in Europe without procurement restrictions. The purpose of this writing is to give details about the devices' main features, characterization for static, dynamic and radiation performances.

  3. Single-Shot Charge Readout Using a Cryogenic Heterojunction Bipolar Transistor Preamplifier Inline with a Silicon Single Electron Transistor at Millikelvin Temperatures

    NASA Astrophysics Data System (ADS)

    Curry, Matthew; England, Troy; Wendt, Joel; Pluym, Tammy; Lilly, Michael; Carr, Stephen; Carroll, Malcolm

    Single-shot readout is a requirement for many implementations of quantum information processing. The single-shot readout fidelity is dependent on the signal-to-noise-ratio (SNR) and bandwidth of the readout detection technique. Several different approaches are being pursued to enhance read-out including RF-reflectometry, RF-transmission, parametric amplification, and transistor-based cryogenic preamplification. The transistor-based cryogenic preamplifier is attractive in part because of the reduced experimental complexity compared with the RF techniques. Here we present single-shot charge readout using a cryogenic Heterojunction-Bipolar-Transistor (HBT) inline with a silicon SET charge-sensor at millikelvin temperatures. For the relevant range of HBT DC-biasing, the current gain is 100 to 2000 and the power dissipation is 50 nW to 5 μW, with the microfabricated SET and discrete HBT in an integrated package mounted to the mixing chamber stage of a dilution refrigerator. We experimentally demonstrate a SNR of up to 10 with a bandwidth of 1 MHz, corresponding to a single-shot time-domain charge-sensitivity of approximately 10-4 e / √Hz. This measured charge-sensitivity is comparable to the values reported using the RF techniques. Sandia National Laboratories is a multi-program laboratory operated by Sandia Corporation, a Lockheed-Martin Company, for the U. S. Department of Energy under Contract No. DE-AC04-94AL85000.

  4. Damage effect and mechanism of the GaAs pseudomorphic high electron mobility transistor induced by the electromagnetic pulse

    NASA Astrophysics Data System (ADS)

    Xiao-Wen, Xi; Chang-Chun, Chai; Gang, Zhao; Yin-Tang, Yang; Xin-Hai, Yu; Yang, Liu

    2016-04-01

    The damage effect and mechanism of the electromagnetic pulse (EMP) on the GaAs pseudomorphic high electron mobility transistor (PHEMT) are investigated in this paper. By using the device simulation software, the distributions and variations of the electric field, the current density and the temperature are analyzed. The simulation results show that there are three physical effects, i.e., the forward-biased effect of the gate Schottky junction, the avalanche breakdown, and the thermal breakdown of the barrier layer, which influence the device current in the damage process. It is found that the damage position of the device changes with the amplitude of the step voltage pulse. The damage appears under the gate near the drain when the amplitude of the pulse is low, and it also occurs under the gate near the source when the amplitude is sufficiently high, which is consistent with the experimental results. Project supported by the National Basic Research Program of China (Grant No. 2014CB339900), and the Open Fund of Key Laboratory of Complex Electromagnetic Environment Science and Technology, China Academy of Engineering Physics (CAEP) (Grant No. 2015-0214.XY.K).

  5. Modeling and Simulation of - and Silicon Germanium-Base Bipolar Transistors Operating at a Wide Range of Temperatures.

    NASA Astrophysics Data System (ADS)

    Shaheed, M. Reaz

    1995-01-01

    Higher speed at lower cost and at low power consumption is a driving force for today's semiconductor technology. Despite a substantial effort toward achieving this goal via alternative technologies such as III-V compounds, silicon technology still dominates mainstream electronics. Progress in silicon technology will continue for some time with continual scaling of device geometry. However, there are foreseeable limits on achievable device performance, reliability and scaling for room temperature technologies. Thus, reduced temperature operation is commonly viewed as a means for continuing the progress towards higher performance. Although silicon CMOS will be the first candidate for low temperature applications, bipolar devices will be used in a hybrid fashion, as line drivers or in limited critical path elements. Silicon -germanium-base bipolar transistors look especially attractive for low-temperature bipolar applications. At low temperatures, various new physical phenomena become important in determining device behavior. Carrier freeze-out effects which are negligible at room temperature, become of crucial importance for analyzing the low temperature device characteristics. The conventional Pearson-Bardeen model of activation energy, used for calculation of carrier freeze-out, is based on an incomplete picture of the physics that takes place and hence, leads to inaccurate results at low temperatures. Plasma -induced bandgap narrowing becomes more pronounced in device characteristics at low temperatures. Even with modern numerical simulators, this effect is not well modeled or simulated. In this dissertation, improved models for such physical phenomena are presented. For accurate simulation of carrier freeze-out, the Pearson-Bardeen model has been extended to include the temperature dependence of the activation energy. The extraction of the model is based on the rigorous, first-principle theoretical calculations available in the literature. The new model is shown

  6. Characteristics of cylindrical surrounding-gate GaAs x Sb1-x /In y Ga1-y As heterojunction tunneling field-effect transistors

    NASA Astrophysics Data System (ADS)

    Guan, Yun-He; Li, Zun-Chao; Luo, Dong-Xu; Meng, Qing-Zhi; Zhang, Ye-Fei

    2016-10-01

    A III-V heterojunction tunneling field-effect transistor (TFET) can enhance the on-state current effectively, and GaAs x Sb1-x /In y Ga1-y As heterojunction exhibits better performance with the adjustable band alignment by modulating the alloy composition. In this paper, the performance of the cylindrical surrounding-gate GaAs x Sb1-x /In y Ga1-y As heterojunction TFET with gate-drain underlap is investigated by numerical simulation. We validate that reducing drain doping concentration and increasing gate-drain underlap could be effective ways to reduce the off-state current and subthreshold swing (SS), while increasing source doping concentration and adjusting the composition of GaAs x Sb1-x /In y Ga1-y As can improve the on-state current. In addition, the resonant TFET based on GaAs x Sb1-x /In y Ga1-y As is also studied, and the result shows that the minimum and average of SS reach 11 mV/decade and 20 mV/decade for five decades of drain current, respectively, and is much superior to the conventional TFET. Project supported by the National Natural Science Foundation of China (Grant Nos. 61176038 and 61474093), the Science and Technology Planning Project of Guangdong Province, China (Grant No. 2015A010103002), and the Technology Development Program of Shaanxi Province, China (Grant No. 2016GY-075).

  7. Low Gate Voltage Operated Multi-emitter-dot H+ Ion-Sensitive Gated Lateral Bipolar Junction Transistor

    NASA Astrophysics Data System (ADS)

    Yuan, Heng; Zhang, Ji-Xing; Zhang, Chen; Zhang, Ning; Xu, Li-Xia; Ding, Ming; Patrick, J. Clarke

    2015-02-01

    A low gate voltage operated multi-emitter-dot gated lateral bipolar junction transistor (BJT) ion sensor is proposed. The proposed device is composed of an arrayed gated lateral BJT, which is driven in the metal-oxide-semiconductor field-effect transistor (MOSFET)-BJT hybrid operation mode. Further, it has multiple emitter dots linked to each other in parallel to improve ionic sensitivity. Using hydrogen ionic solutions as reference solutions, we conduct experiments in which we compare the sensitivity and threshold voltage of the multi-emitter-dot gated lateral BJT with that of the single-emitter-dot gated lateral BJT. The multi-emitter-dot gated lateral BJT not only shows increased sensitivity but, more importantly, the proposed device can be operated under very low gate voltage, whereas the conventional ion-sensitive field-effect transistors cannot. This special characteristic is significant for low power devices and for function devices in which the provision of a gate voltage is difficult.

  8. Comparison of total dose effects on SiGe heterojunction bipolar transistors induced by different swift heavy ion irradiation

    NASA Astrophysics Data System (ADS)

    Sun, Ya-Bin; Fu, Jun; Xu, Jun; Wang, Yu-Dong; Zhou, Wei; Zhang, Wei; Cui, Jie; Li, Gao-Qing; Liu, Zhi-Hong

    2014-11-01

    The degradations in NPN silicon-germanium (SiGe) heterojunction bipolar transistors (HBTs) were fully studied in this work, by means of 25-MeV Si, 10-MeV Cl, 20-MeV Br, and 10-MeV Br ion irradiation, respectively. Electrical parameters such as the base current (IB), current gain (β), neutral base recombination (NBR), and Early voltage (VA) were investigated and used to evaluate the tolerance to heavy ion irradiation. Experimental results demonstrate that device degradations are indeed radiation-source-dependent, and the larger the ion nuclear energy loss is, the more the displacement damages are, and thereby the more serious the performance degradation is. The maximum degradation was observed in the transistors irradiated by 10-MeV Br. For 20-MeV and 10-MeV Br ion irradiation, an unexpected degradation in IC was observed and Early voltage decreased with increasing ion fluence, and NBR appeared to slow down at high ion fluence. The degradations in SiGe HBTs were mainly attributed to the displacement damages created by heavy ion irradiation in the transistors. The underlying physical mechanisms are analyzed and investigated in detail.

  9. Improved methods of forming monolithic integrated circuits having complementary bipolar transistors

    NASA Technical Reports Server (NTRS)

    Bohannon, R. O., Jr.; Cashion, W. F.; Stehlin, R. A.

    1971-01-01

    Two new processes form complementary transistors in monolithic semiconductor circuits, require fewer steps /infusions/ than previous methods, and eliminate such problems as nonuniform h sub FE distribution, low yield, and large device formation.

  10. Degradation of dc characteristics of InGaAs/InP single heterojunction bipolar transistors under electron irradiation

    SciTech Connect

    Bandyopadhyay, A.; Subramanian, S.; Chandrasekhar, S.; Dentai, A.G.; Goodnick, S.M.

    1999-05-01

    The effects of high-energy ({approximately}1 MeV) electron irradiation on the dc characteristics of InGaAs/InP single heterojunction bipolar transistors (SHBT`s) are investigated. The device characteristics do not show any significant change for electron doses <10{sup 15}/cm{sup 2}. For higher doses, devices show a decrease in collector current, a degradation of common-emitter current gain, an increase in collector saturation voltage and an increase in the collector output conductance. A simple SPICE-like device model is developed to describe the dc characteristics of SHBT`s. The model parameters extracted from the measured dc characteristics of the devices before and after irradiation are used to get an insight into the physical mechanisms responsible for the degradation of the devices.

  11. Influence of the external component on the damage of the bipolar transistor induced by the electromagnetic pulse

    NASA Astrophysics Data System (ADS)

    Xiaowen, Xi; Changchun, Chai; Xingrong, Ren; Yintang, Yang; Zhenyang, Ma; Jing, Wang

    2010-07-01

    A study on the influence of the external resistor and the external voltage source during the injection of the electromagnetic pulse (EMP) into the bipolar transistor (BJT) is carried out. Research shows that the increase of the external resistor Rb at base makes the burnout time of the device decrease slightly, the increase of the external voltage source Vbe at base can aid the damage of the device when the magnitude of the injecting voltage is relatively low and has little influence when the magnitude is sufficiently high causing the device appearing the PIN structure damage, and the increase of the external resistor Re can remarkably reduce the voltage drops added to the device and improve the durability of the device. In the final analysis, the effect of the external circuit component on the BJT damage is the influence on the condition which makes the device appear current-mode second breakdown.

  12. SEMICONDUCTOR DEVICES: EMP injection damage effects of a bipolar transistor and its relationship between the injecting voltage and energy

    NASA Astrophysics Data System (ADS)

    Xiaowen, Xi; Changchun, Chai; Xingrong, Ren; Yintang, Yang; Bing, Zhang; Xiao, Hong

    2010-04-01

    The response of a bipolar transistor (BJT) under a square-wave electromagnetic pulse (EMP) with different injecting voltages is investigated. Adopting the curve fitting method, the relationship between the burnout time, the damage energy and the injecting voltage is obtained. Research shows that the damage energy is not a constant value, but changes with the injecting voltage level. By use of the device simulator Medici, the internal behavior of the burned device is analyzed. Simulation results indicate that the variation of the damage energy with injecting voltage is caused by the distribution change of hot spot position under different injection levels. Therefore, the traditional way to evaluate the trade-off between the burnout time and the injecting voltage is not comprehensive due to the variation of the damage energy.

  13. Electrical stress-induced instability of amorphous indium-gallium-zinc oxide thin-film transistors under bipolar ac stress

    SciTech Connect

    Lee, Sangwon; Jeon, Kichan; Park, Jun-Hyun; Kim, Sungchul; Kong, Dongsik; Kim, Dong Myong; Kim, Dae Hwan; Kim, Sangwook; Kim, Sunil; Hur, Jihyun; Park, Jae Chul; Song, Ihun; Kim, Chang Jung; Park, Youngsoo; Jung, U-In

    2009-09-28

    Bipolar ac stress-induced instability of amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistors is comparatively investigated with that under a positive dc gate bias stress. While the positive dc gate bias stress-induced threshold voltage shift ({delta}V{sub T}) is caused by the charge trapping into the interface/gate dielectric as reported in previous works, the dominant mechanism of the ac stress-induced {delta}V{sub T} is observed to be due to the increase in the acceptorlike deep states of the density of states (DOS) in the a-IGZO active layer. Furthermore, it is found that the variation of deep states in the DOS makes a parallel shift in the I{sub DS}-V{sub GS} curve with an insignificant change in the subthreshold slope, as well as the deformation of the C{sub G}-V{sub G} curves.

  14. Development of a radiation hardened npn bipolar transistor for a 64K CMOS fusible-link PROM

    SciTech Connect

    Fuller, R.; Newman, W. )

    1994-12-01

    A 1.2 [mu]m CMOS production process was adapted to produce a 64K CMOS fusible-link Programmable Read-Only Memory (PROM) for space applications. The circuit requirement of less than 50 nS access time combined with the need for 9 volt single pulse programming of the fusible links and radiation tolerance to levels over 300 Krad(Si) made close collaboration between design engineering, reliability engineering, and device engineering essential for a successful project. A vertical NPN bipolar transistor was integrated into a standard CMOS process to be used for programming and reading the fuses. The device characteristics were carefully matched to the product speed and programmability requirements. The NPN device was optimized for radiation performances. Successful development required extensive use of process and device modeling, test structure design and measurement, and experimental design methods.

  15. Kirk effect mechanism in type-II InP /GaAsSb double heterojunction bipolar transistors

    NASA Astrophysics Data System (ADS)

    Tao, N. G.; Bolognesi, C. R.

    2007-09-01

    The Kirk effect mechanism is studied in type-II InP /GaAsSb/InP NpN double heterojunction bipolar transistors (DHBTs) both experimentally and through two-dimensional hydrodynamic numerical simulations. We show that the large valence band discontinuity ΔEV at the GaAsSb-InP base/collector heterojunction does not allow hole injection into the InP collector as is the case in homojunction collectors. Instead, a blocking barrier is electrostatically induced in the base layer at high collector current densities: this barrier increases base recombination and decreases the current gain. We show that tunneling transport must be considered at the base/collector heterojunction and that the induced barrier depends on the base layer doping level—effectively, InP /GaAsSb DHBTs display high-current limitations that are also controlled to some extent by the base doping level.

  16. First- and second-order electrical modelling and experiment on very high speed SiGeC heterojunction bipolar transistors

    NASA Astrophysics Data System (ADS)

    Nunez-Perez, José Cruz; Lakhdara, Maya; Bouhouche, Manel; Verdier, Jacques; Latreche, Saïda; Gontrand, Christian

    2009-04-01

    We present in this paper an electrical study centred on NPN heterojunction bipolar transistors (HBTs), realized in an industrial BiCMOS SiGe:C process, featuring high attractive performances (ft > 200 GHz) in terms of microwave behaviour and low-frequency noise; reaching this level of performance with good dc characteristics could be however a difficult challenge. Electrical modelling is investigated, using our 2D simulator, based on the drift-diffusion model (DDM). The simulations were very efficient for optimizing the devices. The dc and ac results obtained in this work are efficiently compared with electrical characteristics coming from measurements and SPICE-like parameter extractions, from simulations via a compact model (HICUM) implemented in the so-called commercial simulator ADS (advanced design system). This work was a first step for designing RF circuits like oscillators in a simple way.

  17. A model for the dependence of maximum oscillation frequency on collector to substrate capacitance in bipolar transistors

    NASA Astrophysics Data System (ADS)

    Armstrong, G. A.; French, W. D.

    1995-08-01

    Parasitic effects associated with the collector degrade the frequency performance of a bipolar transistor. These effects include collector series resistance and collector-substrate capacitance. A simple analytical model has been derived to show the dependence of the maximum oscillation frequency fmax on these parameters. The significance of using bonded SOI material to reduce collector-substrate capacitance is discussed. The analytical model is used to predict the factor of improvement of this technology over conventional diffusion isolated bulk silicon technology. By considering the impact of process optimisation, an improvement in fmax by a factor of between two and three is predicted at maximum power output. By trading off this improvement in fmax for lower power operation, it is possible to achieve a significant reduction in power-delay product.

  18. MOSFET-BJT hybrid mode of the gated lateral bipolar junction transistor for C-reactive protein detection.

    PubMed

    Yuan, Heng; Kwon, Hyurk-Choon; Yeom, Se-Hyuk; Kwon, Dae-Hyuk; Kang, Shin-Won

    2011-10-15

    In this study, we propose a novel biosensor based on a gated lateral bipolar junction transistor (BJT) for biomaterial detection. The gated lateral BJT can function as both a BJT and a metal-oxide-semiconductor field-effect transistor (MOSFET) with both the emitter and source, and the collector and drain, coupled. C-reactive protein (CRP), which is an important disease marker in clinical examinations, can be detected using the proposed device. In the MOSFET-BJT hybrid mode, the sensitivity, selectivity, and reproducibility of the gated lateral BJT for biosensors were evaluated in this study. According to the results, in the MOSFET-BJT hybrid mode, the gated lateral BJT shows good selectivity and reproducibility. Changes in the emitter (source) current of the device for CRP antigen detection were approximately 0.65, 0.72, and 0.80 μA/decade at base currents of -50, -30, and -10 μA, respectively. The proposed device has significant application in the detection of certain biomaterials that require a dilution process using a common biosensor, such as a MOSFET-based biosensor. PMID:21835604

  19. Comments on determination of bandgap narrowing from activation plots. [for bipolar transistors

    NASA Technical Reports Server (NTRS)

    Park, J.-S.; Neugroschel, A.; Lindholm, F. A.

    1986-01-01

    A determination is made of the temperature-dependence of emitter saturation current in bipolar devices which allows the derivation of a value for bandgap narrowing that is in better agreement with other determinations than previous results based on ohmic contact measurements of temperature dependence. The new values were obtained by varying the surface recombination velocity at the emitter surface. This improves accuracy by varying the minority carrier surface recombination velocity at the emitter contacts of otherwise indistinguishable emitters.

  20. Direct-current and radio-frequency characterizations of GaAs metal-insulator-semiconductor field-effect transistors enabled by self-assembled nanodielectrics

    NASA Astrophysics Data System (ADS)

    Lin, H. C.; Kim, S. K.; Chang, D.; Xuan, Y.; Mohammadi, S.; Ye, P. D.; Lu, G.; Facchetti, A.; Marks, T. J.

    2007-08-01

    Direct-current and radio-frequency characterizations of GaAs metal-insulator-semiconductor field-effect transistors (MISFETs) with very thin self-assembled organic nanodielectrics (SANDs) are presented. The application of SAND on compound semiconductors offers unique opportunities for high-performance devices. Thus, 1μm gate-length depletion-mode n-channel SAND/GaAs MISFETs exhibit low gate leakage current densities of 10-2-10-5A/cm2, a maximum drain current of 260mA/mm at 2V forward gate bias, and a maximum intrinsic transconductance of 127mS/mm. These devices achieve a current cutoff frequency (fT) of 10.6GHz and a maximum oscillation frequency (fmax) of 6.9GHz. Nearly hysteresis-free Ids-Vgs characteristics and low flicker noise indicate that a high-quality SAND-GaAs interface is achieved.

  1. Ensemble Monte Carlo particle investigation of hot electron induced source-drain burnout characteristics of GaAs field-effect transistors

    NASA Astrophysics Data System (ADS)

    Moglestue, C.; Buot, F. A.; Anderson, W. T.

    1995-08-01

    The lattice heating rate has been calculated for GaAs field-effect transistors of different source-drain channel design by means of the ensemble Monte Carlo particle model. Transport of carriers in the substrate and the presence of free surface charges are also included in our simulation. The actual heat generation was obtained by accounting for the energy exchanged with the lattice of the semiconductor during phonon scattering. It was found that the maximum heating rate takes place below the surface near the drain end of the gate. The results correlate well with a previous hydrodynamic energy transport estimate of the electronic energy density, but shifted slightly more towards the drain. These results further emphasize the adverse effects of hot electrons on the Ohmic contacts.

  2. DC modeling and characterization of AlGaAs/GaAs heterojunction bipolar transistors for high-temperature applications

    SciTech Connect

    Dikmen, C.T.; Dogan, N.S.; Osman, M.A. . School of Electrical Engineering and Computer Science)

    1994-02-01

    There is currently a demand for active electronic devices operating reliably over wide range of temperatures. Potential applications for the high-temperature devices and integrated circuits are in the areas of jet engine and control instrumentation for nuclear power plants. Here, the large signal dc characteristics of AlGaAs/GaAs heterojunction bipolar transistors (HBT) at high temperatures (27--300 C) are reported. A high-temperature SPICE model is developed which includes the recombination-generation current components and avalanche multiplication which become extremely important at high temperatures. The effect of avalanche breakdown is also included to model the current due to thermal generation of electron/hole pairs causing breakdown at high temperatures. A parameter extraction program is developed used to extract the model parameters of HBT's at different temperatures. Fitting functions for the model parameters as a function of temperature are developed. These parameters are then used in the SPICE Ebers-Moll model for the dc characterization of the HBT at any temperature between (27--300 C).

  3. A novel 4H-SiC lateral bipolar junction transistor structure with high voltage and high current gain

    NASA Astrophysics Data System (ADS)

    Deng, Yong-Hui; Xie, Gang; Wang, Tao; Sheng, Kuang

    2013-09-01

    In this paper, a novel structure of a 4H-SiC lateral bipolar junction transistor (LBJT) with a base field plate and double RESURF in the drift region is presented. Collector-base junction depletion extension in the base region is restricted by the base field plate. Thin base as well as low base doping of the LBJT therefore can be achieved under the condition of avalanche breakdown. Simulation results show that thin base of 0.32 μm and base doping of 3 × 1017 cm-3 are obtained, and corresponding current gain is as high as 247 with avalanche breakdown voltage of 3309 V when the drift region length is 30 μm. Besides, an investigation of a 4H-SiC vertical BJT (VBJT) with comparable breakdown voltage (3357 V) shows that the minimum base width of 0.25 μm and base doping as high as 8 × 1017 cm-3 contribute to a maximum current gain of only 128.

  4. Annealing neutron damaged silicon bipolar transistors: Relating gain degradation to specific lattice defects

    NASA Astrophysics Data System (ADS)

    Fleming, R. M.; Seager, C. H.; Lang, D. V.; Campbell, J. M.

    2010-09-01

    Isochronal anneal sequences have been carried out on pnp and npn transistors irradiated with fast neutrons at a variety of fluences. The evolution of base and collector currents was utilized to characterize the annealing behavior of defects in both the emitter-base depletion region and the neutral base. Various annealing biases, theoretical modeling, as well as previous deep level transient spectroscopy (DLTS) data, were used to assign the relative magnitude of each of the important defects to the total recombination current. We find that donor-vacancy pairs in the neutral n-type base of our pnp transistors are responsible for about 1/3 of the postdamage lifetime degradation, while the remaining recombination currents can be largely attributed to a cluster-related divacancylike defect which has no shallow state DLTS emission peak. This latter defect anneals gradually from 350 to 590 K. Generation/recombination currents in the base-emitter junctions in both types of devices were found to anneal in a similar, gradual fashion, suggesting that this same cluster-related intrinsic lattice defect is also responsible for the large, damage-induced base currents.

  5. Three-terminal heterojunction bipolar transistor solar cell for high-efficiency photovoltaic conversion.

    PubMed

    Martí, A; Luque, A

    2015-01-01

    Here we propose, for the first time, a solar cell characterized by a semiconductor transistor structure (n/p/n or p/n/p) where the base-emitter junction is made of a high-bandgap semiconductor and the collector is made of a low-bandgap semiconductor. We calculate its detailed-balance efficiency limit and prove that it is the same one than that of a double-junction solar cell. The practical importance of this result relies on the simplicity of the structure that reduces the number of layers that are required to match the limiting efficiency of dual-junction solar cells without using tunnel junctions. The device naturally emerges as a three-terminal solar cell and can also be used as building block of multijunction solar cells with an increased number of junctions. PMID:25902374

  6. Three-terminal heterojunction bipolar transistor solar cell for high-efficiency photovoltaic conversion

    PubMed Central

    Martí, A.; Luque, A.

    2015-01-01

    Here we propose, for the first time, a solar cell characterized by a semiconductor transistor structure (n/p/n or p/n/p) where the base–emitter junction is made of a high-bandgap semiconductor and the collector is made of a low-bandgap semiconductor. We calculate its detailed-balance efficiency limit and prove that it is the same one than that of a double-junction solar cell. The practical importance of this result relies on the simplicity of the structure that reduces the number of layers that are required to match the limiting efficiency of dual-junction solar cells without using tunnel junctions. The device naturally emerges as a three-terminal solar cell and can also be used as building block of multijunction solar cells with an increased number of junctions. PMID:25902374

  7. Unipolar and bipolar operation of InAs/InSb nanowire heterostructure field-effect transistors

    NASA Astrophysics Data System (ADS)

    Nilsson, Henrik A.; Caroff, Philippe; Lind, Erik; Pistol, Mats-Erik; Thelander, Claes; Wernersson, Lars-Erik

    2011-09-01

    We present temperature dependent electrical measurements on n-type InAs/InSb nanowire heterostructure field-effect transistors. The barrier height of the heterostructure junction is determined to be 220 meV, indicating a broken bandgap alignment. A clear asymmetry is observed when applying a bias to either the InAs or the InSb side of the junction. Impact ionization and band-to-band tunneling is more pronounced when the large voltage drop occurs in the narrow bandgap InSb segment. For small negative gate-voltages, the InSb segment can be tuned toward p-type conduction, which induces a strong band-to-band tunneling across the heterostructucture junction.

  8. Low-power exciton-based heterojunction bipolar transistors for thresholding logic applications

    NASA Astrophysics Data System (ADS)

    Goswami, Subrata; Bhattacharya, Pallab K.; Singh, Jasprit; Hong, Song-Cheol; Biswas, D.

    1991-03-01

    The principles of an integrated optoelectronic controller-modulator device, based on excitonic transitions and the enhanced Stark effect in quantum wells, are outlined. The device consists of a controller and a modulator as components. The controller is a heterojunction phototransistor with multiquantum wells incorporated in the base-collector depletion region. The amplified output of the controller enables switching of the modulator for low optical power levels. Experimental results on GaAs-AlGaAs based devices, realized by one-step molecular beam epitaxy and selective etching, are presented. The bipolar devices have current gains of about 35-40. The integrating-thresholding properties of the device are demonstrated and switching characteristics for 10 micro-W input to the controller are measured. Cascadability, optoelectronic amplification, and multistage operation are demonstrated in terms of a fan out of eight devices. The integrating-thresholding properties also lend themselves to the implementation of neurons and to the realization of decision making processes. The controller-modulator device can form a versatile basic module for optical computation architectures.

  9. Pure valley- and spin-entangled states in a MoS2-based bipolar transistor

    NASA Astrophysics Data System (ADS)

    Bai, Chunxu; Zou, Yonglian; Lou, Wen-Kai; Chang, Kai

    2014-11-01

    In this study, we show that the local Andreev reflection not only can be tuned largely by the type of the normal metal electrode, it also is related to the electrostatic potential in the superconductor region in a MoS2-based n (p ) -type metal/superconductor junction. In a MoS2-based n -type metal/n (p ) -type superconductor/p -type metal (n Sp ) transistor, nonlocal pure valley- and spin-entangled current can be tuned by the length and local gate voltage of a superconductor region. In particular, switching the quasiparticle type in both structures results in a series of intriguing features. Such an effect is not attainable in a graphene-based junction where the electron-hole symmetry enables the symmetry results to be observed. Besides, we have shown that the crossed Andreev reflection exhibits a maximum around ξ /2 instead of the exponential decay behavior in conventional superconductors and a maximum around ξ in the graphene material. The proposed straightforward experimental design and pure valley- and spin-entangled state can pave the way for a wider use in the entanglement based on material group-VI dichalcogenides.

  10. Collector-up aluminum gallium arsenide/gallium arsenide heterojunction bipolar transistors using oxidized aluminum arsenide for current confinement

    NASA Astrophysics Data System (ADS)

    Massengale, Alan Ross

    1998-12-01

    The discovery in 1990 that the wet thermal oxidation of AlAs can create a stable native oxide has added a new constituent, AlAs-oxide, to the AlGaAs/GaAs materials system. Native oxides of high Al mole-fraction AlGaAs are being used to confine electrical and/or optical fields in many types of electronic and optoelectronic structures with very promising results. Among these devices are collector-up heterojunction bipolar transistors (HBTs). Collector-up HBTs offer a means to reduce base-collector capacitance relative to their emitter-up counterparts, and thus to improve device performance. A novel method for fabricating collector-up AlGaAs/GaAs HBTs where an AlAs layer is inserted into the emitter layer and is oxidized in water vapor at 450sp°C has been developed. The resulting AlAs-oxide serves as a current confining layer that constricts collector current flow to the intrinsic portion of the device. Compared to previous methods of fabricating these devices, the process of converting AlAs into an insulator requires only one growth, and does not suffer from implant damage in the base. Because the lateral oxidation of AlAs is a process that proceeds at rates of microns per minute, one of the major challenges facing its implementation is the ability to accurately control the oxidation rate over the wafer, and from one wafer to the next. In the course of work on the oxidation of AlAs, a method to lithographically form lateral oxidation stop layers has been achieved. This technique utilizes impurity induced layer disordering (IILD) in heavily Si-doped buried planes, combined with selective surface patterning and thermal annealing, to create a lateral variation in the Al mole-fraction of the layer to be oxidized.

  11. Heavy-ion broad-beam and microprobe studies of single-event upsets in 0.20 um SiGe heterojunction bipolar transistors and circuits.

    SciTech Connect

    Fritz, Karl; Irwin, Timothy J.; Niu, Guofu; Fodness, Bryan; Carts, Martin A.; Marshall, Paul W.; Reed, Robert A.; Gilbert, Barry; Randall, Barbara; Prairie, Jason; Riggs, Pam; Pickel, James C.; LaBel, Kenneth; Cressler, John D.; Krithivasan, Ramkumar; Dodd, Paul Emerson; Vizkelethy, Gyorgy

    2003-09-01

    Combining broad-beam circuit level single-event upset (SEU) response with heavy ion microprobe charge collection measurements on single silicon-germanium heterojunction bipolar transistors improves understanding of the charge collection mechanisms responsible for SEU response of digital SiGe HBT technology. This new understanding of the SEU mechanisms shows that the right rectangular parallele-piped model for the sensitive volume is not applicable to this technology. A new first-order physical model is proposed and calibrated with moderate success.

  12. Temperature dependence of current-voltage characteristics of npn-type GaN /InGaN double heterojunction bipolar transistors

    NASA Astrophysics Data System (ADS)

    Nishikawa, Atsushi; Kumakura, Kazuhide; Makimoto, Toshiki

    2007-09-01

    We investigated the temperature dependence of the common-emitter current-voltage (I-V) characteristics of npn-type GaN /InGaN double heterojunction bipolar transistors. Although the current gain decreases with increasing measurement temperature, the current gain measured at 300°C is still as high as 308. The reduction of the current gain with temperature is attributed not only to the hole back-injection current from the base into the emitter but also to the shorter minority carrier diffusion length due to the increase in the carrier concentration of the p-InGaN base.

  13. I-V and DLTS study of generation and annihilation of deep-level defects in an oxygen-ion irradiated bipolar junction transistor

    NASA Astrophysics Data System (ADS)

    Madhu, K. V.; Kulkarni, S. R.; Ravindra, M.; Damle, R.

    A commercial bipolar junction transistor (2N 2219A, npn) irradiated with 84 MeV O6+-ions with fluence of the order of 1013 ions cm-2 is studied for radiation-induced gain degradation and deep-level defects or recombination centers. I-V measurements are made to study the gain degradation as a function of ion fluence. Properties such as activation energy, trap concentration and capture cross section of deep levels are studied by deep-level transient spectroscopy. Minority carrier trap energy levels with energies ranging from EC -0.17 eV to EC -0.55 eV are observed in the base-collector junction of the transistor. Majority carrier defect levels are also observed with energies ranging from EV +0.26 eV to EV +0.44 eV. The irradiated device is subjected to isothermal and isochronal annealing. The defects are seen to anneal above 250 °C. The defects generated in the base region of the transistor by displacement damage appear to be responsible for an increase in base current through Shockley-Read-Hall or multi-phonon recombination and consequent transistor gain degradation.

  14. Analytical description of the injection ratio of self-biased bipolar transistors under the very high injection conditions of ESD events

    NASA Astrophysics Data System (ADS)

    Gendron, A.; Renaud, P.; Bafleur, M.; Nolhier, N.

    2008-05-01

    This paper proposes a 1D-analytical description of the injection ratio of a self-biased bipolar transistor under very high current injection conditions. Starting from an expression of the current gain based on the stored charge into the emitter and base regions, we derive a new analytical expression of the current injection ratio. This analytical description demonstrates the presence of an asymptotic limit for the injection ratio at very high current densities, as the ratio of electron/hole mobilities in the case of an NPN transistor and to the ratio of hole/electron saturation velocities for a PNP. Moreover, for the first time, a base narrowing effect is demonstrated and explained in the case of a self-biased PNP, in contrast with the base widening effect (Kirk effect [Kirk CT, A theory of transistor cutoff frequency (fT) falloff at high current densities, IRE Trans Electr Dev 1961: p. 164-73]) reported for lower current density. These results are validated by numerical simulation and show a good agreement with experimental characterizations of transistors especially designed to operate under extreme condition such as electrostatic discharge (ESD) events.

  15. Investigation on phonon scattering in a GaAs nanowire field effect transistor using the non-equilibrium Green's function formalism

    SciTech Connect

    Price, A. Martinez, A.

    2015-04-28

    Using quantum transport simulations, the impact of electron-phonon scattering on the transfer characteristic of a gate-all-around nanowire (GaAs) field effect transistor (NWFET) has been thoroughly investigated. The Non-Equilibrium Green's Function formalism in the effective mass approximation using a decoupled mode decomposition has been deployed. NWFETs of different dimensions have been considered, and scattering mechanisms including acoustic, optical and polar optical phonons have been included. The effective masses were extracted from tight binding simulations. High and low drain bias have been considered. We found substantial source to drain tunnelling current and significant impact of phonon scattering on the performance of the NWFET. At low drain bias, for a 2.2 × 2.2 nm{sup 2} cross-section transistor, scattering caused a 72%, 77%, and 81% decrease in the on-current for a 6 nm, 10 nm, and 20 nm channel length, respectively. This reduction in the current due to scattering is influenced by the increase in the tunnelling current. We include the percentage tunnelling for each valley at low and high drain bias. It was also found that the strong quantisation caused the relative position of the valleys to vary with the cross-section. This had a large effect on the overall tunnelling current. The phonon-limited mobility was also calculated, finding a mobility of 950 cm{sup 2}/V s at an inversion charge density of 10{sup 12 }cm{sup −2} for a 4.2 × 4.2 nm{sup 2} cross-section device.

  16. Procedure to derive analytical models for microwave noise performances of Si/SiGe:C and InP/InGaAs heterojunction bipolar transistors

    NASA Astrophysics Data System (ADS)

    Ramirez-Garcia, E.; Aniel, F. P.; Enciso-Aguilar, M. A.; Zerounian, N.

    2013-04-01

    We present a useful procedure to derive simplified expressions to model the minimum noise factor and the equivalent noise resistance of Si/SiGe:C and InP/InGaAs heterojunction bipolar transistors (HBTs). An acceptable agreement between models and measurements at operation frequencies up to 18 GHz and at several bias points is demonstrated. The development procedure includes all the significant microwave noise sources of the HBTs. These relations should be useful to model Fmin and Rn for state-of-the-art IV-IV and III-V HBTs. The method is the first step to derive noise analyses formulas valid for operation frequencies near the unitary current gain frequency (fT); however, to achieve this goal a necessary condition is to have access to HFN measurements up to this frequency regime.

  17. A New 600 V Punch Through-Insulated Gate Bipolar Transistor with the Monolithic Fault Protection Circuit Using the Floating p-Well Voltage Detection

    NASA Astrophysics Data System (ADS)

    Ji, In-Hwan; Jeon, Byung-Chul; Choi, Young-Hwan; Ha, Min-Woo; Han, Min-Koo

    2006-10-01

    A new fault sensing scheme of the insulated gate bipolar transistor (IGBT) employing the floating p-well, which detects the over-voltage of the floating p-well under the short circuit fault condition, is proposed and implemented by fabricating the main IGBT and gate voltage pull-down circuit using the widely used planar IGBT process. The floating p-well structure also improves the avalanche energy of IGBT in addition to detecting the fault signal. The detection of fault and gate voltage pull-down operation is achieved by the proposed fault protection scheme employing the floating p-well voltage detection. The proposed fault protection circuit was measured under the hard switching fault (HSF) and fault under load (FUL) conditions. The normal switching behavior of the main IGBT with the proposed protection circuit was also investigated under inductive load switching conditions.

  18. NpN-GaN/InxGa1-xN/GaN heterojunction bipolar transistor on free-standing GaN substrate

    NASA Astrophysics Data System (ADS)

    Lochner, Zachary; Jin Kim, Hee; Lee, Yi-Che; Zhang, Yun; Choi, Suk; Shen, Shyh-Chiang; Doug Yoder, P.; Ryou, Jae-Hyun; Dupuis, Russell D.

    2011-11-01

    Data and analysis are presented for NpN-GaN/InGaN/GaN double-heterojunction bipolar transistors (HBTs) grown and fabricated on a free-standing GaN (FS-GaN) substrate in comparison to that on a sapphire substrate to investigate the effect of dislocations in III-nitride HBT epitaxial structures. The performance characteristics of HBTs on FS-GaN exhibit a maximum collector current density of ˜12.3 kA/cm2, dc current gain of ˜90, and maximum differential gain of ˜120 without surface passivation, representing a substantial improvement over similar devices grown on sapphire. This is attributed to the reduction in threading dislocation density afforded by using a homoepitaxial growth on a high-crystalline-quality substrate. The minority carrier diffusion length increases significantly owing to not only a mitigated carrier trap effect via fewer dislocations, but also possibly reduced microscopic localized states.

  19. Effects of base doping and carrier lifetime on differential current gain and temperature coefficient of 4H-SiC power bipolar junction transistors

    NASA Astrophysics Data System (ADS)

    Niu, X.; Fardi, H.

    2012-04-01

    4H-SiC NPN bipolar junction transistor (BJT) is studied systematically by performing two-dimensional numerical simulations. Several design issues are discussed. Depending on the doping concentration of the base and the carrier lifetimes, both positive and negative temperature coefficients in the common emitter current gain could exist in 4H-SiC NPN BJTs with aluminium-doped base. The temperature coefficients of the current gain at different base doping concentrations and different carrier lifetimes have been determined. A high base doping concentration can reduce the requirement for the carrier lifetime in order to obtain negative temperature coefficient in current gain. Device simulations are performed to evaluate the carrier lifetimes by fitting the measured output IC -VCE curves. An excellent fitting is obtained and the base electron lifetime and the emitter hole lifetime are extracted to be about 22 and 5.7 ns, respectively.

  20. Analytical base-collector depletion capacitance in vertical SiGe heterojunction bipolar transistors fabricated on CMOS-compatible silicon on insulator

    NASA Astrophysics Data System (ADS)

    Xu, Xiao-Bo; Zhang, He-Ming; Hu, Hui-Yong; Ma, Jian-Li; Xu, Li-Jun

    2011-01-01

    The base—collector depletion capacitance for vertical SiGe npn heterojunction bipolar transistors (HBTs) on silicon on insulator (SOI) is split into vertical and lateral parts. This paper proposes a novel analytical depletion capacitance model of this structure for the first time. A large discrepancy is predicted when the present model is compared with the conventional depletion model, and it is shown that the capacitance decreases with the increase of the reverse collector—base bias—and shows a kink as the reverse collector—base bias reaches the effective vertical punch-through voltage while the voltage differs with the collector doping concentrations, which is consistent with measurement results. The model can be employed for a fast evaluation of the depletion capacitance of an SOI SiGe HBT and has useful applications on the design and simulation of high performance SiGe circuits and devices.

  1. Boron, bismuth co-doping of gallium arsenide and other compounds for photonic and heterojunction bipolar transistor devices

    DOEpatents

    Mascarenhas, Angelo

    2015-07-07

    Isoelectronic co-doping of semiconductor compounds and alloys with acceptors and deep donors is sued to decrease bandgap, to increase concentration of the dopant constituents in the resulting alloys, and to increase carrier mobilities lifetimes. For example, Group III-V compounds and alloys, such as GaAs and GaP, are isoelectronically co-doped with, for example, B and Bi, to customize solar cells, and other semiconductor devices. Isoelectronically co-doped Group II-VI compounds and alloys are also included.

  2. The super junction bipolar transistor: a new silicon power device concept for ultra low loss switching applications at medium to high voltages

    NASA Astrophysics Data System (ADS)

    Bauer, Friedhelm D.

    2004-05-01

    A new silicon power device concept based on the super junction (SJ) principle for power electronics in a broad spectrum of consumer, industrial and other energy conversion applications is presented in this paper. This new concept can help to sustain the trend towards ultra low loss switching--the past, present and future dominant driving force in the development of silicon high power switches. The super junction bipolar transistor (SJBT) shares many similarities with the super junction MOSFET. It has a similar MOS control structure integrated on the cathode side on top of a base region, which is organized into a columnar structure of alternating p- and n-doped pillars. The anode consists of a p-doped emitter--the SJBT is thus a bipolar super junction power device with carrier modulation taking place in only some portion of the base. The super junction structure makes up for fundamentally different device characteristics compared to an IGBT: carrier modulation in the SJBT is made possible by elimination of the reverse bias between p- and n-doped pillars when large quantities of majority carriers are injected from the p-emitter into the p-type pillar. With the electrostatic potential being grounded at the cathode, de-biasing of the pillars as well as carrier modulation will vanish towards the cathode. The unique characteristic of the SJBT on-state is an electron-hole plasma originating at the anode, which will segregate and give place to unipolar current flow in both pillars (de-mixing of the plasma) in the base region close to the cathode. Compared to an IGBT, the SJBT offers the same or lower conduction losses at a very small fraction (25%) of the cost in terms of switching losses.

  3. Comparative investigation of InGaP/GaAs/GaAsBi and InGaP/GaAs heterojunction bipolar transistors

    SciTech Connect

    Wu, Yi-Chen; Tsai, Jung-Hui; Chiang, Te-Kuang; Wang, Fu-Min

    2015-10-15

    In this article the characteristics of In{sub 0.49}Ga{sub 0.51}P/GaAs/GaAs{sub 0.975}Bi{sub 0.025} and In{sub 0.49}Ga{sub 0.51}P/GaAs heterojunction bipolar transistor (HBTs) are demonstrated and compared by two-dimensional simulated analysis. As compared to the traditional InGaP/GaAs HBT, the studied InGaP/GaAs/GaAsBi HBT exhibits a higher collector current, a lower base-emitter (B–E) turn-on voltage, and a relatively lower collector-emitter offset voltage of only 7 mV. Because the more electrons stored in the base is further increased in the InGaP/GaAs/GaAsBi HBT, it introduces the collector current to increase and the B–E turn-on voltage to decrease for low input power applications. However, the current gain is slightly smaller than the traditional InGaP/GaAs HBT attributed to the increase of base current for the minority carriers stored in the GaAsBi base.

  4. Emitter-base bias dependence of the collector current ideality factor in abrupt Pnp AlGaAs/GaAs heterojunction bipolar transistors

    NASA Astrophysics Data System (ADS)

    Ekbote, S.; Cahay, M.; Roenker, K.

    2000-02-01

    Starting with the 4×4 Luttinger-Kohn Hamiltonian and making use of the axial approximation, we calculate the emitter current as a function of the applied forward emitter-base bias for a typical Pnp AlGaAs/GaAs single heterojunction bipolar transistor (HBT). While including the effects of emitter series resistance and recombination in the quasi-neutral base and emitter-base space-charge region, we then calculate the collector current density versus emitter to base bias and find it to be in excellent agreement with the experimental results for a Al0.4Ga0.6As/GaAs Pnp HBT recently reported in the literature. For that structure, the collector current ideality factor is found to increase from 1.1 at low forward bias VEB to 3.0 at large applied emitter-base forward bias approaching the built-in potential. Experimental values are equal to 1.2 and 2.25 at low and large VEB, respectively.

  5. A G-band terahertz monolithic integrated amplifier in 0.5-μm InP double heterojunction bipolar transistor technology

    NASA Astrophysics Data System (ADS)

    Ou-Peng, Li; Yong, Zhang; Rui-Min, Xu; Wei, Cheng; Yuan, Wang; Bing, Niu; Hai-Yan, Lu

    2016-05-01

    Design and characterization of a G-band (140-220 GHz) terahertz monolithic integrated circuit (TMIC) amplifier in eight-stage common-emitter topology are performed based on the 0.5-μm InGaAs/InP double heterojunction bipolar transistor (DHBT). An inverted microstrip line is implemented to avoid a parasitic mode between the ground plane and the InP substrate. The on-wafer measurement results show that peak gains are 20 dB at 140 GHz and more than 15-dB gain at 140-190 GHz respectively. The saturation output powers are -2.688 dBm at 210 GHz and -2.88 dBm at 220 GHz, respectively. It is the first report on an amplifier operating at the G-band based on 0.5-μm InP DHBT technology. Compared with the hybrid integrated circuit of vacuum electronic devices, the monolithic integrated circuit has the advantage of reliability and consistency. This TMIC demonstrates the feasibility of the 0.5-μm InGaAs/InP DHBT amplifier in G-band frequencies applications. Project supported by the National Natural Science Foundation of China (Grant No. 61501091) and the Fundamental Research Funds for the Central Universities of Ministry of Education of China (Grant Nos. ZYGX2014J003 and ZYGX2013J020).

  6. InP/InGaAs/InP double heterojunction bipolar transistors with improved dc and microwave performance grown by solid source molecular beam epitaxy

    NASA Astrophysics Data System (ADS)

    Wang, Hong; Ng, Geok I.; Zheng, Hai Qun; Radhakrishnan, Kaladhar; Yoon, Soon Fatt; Xiong, Yongzhong; Chua, Lye H.; Yang, Hongru; Halder, Subrata; Tan, Chee L.

    2000-10-01

    This paper describes the fabrication and characterization of the InP/InAs/InP double heterojunction bipolar transistors grown by solid-source molecular beam epitaxy (SSMBE). An improvement in current gain and microwave noise has been observed for the SSMBE-grown InP/InGaAs DHBTs. The HBT with a 50 nm, 2 X 19 cm-3 Be-doped base exhibits dc current gain as high as 350, which is about two times of that measured on the referenced devices grown by gas-source molecular beam epitaxy. The HBT with 5 X 5 micrometers 2 emitter shows a minimum noise figure of 1.04 dB and associated gain of 16 dB measured at 2 GHz with Ic equals 1 mA. In comparison, the HBT grown by GSMBE gives an Fmin of 1.9 dB under same measurement condition. A slight increase in fT and fmax for the SSMBE-grown HBT has also been observed. The drastic increase of current gain for the SSMBE-grown HBT could be explained by reducing base recombination due to the ful elimination of hydrogen contamination during the material growth.

  7. Radiation effects on silicon bipolar transistors caused by 3-10 MeV protons and 20-60 MeV bromine ions

    NASA Astrophysics Data System (ADS)

    Li, Xingji; Geng, Hongbin; Lan, Mujie; Liu, Chaoming; Yang, Dezhuang; He, Shiyu

    2010-03-01

    The current gain degradation in silicon NPN bipolar junction transistors (BJTs) was examined under irradiation with 3-10 MeV protons and 20-60 MeV bromine (Br) ions with various dose levels. To characterize the radiation damage of the NPN BJTs, the ionizing dose D i and displacement dose D d as a function of chip depth in the NPN BJTs were calculated for both the protons and Br ions with different energies. Based on the irradiation testing and calculated results, it is shown that the current gain degradation of NPN BJTs is sensitive to the ratio of D d/( D d+ D i) in the sensitive region given by protons and Br ions. The irradiation particles (protons and Br ions), which give larger D d/( D d+ D i) at a given total dose, would generate more severe damage to the NPN BJTs. The reciprocal of the gain variation as a function of the displacement dose was compared, showing that the Messenger-Spratt equation becomes relevant to describe the experimental data, when the ratio of the D d/( D d+ D i) are larger and the displacement dose are higher than a certain value.

  8. Epitaxial growth and characterization of thick multi-layer 4H-SiC for very high-voltage insulated gate bipolar transistors

    NASA Astrophysics Data System (ADS)

    Miyazawa, Tetsuya; Nakayama, Koji; Tanaka, Atsushi; Asano, Katsunori; Ji, Shi-yang; Kojima, Kazutoshi; Ishida, Yuuki; Tsuchida, Hidekazu

    2015-08-01

    Techniques to fabricate thick multi-layer 4H-SiC epitaxial wafers were studied for very high-voltage p- and n-channel insulated gate bipolar transistors (IGBTs). Multi-layer epitaxial growth, including a thick p- drift layer (˜180 μm), was performed on a 4H-SiC n+ substrate to form a p-IGBT structure. For an n-IGBT structure, an inverted growth process was employed, in which a thick n- drift layer (˜180 μm) and a thick p++ injector layer (>55 μm) were epitaxially grown. The epitaxial growth conditions were modified to attain a low defect density, a low doping concentration, and a long carrier lifetime in the drift layers. Reduction of the forward voltage drop was attempted by using carrier lifetime enhancement processes, specifically, carbon ion implantation/annealing and thermal oxidation/annealing or hydrogen annealing. Simple PiN diodes were fabricated to demonstrate the effective conductivity modulation in the thick drift layers. The forward voltage drops of the PiN diodes with the p- and n-IGBT structures promise to obtain the extremely low-loss and very high-voltage IGBTs. The change in wafer shape during the processing of the very thick multi-layer 4H-SiC is also discussed.

  9. Gallium arsenide-gallium nitride wafer fusion and the n-aluminum gallium arsenide/p-gallium arsenide/n-gallium nitride double heterojunction bipolar transistor

    NASA Astrophysics Data System (ADS)

    Estrada, Sarah M.

    This dissertation describes the n-AlGaAs/p-GaAs/n-GaN heterojunction bipolar transistor (HBT), the first transistor formed via wafer fusion. The fusion process was developed as a way to combine lattice-mismatched materials for high-performance electronic devices, not obtainable via conventional all-epitaxial formation methods. Despite the many challenges of wafer fusion, successful transistors were demonstrated and improved, via the optimization of material structure and fusion process conditions. Thus, this project demonstrated the integration of disparate device materials, chosen for their optimal electronic properties, unrestricted by the conventional (and very limiting) requirement of lattice-matching. By combining an AlGaAs-GaAs emitter-base with a GaN collector, the HBT benefited from the high breakdown voltage of GaN, and from the high emitter injection efficiency and low base transit time of AlGaAs-GaAs. Because the GaAs-GaN lattice mismatch precluded an all-epitaxial formation of the HBT, the GaAs-GaN heterostructure was formed via fusion. This project began with the development of a fusion process that formed mechanically robust and electrically active GaAs-GaN heterojunctions. During the correlation of device electrical performance with a systematic variation of fusion conditions over a wide range (500--750°C, 0.5--2hours), a mid-range fusion temperature was found to induce optimal HBT electrical performance. Transmission electron microscopy (TEM) and secondary ion mass spectrometry (SIMS) were used to assess possible reasons for the variations observed in device electrical performance. Fusion process conditions were correlated with electrical (I-V), structural (TEM), and chemical (SIMS) analyses of the resulting heterojunctions, in order to investigate the trade-off between increased interfacial disorder (TEM) with low fusion temperature and increased diffusion (SIMS) with high fusion temperature. The best do device results (IC ˜ 2.9 kA/cm2 and beta

  10. Microwave performance of an optically controlled AlGaAs/GaAs high electron mobility transistor and GaAs MESFET

    NASA Astrophysics Data System (ADS)

    Simons, Rainee N.; Bhasin, Kul. B.

    Direct current and also the microwave characteristics of optically illuminated AlGaAs/GaAs HEMT are experimentally measured for the first time and compared with that of GaAs MESFET. The results showed that the average increase in the gain is 2.89 dB under 1.7 nW/sq cm optical intensity at 0.83 microns. Further, the effect of illumination on S-parameters is more pronounced when the devices are biased close to pinch off. Novel applications of optically illuminated HEMT as a variable gain amplifier, high speed high frequency photo detector, and mixer are demonstrated.

  11. Microwave performance of an optically controlled AlGaAs/GaAs high electron mobility transistor and GaAs MESFET

    NASA Astrophysics Data System (ADS)

    Simons, Rainee N.

    1987-12-01

    Direct current and also the microwave characteristics of optically illuminated AlGaAs/GaAs HEMT are experimentally measured for the first time and compared with that of GaAs MESFET. The results showed that the average increase in the gain is 2.89 dB under 1.7 mW optical intensity at 0.83 microns. Further, the effect of illumination on S-parameters is more pronounced when the devices are biased close to pinch off. Novel applications of optically illuminated HEMT as a variable gain amplifier, high speed high frequency photodetector, and mixer are demonstrated.

  12. Interpreting Transistor Noise

    NASA Astrophysics Data System (ADS)

    Pospieszalski, M. W.

    2010-10-01

    The simple noise models of field effect and bipolar transistors reviewed in this article are quite useful in engineering practice, as illustrated by measured and modeled results. The exact and approximate expressions for the noise parameters of FETs and bipolar transistors reveal certain common noise properties and some general noise properties of both devices. The usefulness of these expressions in interpreting the dependence of measured noise parameters on frequency, bias, and temperature and, consequently, in checking of consistency of measured data has been demonstrated.

  13. Carbon doping in molecular beam epitaxy of GaAs from a heated graphite filament

    NASA Technical Reports Server (NTRS)

    Malik, R. J.; Nottenberg, R. N.; Schubert, E. F.; Walker, J. F.; Ryan, R. W.

    1988-01-01

    Carbon doping of GaAs grown by molecular beam epitaxy has been obtained for the first time by use of a heated graphite filament. Controlled carbon acceptor concentrations over the range of 10 to the 17th-10 to the 20th/cu cm were achieved by resistively heating a graphite filament with a direct current power supply. Capacitance-voltage, p/n junction and secondary-ion mass spectrometry measurements indicate that there is negligible diffusion of carbon during growth and with postgrowth rapid thermal annealing. Carbon was used for p-type doping in the base of Npn AlGaAs/GaAs heterojunction bipolar transistors. Current gains greater than 100 and near-ideal emitter heterojunctions were obtained in transistors with a carbon base doping of 1 x 10 to the 19th/cu cm. These preliminary results indicate that carbon doping from a solid graphite source may be an attractive substitute for beryllium, which is known to have a relatively high diffusion coefficient in GaAs.

  14. Broad Beam and Ion Microprobe Studies of Single-Event Upsets in High Speed 0.18micron Silicon Germanium Heterojunction Bipolar Transistors and Circuits

    NASA Technical Reports Server (NTRS)

    Reed, Robert A.; Marshall, Paul W.; Pickel, Jim; Carts, Martin A.; Irwin, TIm; Niu, Guofu; Cressler, John; Krithivasan, Ramkumar; Fritz, Karl; Riggs, Pam

    2003-01-01

    SiGe based technology is widely recognized for its tremendous potential to impact the high speed microelectronic industry, and therefore the space industry, by monolithic incorporation of low power complementary logic with extremely high speed SiGe Heterojunction Bipolar Transistor (HBT) logic. A variety of studies have examined the ionizing dose, displacement damage and single event characteristics, and are reported. Accessibility to SiGe through an increasing number of manufacturers adds to the importance of understanding its intrinsic radiation characteristics, and in particular the single event effect (SEE) characteristics of the high bandwidth HBT based circuits. IBM is now manufacturing in its 3rd generation of their commercial SiGe processes, and access is currently available to the first two generations (known as and 6HP) through the MOSIS shared mask services with anticipated future release of the latest (7HP) process. The 5 HP process is described and is characterized by a emitter spacing of 0.5 micron and a cutoff frequency ff of 50 GHz, whereas the fully scaled 7HP HBT employs a 0.18 micron emitter and has an fT of 120 GHz. Previous investigations have the examined SEE response of 5 HP HBT circuits through both circuit testing and modeling. Charge collection modeling studies in the 5 H P process have also been conducted, but to date no measurements have been reported of charge collection in any SiGe HBT structures. Nor have circuit models for charge collection been developed in any version other than the 5 HP HBT structure. Our investigation reports the first indications of both charge collection and circuit response in IBM s 7HP-based SiGe process. We compare broad beam heavy ion SEU test results in a fully function Pseudo-Random Number (PRN) sequence generator up to frequencies of 12 Gbps versus effective LET, and also report proton test results in the same circuit. In addition, we examine the charge collection characteristics of individual 7HP HBT

  15. Molecular beam epitaxial growth of metamorphic AlInSb/GaInSb high-electron-mobility-transistor structures on GaAs substrates for low power and high frequency applications

    SciTech Connect

    Loesch, R.; Aidam, R.; Kirste, L.; Leuther, A.

    2011-02-01

    We report on molecular beam epitaxial growth of AlInSb/GaInSb metamorphic high-electron-mobility-transistor structures for low power, high frequency applications on 4 in. GaAs substrates. The structures consist of a Ga{sub 0.4}In{sub 0.6}Sb channel embedded in Al{sub 0.4}In{sub 0.6}Sb barrier layers which are grown on top of an insulating metamorphic buffer, which is based on the linear exchange of Ga versus In and a subsequent exchange of As versus Sb. Precise control of group V fluxes and substrate temperature in the Al{sub 0.4}In{sub 0.6}As{sub 1-x}Sb{sub x} buffer is essential to achieve high quality device structures. Good morphological properties were achieved demonstrated by the appearance of crosshatching and root mean square roughness values of 2.0 nm. Buffer isolation is found to be >100 k{Omega}/{open_square} for optimized growth conditions. Hall measurements at room temperature reveal electron densities of 2.8x10{sup 12} cm{sup -2} in the channel at mobility values of 21.000 cm{sup 2}/V s for single-sided Te volume doping and 5.4x10{sup 12} cm{sup -2} and 17.000 cm{sup 2}/V s for double-sided Te {delta}-doping, respectively.

  16. Studies and comparisons of a N+-InGaP/δ(P+)-InGaP/n- GaAs hetero-planar-doped structure to high-linearity microwave field-effect transistors

    NASA Astrophysics Data System (ADS)

    Lour, W. S.; Tsai, M. K.; Lai, K. Y.; Chen, B. L.; Yang, Y. J.

    2001-04-01

    We report a promising N+-InGaP/δ(P+)-InGaP/n-GaAs hetero-planar-doped barrier, which is used to fabricate both high-breakdown and self-aligned T-gate (SAT-gate) field-effect transistors (FETs). The characteristics of the devices and comparisons with previous reports are discussed. The enhanced conduction- and valence-band offsets associated with the new hetero-planar doped barrier show high-breakdown behaviour. In addition, high selective etching between InGaP and GaAs layers together with an ohmic gate allows the fabrication of a SAT-gate with a reduced gate-length of 0.8 µm. In the case of a high-breakdown FET, the drain-source breakdown voltage is as high as 32 V. In addition to competitive direct-current (dc) performances, a reduced knee voltage and improved frequency performances are obtained in SAT-gate FETs. The available unity-current-gain and unity-power-gain frequencies are, respectively, 19.5 and 30 GHz achieved as a 0.6 µm gate is obtained by forming a 1 µm metal gate. Furthermore, all the measured SAT-gate FETs exhibit high-linearity and high-uniformity dc and alternating-current performances.

  17. Bipolar Disorder

    MedlinePlus

    ... How Can I Help a Friend Who Cuts? Bipolar Disorder KidsHealth > For Teens > Bipolar Disorder Print A A ... Bipolar Disorder en español Trastorno bipolar What Is Bipolar Disorder? Bipolar disorders are one of several medical conditions ...

  18. Charge separation for bipolar transistors

    SciTech Connect

    Kosier, S.L.; Schrimpf, R.D.; Wei, A.; Chai, F. ); Nowlin, R.N. ); Fleetwood, D.M. ); DeLaus, M. ); Pease, R.L. ); Combs, W.E. )

    1993-12-01

    The role of net positive oxide trapped charge and surface recombination velocity on excess base current in BJTs is identified. Although the interaction of these two radiation-induced defects is physically complex, simple approaches for estimating these quantities from measured BJT characteristics are presented. The oxide charge is estimated using a transition voltage in the plot of excess base current vs. emitter bias. Two approaches for quantifying die effects of surface recombination velocity are described; the first measures surface recombination directly using a gated diode. The second estimates its effects using an intercept current that is easily obtained from the BJT itself. The results are compared to two-dimensional simulations and measurements made on test structures. The techniques are simple to implement and provide insight into the mechanisms and magnitudes of the radiation-induced damage in BJTs.

  19. GaAs optoelectronic neuron arrays.

    PubMed

    Lin, S; Grot, A; Luo, J; Psaltis, D

    1993-03-10

    A simple optoelectronic circuit integrated monolithically in GaAs to implement sigmoidal neuron responses is presented. The circuit integrates a light-emitting diode with one or two transistors and one or two photodetectors. The design considerations for building arrays with densities of up to 10(4) cm(-2) are discussed.

  20. GaAs optoelectronic neuron arrays

    NASA Technical Reports Server (NTRS)

    Lin, Steven; Grot, Annette; Luo, Jiafu; Psaltis, Demetri

    1993-01-01

    A simple optoelectronic circuit integrated monolithically in GaAs to implement sigmoidal neuron responses is presented. The circuit integrates a light-emitting diode with one or two transistors and one or two photodetectors. The design considerations for building arrays with densities of up to 10,000/sq cm are discussed.

  1. Variable Temperature High-Frequency Response of Heterostructure Transistors

    NASA Astrophysics Data System (ADS)

    Laskar, Joy

    1992-01-01

    The development of high performance heterostructure transistors is essential for emerging opto-electronic integrated circuits (OEICs) and monolithic microwave integrated circuits (MMICs). Applications for OEICs and MMICs include the rapidly growing telecommunications and personal communications markets. The key to successful OEIC and MMIC chip sets is the development of high performance, cost-effective technologies. In this work, several different transistor structures are investigated to determine the potential for high speed performance and the physical mechanisms controlling the ultimate device operation. A cryogenic vacuum microwave measurement system has been developed to study the high speed operation of modulation doped field-effect transistors (MODFETs), doped channel metal insulator field-effect transistors (MISFETs), and metal semiconductor field-effect transistors (MESFETs). This study has concluded that the high field velocity and not the low field mobility is what controls high frequency operation of GaAs based field-effect transistors. Both Al_{rm x} Ga_{rm 1-x}As/GaAs and InP/In_{rm y}Ga _{rm 1-y}As heterostructure bipolar transistors (HBTs) have also been studied at reduced lattice temperatures to understand the role of diffusive transport in the Al_{rm x} Ga_{rm 1-x}As/GaAs HBT and nonequilibrium transport in the InP/In _{rm y}Ga_ {rm 1-y}As HBT. It is shown that drift/diffusion formulation must be modified to accurately estimate the base delay time in the conventional Al _{rm x}Ga_ {rm 1-x}As/GaAs HBT. The reduced lattice temperature operation of the InP/In_ {rm y}Ga_{rm 1-y}As HBT demonstrates extreme nonequilibrium transport in the neutral base and collector space charge region with current gain cut-off frequency exceeding 300 GHz, which is the fastest reported transistor to date. Finally, the MODFET has been investigated as a three-terminal negative differential resistance (NDR) transistor. The existence of real space transfer is confirmed by

  2. Growth and characterization of NpN heterojunction bipolar transistors with In 0.03Ga 0.97N and In 0.05Ga 0.95N bases

    NASA Astrophysics Data System (ADS)

    Lochner, Zachary; Jin Kim, Hee; Choi, Suk; Lee, Yi-Che; Zhang, Yun; Shen, Shyh-Chiang; Ryou, Jae-Hyun; Dupuis, Russell D.

    2011-01-01

    The material and device characteristics of InGaN/GaN heterojunction bipolar transistors (HBTs) grown by metalorganic chemical vapor deposition are examined. Two structures with different p-In xGa 1- xN base region compositions, xIn=0.03 and 0.05, are presented in a comparative study. The higher indium content base is expected to provide improvements in device performance via its higher p-type doping efficiency and lower bulk resistivity. However, the DC gain for both devices is the same at ˜37. The tradeoffs involved with using higher indium composition in the base for NpN HBTs are investigated by atomic force microscopy, Hall-effect measurement, and device characterization.

  3. Rapid thermal anneal in InP, GaAs and GaAs/GaAlAs

    NASA Astrophysics Data System (ADS)

    Descouts, B.; Duhamel, N.; Godefroy, S.; Krauz, P.

    Ion implantation in semiconductors provides a doping technique with several advantages over more conventional doping methods and is now extensively used for device applications, e.g. field effect transistors (MESFET GaAs, MIS (InP), GaAs/GaAlAs heterojunction bipolar transistors (HBT). Because of the lattice disorder produced by the implantation, the dopant must be made electrically active by a postimplant anneal. As the device performances are very dependent on its electrical characteristics, the anneal is a very important stage of the process. Rapid anneal is known to provide less exodiffusion and less induffusion of impurities compared to conventional furnace anneal, so this technique has been used in this work to activate an n-type dopant (Si) in InP and a p-type dopant (Mg) in GaAs and GaAs/GaAIAs. These two ions have been chosen to realize implanted MIS InP and the base contacts for GaAs/GaAlAs HBTs. The experimental conditions to obtain the maximum electrical activity in these two cases will be detailed. For example, although we have not been able to obtain a flat profile in Mg + implanted GaAs/GaAlAs heterostructure by conventional thermal anneal, rapid thermal anneal gives a flat hole profile over a depth of 0.5 μm with a concentration of 1 x 10 19 cm -3.

  4. Ultra-stable oscillator with complementary transistors

    NASA Technical Reports Server (NTRS)

    Kleinberg, L. L. (Inventor)

    1974-01-01

    A high frequency oscillator, having both good short and long term stability, is formed by including a piezoelectric crystal in the base circuit of a first bi-polar transistor circuit, the bi-polar transistor itself operated below its transitional frequency and having its emitter load chosen so that the input impedance, looking into the base thereof, exhibits a negative resistance in parallel with a capacitive reactance. Combined with this basic circuit is an auxiliary, complementary, second bi-polar transistor circuit of the same form with the piezoelectric crystal being common to both circuits. By this configuration small changes in quiescent current are substantially cancelled by opposite variations in the second bi-polar transistor circuit, thereby achieving from the oscillator a signal having its frequency of oscillation stable over long time periods as well as short time periods.

  5. A 6-bit 3-Gsps ADC implemented in 1 μm GaAs HBT technology

    NASA Astrophysics Data System (ADS)

    Jincan, Zhang; Yuming, Zhang; Hongliang, Lü; Yimen, Zhang; Guangxing, Xiao; Guiping, Ye

    2014-08-01

    The design and test results of a 6-bit 3-Gsps analog-to-digital converter (ADC) using 1 μm GaAs heterojunction bipolar transistor (HBT) technology are presented. The monolithic folding-interpolating ADC makes use of a track-and-hold amplifier (THA) with a highly linear input buffer to maintain a highly effective number of bits (ENOB). The ADC occupies an area of 4.32 × 3.66 mm2 and achieves 5.53 ENOB with an effective resolution bandwidth of 1.1 GHz at a sampling rate of 3 Gsps. The maximum DNL and INL are 0.36 LSB and 0.48 LSB, respectively.

  6. Novel InGaAs contact layer growth for hetero-junction bipolar transistors (HBTs) by using the multiple group-V source molecular beam epitaxy (MBE) system

    NASA Astrophysics Data System (ADS)

    Kadoiwa, Kaoru; Izumi, Shigekazu; Yamamoto, Yoshitsugu; Hayafuji, Norio; Sonoda, Takuji

    1999-05-01

    Dependence of layer surface morphology and electrical properties on growth conditions, growth temperature and supplying conditions of group-V sources such as solid-As and AsH 3 hydride gas, has been investigated with specially designed MBE system, including both solid-As source cell and gas source cracking cell, for highly lattice-mismatched (+4%) In 0.5Ga 0.5As layer grown on GaAs. We demonstrate that utilizing of AsH 3 hydride source enables us to obtain a superior smooth surface in comparison with utilizing solid-As source. The HAZE level for the former source is reduced to one twentieth of the latter. The advantage of gas-source MBE (GS-MBE) method (hydrogen effect) was realized as suppressing In segregation. The effective hydrogen comes from AsH 3 hydride that acts as the surfactant that controls coherent small 3D islands formation during initial growth stage. The optimized GS-MBE growth method, under AsH 3 flow rate of 3 SCCM and growth temperature of 470°C, establishes that the In xGa 1- xAs ( x=0.6) layer grown on GaAs with the surface is as smooth as the surface of GaAs substrate, and also shows the contact resistance to be 4×10 -8 Ω cm 2. This value is well-fitted for nonalloy ohmic contact by using W/Si as emitter electrodes for HBTs.

  7. Bipolar Disorder.

    PubMed

    Miller, Thomas H

    2016-06-01

    Bipolar disorder is a chronic mental health disorder that is frequently encountered in primary care. Many patients with depression may actually have bipolar disorder. The management of bipolar disorder requires proper diagnosis and awareness or referral for appropriate pharmacologic therapy. Patients with bipolar disorder require primary care management for comorbidities such as cardiovascular and metabolic disorders. PMID:27262007

  8. Field effect transistors improve buffer amplifier

    NASA Technical Reports Server (NTRS)

    1967-01-01

    Unity gain buffer amplifier with a Field Effect Transistor /FET/ differential input stage responds much faster than bipolar transistors when operated at low current levels. The circuit uses a dual FET in a unity gain buffer amplifier having extremely high input impedance, low bias current requirements, and wide bandwidth.

  9. Accelerated life testing and temperature dependence of device characteristics in GaAs CHFET devices

    NASA Technical Reports Server (NTRS)

    Gallegos, M.; Leon, R.; Vu, D. T.; Okuno, J.; Johnson, A. S.

    2002-01-01

    Accelerated life testing of GaAs complementary heterojunction field effect transistors (CHFET) was carried out. Temperature dependence of single and synchronous rectifier CHFET device characteristics were also obtained.

  10. Dose rate dependence of radiation-induced lattice defects and performance degradation in npn Si bipolar transistors by 2-MeV electron irradiation

    NASA Astrophysics Data System (ADS)

    Hayama, K.; Takakura, K.; Ohyama, H.; Kuboyama, S.; Simoen, E.; Mercha, A.; Claeys, C.

    2007-12-01

    Total-dose response of npn Si transistors by 2-MeV electrons is presented for different dose rates. The base current increases after irradiation, whereas the collector current decreases. Therefore, the current gain ( β) decreases by irradiation. The degradation of electrical properties by 2-MeV electrons for low dose rate is higher than that for high dose rate. Similar dose rate dependence of the radiation-induced electron trap densities is observed by deep-level transient spectroscopy (DLTS) measurements.

  11. Cryogenic measurements of aerojet GaAs n-JFETs

    NASA Technical Reports Server (NTRS)

    Goebel, John H.; Weber, Theodore T.

    1993-01-01

    The spectral noise characteristics of Aerojet gallium arsenide (GaAs) junction field effect transistors (JFET's) have been investigated down to liquid-helium temperatures. Noise characterization was performed with the field effect transistor (FET) in the floating-gate mode, in the grounded-gate mode to determine the lowest noise readings possible, and with an extrinsic silicon photodetector at various detector bias voltages to determine optimum operating conditions. The measurements indicate that the Aerojet GaAs JFET is a quiet and stable device at liquid helium temperatures. Hence, it can be considered a readout line driver or infrared detector preamplifier as well as a host of other cryogenic applications. Its noise performance is superior to silicon (Si) metal oxide semiconductor field effect transistor (MOSFET's) operating at liquid helium temperatures, and is equal to the best Si n channel junction field effect transistor (n-JFET's) operating at 300 K.

  12. Study of In 0.49Ga 0.51P/GaAs/In 0.49Ga 0.51P double δ-doped heterojunction bipolar transistor

    NASA Astrophysics Data System (ADS)

    Wang, Wei-Chou; Chen, Jing-Yuh; Pan, Hsi-Jen; Feng, Shun-Ching; Yu, Kuo-Hui; Liu, Wen-Chau

    1999-07-01

    A lattice-matched In 0.49Ga 0.51P/GaAs/In 0.49Ga 0.51P double δ -doped heterojunction bipolar transistor, prepared by low-pressure metal organic chemical vapor deposition (LP-MOCVD), is fabricated successfully and reported. Due to the insertion of δ -doped sheets and setback layers both at base-emitter (B-E) and base-collector (B-C) heterojunctions, the potential spikes are suppressed significantly. In addition, the electron blocking effect is removed and a dramatic improvement of current gain is obtained. A modified Ebers-Moll model is employed to study and analyse the device performances. The experimental results show that the common-emitter current gain over 210 at the collector current of 35 mA and an offset voltage ΔVCE smaller than 50 mV are obtained. Also, a lower knee-shaped voltage of 1.4 V at the collector current of 40 mA is observed. These results indicate that the device studied is a good candidate for high-speed and high-power circuit applications.

  13. Quantum Thermal Transistor.

    PubMed

    Joulain, Karl; Drevillon, Jérémie; Ezzahri, Younès; Ordonez-Miranda, Jose

    2016-05-20

    We demonstrate that a thermal transistor can be made up with a quantum system of three interacting subsystems, coupled to a thermal reservoir each. This thermal transistor is analogous to an electronic bipolar one with the ability to control the thermal currents at the collector and at the emitter with the imposed thermal current at the base. This is achieved by determining the heat fluxes by means of the strong-coupling formalism. For the case of three interacting spins, in which one of them is coupled to the other two, that are not directly coupled, it is shown that high amplification can be obtained in a wide range of energy parameters and temperatures. The proposed quantum transistor could, in principle, be used to develop devices such as a thermal modulator and a thermal amplifier in nanosystems.

  14. Quantum Thermal Transistor.

    PubMed

    Joulain, Karl; Drevillon, Jérémie; Ezzahri, Younès; Ordonez-Miranda, Jose

    2016-05-20

    We demonstrate that a thermal transistor can be made up with a quantum system of three interacting subsystems, coupled to a thermal reservoir each. This thermal transistor is analogous to an electronic bipolar one with the ability to control the thermal currents at the collector and at the emitter with the imposed thermal current at the base. This is achieved by determining the heat fluxes by means of the strong-coupling formalism. For the case of three interacting spins, in which one of them is coupled to the other two, that are not directly coupled, it is shown that high amplification can be obtained in a wide range of energy parameters and temperatures. The proposed quantum transistor could, in principle, be used to develop devices such as a thermal modulator and a thermal amplifier in nanosystems. PMID:27258859

  15. Bipolar Disorder

    MedlinePlus

    Bipolar disorder is a serious mental illness. People who have it go through unusual mood changes. They go ... The down feeling is depression. The causes of bipolar disorder aren't always clear. It runs in families. ...

  16. Simulating Single-Event Upsets in Bipolar RAM's

    NASA Technical Reports Server (NTRS)

    Zoutendyk, J. A.

    1986-01-01

    Simulation technique saves testing. Uses interactive version of SPICE (Simulation Program with Integrated Circuit Emphasis). Device and subcircuit models available in software used to construct macromodel for an integrated bipolar transistor. Time-dependent current generators placed inside transistor macromodel to simulate charge collection from ion track. Significant finding of experiments is standard design practice of reducing power in unaddressed bipolar RAM cell increases sensitivity of cell to single-event upsets.

  17. The 20 GHz power GaAs FET development

    NASA Technical Reports Server (NTRS)

    Crandell, M.

    1986-01-01

    The development of power Field Effect Transistors (FET) operating in the 20 GHz frequency band is described. The major efforts include GaAs FET device development (both 1 W and 2 W devices), and the development of an amplifier module using these devices.

  18. Calculation of the base current components and determination of their relative importance in AlGaAs/GaAs and InAlAs/InGaAs heterojunction bipolar transistors

    NASA Astrophysics Data System (ADS)

    Liou, J. J.

    1991-03-01

    The base current density JB is an important parameter in determining the common-emitter current gain β of heterojunction bipolar transistors (HBTs). To develop an analytical β model with which a circuit designer can quickly estimate the current gain in a HBT, it is also important to identify the dominant component of JB so that minimum computations are required. Based on heterojunction device physics, the three components of JB have been calculated, namely, the recombination current density in the base JRB, the recombination current density in the space-charge region JSCR, and the injection current density from the base to the emitter JRE, and have determined their relative importance to JB for abrupt AlGaAs/GaAs and InAlAs/InGaAs HBTs under normal bias conditions. It is found that relative importance of the three current densities depends strongly on the bias condition, strongly on the density of states NtI at the emitter-base heterointerface, but weakly on the density of trapping states NtB in the bulk of the emitter-base space-charge region. Also, JB is relatively insensitive to device makeup such as doping concentration and layer thickness. Depending on NtI and on the bias condition, either JSCR or JRE is the dominant component for AlGaAs/GaAs HBTs and either JSCR or JRB is the dominant component for InAlAs/InGaAs HBTs. Effects of base and heterojunction grading on the present findings are also addressed.

  19. Design considerations for FET-gated power transistors

    NASA Technical Reports Server (NTRS)

    Chen, D. Y.; Chin, S. A.

    1983-01-01

    An FET-bipolar combinational power transistor configuration (tested up to 300 V, 20 A at 100 kHz) is described. The critical parameters for integrating the chips in hybrid form are examined, and an effort to optimize the overall characteristics of the configuration is discussed. Chip considerations are examined with respect to the voltage and current rating of individual chips, the FET surge capability, the choice of triple diffused transistor or epitaxial transistor for the bipolar element, the current tailing effect, and the implementation of the bipolar transistor and an FET as single chip or separate chips. Package considerations are discussed with respect to package material and geometry, surge current capability of bipolar base terminal bonding, and power losses distribution.

  20. Bipolar Disorder

    MedlinePlus

    ... or digestive problems Problems sleeping, or wanting to sleep all of the time Feeling tired all of the time Thoughts about death and suicide Causes & Risk Factors What causes bipolar disorder? Bipolar disorder may be caused by a chemical imbalance in the brain. It sometimes runs in ...

  1. Bipolar Disorder.

    ERIC Educational Resources Information Center

    Spearing, Melissa

    Bipolar disorder, a brain disorder that causes unusual shifts in a person's mood, affects approximately one percent of the population. It commonly occurs in late adolescence and is often unrecognized. The diagnosis of bipolar disorder is made on the basis of symptoms, course of illness, and when possible, family history. Thoughts of suicide are…

  2. A New Bipolar Imaging Device (BASIS)

    NASA Astrophysics Data System (ADS)

    Tanaka, Nobuyoshi; Nakamura, Yoshio; Matsumoto, Shigeyuki; Ohmi, Tadahiro

    1989-10-01

    A bipolar imaging device consisting of a capacitor loaded emitter follower circuit for a photo-transistor has been implemented into linear image sensors, which has capabilities of charge amplification and self-noise-reduction. The linear sensors are demonstrated experimentally to exhibit excellent performance such as a linearity in a wide dynamic range and a high sensitivity.

  3. Method for double-sided processing of thin film transistors

    DOEpatents

    Yuan, Hao-Chih; Wang, Guogong; Eriksson, Mark A.; Evans, Paul G.; Lagally, Max G.; Ma, Zhenqiang

    2008-04-08

    This invention provides methods for fabricating thin film electronic devices with both front- and backside processing capabilities. Using these methods, high temperature processing steps may be carried out during both frontside and backside processing. The methods are well-suited for fabricating back-gate and double-gate field effect transistors, double-sided bipolar transistors and 3D integrated circuits.

  4. Ion implanted GaAs microwave FET's

    NASA Astrophysics Data System (ADS)

    Gill, S. S.; Blockley, E. G.; Dawsey, J. R.; Foreman, B. J.; Woodward, J.; Ball, G.; Beard, S. J.; Gaskell, J. M.; Allenson, M. B.

    1988-06-01

    The combination of ion implantation and photolithographic patterning techniques was applied to the fabrication of GaAs microwave FETs to provide a large number of devices having consistently predictable dc and high frequency characteristics. To validate the accuracy and repeatability of the high frequency device parameters, an X-band microwave circuit was designed and realized. The performance of this circuit, a buffered amplifier, is very close to the design specification. The availability of a large number of reproducible, well-characterized transistors enabled work to commence on the development of a large signal model for FETs. Work in this area is also described.

  5. Bipolar disorder

    MedlinePlus

    ... Loss of self-esteem Thoughts of death or suicide Trouble getting to sleep or sleeping too much ... with bipolar disorder are at high risk of suicide . They may use alcohol or other substances . This ...

  6. Bipolar Disorder

    MedlinePlus

    ... health professional before making a commitment. Learn More Free Booklets and Brochures Bipolar Disorder: A brochure on ... in the public domain and available for use free of charge. Citation of the NIMH is appreciated. ...

  7. Bipolar battery

    DOEpatents

    Kaun, Thomas D.

    1992-01-01

    A bipolar battery having a plurality of cells. The bipolar battery includes: a negative electrode; a positive electrode and a separator element disposed between the negative electrode and the positive electrode, the separator element electrically insulating the electrodes from one another; an electrolyte disposed within at least one of the negative electrode, the positive electrode and the separator element; and an electrode containment structure including a cup-like electrode holder.

  8. Performance analysis of undoped cylindrical gate all around (GAA) MOSFET at subthreshold regime

    NASA Astrophysics Data System (ADS)

    Jena, B.; Pradhan, K. P.; Dash, S.; Mishra, G. P.; Sahu, P. K.; Mohapatra, S. K.

    2015-09-01

    In this work the sensitivity of process parameters like channel length (L), channel thickness (tSi), and gate work function (φM) on various performance metrics of an undoped cylindrical gate all around (GAA) metal-oxide-semiconductor field effect transistor (MOSFET) are systematically analyzed. Undoped GAA MOSFET is a radical invention as it introduces a new direction for transistor scaling. In conventional MOSFET, generally the channel doping concentration is very high to provide high on-state current, but in contrary it causes random dopant fluctuation and threshold voltage variation. So, the undoped nature of GAA MOSFET solves the above complications. Hence, we have analyzed the electrical characteristics as well as the analog/RF performances of undoped GAA MOSFET through Sentaurus device simulator.

  9. Modeling of single-event upset in bipolar integrated circuits

    NASA Technical Reports Server (NTRS)

    Zoutendyk, J. A.

    1983-01-01

    The results of work done on the quantitative characterization of single-event upset (SEU) in bipolar random-access memories (RAMs) have been obtained through computer simulation of SEU in RAM cells that contain circuit models for bipolar transistors. The models include current generators that emulate the charge collected from ion tracks. The computer simulation results are compared with test data obtained from a RAM in a bipolar microprocessor chip. This methodology is applicable to other bipolar integrated circuit constructions in addition to RAM cells.

  10. A comparison of the kink effect in polysilicon thin film transistors and silicon on insulator transistors

    NASA Astrophysics Data System (ADS)

    Armstrong, G. A.; Brotherton, S. D.; Ayres, J. R.

    1996-09-01

    Polysilicon thin film transistors (TFTs) differ from conventional silicon on insulator (SOI) transistors in that the TFT exhibits a fundamental gate length dependence of the voltage at which a kink occurs in the output characteristics. This difference is shown to be caused by the peak lateral electric field being strongly dependent on the doping density in an SOI transistor, but relatively insensitive to trap distribution in a TFT. Source barrier lowering which occurs in SOI transistors is absent in a TFT, where the increase in current is the result of a field redistribution along the channel. For very short gate lengths, the TFT exhibits a small pseudo-bipolar gain. Estimates of this bipolar gain can be made by simulation of TFT characteristics with and without impact ionisation. The magnitude of the gain is shown to be approximately inversely proportional to gate length.

  11. Magnetic Vortex Based Transistor Operations

    PubMed Central

    Kumar, D.; Barman, S.; Barman, A.

    2014-01-01

    Transistors constitute the backbone of modern day electronics. Since their advent, researchers have been seeking ways to make smaller and more efficient transistors. Here, we demonstrate a sustained amplification of magnetic vortex core gyration in coupled two and three vortices by controlling their relative core polarities. This amplification is mediated by a cascade of antivortex solitons travelling through the dynamic stray field. We further demonstrated that the amplification can be controlled by switching the polarity of the middle vortex in a three vortex sequence and the gain can be controlled by the input signal amplitude. An attempt to show fan–out operation yielded gain for one of the symmetrically placed branches which can be reversed by switching the core polarity of all the vortices in the network. The above observations promote the magnetic vortices as suitable candidates to work as stable bipolar junction transistors (BJT). PMID:24531235

  12. New dynamic FET logic and serial memory circuits for VLSI GaAs technology

    NASA Technical Reports Server (NTRS)

    Eldin, A. G.

    1991-01-01

    The complexity of GaAs field effect transistor (FET) very large scale integration (VLSI) circuits is limited by the maximum power dissipation while the uniformity of the device parameters determines the functional yield. In this work, digital GaAs FET circuits are presented that eliminate the DC power dissipation and reduce the area to 50% of that of the conventional static circuits. Its larger tolerance to device parameter variations results in higher functional yield.

  13. Bipolar disorder

    PubMed Central

    Goodwin, Frederick K.; Ghaemi, S. Nassir

    1999-01-01

    Bipolar disorder's unique combination of three characteristics - clear genetic diathesis, distinctive clinical features, early availability of an effective treatment (lithium) - explains its special place in the history of psychiatry and its contribution to the current explosive growth of neuroscience. This article looks at the state of the art in bipolar disorder from the vantage point of: (i) genetics (possible linkages on chromosomes 18 and 21q, polygenic hypothesis, research into genetic markers); (ii) diagnosis (new focus on the subjective aspects of bipolar disorder to offset the current trend of underdiagnosis due to overreliance on standardized interviews and rating scales); (iii) outcome (increase in treatment-resistant forms signaling a change in the natural history of bipolar disorder); (iv) pathophysiology (research into circadian biological rhythms and the kindling hypothesis to explain recurrence); (v) treatment (emergence of the anticonvulsants, suggested role of chronic antidepressant treatment in the development of treatment resistance); (vi) neurobiology (evaluation of regulatory function in relation to affective disturbances, role of postsynaptic second-messenger mechanisms, advances in functional neuroimaging); and (vii) psychosocial research (shedding overly dualistic theories of the past to understand the mind and brain as an entity, thus emphasizing the importance of balancing the psychopharmacological and psychotherapeutic approaches). Future progress in the understanding and treatment of bipolar disorder will rely on successful integration of the biological and psychosocial lines of investigation. PMID:22033232

  14. GaAs Optoelectronic Integrated-Circuit Neurons

    NASA Technical Reports Server (NTRS)

    Lin, Steven H.; Kim, Jae H.; Psaltis, Demetri

    1992-01-01

    Monolithic GaAs optoelectronic integrated circuits developed for use as artificial neurons. Neural-network computer contains planar arrays of optoelectronic neurons, and variable synaptic connections between neurons effected by diffraction of light from volume hologram in photorefractive material. Basic principles of neural-network computers explained more fully in "Optoelectronic Integrated Circuits For Neural Networks" (NPO-17652). In present circuits, devices replaced by metal/semiconductor field effect transistors (MESFET's), which consume less power.

  15. Forward-bias tunneling - A limitation to bipolar device scaling

    NASA Technical Reports Server (NTRS)

    Del Alamo, Jesus A.; Swanson, Richard M.

    1986-01-01

    Forward-bias tunneling is observed in heavily doped p-n junctions of bipolar transistors. A simple phenomenological model suitable to incorporation in device codes is developed. The model identifies as key parameters the space-charge-region (SCR) thickness at zero bias and the reduced doping level at its edges which can both be obtained from CV characteristics. This tunneling mechanism may limit the maximum gain achievable from scaled bipolar devices.

  16. Logic gates based on ion transistors.

    PubMed

    Tybrandt, Klas; Forchheimer, Robert; Berggren, Magnus

    2012-01-01

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

  17. Logic gates based on ion transistors

    NASA Astrophysics Data System (ADS)

    Tybrandt, Klas; Forchheimer, Robert; Berggren, Magnus

    2012-05-01

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

  18. Bipolar electrochemistry.

    PubMed

    Fosdick, Stephen E; Knust, Kyle N; Scida, Karen; Crooks, Richard M

    2013-09-27

    A bipolar electrode (BPE) is an electrically conductive material that promotes electrochemical reactions at its extremities (poles) even in the absence of a direct ohmic contact. More specifically, when sufficient voltage is applied to an electrolyte solution in which a BPE is immersed, the potential difference between the BPE and the solution drives oxidation and reduction reactions. Because no direct electrical connection is required to activate redox reactions, large arrays of electrodes can be controlled with just a single DC power supply or even a battery. The wireless aspect of BPEs also makes it possible to electrosynthesize and screen novel materials for a wide variety of applications. Finally, bipolar electrochemistry enables mobile electrodes, dubbed microswimmers, that are able to move freely in solution.

  19. Types of Bipolar Disorder

    MedlinePlus

    ... Research Studies Peer Support Research WeSearchTogether Types of Bipolar Disorder There are several kinds of bipolar disorder. Each ... like an illness. What is the difference between bipolar disorder and ordinary mood swings? The three main things ...

  20. Bipolar-Battery Construction

    NASA Technical Reports Server (NTRS)

    Rippel, Wally E.; Edwards, Dean B.

    1988-01-01

    Bipolar batteries fabricated in continuous quasi-automated process. Components of battery configured so processing steps run sequentially. Key components of battery, bipolar plate and bipolar separator, fabricated separately and later joined together.

  1. Numerical model and analysis of transistors with polysilicon emitters

    NASA Astrophysics Data System (ADS)

    Yu, Z.

    With the advent of Very Large Scale Integration (VLS) technology, innovative bipolar devices with shallow junctions and high performances are being developed both for silicon and compound semiconductor materials. In the composite structure, such as HBJT (Heterojunction Bipolar Junction Transistor), the device characteristics are controlled not only by the doping profile but also by the composition of the structure. A complete physical and numerical model was developed to handle the carrier transport in such composite structure. An analytical approach (the introduction of an effective recombination velocity) to analyze carrier transport in the emitter of the bipolar transistor is discussed. Both analytical and numerical methods are then applied to the analysis of the device characteristics of transistors with polysilicon emitters. Good agreement between simulations and experimental results is achieved, and a regime of carrier distribution in the base space charge region is revealed. The numerical implementation of the model--a general purpose, one dimensional device simulation program (SEDAN) is briefly discussed.

  2. Transistor Effect in Improperly Connected Transistors.

    ERIC Educational Resources Information Center

    Luzader, Stephen; Sanchez-Velasco, Eduardo

    1996-01-01

    Discusses the differences between the standard representation and a realistic representation of a transistor. Presents an experiment that helps clarify the explanation of the transistor effect and shows why transistors should be connected properly. (JRH)

  3. Orientation-dependent perimeter recombination in GaAs diodes

    NASA Astrophysics Data System (ADS)

    Stellwag, T. B.; Melloch, M. R.; Lundstrom, M. S.; Carpenter, M. S.; Pierret, R. F.

    1990-04-01

    Perimeter recombination currents affect the performance of GaAs-based devices such as solar cells, heterojunction bipolar transistors, and injection lasers. We report that the n≂2 perimeter recombination current has a strong orientation dependence. More than a factor of five variation in the surface recombination current at mesa-etched edges has been observed. These results suggest that with proper device design, perimeter recombination currents could be substantially reduced.

  4. Orientation-dependent perimeter recombination in GaAs diodes

    SciTech Connect

    Stellwag, T.B.; Melloch, M.R.; Lundstrom, M.S.; Carpenter, M.S.; Pierret, R.F. )

    1990-04-23

    Perimeter recombination currents affect the performance of GaAs-based devices such as solar cells, heterojunction bipolar transistors, and injection lasers. We report that the {ital n}{congruent}2 perimeter recombination current has a strong orientation dependence. More than a factor of five variation in the surface recombination current at mesa-etched edges has been observed. These results suggest that with proper device design, perimeter recombination currents could be substantially reduced.

  5. Total Dose Effects on Bipolar Integrated Circuits at Low Temperature

    NASA Technical Reports Server (NTRS)

    Johnston, A. H.; Swimm, R. T.; Thorbourn, D. O.

    2012-01-01

    Total dose damage in bipolar integrated circuits is investigated at low temperature, along with the temperature dependence of the electrical parameters of internal transistors. Bandgap narrowing causes the gain of npn transistors to decrease far more at low temperature compared to pnp transistors, due to the large difference in emitter doping concentration. When irradiations are done at temperatures of -140 deg C, no damage occurs until devices are warmed to temperatures above -50 deg C. After warm-up, subsequent cooling shows that damage is then present at low temperature. This can be explained by the very strong temperature dependence of dispersive transport in the continuous-time-random-walk model for hole transport. For linear integrated circuits, low temperature operation is affected by the strong temperature dependence of npn transistors along with the higher sensitivity of lateral and substrate pnp transistors to radiation damage.

  6. Comparison of the degradation effects of heavy ion, electron, and cobalt-60 irradiation in an advanced bipolar process

    NASA Technical Reports Server (NTRS)

    Zoutendyk, John A.; Goben, Charles A.; Berndt, Dale F.

    1988-01-01

    Experimental measurements are reported of the degradation effects of high-energy particles (heavy Br ions and electrons) and Co-60 gamma-rays on the current gain of minimum-geometry bipolar transistors made from an advanced process. The data clearly illustrate the total-ionizing-dose vs particle-fluence behavior of this bipolar transistor produced by an advanced process. In particular, bulk damage from Co-60 gamma rays in bipolar transistors (base transport factor degradation) and surface damage in bipolar transistors from ionizing radiation (emitter-efficiency degradation) have been observed. The true equivalence between various types of radiation for this process technology has been determined on the basis of damage from the log K1 intercepts.

  7. Development, Demonstration, and Device Physics of Fet-Accessed One-Transistor Gallium Arsenide Dynamic Memory Technologies

    NASA Astrophysics Data System (ADS)

    Neudeck, Philip Gerold

    The introduction of digital GaAs into modern high -speed computing systems has led to an increasing demand for high-density memory in these GaAs technologies. To date, most of the memory development efforts in GaAs have been directed toward four- and six-transistor static RAM's, which consume substantial chip area and dissipate much static power resulting in limited single-chip GaAs storage capacities. As it has successfully done in silicon, a one-transistor dynamic RAM approach could alleviate these problems making higher density GaAs memories possible. This dissertation discusses theoretical and experimental work that presents the possibility for a high-speed, low-power, one-transistor dynamic RAM technology in GaAs. The two elements of the DRAM cell, namely the charge storage capacitor and the access field-effect transistor have been studied in detail. Isolated diode junction charge storage capacitors have demonstrated 30 minutes of storage time at room temperature with charge densities comparable to those obtained in planar silicon DRAM capacitors. GaAs JFET and MESFET technologies have been studied, and with careful device design and choice of proper operating voltages experimental results show that both can function as acceptable access transistors. One-transistor MESFET- and JFET-accessed DRAM cells have been fabricated and operated at room temperature and above with a standby power dissipation that is only a small fraction of the power dissipated by the best commercial GaAs static RAM cells. A 2 x 2 bit demonstration array was built and successfully operated at room temperature to demonstrate the addressable read/write capability of this new technology.

  8. Switching Transistor

    NASA Astrophysics Data System (ADS)

    1981-01-01

    Westinghouse Electric Corporation's D60T transistors are used primarily as switching devices for controlling high power in electrical circuits. It enables reduction in the number and size of circuit components and promotes more efficient use of energy. Wide range of application from a popcorn popper to a radio frequency generator for solar cell production.

  9. Vertical Ge/Si Core/Shell Nanowire Junctionless Transistor.

    PubMed

    Chen, Lin; Cai, Fuxi; Otuonye, Ugo; Lu, Wei D

    2016-01-13

    Vertical junctionless transistors with a gate-all-around (GAA) structure based on Ge/Si core/shell nanowires epitaxially grown and integrated on a ⟨111⟩ Si substrate were fabricated and analyzed. Because of efficient gate coupling in the nanowire-GAA transistor structure and the high density one-dimensional hole gas formed in the Ge nanowire core, excellent P-type transistor behaviors with Ion of 750 μA/μm were obtained at a moderate gate length of 544 nm with minimal short-channel effects. The experimental data can be quantitatively modeled by a GAA junctionless transistor model with few fitting parameters, suggesting the nanowire transistors can be fabricated reliably without introducing additional factors that can degrade device performance. Devices with different gate lengths were readily obtained by tuning the thickness of an etching mask film. Analysis of the histogram of different devices yielded a single dominate peak in device parameter distribution, indicating excellent uniformity and high confidence of single nanowire operation. Using two vertical nanowire junctionless transistors, a PMOS-logic inverter with near rail-to-rail output voltage was demonstrated, and device matching in the logic can be conveniently obtained by controlling the number of nanowires employed in different devices rather than modifying device geometry. These studies show that junctionless transistors based on vertical Ge/Si core/shell nanowires can be fabricated in a controlled fashion with excellent performance and may be used in future hybrid, high-performance circuits where bottom-up grown nanowire devices with different functionalities can be directly integrated with an existing Si platform.

  10. Vertical Ge/Si Core/Shell Nanowire Junctionless Transistor.

    PubMed

    Chen, Lin; Cai, Fuxi; Otuonye, Ugo; Lu, Wei D

    2016-01-13

    Vertical junctionless transistors with a gate-all-around (GAA) structure based on Ge/Si core/shell nanowires epitaxially grown and integrated on a ⟨111⟩ Si substrate were fabricated and analyzed. Because of efficient gate coupling in the nanowire-GAA transistor structure and the high density one-dimensional hole gas formed in the Ge nanowire core, excellent P-type transistor behaviors with Ion of 750 μA/μm were obtained at a moderate gate length of 544 nm with minimal short-channel effects. The experimental data can be quantitatively modeled by a GAA junctionless transistor model with few fitting parameters, suggesting the nanowire transistors can be fabricated reliably without introducing additional factors that can degrade device performance. Devices with different gate lengths were readily obtained by tuning the thickness of an etching mask film. Analysis of the histogram of different devices yielded a single dominate peak in device parameter distribution, indicating excellent uniformity and high confidence of single nanowire operation. Using two vertical nanowire junctionless transistors, a PMOS-logic inverter with near rail-to-rail output voltage was demonstrated, and device matching in the logic can be conveniently obtained by controlling the number of nanowires employed in different devices rather than modifying device geometry. These studies show that junctionless transistors based on vertical Ge/Si core/shell nanowires can be fabricated in a controlled fashion with excellent performance and may be used in future hybrid, high-performance circuits where bottom-up grown nanowire devices with different functionalities can be directly integrated with an existing Si platform. PMID:26674542

  11. A Heteroepitaxial Perovskite Metal-Base Transistor

    SciTech Connect

    Yajima, T.; Hikita, Y.; Hwang, H.Y.; /Tokyo U. /JST, PRESTO /SLAC

    2011-08-11

    'More than Moore' captures a concept for overcoming limitations in silicon electronics by incorporating new functionalities in the constituent materials. Perovskite oxides are candidates because of their vast array of physical properties in a common structure. They also enable new electronic devices based on strongly-correlated electrons. The field effect transistor and its derivatives have been the principal oxide devices investigated thus far, but another option is available in a different geometry: if the current is perpendicular to the interface, the strong internal electric fields generated at back-to-back heterojunctions can be used for oxide electronics, analogous to bipolar transistors. Here we demonstrate a perovskite heteroepitaxial metal-base transistor operating at room temperature, enabled by interface dipole engineering. Analysis of many devices quantifies the evolution from hot-electron to permeable-base behaviour. This device provides a platform for incorporating the exotic ground states of perovskite oxides, as well as novel electronic phases at their interfaces.

  12. Superconducting transistor

    DOEpatents

    Gray, Kenneth E.

    1979-01-01

    A superconducting transistor is formed by disposing three thin films of superconducting material in a planar parallel arrangement and insulating the films from each other by layers of insulating oxides to form two tunnel junctions. One junction is biased above twice the superconducting energy gap and the other is biased at less than twice the superconducting energy gap. Injection of quasiparticles into the center film by one junction provides a current gain in the second junction.

  13. Synergistic effect of mixed neutron and gamma irradiation in bipolar operational amplifier OP07

    NASA Astrophysics Data System (ADS)

    Yan, Liu; Wei, Chen; Shanchao, Yang; Xiaoming, Jin; Chaohui, He

    2016-09-01

    This paper presents the synergistic effects in bipolar operational amplifier OP07. The radiation effects are studied by neutron beam, gamma ray, and mixed neutron/gamma ray environments. The characterateristics of the synergistic effects are studied through comparison of different experiment results. The results show that the bipolar operational amplifier OP07 exhibited significant synergistic effects in the mixed neutron and gamma irradiation. The bipolar transistor is identified as the most radiation sensitive unit of the operational amplifier. In this paper, a series of simulations are performed on bipolar transistors in different radiation environments. In the theoretical simulation, the geometric model and calculations based on the Medici toolkit are built to study the radiation effects in bipolar components. The effect of mixed neutron and gamma irradiation is simulated based on the understanding of the underlying mechanisms of radiation effects in bipolar transistors. The simulated results agree well with the experimental data. The results of the experiments and simulation indicate that the radiation effects in the bipolar devices subjected to mixed neutron and gamma environments is not a simple combination of total ionizing dose (TID) effects and displacement damage. The data suggests that the TID effect could enhance the displacement damage. The synergistic effect should not be neglected in complex radiation environments.

  14. The HP 85192B EEFet3 GaAs FET Nonlinear Model Used in the High Efficiency Microwave Power Amplifier (HEMPA)

    NASA Technical Reports Server (NTRS)

    Sims, William Herbert, III; Bell, Joseph L. (Technical Monitor)

    2001-01-01

    Most nonlinear circuit analysis programs that exist today were designed primarily for transient analysis. By incorporating more accurate models in simulation programs, accurate predictions of GaAs field effect transistors (FET) behavior can be accomplished. However, should the designer need to simulate GaAs FETs that operate at high DC-to-RF conversion efficiencies, a more sophisticated model is needed. A relevant and appropriate method is called harmonic-balance, as described by Quere et al.

  15. High Accuracy Transistor Compact Model Calibrations

    SciTech Connect

    Hembree, Charles E.; Mar, Alan; Robertson, Perry J.

    2015-09-01

    Typically, transistors are modeled by the application of calibrated nominal and range models. These models consists of differing parameter values that describe the location and the upper and lower limits of a distribution of some transistor characteristic such as current capacity. Correspond- ingly, when using this approach, high degrees of accuracy of the transistor models are not expected since the set of models is a surrogate for a statistical description of the devices. The use of these types of models describes expected performances considering the extremes of process or transistor deviations. In contrast, circuits that have very stringent accuracy requirements require modeling techniques with higher accuracy. Since these accurate models have low error in transistor descriptions, these models can be used to describe part to part variations as well as an accurate description of a single circuit instance. Thus, models that meet these stipulations also enable the calculation of quantifi- cation of margins with respect to a functional threshold and uncertainties in these margins. Given this need, new model high accuracy calibration techniques for bipolar junction transis- tors have been developed and are described in this report.

  16. Improved physics for simulating submicron bipolar devices

    NASA Astrophysics Data System (ADS)

    Bennett, H. S.; Fuoss, D. E.

    1985-10-01

    The conventional device physics in most numerical simulations of bipolar transistors may not predict the measured electrical performance of shallow heavily doped emitters and bases. This paper summarizes improved device physics for numerical simulations of solid state devices with dopant densities up to aobut 3 x 10 to the 20th/cu cm and with junction depths as small as 0.1 micron. This improved device physics pertains to bandgap narrowing, effective intrinsic carrier concentrations, carrier mobilities, and lifetimes. When this improved physics is incorporated into device analysis codes such as SEDAN and then used to compute the electrical performance of n-p-n transistors, the predicted values agree very well with the measured values of the current-voltage characteristics and dc common emitter gains for devices with emitter-base junction depths between 10-0.16 microns.

  17. Nutrition and Bipolar Depression.

    PubMed

    Beyer, John L; Payne, Martha E

    2016-03-01

    As with physical conditions, bipolar disorder is likely to be impacted by diet and nutrition. Patients with bipolar disorder have been noted to have relatively unhealthy diets, which may in part be the reason they also have an elevated risk of metabolic syndrome and obesity. An improvement in the quality of the diet should improve a bipolar patient's overall health risk profile, but it may also improve their psychiatric outcomes. New insights into biological dysfunctions that may be present in bipolar disorder have presented new theoretic frameworks for understanding the relationship between diet and bipolar disorder.

  18. Oxide bipolar electronics: materials, devices and circuits

    NASA Astrophysics Data System (ADS)

    Grundmann, Marius; Klüpfel, Fabian; Karsthof, Robert; Schlupp, Peter; Schein, Friedrich-Leonhard; Splith, Daniel; Yang, Chang; Bitter, Sofie; von Wenckstern, Holger

    2016-06-01

    We present the history of, and the latest progress in, the field of bipolar oxide thin film devices. As such we consider primarily pn-junctions in which at least one of the materials is a metal oxide semiconductor. A wide range of n-type and p-type oxides has been explored for the formation of such bipolar diodes. Since most oxide semiconductors are unipolar, challenges and opportunities exist with regard to the formation of heterojunction diodes and band lineups. Recently, various approaches have led to devices with high rectification, namely p-type ZnCo2O4 and NiO on n-type ZnO and amorphous zinc-tin-oxide. Subsequent bipolar devices and applications such as photodetectors, solar cells, junction field-effect transistors and integrated circuits like inverters and ring oscillators are discussed. The tremendous progress shows that bipolar oxide electronics has evolved from the exploration of various materials and heterostructures to the demonstration of functioning integrated circuits. Therefore a viable, facile and high performance technology is ready for further exploitation and performance optimization.

  19. Transport properties of Nb/InAs(2DEG)/Nb Josephson field-effect transistors

    NASA Astrophysics Data System (ADS)

    Richter, A.; Koch, M.; Matsuyama, T.; Merkt, U.

    1999-11-01

    We investigate transport properties of mesoscopic semiconductor-superconductor weak links. The superconducting Nb electrodes of our junctions are coupled by the two-dimensional electron gas of an InAs heterostructure grown on a GaAs substrate. We report on the properties of Josephson field-effect transistors utilizing these junctions.

  20. High-performance silicon nanowire bipolar phototransistors

    NASA Astrophysics Data System (ADS)

    Tan, Siew Li; Zhao, Xingyan; Chen, Kaixiang; Crozier, Kenneth B.; Dan, Yaping

    2016-07-01

    Silicon nanowires (SiNWs) have emerged as sensitive absorbing materials for photodetection at wavelengths ranging from ultraviolet (UV) to the near infrared. Most of the reports on SiNW photodetectors are based on photoconductor, photodiode, or field-effect transistor device structures. These SiNW devices each have their own advantages and trade-offs in optical gain, response time, operating voltage, and dark current noise. Here, we report on the experimental realization of single SiNW bipolar phototransistors on silicon-on-insulator substrates. Our SiNW devices are based on bipolar transistor structures with an optically injected base region and are fabricated using CMOS-compatible processes. The experimentally measured optoelectronic characteristics of the SiNW phototransistors are in good agreement with simulation results. The SiNW phototransistors exhibit significantly enhanced response to UV and visible light, compared with typical Si p-i-n photodiodes. The near infrared responsivities of the SiNW phototransistors are comparable to those of Si avalanche photodiodes but are achieved at much lower operating voltages. Compared with other reported SiNW photodetectors as well as conventional bulk Si photodiodes and phototransistors, the SiNW phototransistors in this work demonstrate the combined advantages of high gain, high photoresponse, low dark current, and low operating voltage.

  1. A silicon nanocrystal tunnel field effect transistor

    SciTech Connect

    Harvey-Collard, Patrick; Drouin, Dominique; Pioro-Ladrière, Michel

    2014-05-12

    In this work, we demonstrate a silicon nanocrystal Field Effect Transistor (ncFET). Its operation is similar to that of a Tunnelling Field Effect Transistor (TFET) with two barriers in series. The tunnelling barriers are fabricated in very thin silicon dioxide and the channel in intrinsic polycrystalline silicon. The absence of doping eliminates the problem of achieving sharp doping profiles at the junctions, which has proven a challenge for large-scale integration and, in principle, allows scaling down the atomic level. The demonstrated ncFET features a 10{sup 4} on/off current ratio at room temperature, a low 30 pA/μm leakage current at a 0.5 V bias, an on-state current on a par with typical all-Si TFETs and bipolar operation with high symmetry. Quantum dot transport spectroscopy is used to assess the band structure and energy levels of the silicon island.

  2. STABILIZED TRANSISTOR AMPLIFIER

    DOEpatents

    Noe, J.B.

    1963-05-01

    A temperature stabilized transistor amplifier having a pair of transistors coupled in cascade relation that are capable of providing amplification through a temperature range of - 100 un. Concent 85% F to 400 un. Concent 85% F described. The stabilization of the amplifier is attained by coupling a feedback signal taken from the emitter of second transistor at a junction between two serially arranged biasing resistances in the circuit of the emitter of the second transistor to the base of the first transistor. Thus, a change in the emitter current of the second transistor is automatically corrected by the feedback adjustment of the base-emitter potential of the first transistor and by a corresponding change in the base-emitter potential of the second transistor. (AEC)

  3. n-Type Doping of Vapor-Liquid-Solid Grown GaAs Nanowires

    NASA Astrophysics Data System (ADS)

    Gutsche, Christoph; Lysov, Andrey; Regolin, Ingo; Blekker, Kai; Prost, Werner; Tegude, Franz-Josef

    2011-12-01

    In this letter, n-type doping of GaAs nanowires grown by metal-organic vapor phase epitaxy in the vapor-liquid-solid growth mode on (111)B GaAs substrates is reported. A low growth temperature of 400°C is adjusted in order to exclude shell growth. The impact of doping precursors on the morphology of GaAs nanowires was investigated. Tetraethyl tin as doping precursor enables heavily n-type doped GaAs nanowires in a relatively small process window while no doping effect could be found for ditertiarybutylsilane. Electrical measurements carried out on single nanowires reveal an axially non-uniform doping profile. Within a number of wires from the same run, the donor concentrations N D of GaAs nanowires are found to vary from 7 × 1017 cm-3 to 2 × 1018 cm-3. The n-type conductivity is proven by the transfer characteristics of fabricated nanowire metal-insulator-semiconductor field-effect transistor devices.

  4. n-Type Doping of Vapor-Liquid-Solid Grown GaAs Nanowires.

    PubMed

    Gutsche, Christoph; Lysov, Andrey; Regolin, Ingo; Blekker, Kai; Prost, Werner; Tegude, Franz-Josef

    2011-12-01

    In this letter, n-type doping of GaAs nanowires grown by metal-organic vapor phase epitaxy in the vapor-liquid-solid growth mode on (111)B GaAs substrates is reported. A low growth temperature of 400°C is adjusted in order to exclude shell growth. The impact of doping precursors on the morphology of GaAs nanowires was investigated. Tetraethyl tin as doping precursor enables heavily n-type doped GaAs nanowires in a relatively small process window while no doping effect could be found for ditertiarybutylsilane. Electrical measurements carried out on single nanowires reveal an axially non-uniform doping profile. Within a number of wires from the same run, the donor concentrations ND of GaAs nanowires are found to vary from 7 × 10(17) cm(-3) to 2 × 10(18) cm(-3). The n-type conductivity is proven by the transfer characteristics of fabricated nanowire metal-insulator-semiconductor field-effect transistor devices.

  5. High-Gain AlxGa1-xAs/GaAs Transistors For Neural Networks

    NASA Technical Reports Server (NTRS)

    Kim, Jae-Hoon; Lin, Steven H.

    1991-01-01

    High-gain AlxGa1-xAs/GaAs npn double heterojunction bipolar transistors developed for use as phototransistors in optoelectronic integrated circuits, especially in artificial neural networks. Transistors perform both photodetection and saturating-amplification functions of neurons. Good candidates for such application because structurally compatible with laser diodes and light-emitting diodes, detect light, and provide high current gain needed to compensate for losses in holographic optical elements.

  6. Effects of orientation of substrate on the enhanced low-dose-rate sensitivity (ELDRS) in NPN transistors

    NASA Astrophysics Data System (ADS)

    Lu, Wu; Zheng, Yu-Zhan; Wang, Yi-Yuan; Ren, Di-Yuan; Guo, Qi; Wang, Zhi-Kuan; Wang, Jian-An

    2011-02-01

    The radiation effects and annealing characteristics of two types of domestic NPN bipolar junction transistors, fabricated with different orientations, were investigated under different dose-rate irradiation. The experimental results show that both types of the NPN transistors exhibit remarkable Enhanced Low-Dose-Rate Sensitivity (ELDRS). After irradiation at high or low dose rate, the excess base current of NPN transistors obviously increased, and the current gain would degrade rapidly. Moreover, the decrease of collector current was also observed. The NPN transistor with <111> orientation was more sensitive to ionizing radiation than that with <100> orientation. The underlying mechanisms of various experimental phenomena are discussed in detail in this paper.

  7. Bipolar Disorder, Bipolar Depression and Comorbid Illness.

    PubMed

    Manning, J Sloan

    2015-06-01

    There is a substantial need for the early recognition and treatment of the psychiatric and medical comorbidities of bipolar disorder in primary care. If comorbid conditions are recognized and treated, serious adverse health outcomes may be averted, including substantial morbidity and mortality. PMID:26172635

  8. Bipolar Disorder, Bipolar Depression and Comorbid Illness.

    PubMed

    Manning, J Sloan

    2015-06-01

    There is a substantial need for the early recognition and treatment of the psychiatric and medical comorbidities of bipolar disorder in primary care. If comorbid conditions are recognized and treated, serious adverse health outcomes may be averted, including substantial morbidity and mortality.

  9. Method and apparatus for increasing resistance of bipolar buried layer integrated circuit devices to single-event upsets

    NASA Technical Reports Server (NTRS)

    Zoutendyk, John A. (Inventor)

    1991-01-01

    Bipolar transistors fabricated in separate buried layers of an integrated circuit chip are electrically isolated with a built-in potential barrier established by doping the buried layer with a polarity opposite doping in the chip substrate. To increase the resistance of the bipolar transistors to single-event upsets due to ionized particle radiation, the substrate is biased relative to the buried layer with an external bias voltage selected to offset the built-in potential just enough (typically between about +0.1 to +0.2 volt) to prevent an accumulation of charge in the buried-layer-substrate junction.

  10. Calculating drain delay in high electron mobility transistors

    NASA Astrophysics Data System (ADS)

    Coffie, R.

    2015-12-01

    An expression for the signal delay (drain delay) associated with electrons traveling through the gate-drain depletion region has been obtained for nonuniform electron velocity. Due to the presence of the gate metal, the signal delay through the gate-drain depletion region was shown to be larger than the signal delay in the base-collector depletion region of a bipolar transistor when equal depletion lengths and velocity profiles were assumed. Drain delay is also shown to be larger in transistors with field plates (independent of field plate connection) compared to transistors without field plates when equal depletion lengths and velocity profiles were assumed. For the case of constant velocity, two expressions for the proportionality constant relating drain delay and electron transit time across the depletion were obtained.

  11. Specifics of Pulsed Arc Welding Power Supply Performance Based On A Transistor Switch

    NASA Astrophysics Data System (ADS)

    Krampit, N. Yu; Kust, T. S.; Krampit, M. A.

    2016-08-01

    Specifics of designing a pulsed arc welding power supply device are presented in the paper. Electronic components for managing large current was analyzed. Strengths and shortcomings of power supply circuits based on thyristor, bipolar transistor and MOSFET are outlined. As a base unit for pulsed arc welding was chosen MOSFET transistor, which is easy to manage. Measures to protect a transistor are given. As for the transistor control device is a microcontroller Arduino which has a low cost and adequate performance of the work. Bead transfer principle is to change the voltage on the arc in the formation of beads on the wire end. Microcontroller controls transistor when the arc voltage reaches the threshold voltage. Thus there is a separation and transfer of beads without splashing. Control strategies tested on a real device and presented. The error in the operation of the device is less than 25 us, it can be used controlling drop transfer at high frequencies (up to 1300 Hz).

  12. A dc model for power switching transistors suitable for computer-aided design and analysis

    NASA Technical Reports Server (NTRS)

    Wilson, P. M.; George, R. T., Jr.; Owen, H. A.; Wilson, T. G.

    1979-01-01

    A model for bipolar junction power switching transistors whose parameters can be readily obtained by the circuit design engineer, and which can be conveniently incorporated into standard computer-based circuit analysis programs is presented. This formulation results from measurements which may be made with standard laboratory equipment. Measurement procedures, as well as a comparison between actual and computed results, are presented.

  13. Simulation of ultra thin film SOI transistors using a non-local ballistic model for impact ionisation

    NASA Astrophysics Data System (ADS)

    Armstrong, G. A.; French, W. D.

    1992-12-01

    To model bipolar snapback in thin film SOI transistors accurately, it is necessary to employ a non-local model of impact ionisation. Such a model, based on the "Lucky electron" theory, has been incorporated in a two-dimensional device simulator. Accurate prediction of bipolar holding voltage has been obtained for SOI transistors with sub-micron gate lengths. The model has been applied to analyse separately the effects of both lightly doped source and lightly doped drain in maximising the holding voltage. The advantage of using ultra thin highly doped SOI films in conjunction with a lightly doped drain is discussed.

  14. Growth and properties of crystalline barium oxide on the GaAs(100) substrate

    SciTech Connect

    Yasir, M.; Dahl, J.; Lång, J.; Tuominen, M.; Punkkinen, M. P. J.; Laukkanen, P. Kokko, K.; Kuzmin, M.; Korpijärvi, V.-M.; Polojärvi, V.; Guina, M.

    2013-11-04

    Growing a crystalline oxide film on III-V semiconductor renders possible approaches to improve operation of electronics and optoelectronics heterostructures such as oxide/semiconductor junctions for transistors and window layers for solar cells. We demonstrate the growth of crystalline barium oxide (BaO) on GaAs(100) at low temperatures, even down to room temperature. Photoluminescence (PL) measurements reveal that the amount of interface defects is reduced for BaO/GaAs, compared to Al{sub 2}O{sub 3}/GaAs, suggesting that BaO is a useful buffer layer to passivate the surface of the III-V device material. PL and photoemission data show that the produced junction tolerates the post heating around 600 °C.

  15. A highly selective, chlorofluorocarbon-free GaAs on AlGaAs etch

    SciTech Connect

    Smith, L.E. . Solid State Technology Center)

    1993-07-01

    A highly selective reactive ion etching process using SiCl[sub 4], CF[sub 4], O[sub 2], and He is reported. The selectivity of the etch, which is adjustable, ranges from 308:1 to 428:1 for GaAs to Al[sub 0.11]Ga[sub 0.89]As. This variability in selectivity is achieved by adjusting the helium flow rate. One very attractive feature of this etch is that it uses no chlorofluorocarbons and therefore complies with future bans on these substances imposed at both federal and corporate levels. The etch is demonstrated on a GaAs field effect transistor structure with an underlying Al[sub 0.11]Ga[sub 0.89]As stop-etch layer. The etch can be used for both anisotropic and isotropic applications.

  16. Soft switch-avalanche IGBT convertor. [Insulated Gate Bipolar Transistor

    NASA Technical Reports Server (NTRS)

    Chen, K.; Stuart, T. A.

    1990-01-01

    A full bridge dc-dc converter using a zero voltage and zero current switching technique is described. This circuit utilizes the characteristics of the IGBT to achieve power and frequency combinations that are much higher than those previously reported for this device. Experimental results are included for a 1.5 kW, 100 kHz converter with 94 percent efficiency.

  17. Lightweight bipolar storage battery

    NASA Technical Reports Server (NTRS)

    Rowlette, John J. (Inventor)

    1992-01-01

    An apparatus [10] is disclosed for a lightweight bipolar battery of the end-plate cell stack design. Current flow through a bipolar cell stack [12] is collected by a pair of copper end-plates [16a,16b] and transferred edgewise out of the battery by a pair of lightweight, low resistance copper terminals [28a,28b]. The copper terminals parallel the surface of a corresponding copper end-plate [16a,16b] to maximize battery throughput. The bipolar cell stack [12], copper end-plates [16a,16b] and copper terminals [28a,28b] are rigidly sandwiched between a pair of nonconductive rigid end-plates [20] having a lightweight fiber honeycomb core which eliminates distortion of individual plates within the bipolar cell stack due to internal pressures. Insulating foam [30] is injected into the fiber honeycomb core to reduce heat transfer into and out of the bipolar cell stack and to maintain uniform cell performance. A sealed battery enclosure [ 22] exposes a pair of terminal ends [26a,26b] for connection with an external circuit.

  18. Bipolar Affective Disorder and Migraine

    PubMed Central

    Engmann, Birk

    2012-01-01

    This paper consists of a case history and an overview of the relationship, aetiology, and treatment of comorbid bipolar disorder migraine patients. A MEDLINE literature search was used. Terms for the search were bipolar disorder bipolar depression, mania, migraine, mood stabilizer. Bipolar disorder and migraine cooccur at a relatively high rate. Bipolar II patients seem to have a higher risk of comorbid migraine than bipolar I patients have. The literature on the common roots of migraine and bipolar disorder, including both genetic and neuropathological approaches, is broadly discussed. Moreover, bipolar disorder and migraine are often combined with a variety of other affective disorders, and, furthermore, behavioural factors also play a role in the origin and course of the diseases. Approach to treatment options is also difficult. Several papers point out possible remedies, for example, valproate, topiramate, which acts on both diseases, but no first-choice treatments have been agreed upon yet. PMID:22649454

  19. Long-Wavelength-Infrared Hot-Electron Transistor

    NASA Technical Reports Server (NTRS)

    Gunapala, Sarath D.; Liu, John K.; Park, Jin S.; Lin, True-Lon

    1995-01-01

    Dark current reduced by energy-discriminating quantum filter. Very long-wavelength-infrared hot-electron transistor developed. Device detects photons at wavelengths around 16 micrometers. Comprises photodector integrated with energy-discriminating quantum filter in multiple-quantum-well structure. Made of variously doped and undoped layers of GaAs (quantum wells) and Al(x)Ga(1-x)As (barriers between wells). In transistor, bound-to-continuum GaAs/Al(x)Ga(1-x)As multiple-quantum-well infrared photodectors (QWIP) serves as photosensitive emitter. Wide quantum well serves as base, and there is thick barrier between base and collector. Combination of barrier and base quantum well acts as energy-discriminating filter: electrons with higher energies pass through filter to collector, those with lower energies blocked and diverted from output-current path through base contact.

  20. Pulsed Molecular Beams For Growth Of InAs On GaAs

    NASA Technical Reports Server (NTRS)

    Grunthaner, Frank J.

    1989-01-01

    Pauses for annealing reduce number of defects. Deposition process that includes pulsed molecular beams produces high-quality epitaxial layers of indium arsenide on gallium arsenide substrates. Layers made as much as 30 atoms thick without introducing excessive numbers of dislocations, despite 7.4-percent mismatch between InAs and GaAs crystal lattices. Layers offer superior electrical properties in such devices as optically addressed light modulators, infrared sensors, semiconductor lasers, and high-electron-mobility transistors. Technique applicable to other epitaxial systems in which lattices highly mismatched.

  1. [Neuropsychology of bipolar disorders].

    PubMed

    Rathgeber, Katrin; Gauggel, Siegfried

    2006-03-01

    In this article the contribution of neuropsychological research for a better understanding of the psychopathology of mood disorders is reviewed. First, the broad spectrum of bipolar disorders is described. Second, a selective review of important results of neuropsychological studies with patients with mood disorders is presented. Although several methodological problems limit the interpretation of the findings, there is evidence that patients with a bipolar disorder show a consistent impairment in attention, memory/learning and executive functions. The cognitive deficits are still visible during clinical recovery (euthymia) and closely associated with psychosocial limitation in daily life. Finally, the impact of neuropsychological findings is considered in relation to assessment, treatment and prognosis.

  2. Bipolar battery construction

    NASA Technical Reports Server (NTRS)

    Rippel, Wally E. (Inventor); Edwards, Dean B. (Inventor)

    1981-01-01

    A lightweight, bipolar battery construction for lead acid batteries in which a plurality of thin, rigid, biplates each comprise a graphite fiber thermoplastic composition in conductive relation to lead stripes plated on opposite flat surfaces of the plates, and wherein a plurality of nonconductive thermoplastic separator plates support resilient yieldable porous glass mats in which active material is carried, the biplates and separator plates with active material being contained and maintained in stacked assembly by axial compression of the stacked assembly. A method of assembling such a bipolar battery construction.

  3. Biomolecular detection using a metal semiconductor field effect transistor

    NASA Astrophysics Data System (ADS)

    Estephan, Elias; Saab, Marie-Belle; Buzatu, Petre; Aulombard, Roger; Cuisinier, Frédéric J. G.; Gergely, Csilla; Cloitre, Thierry

    2010-04-01

    In this work, our attention was drawn towards developing affinity-based electrical biosensors, using a MESFET (Metal Semiconductor Field Effect Transistor). Semiconductor (SC) surfaces must be prepared before the incubations with biomolecules. The peptides route was adapted to exceed and bypass the limits revealed by other types of surface modification due to the unwanted unspecific interactions. As these peptides reveal specific recognition of materials, then controlled functionalization can be achieved. Peptides were produced by phage display technology using a library of M13 bacteriophage. After several rounds of bio-panning, the phages presenting affinities for GaAs SC were isolated; the DNA of these specific phages were sequenced, and the peptide with the highest affinity was synthesized and biotinylated. To explore the possibility of electrical detection, the MESFET fabricated with the GaAs SC were used to detect the streptavidin via the biotinylated peptide in the presence of the bovine Serum Albumin. After each surface modification step, the IDS (current between the drain and the source) of the transistor was measured and a decrease in the intensity was detected. Furthermore, fluorescent microscopy was used in order to prove the specificity of this peptide and the specific localisation of biomolecules. In conclusion, the feasibility of producing an electrical biosensor using a MESFET has been demonstrated. Controlled placement, specific localization and detection of biomolecules on a MESFET transistor were achieved without covering the drain and the source. This method of functionalization and detection can be of great utility for biosensing application opening a new way for developing bioFETs (Biomolecular Field-Effect Transistor).

  4. Development of a HgCdTe photomixer and impedance matched GaAs FET amplifier

    NASA Technical Reports Server (NTRS)

    Shanley, J. F.; Paulauskas, W. A.; Taylor, D. R.

    1982-01-01

    A research program for the development of a 10.6 micron HgCdTe photodiode/GaAs field effect transistor amplifier package for use at cryogenic temperatures (77k). The photodiode/amplifier module achieved a noise equivalent power per unit bandwidth of 5.7 times 10 to the 20th power W/Hz at 2.0 GHz. The heterodyne sensitivity of the HgCdTe photodiode was improved by designing and building a low noise GaAs field effect transistor amplifier operating at 77K. The Johnson noise of the amplifier was reduced at 77K, and thus resulted in an increased photodiode heterodyne sensitivity.

  5. Resonant Transport in Nb/gaas/algaas/gaas Microstructures

    NASA Astrophysics Data System (ADS)

    Giazotto, F.; Pingue, P.; Beltram, F.; Lazzarino, M.; Orani, D.; Rubini, S.; Franciosi, A.

    2003-03-01

    Resonant transport in a hybrid semiconductor-superconductor microstructure grown by MBE on GaAs in presented. This structure experimentally realizes the prototype system originally proposed by de Gennes and Saint-James in 1963 in all-metal structures. A low temperature single peak superimposed to the characteristic Andreev-dominated subgap conductance represents the mark of such resonant behavior. Random matrix theory of quantum transport was employed in order to analyze the observed magnetotransport properties and ballistic effects were included by directly solving the Bogoliubov-de Gennes equations.

  6. Polyphosphonium‐based bipolar membranes for rectification of ionic currents

    PubMed Central

    Gabrielsson, Erik O.; Berggren, Magnus

    2013-01-01

    Bipolar membranes (BMs) have interesting applications within the field of bioelectronics, as they may be used to create non-linear ionic components (e.g., ion diodes and transistors), thereby extending the functionality of, otherwise linear, electrophoretic drug delivery devices. However, BM based diodes suffer from a number of limitations, such as narrow voltage operation range and/or high hysteresis. In this work, we circumvent these problems by using a novel polyphosphonium-based BM, which is shown to exhibit improved diode characteristics. We believe that this new type of BM diode will be useful for creating complex addressable ionic circuits for delivery of charged biomolecules. PMID:24400035

  7. Genetics of bipolar disorder

    PubMed Central

    Craddock, N.; Jones, I.

    1999-01-01

    Bipolar disorder (also known as manic depressive illness) is a complex genetic disorder in which the core feature is pathological disturbance in mood (affect) ranging from extreme elation, or mania, to severe depression usually accompanied by disturbances in thinking and behaviour. The lifetime prevalence of 1% is similar in males and females and family, twin, and adoption studies provide robust evidence for a major genetic contribution to risk. There are methodological impediments to precise quantification, but the approximate lifetime risk of bipolar disorder in relatives of a bipolar proband are: monozygotic co-twin 40-70%; first degree relative 5-10%; unrelated person 0.5-1.5%. Occasional families may exist in which a single gene plays the major role in determining susceptibility, but the majority of bipolar disorder involves the interaction of multiple genes (epistasis) or more complex genetic mechanisms (such as dynamic mutation or imprinting). Molecular genetic positional and candidate gene approaches are being used for the genetic dissection of bipolar disorder. No gene has yet been identified but promising findings are emerging. Regions of interest identified in linkage studies include 4p16, 12q23-q24, 16p13, 21q22, and Xq24-q26. Chromosome 18 is also of interest but the findings are confusing with up to three possible regions implicated. To date most candidate gene studies have focused on neurotransmitter systems influenced by medication used in clinical management of the disorder but no robust positive findings have yet emerged. It is, however, almost certain that over the next few years bipolar susceptibility genes will be identified. This will have a major impact on our understanding of disease pathophysiology and will provide important opportunities to investigate the interaction between genetic and environmental factors involved in pathogenesis. This is likely to lead to major improvements in treatment and patient care but will also raise important

  8. GaAs solar cell development

    NASA Technical Reports Server (NTRS)

    Knechtli, R. C.; Kamath, S.; Loo, R.

    1977-01-01

    The motivation for developing GaAs solar cells is based on their superior efficiency when compared to silicon cells, their lower degradation with increasing temperature, and the expectation for better resistance to space radiation damage. The AMO efficiency of GaAs solar cells was calculated. A key consideration in the HRL technology is the production of GaAs cells of large area (greater than 4 sg cm) at a reasonable cost without sacrificing efficiency. An essential requirement for the successful fabrication of such cells is the ability to grow epitaxially a uniform layer of high quality GaAs (buffer layer) on state-of-the-art GaAs substrates, and to grow on this buffer layer the required than layer of (AlGa)As. A modified infinite melt liquid phase epitaxy (LPE) growth technique is detailed.

  9. High Power Switching Transistor

    NASA Technical Reports Server (NTRS)

    Hower, P. L.; Kao, Y. C.; Carnahan, D. C.

    1983-01-01

    Improved switching transistors handle 400-A peak currents and up to 1,200 V. Using large diameter silicon wafers with twice effective area as D60T, form basis for D7 family of power switching transistors. Package includes npn wafer, emitter preform, and base-contact insert. Applications are: 25to 50-kilowatt high-frequency dc/dc inverters, VSCF converters, and motor controllers for electrical vehicles.

  10. Black Phosphorus RF Transistor

    NASA Astrophysics Data System (ADS)

    Wang, Han; Wang, Xiaomu; Xia, Fengnian; Wang, Luhao; Jiang, Hao; Xia, Qiangfei; Chin, Mattew L.; Dubey, Madan; Han, Shu-Jen

    2015-03-01

    Few-layer and thin film form of layered black phosphorus (BP) has recently emerged as a promising material for applications in high performance thin film electronics and infrared optoelectronics. Layered BP offers a ~ 0.3eV bandgap and high mobility, leading to transistor devices with decent on/off ratio and high on-state current density. Here, we demonstrate the GHz frequency operation of black phosphorus field-effect transistor for the first time. BP transistors demonstrated here show excellent current saturation with an on-off ratio exceeding 2 × 103. The S-parameter characterization is performed for the first time on black phosphorus transistors, giving a 12 GHz short-circuit current-gain cut-off frequency and 20 GHz maximum oscillation frequency in 300 nm channel length devices. A current density in excess of 270 mA/mm and DC transconductance above 180 mS/mm are achieved for hole conductions. The results reveal the promising potential of black phosphorus transistors for enabling the next generation thin film transistor technology that can operate in the multi-GHz frequency range and beyond.

  11. Transistor-based interface circuitry

    DOEpatents

    Taubman, Matthew S.

    2004-02-24

    Among the embodiments of the present invention is an apparatus that includes a transistor, a servo device, and a current source. The servo device is operable to provide a common base mode of operation of the transistor by maintaining an approximately constant voltage level at the transistor base. The current source is operable to provide a bias current to the transistor. A first device provides an input signal to an electrical node positioned between the emitter of the transistor and the current source. A second device receives an output signal from the collector of the transistor.

  12. Transistor-based interface circuitry

    DOEpatents

    Taubman, Matthew S.

    2007-02-13

    Among the embodiments of the present invention is an apparatus that includes a transistor, a servo device, and a current source. The servo device is operable to provide a common base mode of operation of the transistor by maintaining an approximately constant voltage level at the transistor base. The current source is operable to provide a bias current to the transistor. A first device provides an input signal to an electrical node positioned between the emitter of the transistor and the current source. A second device receives an output signal from the collector of the transistor.

  13. A comparison of radiation damage in transistors from cobalt-60 gamma rays and 2.2 MeV electrons

    NASA Technical Reports Server (NTRS)

    Nichols, D. K.; Price, W. E.; Gauthier, M. K.

    1982-01-01

    The total ionizing dose response of ten bipolar transistor types has been measured using Co-60 gamma rays and 2.2 MeV electrons from exposure levels of 750, 1500, and 3000 Gy(Si). Gain measurements were made for a range of collector-emitter voltages and collector currents.

  14. Preventing Simultaneous Conduction In Switching Transistors

    NASA Technical Reports Server (NTRS)

    Mclyman, William T.

    1990-01-01

    High voltage spikes and electromagnetic interference suppressed. Power-supply circuit including two switching transistors easily modified to prevent simultaneous conduction by both transistors during switching intervals. Diode connected between collector of each transistor and driving circuit for opposite transistor suppresses driving signal to transistor being turned on until transistor being turned off ceases to carry current.

  15. Total Dose Effects on Single Event Transients in Digital CMOS and Linear Bipolar Circuits

    NASA Technical Reports Server (NTRS)

    Buchner, S.; McMorrow, D.; Sibley, M.; Eaton, P.; Mavis, D.; Dusseau, L.; Roche, N. J-H.; Bernard, M.

    2009-01-01

    This presentation discusses the effects of ionizing radiation on single event transients (SETs) in circuits. The exposure of integrated circuits to ionizing radiation changes electrical parameters. The total ionizing dose effect is observed in both complementary metal-oxide-semiconductor (CMOS) and bipolar circuits. In bipolar circuits, transistors exhibit grain degradation, while in CMOS circuits, transistors exhibit threshold voltage shifts. Changes in electrical parameters can cause changes in single event upset(SEU)/SET rates. Depending on the effect, the rates may increase or decrease. Therefore, measures taken for SEU/SET mitigation might work at the beginning of a mission but not at the end following TID exposure. The effect of TID on SET rates should be considered if SETs cannot be tolerated.

  16. Bipolar and unipolar depression.

    PubMed

    Rogers, Jonathan; Agius, Mark

    2012-09-01

    Since Kraepelin grouped affective disorders under the title of 'manic-depressive insanity', there has been controversy over whether the bipolar and unipolar entities within this are distinct affective disorders or whether they are merely two ends of an affective continuum. In order to bring some clarity and goal-posts to this argument, we define the criteria that must be fulfilled by diseases in order to be considered as part of a spectrum. We analyse bipolar disorder and major depressive disorder with respect to these criteria and find the model fits in many respects but fails to account for either the poor correlation in severity of manic and depressive symptoms or for the apparent discontinuity in the distribution of familial mania. A one-dimensional spectrum is thus too simple and a two-dimensional approach is required; this also fits much better with our current understanding of the genetic picture.

  17. Epilepsy and bipolar disorder.

    PubMed

    Knott, Sarah; Forty, Liz; Craddock, Nick; Thomas, Rhys H

    2015-11-01

    It is well recognized that mood disorders and epilepsy commonly co-occur. Despite this, our knowledge regarding the relationship between epilepsy and bipolar disorder is limited. Several shared features between the two disorders, such as their episodic nature and potential to run a chronic course, and the efficacy of some antiepileptic medications in the prophylaxis of both disorders, are often cited as evidence of possible shared underlying pathophysiology. The present paper aims to review the bidirectional associations between epilepsy and bipolar disorder, with a focus on epidemiological links, evidence for shared etiology, and the impact of these disorders on both the individual and wider society. Better recognition and understanding of these two complex disorders, along with an integrated clinical approach, are crucial for improved evaluation and management of comorbid epilepsy and mood disorders.

  18. [Creativity and bipolar disorder].

    PubMed

    Maçkalı, Zeynep; Gülöksüz, Sinan; Oral, Timuçin

    2014-01-01

    The relationship between creativity and bipolar disorder has been an intriguing topic since ancient times. Early studies focused on describing characteristics of creative people. From the last quarter of the twentieth century, researchers began to focus on the relationship between mood disorders and creativity. Initially, the studies were based on biographical texts and the obtained results indicated a relationship between these two concepts. The limitations of the retrospective studies led the researchers to develop systematic investigations into this area. The systematic studies that have focused on artistic creativity have examined both the prevalence of mood disorders and the creative process. In addition, a group of researchers addressed the relationship in terms of affective temperaments. Through the end of the 90's, the scope of creativity was widened and the notion of everyday creativity was proposed. The emergence of this notion led researchers to investigate the associations of the creative process in ordinary (non-artist) individuals. In this review, the descriptions of creativity and creative process are mentioned. Also, the creative process is addressed with regards to bipolar disorder. Then, the relationship between creativity and bipolar disorder are evaluated in terms of aforementioned studies (biographical, systematic, psychobiographical, affective temperaments). In addition, a new model, the "Shared Vulnerability Model" which was developed to explain the relationship between creativity and psychopathology is introduced. Finally, the methodological limitations and the suggestions for resolving these limitations are included.

  19. Improvement of terahertz field effect transistor detectors by substrate thinning and radiation losses reduction.

    PubMed

    Coquillat, Dominique; Marczewski, Jacek; Kopyt, Pawel; Dyakonova, Nina; Giffard, Benoit; Knap, Wojciech

    2016-01-11

    Phenomena of the radiation coupling to the field effect transistors based terahertz (THz) detectors are studied. We show that in the case of planar metal antennas a significant portion of incoming radiation, instead of being coupled to the transistors, is coupled to an antenna substrate leading to responsivity losses and/or cross-talk effects in the field effect based THz detector arrays. Experimental and theoretical investigations of the responsivity versus substrate thickness are performed. They clearly show how to minimize the losses by the detector/ array substrate thinning. In conclusion simple quantitative rules of losses minimization by choosing a proper substrate thickness of field effect transistor THz detectors are presented for common materials (Si, GaAs, InP, GaN) used in semiconductor technologies. PMID:26832258

  20. Bipolar Disorder in Children and Teens

    MedlinePlus

    ... is in crisis. What do I do? Share Bipolar Disorder in Children and Teens Download PDF Download ePub ... brochure will give you more information. What is bipolar disorder? Bipolar disorder is a serious brain illness. It ...

  1. An approach to decrease dimensions of field-effect transistors without p-n-junctions

    NASA Astrophysics Data System (ADS)

    Pankratov, E. L.; Bulaeva, E. A.

    2014-07-01

    It has been recently shown, that manufacturing p-n-junctions, field-effect and bipolar transistors, thyristors in a multilayer structure by diffusion or ion implantation under condition of optimization of dopant and/or radiation defects leads to increasing sharpness of p-n-junctions (both single p-n-junctions and p-n-junctions, which include into their system). In this situation, one can also obtain increase of homogeneity of dopant in doped area. In this paper, we consider manufacturing a field-effect heterotransistor without p-n-junction. Optimization of technological process with using inhomogeneity of heterostructure gives us possibility to manufacture transistors to be more compact.

  2. Effect of 100MeV oxygen ion irradiation on silicon NPN power transistor

    NASA Astrophysics Data System (ADS)

    Kumar, M. Vinay; Krishnakumar, K. S.; Dinesh, C. M.; Krishnaveni, S.; Ramani

    2012-06-01

    The radiation response of npn Bipolar junction transistor (BJT) has been examined for 100 MeV O7+ ion. Key electrical properties like Gummel characteristics, dc current gain and capacitance-voltage of 100MeV O7+ ion irradiated transistor were studied before and after irradiation. The device was decapped and the electrical characterizations were performed at room temperature. Base current is observed to be more sensitive than collector current and gain appears to be degraded with ion fluence, also considerable degradation in C-V characteristics is observed and doping concentration is found to be increased along with the increase in ion fluence.

  3. Si-nanowire CMOS inverter logic fabricated using gate-all-around (GAA) devices and top-down approach

    NASA Astrophysics Data System (ADS)

    Buddharaju, K. D.; Singh, N.; Rustagi, S. C.; Teo, Selin H. G.; Lo, G. Q.; Balasubramanian, N.; Kwong, D. L.

    2008-09-01

    We present the monolithic integration of gate-all-around (GAA) Si-nanowire FETs into CMOS logic using top-down approach. Inverters are chosen as the test vehicles for demonstration. Empirically optimized designs show sharp ON-OFF transitions with high voltage-gains (e.g., ΔVOUT/ΔVIN up to ∼45) and symmetric pull-up and pull-down characteristics. The matching of the drive currents of n- and p-MOSFETs is achieved using different number of nanowire channels for N- and P-MOS transistors. The inverter maintains its good transfer characteristics and noise margins for wide range of VDD tested down to 0.2 V. The detailed experimental characterization is discussed along with the electrical characteristics of the individual transistors comprising the inverter. The performances of the inverters are discussed vis-à-vis those reported in the literature using advanced non-classical device architectures such as FinFETs. The integration potential of GAA Si-nanowire transistors to realize CMOS circuit functionality using top-down approach is thus demonstrated.

  4. Fin width and height dependence of bipolar amplification in bulk FinFETs submitted to heavy ion irradiation

    NASA Astrophysics Data System (ADS)

    Yu, Jun-Ting; Chen, Shu-Ming; Chen, Jian-Jun; Huang, Peng-Cheng

    2015-11-01

    FinFET technologies are becoming the mainstream process as technology scales down. Based on a 28-nm bulk p-FinFET device, we have investigated the fin width and height dependence of bipolar amplification for heavy-ion-irradiated FinFETs by 3D TCAD numerical simulation. Simulation results show that due to a well bipolar conduction mechanism rather than a channel (fin) conduction path, the transistors with narrower fins exhibit a diminished bipolar amplification effect, while the fin height presents a trivial effect on the bipolar amplification and charge collection. The results also indicate that the single event transient (SET) pulse width can be mitigated about 35% at least by optimizing the ratio of fin width and height, which can provide guidance for radiation-hardened applications in bulk FinFET technology. Project supported by the National Natural Science of China (Grant No. 61376109).

  5. An Electrochromic Bipolar Membrane Diode.

    PubMed

    Malti, Abdellah; Gabrielsson, Erik O; Crispin, Xavier; Berggren, Magnus

    2015-07-01

    Conducting polymers with bipolar membranes (a complementary stack of selective membranes) may be used to rectify current. Integrating a bipolar membrane into a polymer electrochromic display obviates the need for an addressing backplane while increasing the device's bistability. Such devices can be made from solution-processable materials.

  6. Dual-Side Wafer Processing and Resonant Tunneling Transistor Applications

    SciTech Connect

    Moon, J.S.; Simmons, J.A.; Wendt, J.R.; Hietala, V.M.; Reno, J.L.; Baca, W.E.; Blount, M.A.

    1999-07-20

    We describe dual-side wafer processing and its application to resonant tunneling transistors in a planar configuration. The fabrication technique utilizes a novel flip-chip, wafer thinning process called epoxy-bond and stop-etch (EBASE) process, where the substrate material is removed by selective wet etching and stopped at an etch-stop layer. This EBASE method results in a semiconductor epitaxial layer that is typically less than a micron thick and has a mirror-finish, allowing backside gates to be placed in close proximity to frontside gates. Utilizing this technique, a resonant tunneling transistor--the double electron layer tunneling transistor (DELTT)--can be fabricated in a fully planar configuration, where the tunneling between two selectively-contacted 2DEGs in GaAs or InGaAs quantum wells is modulated by surface Schottky gate. Low temperature electrical characterization yields source-drain I-V curves with a gate-tunable negative differential resistance.

  7. Ambipolar nonvolatile memory based on a quantum-dot transistor with a nanoscale floating gate

    NASA Astrophysics Data System (ADS)

    Che, Yongli; Zhang, Yating; Cao, Xiaolong; Song, Xiaoxian; Cao, Mingxuan; Dai, Haitao; Yang, Junbo; Zhang, Guizhong; Yao, Jianquan

    2016-07-01

    Using only solution processing methods, we developed ambipolar quantum-dot (QD) transistor floating-gate memory (FGM) that uses Au nanoparticles as a floating gate. Because of the bipolarity of the active channel of PbSe QDs, the memory could easily trap holes or electrons in the floating gate by programming/erasing (P/E) operations, which could shift the threshold voltage both up and down. As a result, the memory exhibited good programmable memory characteristics: a large memory window (ΔVth ˜ 15 V) and a long retention time (>105 s). The magnitude of ΔVth depended on both P/E voltages and the bias voltage (VDS): ΔVth was a cubic function to VP/E and linearly depended on VDS. Therefore, this FGM based on a QD transistor is a promising alternative to its inorganic counterparts owing to its advantages of bipolarity, high mobility, low cost, and large-area production.

  8. VOLTAGE-CONTROLLED TRANSISTOR OSCILLATOR

    DOEpatents

    Scheele, P.F.

    1958-09-16

    This patent relates to transistor oscillators and in particular to those transistor oscillators whose frequencies vary according to controlling voltages. A principal feature of the disclosed transistor oscillator circuit resides in the temperature compensation of the frequency modulating stage by the use of a resistorthermistor network. The resistor-thermistor network components are selected to have the network resistance, which is in series with the modulator transistor emitter circuit, vary with temperature to compensate for variation in the parameters of the transistor due to temperature change.

  9. Tobacco Use in Bipolar Disorder

    PubMed Central

    Thomson, Daniel; Berk, Michael; Dodd, Seetal; Rapado-Castro, Marta; Quirk, Shae E.; Ellegaard, Pernille K.; Berk, Lesley; Dean, Olivia M.

    2015-01-01

    Tobacco use in mental health in general and bipolar disorder in particular remains disproportionally common, despite declining smoking rates in the community. Furthermore, interactions between tobacco use and mental health have been shown, indicating the outcomes for those with mental health disorders are impacted by tobacco use. Factors need to be explored and addressed to improve outcomes for those with these disorders and target specific interventions for people with psychiatric illness to cease tobacco smoking. In the context of bipolar disorder, this review explores; the effects of tobacco smoking on symptoms, quality of life, suicidal behaviour, the biological interactions between tobacco use and bipolar disorder, the interactions between tobacco smoking and psychiatric medications, rates and factors surrounding tobacco smoking cessation in bipolar disorder and suggests potential directions for research and clinical translation. The importance of this review is to bring together the current understanding of tobacco use in bipolar disorder to highlight the need for specific intervention. PMID:25912533

  10. Accelerating the life of transistors

    NASA Astrophysics Data System (ADS)

    Haochun, Qi; Changzhi, Lü; Xiaoling, Zhang; Xuesong, Xie

    2013-06-01

    Choosing small and medium power switching transistors of the NPN type in a 3DK set as the study object, the test of accelerating life is conducted in constant temperature and humidity, and then the data are statistically analyzed with software developed by ourselves. According to degradations of such sensitive parameters as the reverse leakage current of transistors, the lifetime order of transistors is about more than 104 at 100 °C and 100% relative humidity (RH) conditions. By corrosion fracture of transistor outer leads and other failure modes, with the failure truncated testing, the average lifetime rank of transistors in different distributions is extrapolated about 103. Failure mechanism analyses of degradation of electrical parameters, outer lead fracture and other reasons that affect transistor lifetime are conducted. The findings show that the impact of external stress of outer leads on transistor reliability is more serious than that of parameter degradation.

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

    SciTech Connect

    Coquat, J.A.

    1980-01-01

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

  12. Bipolar disorder in women

    PubMed Central

    Parial, Sonia

    2015-01-01

    Bipolar affective disorder in women is a challenging disorder to treat. It is unique in its presentation in women and characterized by later age of onset, seasonality, atypical presentation, and a higher degree of mixed episodes. Medical and psychiatric co-morbidity adversely affects recovery from the bipolar disorder (BD) more often in women. Co-morbidity, particularly thyroid disease, migraine, obesity, and anxiety disorders occur more frequently in women while substance use disorders are more common in men. Treatment of women during pregnancy and lactation is challenging. Pregnancy neither protects nor exacerbates BD, and many women require continuation of medication during the pregnancy. The postpartum period is a time of high risk for onset and recurrence of BD in women. Prophylaxis with mood stabilizers might be needed. Individualized risk/benefits assessments of pregnant and postpartum women with BD are required to promote the health of the women and to avoid or limit exposure of the fetus or infant to potential adverse effects of medication. PMID:26330643

  13. Bipolar pulse forming line

    DOEpatents

    Rhodes, Mark A.

    2008-10-21

    A bipolar pulse forming transmission line module for linear induction accelerators having first, second, third, fourth, and fifth planar conductors which form an interleaved stack with dielectric layers between the conductors. Each conductor has a first end, and a second end adjacent an acceleration axis. The first and second planar conductors are connected to each other at the second ends, the fourth and fifth planar conductors are connected to each other at the second ends, and the first and fifth planar conductors are connected to each other at the first ends via a shorting plate adjacent the first ends. The third planar conductor is electrically connectable to a high voltage source, and an internal switch functions to short a high voltage from the first end of the third planar conductor to the first end of the fourth planar conductor to produce a bipolar pulse at the acceleration axis with a zero net time integral. Improved access to the switch is enabled by an aperture through the shorting plate and the proximity of the aperture to the switch.

  14. Multimode Silicon Nanowire Transistors

    PubMed Central

    2014-01-01

    The combined capabilities of both a nonplanar design and nonconventional carrier injection mechanisms are subject to recent scientific investigations to overcome the limitations of silicon metal oxide semiconductor field effect transistors. In this Letter, we present a multimode field effect transistors device using silicon nanowires that feature an axial n-type/intrinsic doping junction. A heterostructural device design is achieved by employing a self-aligned nickel-silicide source contact. The polymorph operation of the dual-gate device enabling the configuration of one p- and two n-type transistor modes is demonstrated. Not only the type but also the carrier injection mode can be altered by appropriate biasing of the two gate terminals or by inverting the drain bias. With a combined band-to-band and Schottky tunneling mechanism, in p-type mode a subthreshold swing as low as 143 mV/dec and an ON/OFF ratio of up to 104 is found. As the device operates in forward bias, a nonconventional tunneling transistor is realized, enabling an effective suppression of ambipolarity. Depending on the drain bias, two different n-type modes are distinguishable. The carrier injection is dominated by thermionic emission in forward bias with a maximum ON/OFF ratio of up to 107 whereas in reverse bias a Schottky tunneling mechanism dominates the carrier transport. PMID:25303290

  15. Towards the ultimate transistor

    NASA Astrophysics Data System (ADS)

    Natelson, Douglas

    2009-06-01

    The first transistor, made more than 60 years ago at Bell Labs, was a couple of inches across. Today, a typical laptop computer uses a processor chip that contains well over a billion transistors, each one with electrodes separated by less than 50 nm of silicon, which is less than a thousandth of the diameter of a human hair. This continual drive for miniaturization, with the density of transistors doubling roughly every two years, was first noted by Intel co-founder Gordon Moore in 1965, and has been such a mainstay of electronics development that it is now enshrined as "Moore's law". These billions of transistors are made by "top down" methods that involve depositing thin layers of materials, patterning nano-scale stencils and effectively carving away the unwanted bits. The incredible success of this approach is almost impossible to overstate. The end result is billions of individual components on a single chip, essentially all working perfectly and continuously for years on end. No other manufactured technology comes remotely close in reliability or cost-per-widget.

  16. Multimode silicon nanowire transistors.

    PubMed

    Glassner, Sebastian; Zeiner, Clemens; Periwal, Priyanka; Baron, Thierry; Bertagnolli, Emmerich; Lugstein, Alois

    2014-11-12

    The combined capabilities of both a nonplanar design and nonconventional carrier injection mechanisms are subject to recent scientific investigations to overcome the limitations of silicon metal oxide semiconductor field effect transistors. In this Letter, we present a multimode field effect transistors device using silicon nanowires that feature an axial n-type/intrinsic doping junction. A heterostructural device design is achieved by employing a self-aligned nickel-silicide source contact. The polymorph operation of the dual-gate device enabling the configuration of one p- and two n-type transistor modes is demonstrated. Not only the type but also the carrier injection mode can be altered by appropriate biasing of the two gate terminals or by inverting the drain bias. With a combined band-to-band and Schottky tunneling mechanism, in p-type mode a subthreshold swing as low as 143 mV/dec and an ON/OFF ratio of up to 10(4) is found. As the device operates in forward bias, a nonconventional tunneling transistor is realized, enabling an effective suppression of ambipolarity. Depending on the drain bias, two different n-type modes are distinguishable. The carrier injection is dominated by thermionic emission in forward bias with a maximum ON/OFF ratio of up to 10(7) whereas in reverse bias a Schottky tunneling mechanism dominates the carrier transport. PMID:25303290

  17. Radiation-hardened transistor and integrated circuit

    DOEpatents

    Ma, Kwok K.

    2007-11-20

    A composite transistor is disclosed for use in radiation hardening a CMOS IC formed on an SOI or bulk semiconductor substrate. The composite transistor has a circuit transistor and a blocking transistor connected in series with a common gate connection. A body terminal of the blocking transistor is connected only to a source terminal thereof, and to no other connection point. The blocking transistor acts to prevent a single-event transient (SET) occurring in the circuit transistor from being coupled outside the composite transistor. Similarly, when a SET occurs in the blocking transistor, the circuit transistor prevents the SET from being coupled outside the composite transistor. N-type and P-type composite transistors can be used for each and every transistor in the CMOS IC to radiation harden the IC, and can be used to form inverters and transmission gates which are the building blocks of CMOS ICs.

  18. Structured-gate organic field-effect transistors

    NASA Astrophysics Data System (ADS)

    Aljada, Muhsen; Pandey, Ajay K.; Velusamy, Marappan; Burn, Paul L.; Meredith, Paul; Namdas, Ebinazar B.

    2012-06-01

    We report the fabrication and electrical characteristics of structured-gate organic field-effect transistors consisting of a gate electrode patterned with three-dimensional pillars. The pillar gate electrode was over-coated with a gate dielectric (SiO2) and solution processed organic semiconductors producing both unipolar p-type and bipolar behaviour. We show that this new structured-gate architecture delivers higher source-drain currents, higher gate capacitance per unit equivalent linear channel area, and enhanced charge injection (electrons and/or holes) versus the conventional planar structure in all modes of operation. For the bipolar field-effect transistor (FET) the maximum source-drain current enhancements in p- and n-channel mode were >600% and 28%, respectively, leading to p and n charge mobilities with the same order of magnitude. Thus, we have demonstrated that it is possible to use the FET architecture to manipulate and match carrier mobilities of material combinations where one charge carrier is normally dominant. Mobility matching is advantageous for creating organic logic circuit elements such as inverters and amplifiers. Hence, the method represents a facile and generic strategy for improving the performance of standard organic semiconductors as well as new materials and blends.

  19. A Vertically Integrated Junctionless Nanowire Transistor.

    PubMed

    Lee, Byung-Hyun; Hur, Jae; Kang, Min-Ho; Bang, Tewook; Ahn, Dae-Chul; Lee, Dongil; Kim, Kwang-Hee; Choi, Yang-Kyu

    2016-03-01

    A vertically integrated junctionless field-effect transistor (VJ-FET), which is composed of vertically stacked multiple silicon nanowires (SiNWs) with a gate-all-around (GAA) structure, is demonstrated on a bulk silicon wafer for the first time. The proposed VJ-FET mitigates the issues of variability and fabrication complexity that are encountered in the vertically integrated multi-NW FET (VM-FET) based on an identical structure in which the VM-FET, as recently reported, harnesses a source and drain (S/D) junction for its operation and is thus based on the inversion mode. Variability is alleviated by bulk conduction in a junctionless FET (JL-FET), where current flows through the core of the SiNW, whereas it is not mitigated by surface conduction in an inversion mode FET (IM-FET), where current flows via the surface of the SiNW. The fabrication complexity is reduced by the inherent JL structure of the JL-FET because S/D formation is not required. In contrast, it is very difficult to dope the S/D when it is positioned at each floor of a tall SiNW with greater uniformity and with less damage to the crystalline structure of the SiNW in a VM-FET. Moreover, when the proposed VJ-FET is used as nonvolatile flash memory, the endurance and retention characteristics are improved due to the above-mentioned bulk conduction.

  20. A Vertically Integrated Junctionless Nanowire Transistor.

    PubMed

    Lee, Byung-Hyun; Hur, Jae; Kang, Min-Ho; Bang, Tewook; Ahn, Dae-Chul; Lee, Dongil; Kim, Kwang-Hee; Choi, Yang-Kyu

    2016-03-01

    A vertically integrated junctionless field-effect transistor (VJ-FET), which is composed of vertically stacked multiple silicon nanowires (SiNWs) with a gate-all-around (GAA) structure, is demonstrated on a bulk silicon wafer for the first time. The proposed VJ-FET mitigates the issues of variability and fabrication complexity that are encountered in the vertically integrated multi-NW FET (VM-FET) based on an identical structure in which the VM-FET, as recently reported, harnesses a source and drain (S/D) junction for its operation and is thus based on the inversion mode. Variability is alleviated by bulk conduction in a junctionless FET (JL-FET), where current flows through the core of the SiNW, whereas it is not mitigated by surface conduction in an inversion mode FET (IM-FET), where current flows via the surface of the SiNW. The fabrication complexity is reduced by the inherent JL structure of the JL-FET because S/D formation is not required. In contrast, it is very difficult to dope the S/D when it is positioned at each floor of a tall SiNW with greater uniformity and with less damage to the crystalline structure of the SiNW in a VM-FET. Moreover, when the proposed VJ-FET is used as nonvolatile flash memory, the endurance and retention characteristics are improved due to the above-mentioned bulk conduction. PMID:26885948

  1. Ultra-Thin-Film GaAs Solar Cells

    NASA Technical Reports Server (NTRS)

    Wang, K. L.; Shin, B. K.; Yeh, Y. C. M.; Stirn, R. J.

    1982-01-01

    Process based on organo-metallic chemical vapor deposition (OM/CVD) of trimethyl gallium with arsine forms economical ultrathin GaAs epitaxial films. Process has higher potential for low manufacturing cost and large-scale production compared with more-conventional halide CVD and liquid-phase epitaxy processes. By reducing thickness of GaAs and substituting low-cost substrate for single-crystal GaAs wafer, process would make GaAs solar cells commercially more attractive.

  2. Investigation of effective base transit time and current gain modulation of light-emitting transistors under different ambient temperatures

    SciTech Connect

    Yang, Hao-Hsiang; Tu, Wen-Chung; Wang, Hsiao-Lun; Wu, Chao-Hsin

    2014-11-03

    In this report, the modulation of current gain of InGaP/GaAs light-emitting transistors under different ambient temperatures are measured and analyzed using thermionic emission model of quantum well embedded in the transistor base region. Minority carriers captured by quantum wells gain more energy at high temperatures and escape from quantum wells resulting in an increase of current gain and lower optical output, resulting in different I-V characteristics from conventional heterojunction bipolar transistors. The effect of the smaller thermionic lifetime thus reduces the effective base transit time of transistors at high temperatures. The unique current gain enhancement of 27.61% is achieved when operation temperature increase from 28 to 85 °C.

  3. Crystal growth of device quality GaAs in space

    NASA Technical Reports Server (NTRS)

    Gatos, H. C.; Lagowski, J.

    1979-01-01

    The optimization of space processing of GaAs is described. The detailed compositional, structural, and electronic characterization of GaAs on a macro- and microscale and the relationships between growth parameters and the properties of GaAs are among the factors discussed. The key parameters limiting device performance are assessed.

  4. [Revisiting bipolar disorder].

    PubMed

    Senjyu, Yoshika; Ozawa, Hiroki

    2007-09-01

    According to the theory of evolution of Charles Darwin which is an author of The Origin of Species, human being evolves after long time to be profitable to "prosperity of a kind", and it is thought that there is the adaptive meaning. In other words, man stand on various creatures in number, and it may be said that human being building a high civilized society is the creature which was able to have an element of chosen mind and body in natural selection. However, a disease does not disappear from our daily life and tends to consider us to be "the misfortune" even if we human being is easy to suffer from a disease. "Evolution medicine" (Darwinian medicine) drop hint of meaning/the significance in aging and the process of the pathology. This paper refers to such a conception of bipolar disorder. PMID:17877000

  5. [Revisiting bipolar disorder].

    PubMed

    Senjyu, Yoshika; Ozawa, Hiroki

    2007-09-01

    According to the theory of evolution of Charles Darwin which is an author of The Origin of Species, human being evolves after long time to be profitable to "prosperity of a kind", and it is thought that there is the adaptive meaning. In other words, man stand on various creatures in number, and it may be said that human being building a high civilized society is the creature which was able to have an element of chosen mind and body in natural selection. However, a disease does not disappear from our daily life and tends to consider us to be "the misfortune" even if we human being is easy to suffer from a disease. "Evolution medicine" (Darwinian medicine) drop hint of meaning/the significance in aging and the process of the pathology. This paper refers to such a conception of bipolar disorder.

  6. Enhanced Radiation Sensitivity in Short-Channel Partially Depleted Silicon-on-Insulator n-Type Metal-Oxide-Semiconductor Field Effect Transistors

    NASA Astrophysics Data System (ADS)

    Peng, Chao; Zhang, Zheng-Xuan; Hu, Zhi-Yuan; Huang, Hui-Xiang; Ning, Bing-Xu; Bi, Da-Wei

    2013-09-01

    The total ionizing dose effects of partially depleted silicon-on-insulator (SOI) transistors in a 0.13 μm technology are studied by 60Co γ-ray irradiation. Radiation enhanced drain-induced barrier lowering (DIBL) under different bias conditions is related to the parasitic bipolar in the SOI transistor and oxide trapped charge in the buried oxide, and it is experimentally observed for short channel transistors. The enhanced DIBL effect manifests as the DIBL parameter increases with total dose. Body doping concentration is a key factor affecting the total ionizing dose effect of the transistor. The low body doping transistor exhibits not only significant front gate threshold voltage shift as a result of the coupling effect, but also great off-state leakage at high drain voltage due to the enhanced DIBL effect.

  7. GaAs Solar Cell Radiation Handbook

    NASA Technical Reports Server (NTRS)

    Anspaugh, B. E.

    1996-01-01

    The handbook discusses the history of GaAs solar cell development, presents equations useful for working with GaAs solar cells, describes commonly used instrumentation techniques for assessing radiation effects in solar cells and fundamental processes occurring in solar cells exposed to ionizing radiation, and explains why radiation decreases the electrical performance of solar cells. Three basic elements required to perform solar array degradation calculations: degradation data for GaAs solar cells after irradiation with 1 MeV electrons at normal incidence; relative damage coefficients for omnidirectional electron and proton exposure; and the definition of the space radiation environment for the orbit of interest, are developed and used to perform a solar array degradation calculation.

  8. Photoluminescence of Mn+ doped GaAs

    NASA Astrophysics Data System (ADS)

    Zhou, Huiying; Qu, Shengchun; Liao, Shuzhi; Zhang, Fasheng; Liu, Junpeng; Wang, Zhanguo

    2010-10-01

    Photoluminescence is one of the most useful techniques to obtain information about optoelectronic properties and defect structures of materials. In this work, the room-temperature and low temperature photoluminescence of Mn-doped GaAs were investigated, respectively. Mn-doped GaAs structure materials were prepared by Mn+ ion implantation at room temperature into GaAs. The implanted samples were subsequently annealed at various temperatures under N2 atmosphere to recrystallize the samples and remove implant damage. A strong peak was found for the sample annealed at 950 °C for 5 s. Transitions near 0.989 eV (1254 nm), 1.155 eV (1074 nm) and 1.329 eV (933 nm) were identified and formation of these emissions was analyzed for all prepared samples. This structure material could have myriad applications, including information storage, magnet-optical properties and energy level engineering.

  9. Improved chopper circuit uses parallel transistors

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Parallel transistor chopper circuit operates with one transistor in the forward mode and the other in the inverse mode. By using this method, it acts as a single, symmetrical, bidirectional transistor, and reduces and stabilizes the offset voltage.

  10. Transistor voltage comparator performs own sensing

    NASA Technical Reports Server (NTRS)

    Cliff, R. A.

    1965-01-01

    Detection of the highest voltage input among a group of varying voltage inputs is accomplished by a transistorized voltage comparison circuit. The collector circuits of the transistors perform the sensing function. Input voltage levels are governed by the transistors.

  11. Effect of GaAs native oxide upon the surface morphology during GaAs MBE growth

    NASA Astrophysics Data System (ADS)

    Ageev, O. A.; Solodovnik, M. S.; Balakirev, S. V.; Mikhaylin, I. A.; Eremenko, M. M.

    2016-08-01

    The GaAs native oxide effect upon the surface morphology of the GaAs epitaxial layer was studied with taking into account the main growth parameters of MBE technology: substrate temperature, effective As4/Ga flux ratio and growth rate. The MBE modes of atomically smooth and rough surfaces and surfaces with Ga droplet array formation were determined. The possibility of the obtaining of GaAs nanowires via GaAs native oxide layer was shown.

  12. Gyrator employing field effect transistors

    NASA Technical Reports Server (NTRS)

    Hochmair, E. S. (Inventor)

    1973-01-01

    A gyrator circuit of the conventional configuration of two amplifiers in a circular loop, one producing zero phase shift and the other producing 180 deg phase reversal is examined. All active elements are MOS field effect transistors. Each amplifier comprises a differential amplifier configuration with current limiting transistor, followed by an output transistor in cascode configuration, and two load transistors of opposite conductivity type from the other transistors. A voltage divider control circuit comprises a series string of transistors with a central voltage input to provide control, with locations on the amplifiers receiving reference voltages by connection to appropriate points on the divider. The circuit produces excellent response and is well suited for fabrication by integrated circuits.

  13. TRANSISTOR HIGH VOLTAGE POWER SUPPLY

    DOEpatents

    Driver, G.E.

    1958-07-15

    High voltage, direct current power supplies are described for use with battery powered nuclear detection equipment. The particular advantages of the power supply described, are increased efficiency and reduced size and welght brought about by the use of transistors in the circuit. An important feature resides tn the employment of a pair of transistors in an alternatefiring oscillator circuit having a coupling transformer and other circuit components which are used for interconnecting the various electrodes of the transistors.

  14. High voltage power transistor development

    NASA Technical Reports Server (NTRS)

    Hower, P. L.

    1981-01-01

    Design considerations, fabrication procedures, and methods of evaluation for high-voltage power-transistor development are discussed. Technique improvements such as controlling the electric field at the surface and perserving lifetimes in the collector region which have advanced the state of the art in high-voltage transistors are discussed. These improvements can be applied directly to the development of 1200 volt, 200 ampere transistors.

  15. GaAs photoconductive semiconductor switch

    DOEpatents

    Loubriel, Guillermo M.; Baca, Albert G.; Zutavern, Fred J.

    1998-01-01

    A high gain, optically triggered, photoconductive semiconductor switch (PCSS) implemented in GaAs as a reverse-biased pin structure with a passivation layer above the intrinsic GaAs substrate in the gap between the two electrodes of the device. The reverse-biased configuration in combination with the addition of the passivation layer greatly reduces surface current leakage that has been a problem for prior PCSS devices and enables employment of the much less expensive and more reliable DC charging systems instead of the pulsed charging systems that needed to be used with prior PCSS devices.

  16. GaAs photoconductive semiconductor switch

    DOEpatents

    Loubriel, G.M.; Baca, A.G.; Zutavern, F.J.

    1998-09-08

    A high gain, optically triggered, photoconductive semiconductor switch (PCSS) implemented in GaAs as a reverse-biased pin structure with a passivation layer above the intrinsic GaAs substrate in the gap between the two electrodes of the device is disclosed. The reverse-biased configuration in combination with the addition of the passivation layer greatly reduces surface current leakage that has been a problem for prior PCSS devices and enables employment of the much less expensive and more reliable DC charging systems instead of the pulsed charging systems that needed to be used with prior PCSS devices. 5 figs.

  17. Polarization induced doped transistor

    DOEpatents

    Xing, Huili; Jena, Debdeep; Nomoto, Kazuki; Song, Bo; Zhu, Mingda; Hu, Zongyang

    2016-06-07

    A nitride-based field effect transistor (FET) comprises a compositionally graded and polarization induced doped p-layer underlying at least one gate contact and a compositionally graded and doped n-channel underlying a source contact. The n-channel is converted from the p-layer to the n-channel by ion implantation, a buffer underlies the doped p-layer and the n-channel, and a drain underlies the buffer.

  18. Carbon nanotube gated lateral resonant tunneling field-effect transistors

    NASA Astrophysics Data System (ADS)

    Wang, D. P.; Perkins, B. R.; Yin, A. J.; Zaslavsky, A.; Xu, J. M.; Beresford, R.; Snider, G. L.

    2005-10-01

    We have produced a lateral resonant tunneling field-effect transistor using a Y-junction multiwalled carbon nanotube as the dual gate on a narrow channel etched from a modulation-doped GaAs /AlGaAs heterostructure. When the Y-junction nanotube is negatively biased, electrons traveling from source to drain along the channel face a voltage-tunable electrostatic double-barrier potential. We measured the three-terminal IDS(VDS,VGS) characteristics of the device at 4.2 K and observed gate-induced structure in the transconductance and negative differential resistance in the drain current. We interpret the data in terms of resonant tunneling through one-dimensional subbands confined by a self-consistently calculated electrostatic potential.

  19. Threat sensitivity in bipolar disorder.

    PubMed

    Muhtadie, Luma; Johnson, Sheri L

    2015-02-01

    Life stress is a major predictor of the course of bipolar disorder. Few studies have used laboratory paradigms to examine stress reactivity in bipolar disorder, and none have assessed autonomic reactivity to laboratory stressors. In the present investigation we sought to address this gap in the literature. Participants, 27 diagnosed with bipolar I disorder and 24 controls with no history of mood disorder, were asked to complete a complex working memory task presented as "a test of general intelligence." Self-reported emotions were assessed at baseline and after participants were given task instructions; autonomic physiology was assessed at baseline and continuously during the stressor task. Compared to controls, individuals with bipolar disorder reported greater increases in pretask anxiety from baseline and showed greater cardiovascular threat reactivity during the task. Group differences in cardiovascular threat reactivity were significantly correlated with comorbid anxiety in the bipolar group. Our results suggest that a multimethod approach to assessing stress reactivity-including the use of physiological parameters that differentiate between maladaptive and adaptive profiles of stress responding-can yield valuable information regarding stress sensitivity and its associations with negative affectivity in bipolar disorder. (PsycINFO Database Record (c) 2015 APA, all rights reserved). PMID:25688436

  20. Threat Sensitivity in Bipolar Disorder

    PubMed Central

    Muhtadie, Luma; Johnson, Sheri L.

    2015-01-01

    Life stress is a major predictor of the course of bipolar disorder. Few studies have used laboratory paradigms to examine stress reactivity in bipolar disorder, and none have assessed autonomic reactivity to laboratory stressors. In the present investigation we sought to address this gap in the literature. Participants, 27 diagnosed with bipolar I disorder and 24 controls with no history of mood disorder, were asked to complete a complex working memory task presented as “a test of general intelligence.” Self-reported emotions were assessed at baseline and after participants were given task instructions; autonomic physiology was assessed at baseline and continuously during the stressor task. Compared to controls, individuals with bipolar disorder reported greater increases in pretask anxiety from baseline and showed greater cardiovascular threat reactivity during the task. Group differences in cardiovascular threat reactivity were significantly correlated with comorbid anxiety in the bipolar group. Our results suggest that a multimethod approach to assessing stress reactivity—including the use of physiological parameters that differentiate between maladaptive and adaptive profiles of stress responding— can yield valuable information regarding stress sensitivity and its associations with negative affectivity in bipolar disorder. PMID:25688436

  1. Impacts of crystal orientation of GaAs on the interfacial structures and electrical properties of Hf{sub 0.6}La{sub 0.4}O{sub x} films

    SciTech Connect

    Jia, Tingting; Kimura, Hideo; Zhao, Hongyang; Yao, Qiwen; Cheng, Zhenxiang; Cheng, Xinghong; Yu, Yuehui

    2014-04-07

    One of the major challenges in realizing the GaAs channel in the metal oxide semiconductor field effect transistor is the degrading in electron transport properties at the interface between GaAs and the gate oxide. In this study, Hf{sub 0.6}La{sub 0.4}O{sub x} gate oxide films were deposited at a low temperature (200 °C) on GaAs(111)A and GaAs(100) substrates by plasma enhanced atomic layer deposition. Microstructure analysis indicates that residuals of gallium oxide, arsenic oxide, and As element remained at the interface of Hf{sub 0.6}La{sub 0.4}O{sub x}/GaAs(100). On contrast, a smoother interface is observed between Hf{sub 0.6}La{sub 0.4}O{sub x} thin film and GaAs(111)A substrate. Furthermore, a reduction of interfacial layer is observed in Hf{sub 0.6}La{sub 0.4}O{sub x}/GaAs(111)A. Electrical characterization of the metal-insulator-semiconductor Pt/Hf{sub 0.6}La{sub 0.4}O{sub x}/n-GaAs(111)A capacitor indicated a reduction of D{sub it} and leakage current compared with the capacitor fabricated on GaAs(100)

  2. Au impact on GaAs epitaxial growth on GaAs (111)B substrates in molecular beam epitaxy

    NASA Astrophysics Data System (ADS)

    Liao, Zhi-Ming; Chen, Zhi-Gang; Lu, Zhen-Yu; Xu, Hong-Yi; Guo, Ya-Nan; Sun, Wen; Zhang, Zhi; Yang, Lei; Chen, Ping-Ping; Lu, Wei; Zou, Jin

    2013-02-01

    GaAs growth behaviour under the presence of Au nanoparticles on GaAs {111}B substrate is investigated using electron microscopy. It has been found that, during annealing, enhanced Ga surface diffusion towards Au nanoparticles leads to the GaAs epitaxial growth into {113}B faceted triangular pyramids under Au nanoparticles, governed by the thermodynamic growth, while during conventional GaAs growth, growth kinetics dominates, resulting in the flatted triangular pyramids at high temperature and the epitaxial nanowires growth at relatively low temperature. This study provides an insight of Au nanoparticle impact on GaAs growth, which is critical for understanding the formation mechanisms of semiconductor nanowires.

  3. A Cryogenic GaAs PHEMT/ Ferroelectric Ku-Band Tunable Oscillator

    NASA Technical Reports Server (NTRS)

    Romanofsky, Robert R.; Miranda, Felix A.; VanKeuls, Fred W.

    1998-01-01

    A Ku-band tunable oscillator operated at and below 77 K is described. The oscillator is based on two separate technologies: a 0.25 mm GaAs pseudomorphic high electron mobility transistor (PHEMT) circuit optimized for cryogenic operation, and a gold microstrip ring resonator patterned on a thin ferroelectric (SrTiO3) film which was laser ablated onto a LaAlO3 substrate. A tuning range of up to 3% of the center frequency was achieved by applying dc bias between the ring resonator and ground plane. To the best of our knowledge, this is the first tunable oscillator based on a thin film ferroelectric structure demonstrated in the microwave frequency range. The design methodology of the oscillator and the performance characteristics of the tunable resonator are described.

  4. GaAs Solar Cell Radiation Handbook

    NASA Technical Reports Server (NTRS)

    Anspaugh, B. E.

    1996-01-01

    History of GaAs solar cell development is provided. Photovoltaic equations are described along with instrumentation techniques for measuring solar cells. Radiation effects in solar cells, electrical performance, and spacecraft flight data for solar cells are discussed. The space radiation environment and solar array degradation calculations are addressed.

  5. Integrated neurobiology of bipolar disorder.

    PubMed

    Maletic, Vladimir; Raison, Charles

    2014-01-01

    From a neurobiological perspective there is no such thing as bipolar disorder. Rather, it is almost certainly the case that many somewhat similar, but subtly different, pathological conditions produce a disease state that we currently diagnose as bipolarity. This heterogeneity - reflected in the lack of synergy between our current diagnostic schema and our rapidly advancing scientific understanding of the condition - limits attempts to articulate an integrated perspective on bipolar disorder. However, despite these challenges, scientific findings in recent years are beginning to offer a provisional "unified field theory" of the disease. This theory sees bipolar disorder as a suite of related neurodevelopmental conditions with interconnected functional abnormalities that often appear early in life and worsen over time. In addition to accelerated loss of volume in brain areas known to be essential for mood regulation and cognitive function, consistent findings have emerged at a cellular level, providing evidence that bipolar disorder is reliably associated with dysregulation of glial-neuronal interactions. Among these glial elements are microglia - the brain's primary immune elements, which appear to be overactive in the context of bipolarity. Multiple studies now indicate that inflammation is also increased in the periphery of the body in both the depressive and manic phases of the illness, with at least some return to normality in the euthymic state. These findings are consistent with changes in the hypothalamic-pituitary-adrenal axis, which are known to drive inflammatory activation. In summary, the very fact that no single gene, pathway, or brain abnormality is likely to ever account for the condition is itself an extremely important first step in better articulating an integrated perspective on both its ontological status and pathogenesis. Whether this perspective will translate into the discovery of innumerable more homogeneous forms of bipolarity is one of the

  6. Treatment of bipolar disorder.

    PubMed

    Geddes, John R; Miklowitz, David J

    2013-05-11

    We review recent developments in the acute and long-term treatment of bipolar disorder and identify promising future routes to therapeutic innovation. Overall, advances in drug treatment remain quite modest. Antipsychotic drugs are effective in the acute treatment of mania; their efficacy in the treatment of depression is variable with the clearest evidence for quetiapine. Despite their widespread use, considerable uncertainty and controversy remains about the use of antidepressant drugs in the management of depressive episodes. Lithium has the strongest evidence for long-term relapse prevention; the evidence for anticonvulsants such as divalproex and lamotrigine is less robust and there is much uncertainty about the longer term benefits of antipsychotics. Substantial progress has been made in the development and assessment of adjunctive psychosocial interventions. Long-term maintenance and possibly acute stabilisation of depression can be enhanced by the combination of psychosocial treatments with drugs. The development of future treatments should consider both the neurobiological and psychosocial mechanisms underlying the disorder. We should continue to repurpose treatments and to recognise the role of serendipity. We should also investigate optimum combinations of pharmacological and psychotherapeutic treatments at different stages of the illness. Clarification of the mechanisms by which different treatments affect sleep and circadian rhythms and their relation with daily mood fluctuations is likely to help with the treatment selection for individual patients. To be economically viable, existing psychotherapy protocols need to be made briefer and more efficient for improved scalability and sustainability in widespread implementation. PMID:23663953

  7. Bipolar cells of the ground squirrel retina.

    PubMed

    Puller, Christian; Ondreka, Katharina; Haverkamp, Silke

    2011-03-01

    Parallel processing of an image projected onto the retina starts at the first synapse, the cone pedicle, and each cone feeds its light signal into a minimum of eight different bipolar cell types. Hence, the morphological classification of bipolar cells is a prerequisite for analyzing retinal circuitry. Here we applied common bipolar cell markers to the cone-dominated ground squirrel retina, studied the labeling by confocal microscopy and electron microscopy, and compared the resulting bipolar cell types with those of the mouse (rod dominated) and primate retina. Eight different cone bipolar cell types (three OFF and five ON) and one rod bipolar cell were distinguished. The major criteria for classifying the cells were their immunocytochemical identity, their dendritic branching pattern, and the shape and stratification level of their axons in the inner plexiform layer (IPL). Immunostaining with antibodies against Gγ13, a marker for ON bipolar cells, made it possible to separate OFF and ON bipolars. Recoverin-positive OFF bipolar cells partly overlapped with ON bipolar axon terminals at the ON/OFF border of the IPL. Antibodies against HCN4 labeled the S-cone selective (bb) bipolar cell. The calcium-binding protein CaB5 was expressed in two OFF and two ON cone bipolar cell types, and CD15 labeled a widefield ON cone bipolar cell comparable to the DB6 in primate.

  8. Optically-Activated GaAs Switches for Ground Penetrating Radar and Firing Set Applications

    SciTech Connect

    Aurand, J.; Brown, D.J.; Carin, L.; Denison, G.J.; Helgeson, W.D.; Loubriel, G.M.; Mar, A.; O'Malley, M.W.; Rinehart, L.F.; Zutavern, F.J.

    1999-07-14

    Optically activated, high gain GaAs switches are being tested for many different applications. TWO such applications are ground penetrating radar (GPR) and firing set switches. The ability of high gain GaAs Photoconductive Semiconductor Switches (PCSs) to deliver fast risetime pulses makes them suitable for their use in radars that rely on fast impulses. This type of direct time domain radar is uniquely suited for the detection of buried items because it can operate at low frequency, high average power, and close to the ground, greatly increasing power on target. We have demonstrated that a PCSs based system can be used to produce a bipolar waveform with a total duration of about 6 ns and with minimal ringing. Such a pulse is radiated and returns from a 55 gallon drum will be presented. For firing sets, the switch requirements include small size, high current, dc charging, radiation hardness and modest longevity. We have switched 1 kA at 1 kV and 2.8 kA at 3 kV dc charge.

  9. Analytical model of threshold voltage degradation due to localized charges in gate material engineered Schottky barrier cylindrical GAA MOSFETs

    NASA Astrophysics Data System (ADS)

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

    2016-10-01

    The threshold voltage degradation due to the hot carrier induced localized charges (LC) is a major reliability concern for nanoscale Schottky barrier (SB) cylindrical gate all around (GAA) metal-oxide-semiconductor field-effect transistors (MOSFETs). The degradation physics of gate material engineered (GME)-SB-GAA MOSFETs due to LC is still unexplored. An explicit threshold voltage degradation model for GME-SB-GAA-MOSFETs with the incorporation of localized charges (N it) is developed. To accurately model the threshold voltage the minimum channel carrier density has been taken into account. The model renders how +/- LC affects the device subthreshold performance. One-dimensional (1D) Poisson’s and 2D Laplace equations have been solved for two different regions (fresh and damaged) with two different gate metal work-functions. LCs are considered at the drain side with low gate metal work-function as N it is more vulnerable towards the drain. For the reduction of carrier mobility degradation, a lightly doped channel has been considered. The proposed model also includes the effect of barrier height lowering at the metal-semiconductor interface. The developed model results have been verified using numerical simulation data obtained by the ATLAS-3D device simulator and excellent agreement is observed between analytical and simulation results.

  10. [Bipolar disorder in the elderly].

    PubMed

    Monczor, Myriam

    2010-01-01

    Bipolar disorder is a frequent disorder in the elderly, with a prevalence of 0.1 a 0.4%; a 10% of bipolar patients have mania onset after 50 years old. It has in ageing a more heterogeneous clinical presentation. The manic episodes are less severe, mixed depression is common, as well as confusion and cognitive impairment. A first manic episode in ageing can be secondary to medical illness. Treatment for bipolar disorder in ageing is similar to treatment for young patients. The differences are due to pharmacocinetic changes because of the age, with the comorbidity and with the etiology, if it is a secondary mania. Lithium can be the first choice for treating mania in patients with antecedent of good response and have tolerance to adverse effects, but because of its toxicity and secondary effects other possibilities may be considered: divalproate, cabamazepine, antipsychotics. There are some little studies that show lamotrigine efficacy in bipolar depression in elderly. We need more specific studies about bipolar disorder treatment in aging.

  11. Targeting astrocytes in bipolar disorder.

    PubMed

    Peng, Liang; Li, Baoman; Verkhratsky, Alexei

    2016-06-01

    Astrocytes are homeostatic cells of the central nervous system, which are critical for development and maintenance of synaptic transmission and hence of synaptically connected neuronal ensembles. Astrocytic densities are reduced in bipolar disorder, and therefore deficient astroglial function may contribute to overall disbalance in neurotransmission and to pathological evolution. Classical anti-bipolar drugs (lithium salts, valproic acid and carbamazepine) affect expression of astroglial genes and modify astroglial signalling and homeostatic cascades. Many effects of both antidepressant and anti-bipolar drugs are exerted through regulation of glutamate homeostasis and glutamatergic transmission, through K(+) buffering, through regulation of calcium-dependent phospholipase A2 (that controls metabolism of arachidonic acid) or through Ca(2+) homeostatic and signalling pathways. Sometimes anti-depressant and anti-bipolar drugs exert opposite effects, and some effects on gene expression in drug treated animals are opposite in neurones vs. astrocytes. Changes in the intracellular pH induced by anti-bipolar drugs affect uptake of myo-inositol and thereby signalling via inositoltrisphosphate (InsP3), this being in accord with one of the main theories of mechanism of action for these drugs. PMID:27015045

  12. Troubled Childhood May Boost Bipolar Risk

    MedlinePlus

    ... childhood abuse may be at increased risk for bipolar disorder, researchers report. "The link between experiencing a troubled ... said in a university news release. People with bipolar disorder experience emotional extremes -- lows and highs -- which harm ...

  13. REGENERATIVE TRANSISTOR AMPLIFIER

    DOEpatents

    Kabell, L.J.

    1958-11-25

    Electrical circults for use in computers and the like are described. particularly a regenerative bistable transistor amplifler which is iurned on by a clock signal when an information signal permits and is turned off by the clock signal. The amplifier porforms the above function with reduced power requirements for the clock signal and circuit operation. The power requirements are reduced in one way by employing transformer coupling which increases the collector circuit efficiency by eliminating the loss of power in the collector load resistor.

  14. Power transistor switching characterization

    NASA Technical Reports Server (NTRS)

    Blackburn, D. L.

    1981-01-01

    The switching properties of power transistors are investigated. The devices studied were housed in IO-3 cases and were of an n(+)-p-n(-)-n(+) vertical dopant structure. The effects of the magnitude of the reverse-base current and temperature on the reverse-bias second breakdown characteristics are discussed. Brief discussions of device degradation due to second breakdown and of a constant voltage turn-off circuit are included. A description of a vacuum tube voltage clamp circuit which reduces clamped collector voltage overshoot is given.

  15. Characterizing the Switching Thresholds of Magnetophoretic Transistors.

    PubMed

    Abedini-Nassab, Roozbeh; Joh, Daniel Y; Van Heest, Melissa A; Yi, John S; Baker, Cody; Taherifard, Zohreh; Margolis, David M; Garcia, J Victor; Chilkoti, Ashutosh; Murdoch, David M; Yellen, Benjamin B

    2015-10-28

    The switching thresholds of magnetophoretic transistors for sorting cells in microfluidic environments are characterized. The transistor operating conditions require short 20-30 mA pulses of electrical current. By demonstrating both attractive and repulsive transistor modes, a single transistor architecture is used to implement the full write cycle for importing and exporting single cells in specified array sites. PMID:26349853

  16. Acoustic Wave Chemical Microsensors in GaAs

    SciTech Connect

    Albert G. Baca; Edwin J. Heller; Gregory C. Frye-Mason; John L. Reno; Richard Kottenstette; Stephen A. Casalnuovo; Susan L. Hietala; Vincent M. Hietala

    1998-09-20

    High sensitivity acoustic wave chemical microsensors are being developed on GaAs substrates. These devices take advantage of the piezoelectric properties of GaAs as well as its mature microelectronics fabrication technology and nascent micromachining technology. The design, fabrication, and response of GaAs SAW chemical microsensors are reported. Functional integrated GaAs SAW oscillators, suitable for chemical sensing, have been produced. The integrated oscillator requires 20 mA at 3 VK, operates at frequencies up to 500 MHz, and occupies approximately 2 mmz. Discrete GaAs sensor components, including IC amplifiers, SAW delay lines, and IC phase comparators have been fabricated and tested. A temperature compensation scheme has been developed that overcomes the large temperature dependence of GaAs acoustic wave devices. Packaging issues related to bonding miniature flow channels directly to the GaAs substrates have been resolved. Micromachining techniques for fabricating FPW and TSM microsensors on thin GaAs membranes are presented and GaAs FPW delay line performance is described. These devices have potentially higher sensitivity than existing GaAs and quartz SAW sensors.

  17. Mathematical models of bipolar disorder

    NASA Astrophysics Data System (ADS)

    Daugherty, Darryl; Roque-Urrea, Tairi; Urrea-Roque, John; Troyer, Jessica; Wirkus, Stephen; Porter, Mason A.

    2009-07-01

    We use limit cycle oscillators to model bipolar II disorder, which is characterized by alternating hypomanic and depressive episodes and afflicts about 1% of the United States adult population. We consider two non-linear oscillator models of a single bipolar patient. In both frameworks, we begin with an untreated individual and examine the mathematical effects and resulting biological consequences of treatment. We also briefly consider the dynamics of interacting bipolar II individuals using weakly-coupled, weakly-damped harmonic oscillators. We discuss how the proposed models can be used as a framework for refined models that incorporate additional biological data. We conclude with a discussion of possible generalizations of our work, as there are several biologically-motivated extensions that can be readily incorporated into the series of models presented here.

  18. Monolithic metal oxide transistors.

    PubMed

    Choi, Yongsuk; Park, Won-Yeong; Kang, Moon Sung; Yi, Gi-Ra; Lee, Jun-Young; Kim, Yong-Hoon; Cho, Jeong Ho

    2015-04-28

    We devised a simple transparent metal oxide thin film transistor architecture composed of only two component materials, an amorphous metal oxide and ion gel gate dielectric, which could be entirely assembled using room-temperature processes on a plastic substrate. The geometry cleverly takes advantage of the unique characteristics of the two components. An oxide layer is metallized upon exposure to plasma, leading to the formation of a monolithic source-channel-drain oxide layer, and the ion gel gate dielectric is used to gate the transistor channel effectively at low voltages through a coplanar gate. We confirmed that the method is generally applicable to a variety of sol-gel-processed amorphous metal oxides, including indium oxide, indium zinc oxide, and indium gallium zinc oxide. An inverter NOT logic device was assembled using the resulting devices as a proof of concept demonstration of the applicability of the devices to logic circuits. The favorable characteristics of these devices, including (i) the simplicity of the device structure with only two components, (ii) the benign fabrication processes at room temperature, (iii) the low-voltage operation under 2 V, and (iv) the excellent and stable electrical performances, together support the application of these devices to low-cost portable gadgets, i.e., cheap electronics. PMID:25777338

  19. Microwave field effect transistor

    NASA Technical Reports Server (NTRS)

    Huang, Ho-Chung (Inventor)

    1989-01-01

    Electrodes of a high power, microwave field effect transistor are substantially matched to external input and output networks. The field effect transistor includes a metal ground plane layer, a dielectric layer on the ground plane layer, a gallium arsenide active region on the dielectric layer, and substantially coplanar spaced source, gate, and drain electrodes having active segments covering the active region. The active segment of the gate electrode is located between edges of the active segments of the source and drain electrodes. The gate and drain electrodes include inactive pads remote from the active segments. The pads are connected directly to the input and output networks. The source electrode is connected to the ground plane layer. The space between the electrodes and the geometry of the electrodes extablish parasitic shunt capacitances and series inductances that provide substantial matches between the input network and the gate electrode and between the output network and the drain electrode. Many of the devices are connected in parallel and share a common active region, so that each pair of adjacent devices shares the same source electrodes and each pair of adjacent devices shares the same drain electrodes. The gate electrodes for the parallel devices are formed by a continuous stripe that extends between adjacent devices and is connected at different points to the common gate pad.

  20. Auger recombination in heavily doped shallow-emitter silicon p-n-junction solar cells, diodes, and transistors

    NASA Technical Reports Server (NTRS)

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

    1979-01-01

    A rigorous analytic evaluation of an emitter model that includes Auger recombination but excludes bandgap narrowing is presented. It is shown that such a model cannot explain the experimentally observed values of the open-circuit voltage in p-n-junction silicon solar cells. Thus physical mechanisms in addition to Auger recombination are responsible for the experimentally observed values of the open-circuit voltage in silicon solar cells and the common-emitter current gain in bipolar transistors.

  1. Bipolar lead acid battery development

    NASA Technical Reports Server (NTRS)

    Eskra, Michael; Vidas, Robin; Miles, Ronald; Halpert, Gerald; Attia, Alan; Perrone, David

    1991-01-01

    A modular bipolar battery configuration is under development at Johnson Control, Inc. (JCI) and the Jet Propulsion Laboratory (JPL). The battery design, incorporating proven lead acid electrochemistry, yields a rechargeable, high-power source that is light weight and compact. This configuration offers advantages in power capability, weight, and volume over conventional monopolar batteries and other battery chemistries. The lead acid bipolar battery operates in a sealed, maintenance-free mode allowing for maximum application flexibility. It is ideal for high-voltage and high-power applications.

  2. Bipolar dislocation of the clavicle.

    PubMed

    Jiang, Wei; Gao, Shu-Guang; Li, Yu-Sheng; Lei, Guang-Hua

    2012-11-01

    Bipolar dislocation of the clavicle at acromioclavicular and sternoclavicular joint is an uncommon traumatic injury. The conservative treatments adopted in the past is associated with redislocation dysfunction and deformity. A 41 years old lady with bipolar dislocation of right shoulder is treated surgically by open reduction and internal fixation by oblique T-plate at sternoclavicular joint and Kirschner wire stabilization at acromioclavicular joint. The patient showed satisfactory recovery with full range of motion of the right shoulder and normal muscular strength. The case reported in view of rarity and at 2 years followup. PMID:23325981

  3. Optimization of Vertical Double-Diffused Metal-Oxide Semiconductor (VDMOS) Power Transistor Structure for Use in High Frequencies and Medical Devices.

    PubMed

    Farhadi, Rozita; Farhadi, Bita

    2014-01-01

    Power transistors, such as the vertical, double-diffused, metal-oxide semiconductor (VDMOS), are used extensively in the amplifier circuits of medical devices. The aim of this research was to construct a VDMOS power transistor with an optimized structure to enhance the operation of medical devices. First, boron was implanted in silicon by implanting unclamped inductive switching (UIS) and a Faraday shield. The Faraday shield was implanted in order to replace the gate-field parasitic capacitor on the entry part of the device. Also, implanting the UIS was used in order to decrease the effect of parasitic bipolar junction transistor (BJT) of the VDMOS power transistor. The research tool used in this study was Silvaco software. By decreasing the transistor entry resistance in the optimized VDMOS structure, power losses and noise at the entry of the transistor were decreased, and, by increasing the breakdown voltage, the lifetime of the VDMOS transistor lifetime was increased, which resulted in increasing drain flow and decreasing Ron. This consequently resulted in enhancing the operation of high-frequency medical devices that use transistors, such as Radio Frequency (RF) and electrocardiograph machines.

  4. Optimization of Vertical Double-Diffused Metal-Oxide Semiconductor (VDMOS) Power Transistor Structure for Use in High Frequencies and Medical Devices.

    PubMed

    Farhadi, Rozita; Farhadi, Bita

    2014-01-01

    Power transistors, such as the vertical, double-diffused, metal-oxide semiconductor (VDMOS), are used extensively in the amplifier circuits of medical devices. The aim of this research was to construct a VDMOS power transistor with an optimized structure to enhance the operation of medical devices. First, boron was implanted in silicon by implanting unclamped inductive switching (UIS) and a Faraday shield. The Faraday shield was implanted in order to replace the gate-field parasitic capacitor on the entry part of the device. Also, implanting the UIS was used in order to decrease the effect of parasitic bipolar junction transistor (BJT) of the VDMOS power transistor. The research tool used in this study was Silvaco software. By decreasing the transistor entry resistance in the optimized VDMOS structure, power losses and noise at the entry of the transistor were decreased, and, by increasing the breakdown voltage, the lifetime of the VDMOS transistor lifetime was increased, which resulted in increasing drain flow and decreasing Ron. This consequently resulted in enhancing the operation of high-frequency medical devices that use transistors, such as Radio Frequency (RF) and electrocardiograph machines. PMID:25763152

  5. GaAs shallow-homojunction solar cells

    NASA Technical Reports Server (NTRS)

    Fan, J. C. C.

    1981-01-01

    The feasibility of fabricating space resistant, high efficiency, light weight, low cost GaAs shallow homojunction solar cells for space application is investigated. The material preparation of ultrathin GaAs single crystal layers, and the fabrication of efficient GaAs solar cells on bulk GaAs substrates are discussed. Considerable progress was made in both areas, and conversion efficiency about 16% AMO was obtained using anodic oxide as a single layer antireflection coating. A computer design shows that even better cells can be obtained with double layer antireflection coating. Ultrathin, high efficiency solar cells were obtained from GaAs films prepared by the CLEFT process, with conversion efficiency as high as 17% at AMI from a 10 micrometers thick GaAs film. A organometallic CVD was designed and constructed.

  6. LEC GaAs for integrated circuit applications

    NASA Technical Reports Server (NTRS)

    Kirkpatrick, C. G.; Chen, R. T.; Homes, D. E.; Asbeck, P. M.; Elliott, K. R.; Fairman, R. D.; Oliver, J. D.

    1984-01-01

    Recent developments in liquid encapsulated Czochralski techniques for the growth of semiinsulating GaAs for integrated circuit applications have resulted in significant improvements in the quality and quantity of GaAs material suitable for device processing. The emergence of high performance GaAs integrated circuit technologies has accelerated the demand for high quality, large diameter semiinsulating GaAs substrates. The new device technologies, including digital integrated circuits, monolithic microwave integrated circuits and charge coupled devices have largely adopted direct ion implantation for the formation of doped layers. Ion implantation lends itself to good uniformity and reproducibility, high yield and low cost; however, this technique also places stringent demands on the quality of the semiinsulating GaAs substrates. Although significant progress was made in developing a viable planar ion implantation technology, the variability and poor quality of GaAs substrates have hindered progress in process development.

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

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

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

  8. Latch-up based bidirectional npn selector for bipolar resistance-change memory

    NASA Astrophysics Data System (ADS)

    Kim, Sungho; Moon, Dong-Il; Lu, Wei; Hwan Kim, Dae; Myong Kim, Dong; Choi, Yang-Kyu; Choi, Sung-Jin

    2013-07-01

    A vertically integrated latch-up based n-p-n bidirectional diode, which is analogous to an open-base bipolar junction transistor, is demonstrated for bipolar resistance-change memory selector application. A maximum current density of >50 MA/cm2 and a selectivity of >104 are observed at a fast switching speed of within 10 ns. The high selectivity as a consequence of the sudden latch-up process is feasible owing to the positive-feedback process initiated by impact ionization. The optimization of the turn-on voltage is comprehensively investigated by numerical device simulation, which ensures the promising potential of the latch-up based selector device.

  9. Interference-based molecular transistors

    PubMed Central

    Li, Ying; Mol, Jan A.; Benjamin, Simon C.; Briggs, G. Andrew D.

    2016-01-01

    Molecular transistors have the potential for switching with lower gate voltages than conventional field-effect transistors. We have calculated the performance of a single-molecule device in which there is interference between electron transport through the highest occupied molecular orbital and the lowest unoccupied molecular orbital of a single molecule. Quantum interference results in a subthreshold slope that is independent of temperature. For realistic parameters the change in gate potential required for a change in source-drain current of two decades is 20 mV, which is a factor of six smaller than the theoretical limit for a metal-oxide-semiconductor field-effect transistor. PMID:27646692

  10. Interference-based molecular transistors.

    PubMed

    Li, Ying; Mol, Jan A; Benjamin, Simon C; Briggs, G Andrew D

    2016-01-01

    Molecular transistors have the potential for switching with lower gate voltages than conventional field-effect transistors. We have calculated the performance of a single-molecule device in which there is interference between electron transport through the highest occupied molecular orbital and the lowest unoccupied molecular orbital of a single molecule. Quantum interference results in a subthreshold slope that is independent of temperature. For realistic parameters the change in gate potential required for a change in source-drain current of two decades is 20 mV, which is a factor of six smaller than the theoretical limit for a metal-oxide-semiconductor field-effect transistor. PMID:27646692

  11. AlGaAs/GaAs p-i-n photodiode/preamplifier monolithic photoreceiver integrated on a semi-insulating GaAs substrate

    NASA Astrophysics Data System (ADS)

    Wada, O.; Hamaguchi, H.; Miura, S.; Makiuchi, M.; Nakai, K.; Horimatsu, H.; Sakurai, T.

    1985-05-01

    A fully monolithic photoreceiver circuit incorporating an AlGaAs/GaAs p-i-n photodiode and a GaAs field-effect transistor based transimpedance amplifier has been fabricated in the form of a horizontally integrated structure on a semi-insulating GaAs substrate. Parasitic capacitances of the circuit elements have been minimized in the present monolithic circuit, and a short rise and fall time of 1.0 ns, corresponding to an approximate -3 dB frequency of 300 MHz, has been demonstrated at the internal feedback resistance of 1.3 kΩ. Preliminary measurement of the noise characteristics of the present circuit has exhibited an encouraging value of the equivalent input noise current of 13 pA Hz-1/2 at 300 MHz.

  12. New-type silicon bipolar-pixel detector with internal amplification

    NASA Astrophysics Data System (ADS)

    Chubenko, A. P.; Karmanov, D. E.; Legotin, S. A.; Mukhamedshin, R. A.; Murashev, V. N.

    2009-12-01

    New-type silicon detector of charged particles and photons with internal amplification is considered. Bipolar npn-transistor pixel placed on a high-purity n-type silicon substrate is the functional element of the detector. The range being sensitive to ionization is a low-doped ( N˜10 cm) n region of the collector with a thickness virtually coinciding with the substrate thickness. A thin base containing one or more n emitters is formed on the surface. The current-amplification gain factor of the emitterbase junction is about 30. Detector prototypes are manufactured in the form of transistor matrices of 3×3 mm and 6×6 mm dimensions with a interpixel spacing of 50 and 100 microns. Results of testing of matrices are presented. The work is supported by the International Science and Technology Center, Project # 3024.

  13. Eight-Bit-Slice GaAs General Processor Circuit

    NASA Technical Reports Server (NTRS)

    Weissman, John; Gauthier, Robert V.

    1989-01-01

    Novel GaAs 8-bit slice enables quick and efficient implementation of variety of fast GaAs digital systems ranging from central processing units of computers to special-purpose processors for communications and signal-processing applications. With GaAs 8-bit slice, designers quickly configure and test hearts of many digital systems that demand fast complex arithmetic, fast and sufficient register storage, efficient multiplexing and routing of data words, and ease of control.

  14. Development of GaAs solar cells

    NASA Technical Reports Server (NTRS)

    Mcnally, P. J.

    1972-01-01

    This is the second quarterly technical report on a program, the goal of which is to achieve high efficiency GaAs solar cells. Analysis was concerned with providing design information for use in experimentally determining optimum solar cell process parameters. The first quarterly report contained the results of those design calculations. Using those results as a guide, experimental work was initiated to determine optimum cell process parameters. The initial results on this phase of the program are reported.

  15. Piezoelectric field in strained GaAs.

    SciTech Connect

    Chow, Weng Wah; Wieczorek, Sebastian Maciej

    2005-11-01

    This report describes an investigation of the piezoelectric field in strained bulk GaAs. The bound charge distribution is calculated and suitable electrode configurations are proposed for (1) uniaxial and (2) biaxial strain. The screening of the piezoelectric field is studied for different impurity concentrations and sample lengths. Electric current due to the piezoelectric field is calculated for the cases of (1) fixed strain and (2) strain varying in time at a constant rate.

  16. Surface-modified GaAs terahertz plasmon emitter

    NASA Astrophysics Data System (ADS)

    Darmo, J.; Strasser, G.; Muller, T.; Bratschitsch, R.; Unterrainer, K.

    2002-07-01

    We studied the THz emission from n-GaAs plasmon emitters modified by low-temperature-grown (LT) GaAs surface layers. The THz emission is increased since the LT GaAs pins the Fermi level at a midgap position, increasing the surface depletion field. For a THz emitter with a 70-nm-thick LT GaAs layer we observe without external fields a THz emission intensity of 140 nW. In addition, the long-term performance of the modified emitters is improved by the LT GaAs surface layer.

  17. Crystal growth of device quality GaAs in space

    NASA Technical Reports Server (NTRS)

    Gatos, H. C.; Lagowski, J.

    1984-01-01

    The crystal growth, device processing and device related properties and phenomena of GaAs are investigated. Our GaAs research evolves about these key thrust areas. The overall program combines: (1) studies of crystal growth on novel approaches to engineering of semiconductor materials (i.e., GaAs and related compounds); (2) investigation and correlation of materials properties and electronic characteristics on a macro- and microscale; (3) investigation of electronic properties and phenomena controlling device applications and device performance. The ground based program is developed which would insure successful experimentation with and eventually processing of GaAs in a near zero gravity environment.

  18. High efficiency, low cost thin GaAs solar cells

    NASA Technical Reports Server (NTRS)

    Fan, J. C. C.

    1982-01-01

    The feasibility of fabricating space-resistant, high efficiency, light-weight, low-cost GaAs shallow-homojunction solar cells for space application is demonstrated. This program addressed the optimal preparation of ultrathin GaAs single-crystal layers by AsCl3-GaAs-H2 and OMCVD process. Considerable progress has been made in both areas. Detailed studies on the AsCl3 process showed high-quality GaAs thin layers can be routinely grown. Later overgrowth of GaAs by OMCVD has been also observed and thin FaAs films were obtained from this process.

  19. Corrosion resistant metallic bipolar plate

    DOEpatents

    Brady, Michael P.; Schneibel, Joachim H.; Pint, Bruce A.; Maziasz, Philip J.

    2007-05-01

    A corrosion resistant, electrically conductive component such as a bipolar plate for a PEM fuel cell includes 20 55% Cr, balance base metal such as Ni, Fe, or Co, the component having thereon a substantially external, continuous layer of chromium nitride.

  20. Suicidality in Bipolar I Disorder

    ERIC Educational Resources Information Center

    Johnson, Sheri L.; McMurrich, Stephanie L.; Yates, Marisa

    2005-01-01

    People with bipolar disorder are at high suicide risk. The literature suggests that suicidality is predicted by higher symptom severity and less use of pharmacological agents, but few studies have examined the joint contributions of these variables. The present study examines the conjoint contribution of symptom severity and pharmacological…

  1. The management of bipolar disorder.

    PubMed

    Saunders, Kate E A; Geddes, John R

    2016-03-01

    Bipolar disorder is a common mental disorder which is relapsing and remitting in nature. Subsyndromal symptoms are common and associated with poorer outcomes. Management of the disorder can be challenging and depends on the polarity and severity of the mood episode. PMID:26961448

  2. [Cognitive deficits in bipolar disorder].

    PubMed

    Sachs, Gabriele; Schaffer, Markus; Winklbaur, Bernadette

    2007-01-01

    Bipolar disorders are often associated with cognitive deficits which have an influence on social functioning and the course of the illness. These deficits have an impact on occupational ability and social integration. To date, specific cognitive domains have been found which characterize bipolar affective disorders. However, there is evidence of stable and lasting cognitive impairment in all phases of the disorder, including the remission phase, in the following domains: sustained attention, memory and executive functions (e.g. cognitive flexibility and problem solving). Although their cognitive deficits are comparable the deficits in patients with schizophrenia are more severe than those with bipolar disorder. Recent brain imaging findings indicate structural and functional abnormalities in the cortical and limbic networks of the brain in patients with bipolar disorder compared to healthy controls. Mood stabilizer and atypical antipsychotics may reduce cognitive deficits in certain domains (e.g. executive functions and word fluency) and may have a positive effect on quality of life and social functioning. PMID:17640495

  3. The management of bipolar disorder.

    PubMed

    Saunders, Kate E A; Geddes, John R

    2016-03-01

    Bipolar disorder is a common mental disorder which is relapsing and remitting in nature. Subsyndromal symptoms are common and associated with poorer outcomes. Management of the disorder can be challenging and depends on the polarity and severity of the mood episode.

  4. Nicotine dependence and psychosis in Bipolar disorder and Schizoaffective disorder, Bipolar Type

    PubMed Central

    Estrada, Elena; Hartz, Sarah; Tran, Jeffrey; Hilty, Donald; Sklar, Pamela; Smoller, Jordan W.; Pato, Carlos N.; Pato, Michele T.

    2016-01-01

    Objective Patients with Bipolar disorder smoke more than the general population. Smoking negatively impacts mortality and clinical course in Bipolar disorder patients. Prior studies have shown contradictory results regarding the impact of psychosis on smoking behavior in Bipolar disorder. We analyzed a large sample of Bipolar disorder and Schizoaffective disorder, Bipolar Type patients and predicted those with a history of psychosis would be more likely to be nicotine dependent. Methods Data from subjects and controls were collected from the Genomic Psychiatry Cohort (GPC). Subjects were diagnosed with Bipolar disorder without psychosis (N=610), Bipolar disorder with psychosis (N=1591), and Schizoaffective Disorder, Bipolar Type (N=1544). Participants were classified with or without nicotine dependence. Diagnostic groups were compared to controls (N=10065) using logistic regression. Results Among smokers (N=6157), those with Bipolar disorder had an increased risk of nicotine dependence (OR=2.5; p<0.0001). Patients with Bipolar disorder with psychosis were more likely to be dependent than Bipolar disorder patients without psychosis (OR=1.3; p=0.03). Schizoaffective disorder, Bipolar Type patients had more risk of nicotine dependence when compared to Bipolar disorder patients with or without psychosis (OR=1.2; p=0.02). Conclusions Bipolar disorder patients experiencing more severity of psychosis have more risk of nicotine dependence. PMID:26467098

  5. Integrated Neurobiology of Bipolar Disorder

    PubMed Central

    Maletic, Vladimir; Raison, Charles

    2014-01-01

    From a neurobiological perspective there is no such thing as bipolar disorder. Rather, it is almost certainly the case that many somewhat similar, but subtly different, pathological conditions produce a disease state that we currently diagnose as bipolarity. This heterogeneity – reflected in the lack of synergy between our current diagnostic schema and our rapidly advancing scientific understanding of the condition – limits attempts to articulate an integrated perspective on bipolar disorder. However, despite these challenges, scientific findings in recent years are beginning to offer a provisional “unified field theory” of the disease. This theory sees bipolar disorder as a suite of related neurodevelopmental conditions with interconnected functional abnormalities that often appear early in life and worsen over time. In addition to accelerated loss of volume in brain areas known to be essential for mood regulation and cognitive function, consistent findings have emerged at a cellular level, providing evidence that bipolar disorder is reliably associated with dysregulation of glial–neuronal interactions. Among these glial elements are microglia – the brain’s primary immune elements, which appear to be overactive in the context of bipolarity. Multiple studies now indicate that inflammation is also increased in the periphery of the body in both the depressive and manic phases of the illness, with at least some return to normality in the euthymic state. These findings are consistent with changes in the hypothalamic–pituitary–adrenal axis, which are known to drive inflammatory activation. In summary, the very fact that no single gene, pathway, or brain abnormality is likely to ever account for the condition is itself an extremely important first step in better articulating an integrated perspective on both its ontological status and pathogenesis. Whether this perspective will translate into the discovery of innumerable more homogeneous forms of

  6. High transconductance organic electrochemical transistors

    PubMed Central

    Khodagholy, Dion; Rivnay, Jonathan; Sessolo, Michele; Gurfinkel, Moshe; Leleux, Pierre; Jimison, Leslie H.; Stavrinidou, Eleni; Herve, Thierry; Sanaur, Sébastien; Owens, Róisín M.; Malliaras, George G.

    2013-01-01

    The development of transistors with high gain is essential for applications ranging from switching elements and drivers to transducers for chemical and biological sensing. Organic transistors have become well-established based on their distinct advantages, including ease of fabrication, synthetic freedom for chemical functionalization, and the ability to take on unique form factors. These devices, however, are largely viewed as belonging to the low-end of the performance spectrum. Here we present organic electrochemical transistors with a transconductance in the mS range, outperforming transistors from both traditional and emerging semiconductors. The transconductance of these devices remains fairly constant from DC up to a frequency of the order of 1 kHz, a value determined by the process of ion transport between the electrolyte and the channel. These devices, which continue to work even after being crumpled, are predicted to be highly relevant as transducers in biosensing applications. PMID:23851620

  7. Transistorized converter provides nondissipative regulation

    NASA Technical Reports Server (NTRS)

    1964-01-01

    A transistorized regulator converter efficiently converts fluctuating input voltages to a constant output voltage, avoiding the use of saturable reactors. It is nondissipative in operation and functions in an open loop through variable duty cycles.

  8. [Prodromal phase in bipolar disorder].

    PubMed

    Fakra, E; Kaladjian, A; Da Fonseca, D; Maurel, M; Adida, M; Besnier, N; Pringuey, D; Azorin, J-M

    2010-01-01

    The prodromal phase is generally described as a subsyndromal stage preceding the disease onset. The characterization of such phase found its main purpose in secondary prevention. Up to now, clinical research relating to this topic in mental health has primarily focus on schizophrenic disorders. Over the last years, some studies have applied similar methods in order to characterize a preclinical phase in bipolar disorders. In spite of the fact that this strategy appears less adequate in bipolar disorders, these studies have demonstrated the existence of prodromal signs in a majority of patients. However, these features appear for the moment neither sufficiently characteristic, nor sufficiently specific to allow the construction of suitable assessment instruments, or to suggest precise guidelines in the management of these subjects. Also, these prodromal features show considerable overlap with other psychiatric disorders, especially attention-deficit hyperactivity disorder (ADHD) and schizophrenia Interestingly, a limited number of studies have looked at the number of patients considered in a prodromal phase of schizophrenia which later developed a bipolar disorder and reported substantial proportions of subjects in this case, further highlighting the obvious bias in favor of schizophrenia in the actual prevention politics. In order to identify potential candidates at a prodromal phase of bipolar disorders that could benefit from early intervention, studies have relied on both high genetic risk and symptoms at the boundary of the actual classification. However, even within such approach, pharmacological treatments have not proven obvious advantage in terms of prevention. It is suggested that adopting a more longitudinal vision of the disease and, given the mean age of onset of bipolar disorder and a fortiori of its prodromal phase, a more developmental perspective of individuals, could help lowering the confusion in this field ; Also, given the considerable overlap

  9. Single Event Transients Induced by Picosecond Pulsed X-Ray Absorption in III-V Heterojunction Transistors

    SciTech Connect

    Cardoza, David M; LaLumondiere, Stephen D; Tockstein, Michael A; Witczak, Steven C; Sin, Yongkun; Foran, Brendan J; Lotshaw, William T; Moss, Steven C

    2013-01-17

    We perform measurements which show that focused, picosecond pulses of x-rays can be used to generate single event transients (SET) in a GaAs heterostructure field effect transistor (HFET) and a GaN high electron mobility transistor. X-ray pulses with photon energies of 8, 10 and 12 keV from the Advanced Photon Source at Argonne National Laboratory were used to excite transients. SETs are observed when x-ray pulses are incident upon metal layers above sensitive areas on the transistors. We use focused ion beam (FIB) cross-sectioning and scanning transmission electron microscopy energy dispersive x-ray spectroscopy (STEM-EDXS) to determine the compositional structure of the devices. We present a first order analysis of energy deposition in the devices and correlate it to the transient response to make preliminary interpretations of the results. We compare the x-ray transients from the GaAs HFET with transients generated by 750 nm and 870 nm femtosecond laser pulses. We also present results on the total dose susceptibility of the GaN HEMTs.

  10. Solder Bonding for Power Transistors

    NASA Technical Reports Server (NTRS)

    Snytsheuvel, H. A.; Mandel, H.

    1985-01-01

    Indium solder boosts power rating and facilitates circuit changes. Efficient heat conduction from power transistor to heat sink provided by layer of indium solder. Low melting point of indium solder (141 degrees C) allows power transistor to be removed, if circuit must be reworked, without disturbing other components mounted with ordinary solder that melts at 181 degrees C. Solder allows devices operated at higher power levels than does conventional attachment by screws.

  11. MOS-transistor power switches

    NASA Astrophysics Data System (ADS)

    Konev, Iu. I.; Mashukov, E. V.

    The output characteristics of vertical-channel MOS power transistors are analyzed. It is shown that it is possible to remove the basic energy and weight-volume constraints associated with the nonlinearity of the characeristics of devices with carrier injection (i.e., diodes, transistors, and thyristors). This makes it possible to increase the specific power of all types of power switches. The discussion covers switches for ac and dc power circuits, low-voltage rectifiers, and switches with pulse width modulation.

  12. Vertical Silicon Nanowire Field Effect Transistors with Nanoscale Gate-All-Around.

    PubMed

    Guerfi, Youssouf; Larrieu, Guilhem

    2016-12-01

    Nanowires are considered building blocks for the ultimate scaling of MOS transistors, capable of pushing devices until the most extreme boundaries of miniaturization thanks to their physical and geometrical properties. In particular, nanowires' suitability for forming a gate-all-around (GAA) configuration confers to the device an optimum electrostatic control of the gate over the conduction channel and then a better immunity against the short channel effects (SCE). In this letter, a large-scale process of GAA vertical silicon nanowire (VNW) MOSFETs is presented. A top-down approach is adopted for the realization of VNWs with an optimum reproducibility followed by thin layer engineering at nanoscale. Good overall electrical performances were obtained, with excellent electrostatic behavior (a subthreshold slope (SS) of 95 mV/dec and a drain induced barrier lowering (DIBL) of 25 mV/V) for a 15-nm gate length. Finally, a first demonstration of dual integration of n-type and p-type VNW transistors for the realization of CMOS inverter is proposed. PMID:27094824

  13. John Bardeen and transistor physics

    NASA Astrophysics Data System (ADS)

    Huff, Howard R.

    2001-01-01

    John Bardeen and Walter Brattain invented the point-contact semiconductor amplifier (transistor action) in polycrystalline germanium (also observed in polycrystalline silicon) on Dec. 15, 1947, for which they received a patent on Oct. 3, 1950. Bill Shockley was not a co-patent holder on Bardeen and Brattain's point-contact semiconductor amplifier patent since Julius Lilienfeld had already received a patent in 1930 for what would have been Shockley's contribution; namely, the field-effect methodology. Shockley received patents for both his minority-carrier injection concept and junction transistor theory, however, and deservedly shared the Nobel prize with Bardeen and Brattain for his seminal contributions of injection, p-n junction theory and junction transistor theory. We will review the events leading up to the invention of Bardeen and Brattain's point-contact semiconductor amplifier during the magic month of November 17-December 16, 1947 and the invention of Shockley's junction semiconductor amplifier during his magic month of December 24, 1947-January 23, 1948. It was during the course of Bardeen and Brattain's research in November, 1947 that Bardeen also patented the essence of the MOS transistor, wherein the induced minority carriers were confined to the inversion layer enroute to the collector. C. T. Sah has described this device as a sourceless MOS transistor. Indeed, John Bardeen, co-inventor of the point-contact semiconductor amplifier and inventor of the MOS transistor, may rightly be called the father of modern electronics.

  14. Electrical detection of the biological interaction of a charged peptide via gallium arsenide junction-field-effect transistors.

    PubMed

    Lee, Kangho; Nair, Pradeep R; Alam, Muhammad A; Janes, David B; Wampler, Heeyeon P; Zemlyanov, Dmitry Y; Ivanisevic, Albena

    2008-06-01

    GaAs junction-field-effect transistors (JFETs) are utilized to achieve label-free detection of biological interaction between a probe transactivating transcriptional activator (TAT) peptide and the target trans-activation-responsive (TAR) RNA. The TAT peptide is a short sequence derived from the human immunodeficiency virus-type 1 TAT protein. The GaAs JFETs are modified with a mixed adlayer of 1-octadecanethiol (ODT) and TAT peptide, with the ODT passivating the GaAs surface from polar ions in physiological solutions and the TAT peptide providing selective binding sites for TAR RNA. The devices modified with the mixed adlayer exhibit a negative pinch-off voltage (V(P)) shift, which is attributed to the fixed positive charges from the arginine-rich regions in the TAT peptide. Immersing the modified devices into a TAR RNA solution results in a large positive V(P) shift (>1 V) and a steeper subthreshold slope ( approximately 80 mVdecade), whereas "dummy" RNA induced a small positive V(P) shift ( approximately 0.3 V) without a significant change in subthreshold slopes ( approximately 330 mVdecade). The observed modulation of device characteristics is analyzed with analytical modeling and two-dimensional numerical device simulations to investigate the electronic interactions between the GaAs JFETs and biological molecules.

  15. Electrical detection of the biological interaction of a charged peptide via gallium arsenide junction-field-effect transistors

    PubMed Central

    Lee, Kangho; Nair, Pradeep R.; Alam, Muhammad A.; Janes, David B.; Wampler, Heeyeon P.; Zemlyanov, Dmitry Y.; Ivanisevic, Albena

    2008-01-01

    GaAs junction-field-effect transistors (JFETs) are utilized to achieve label-free detection of biological interaction between a probe transactivating transcriptional activator (TAT) peptide and the target trans-activation-responsive (TAR) RNA. The TAT peptide is a short sequence derived from the human immunodeficiency virus-type 1 TAT protein. The GaAs JFETs are modified with a mixed adlayer of 1-octadecanethiol (ODT) and TAT peptide, with the ODT passivating the GaAs surface from polar ions in physiological solutions and the TAT peptide providing selective binding sites for TAR RNA. The devices modified with the mixed adlayer exhibit a negative pinch-off voltage (VP) shift, which is attributed to the fixed positive charges from the arginine-rich regions in the TAT peptide. Immersing the modified devices into a TAR RNA solution results in a large positive VP shift (>1 V) and a steeper subthreshold slope (∼80 mV∕decade), whereas “dummy” RNA induced a small positive VP shift (∼0.3 V) without a significant change in subthreshold slopes (∼330 mV∕decade). The observed modulation of device characteristics is analyzed with analytical modeling and two-dimensional numerical device simulations to investigate the electronic interactions between the GaAs JFETs and biological molecules. PMID:19484151

  16. Electrical detection of the biological interaction of a charged peptide via gallium arsenide junction-field-effect transistors

    NASA Astrophysics Data System (ADS)

    Lee, Kangho; Nair, Pradeep R.; Alam, Muhammad A.; Janes, David B.; Wampler, Heeyeon P.; Zemlyanov, Dmitry Y.; Ivanisevic, Albena

    2008-06-01

    GaAs junction-field-effect transistors (JFETs) are utilized to achieve label-free detection of biological interaction between a probe transactivating transcriptional activator (TAT) peptide and the target trans-activation-responsive (TAR) RNA. The TAT peptide is a short sequence derived from the human immunodeficiency virus-type 1 TAT protein. The GaAs JFETs are modified with a mixed adlayer of 1-octadecanethiol (ODT) and TAT peptide, with the ODT passivating the GaAs surface from polar ions in physiological solutions and the TAT peptide providing selective binding sites for TAR RNA. The devices modified with the mixed adlayer exhibit a negative pinch-off voltage (VP) shift, which is attributed to the fixed positive charges from the arginine-rich regions in the TAT peptide. Immersing the modified devices into a TAR RNA solution results in a large positive VP shift (>1 V) and a steeper subthreshold slope (˜80 mV/decade), whereas "dummy" RNA induced a small positive VP shift (˜0.3 V) without a significant change in subthreshold slopes (˜330 mV/decade). The observed modulation of device characteristics is analyzed with analytical modeling and two-dimensional numerical device simulations to investigate the electronic interactions between the GaAs JFETs and biological molecules.

  17. Evolvable circuit with transistor-level reconfigurability

    NASA Technical Reports Server (NTRS)

    Stoica, Adrian (Inventor); Salazar-Lazaro, Carlos Harold (Inventor)

    2004-01-01

    An evolvable circuit includes a plurality of reconfigurable switches, a plurality of transistors within a region of the circuit, the plurality of transistors having terminals, the plurality of transistors being coupled between a power source terminal and a power sink terminal so as to be capable of admitting power between the power source terminal and the power sink terminal, the plurality of transistors being coupled so that every transistor terminal to transistor terminal coupling within the region of the circuit comprises a reconfigurable switch.

  18. Electronic Model of a Ferroelectric Field Effect Transistor

    NASA Technical Reports Server (NTRS)

    MacLeod, Todd C.; Ho, Fat Duen; Russell, Larry (Technical Monitor)

    2001-01-01

    A pair of electronic models has been developed of a Ferroelectric Field Effect transistor. These models can be used in standard electrical circuit simulation programs to simulate the main characteristics of the FFET. The models use the Schmitt trigger circuit as a basis for their design. One model uses bipolar junction transistors and one uses MOSFET's. Each model has the main characteristics of the FFET, which are the current hysterisis with different gate voltages and decay of the drain current when the gate voltage is off. The drain current from each model has similar values to an actual FFET that was measured experimentally. T'he input and o Output resistance in the models are also similar to that of the FFET. The models are valid for all frequencies below RF levels. No attempt was made to model the high frequency characteristics of the FFET. Each model can be used to design circuits using FFET's with standard electrical simulation packages. These circuits can be used in designing non-volatile memory circuits and logic circuits and is compatible with all SPICE based circuit analysis programs. The models consist of only standard electrical components, such as BJT's, MOSFET's, diodes, resistors, and capacitors. Each model is compared to the experimental data measured from an actual FFET.

  19. Degradation mechanisms of current gain in NPN transistors

    NASA Astrophysics Data System (ADS)

    Li, Xing-Ji; Geng, Hong-Bin; Lan, Mu-Jie; Yang, De-Zhuang; He, Shi-Yu; Liu, Chao-Ming

    2010-06-01

    An investigation of ionization and displacement damage in silicon NPN bipolar junction transistors (BJTs) is presented. The transistors were irradiated separately with 90-keV electrons, 3-MeV protons and 40-MeV Br ions. Key parameters were measured in-situ and the change in current gain of the NPN BJTS was obtained at a fixed collector current (Ic = 1 mA). To characterise the radiation damage of NPN BJTs, the ionizing dose Di and displacement dose Dd as functions of chip depth in the NPN BJTs were calculated using the SRIM and Geant4 code for protons, electrons and Br ions, respectively. Based on the discussion of the radiation damage equation for current gain, it is clear that the current gain degradation of the NPN BJTs is sensitive to both ionization and displacement damage. The degradation mechanism of the current gain is related to the ratio of Dd/(Dd + Di) in the sensitive region given by charged particles. The irradiation particles leading to lower Dd/(Dd + Di) within the same chip depth at a given total dose would mainly produce ionization damage to the NPN BJTs. On the other hand, the charged particles causing larger Dd/(Dd + Di) at a given total dose would tend to generate displacement damage to the NPN BJTs. The Messenger-Spratt equation could be used to describe the experimental data for the latter case.

  20. Panel fabrication utilizing GaAs solar cells

    NASA Technical Reports Server (NTRS)

    Mardesich, N.

    1984-01-01

    The development of the GaAs solar cells for space applications is described. The activities in the fabrication of GaAs solar panels are outlined. Panels were fabricated while introducing improved quality control, soldering laydown and testing procedures. These panels include LIPS II, San Marco Satellite, and a low concentration panel for Rockwells' evaluation. The panels and their present status are discussed.

  1. A novel Tunneling Graphene Nano Ribbon Field Effect Transistor with dual material gate: Numerical studies

    NASA Astrophysics Data System (ADS)

    Ghoreishi, Seyed Saleh; Saghafi, Kamyar; Yousefi, Reza; Moravvej-farshi, Mohammad Kazem

    2016-09-01

    In this work, we present Dual Material Gate Tunneling Graphene Nano-Ribbon Field Effect Transistors (DMG-T-GNRFET) mainly to suppress the am-bipolar current with assumption that sub-threshold swing which is one of the important characteristics of tunneling transistors must not be degraded. In the proposed structure, dual material gates with different work functions are used. Our investigations are based on numerical simulations which self-consistently solves the 2D Poisson based on an atomistic mode-space approach and Schrodinger equations, within the Non-Equilibrium Green's (NEGF). The proposed device shows lower off-current and on-off ratio becomes 5order of magnitude greater than the conventional device. Also two different short channel effects: Drain Induced Barrier Shortening (DIBS) and hot-electron effect are improved in the proposed device compare to the main structure.

  2. Unsplit bipolar pulse forming line

    DOEpatents

    Rhodes, Mark A.

    2011-05-24

    A bipolar pulse forming transmission line module and system for linear induction accelerators having first, second, third, and fourth planar conductors which form a sequentially arranged interleaved stack having opposing first and second ends, with dielectric layers between the conductors. The first and second planar conductors are connected to each other at the first end, and the first and fourth planar conductors are connected to each other at the second end via a shorting plate. The third planar conductor is electrically connectable to a high voltage source, and an internal switch functions to short at the first end a high voltage from the third planar conductor to the fourth planar conductor to produce a bipolar pulse at the acceleration axis with a zero net time integral. Improved access to the switch is enabled by an aperture through the shorting plate and the proximity of the aperture to the switch.

  3. [Poststroke-bipolar affective disorder].

    PubMed

    Bengesser, S A; Wurm, W E; Lackner, N; Birner, A; Reininghaus, B; Kapfhammer, H-P; Reininghaus, E

    2013-08-01

    A few weeks after suffering from a basal ganglia infarction (globus pallidus) with left-sided hemiplegia, a 23-year-old woman exhibited for the first time a pronounced mania with self-endangerment. The use of oral contraceptives was the only determinable risk factor. During the further course, the mother also developed a depressive disorder. Thus a certain genetic predisposition for affective disorders may be relevant, although this would not explain the outbreak by itself. An association between the right-sided basal ganglia infarction and the occurrence of a bipolar affective disorder has been described in the literature. Vascular or, respectively, inflammatory risk factors in synopsis with the aetiopathogenesis of bipolar affective disorders are also discussed in depth in this case report. PMID:23939559

  4. Peeled film GaAs solar cell development

    NASA Technical Reports Server (NTRS)

    Wilt, D. M.; Thomas, R. D.; Bailey, S. G.; Brinker, D. J.; Deangelo, F. L.

    1990-01-01

    Thin-film, single-crystal gallium arsenide (GaAs) solar cells could exhibit a specific power approaching 700 W/kg including coverglass. A simple process has been described whereby epitaxial GaAs layers are peeled from a reusable substrate. This process takes advantage of the extreme selectivity of the etching rate of aluminum arsenide (AlAs) over GaAs in dilute hydrofluoric acid. The feasibility of using the peeled film technique to fabricate high-efficiency, low-mass GaAs solar cells is presently demonstrated. A peeled film GaAs solar cell was successfully produced. The device, although fractured and missing the aluminum gallium arsenide window and antireflective coating, had a Voc of 874 mV and a fill factor of 68 percent under AM0 illumination.

  5. Passivated ambipolar black phosphorus transistors

    NASA Astrophysics Data System (ADS)

    Yue, Dewu; Lee, Daeyeong; Jang, Young Dae; Choi, Min Sup; Nam, Hye Jin; Jung, Duk-Young; Yoo, Won Jong

    2016-06-01

    We report the first air-passivated ambipolar BP transistor formed by applying benzyl viologen, which serves as a surface charge transfer donor for BP flakes. The passivated BP devices exhibit excellent stability under both an ambient atmosphere and vacuum; their transistor performance is maintained semi-permanently. Unlike their intrinsic p-type properties, passivated BP devices present advantageous ambipolar properties with much higher electron mobility up to ~83 cm2 V-1 s-1 from 2-terminal measurement at 300 K, compared to other reported studies on n-type BP transistors. On the basis of the n-type doping effect that originated from benzyl viologen, we also systematically investigated the BP thickness dependence of our devices on electrical properties, in which we found the best electron transport performance to be attained when an ~10 nm thick BP flake was used.We report the first air-passivated ambipolar BP transistor formed by applying benzyl viologen, which serves as a surface charge transfer donor for BP flakes. The passivated BP devices exhibit excellent stability under both an ambient atmosphere and vacuum; their transistor performance is maintained semi-permanently. Unlike their intrinsic p-type properties, passivated BP devices present advantageous ambipolar properties with much higher electron mobility up to ~83 cm2 V-1 s-1 from 2-terminal measurement at 300 K, compared to other reported studies on n-type BP transistors. On the basis of the n-type doping effect that originated from benzyl viologen, we also systematically investigated the BP thickness dependence of our devices on electrical properties, in which we found the best electron transport performance to be attained when an ~10 nm thick BP flake was used. Electronic supplementary information (ESI) available: Transfer characteristics of BP field effect transistors (BV1-BV4) (Fig. S1 and S2 and Table S1); output characteristics of BP field effect transistors in different directions (Fig. S3

  6. Bipolar hemiarthroplasty in femoral neck fractures.

    PubMed

    Malhotra, R; Arya, R; Bhan, S

    1995-01-01

    Thirty-two elderly patients with a femoral neck fracture treated by bipolar hemiarthroplasty and 36 patients (matched for age) with an Austin-Moore hemiarthroplasty were followed-up and compared. Bipolar replacement resulted in a higher percentage of satisfactory results, less postoperative pain, greater range of movement, more rapid return to unassisted activity, fewer unsatisfactory results and no acetabular erosion. The device functioned as bipolar in all the cases studied for inner-bearing motion.

  7. Major Ups and Downs: Bipolar Disorder Brings Extreme Mood Swings

    MedlinePlus

    ... our exit disclaimer . Subscribe Major Ups and Downs Bipolar Disorder Brings Extreme Mood Swings Most people feel happy ... Strike Out Stroke Wise Choices Links Dealing with Bipolar Disorder If you have bipolar disorder, get treatment and ...

  8. Physical mechanisms contributing to enhanced bipolar gain degradation at low dose rates

    SciTech Connect

    Fleetwood, D.M.; Reber, R.A. Jr.; Winokur, P.S. ); Kosier, S.L.; Schrimpf, R.D.; Wei, A. . ECE Dept.); Nowlin, R.N. ); DeLaus, M. ); Combs, W.E. ); Pease, R.L. )

    1994-12-01

    The authors have performed capacitance-voltage (C-V) and thermally-stimulated-current (TSC) measurements on non-radiation-hard MOS capacitors simulating screen oxides of modern bipolar technologies. For 0-V irradiation of [approximately]25 C, the net trapped-positive-charge density (N[sub ox]) inferred from midgap C-V shifts is [approximately]25--40% greater for low-dose-rate (< 10 rad(SiO[sub 2])/s) than for high-dose-rate (> 100 rad(SiO[sub 2])/s) exposure. Device modeling shows that such a difference in screen-oxide N[sub ox] is enough to account for the enhanced low-rate gain degradation often observed in bipolar devices, due to the [approximately] exp(N[sub ox][sup 2]) dependence of the excess base current. At the higher rates, TSC measurements reveal a [approximately]10% decrease in trapped-hole density over low rates. Also, at high rates, up to [approximately]2.5-times as many trapped holes are compensated by electrons in border traps than at low rates for these devices and irradiation conditions. Both the reduction in trapped-hole density and increased charge compensation reduce the high-rate midgap shift. A physical model is developed which suggests that both effects are caused by time-dependent space charge in the bulk of these soft oxides associated with slowly transporting and/or metastably trapped holes (e.g., in E[delta][prime] centers). On the basis of this model, bipolar transistors and screen-oxide capacitors were irradiated at 60 C at 200 rad(SiO[sub 2])/s in a successful effort to match low-rate damage. these surprising results provide insight into enhanced low-rate bipolar gain degradation and suggest potentially promising new approaches to bipolar and BiCMOS hardness assurance for space applications.

  9. Course of Subthreshold Bipolar Disorder in Youth: Diagnostic Progression from Bipolar Disorder Not Otherwise Specified

    ERIC Educational Resources Information Center

    Axelson, David A.; Birmaher, Boris; Strober, Michael A.; Goldstein, Benjamin I.; Ha, Wonho; Gill, Mary Kay; Goldstein, Tina R.; Yen, Shirley; Hower, Heather; Hunt, Jeffrey I.; Liao, Fangzi; Iyengar, Satish; Dickstein, Daniel; Kim, Eunice; Ryan, Neal D.; Frankel, Erica; Keller, Martin B.

    2011-01-01

    Objective: To determine the rate of diagnostic conversion from an operationalized diagnosis of bipolar disorder not otherwise specified (BP-NOS) to bipolar I disorder (BP-I) or bipolar II disorder (BP-II) in youth over prospective follow-up and to identify factors associated with conversion. Method: Subjects were 140 children and adolescents…

  10. [Oxidative stress in bipolar affective disorder].

    PubMed

    Reininghaus, E Z; Zelzer, S; Reininghaus, B; Lackner, N; Birner, A; Bengesser, S A; Fellendorf, F T; Kapfhammer, H-P; Mangge, H

    2014-09-01

    The results of mortality studies have indicated that medical conditions, such as cardiovascular disease, obesity and diabetes are the most important causes of mortality among patients with bipolar disorder. The reasons for the increased incidence and mortality are not fully understood. Oxidative stress and an inadequate antioxidative system might be one missing link and could also help to further elucidate the pathophysiological basis of bipolar disorder. This article provides a comprehensive review of oxidative stress in general and about the existing data for bipolar disorder. In addition information is given about possible therapeutic strategies to reduce oxidative stress and the use in bipolar disorder. PMID:24441847

  11. Treatment of Bipolar Depression: Evolving Recommendations.

    PubMed

    Post, Robert M

    2016-03-01

    Bipolar depression is the most common and difficult-to-treat phase of bipolar disorder. Antidepressants for unipolar depression are among the most widely used drugs, but recent data and meta-analyses indicate a lack of efficacy. Many of the drugs discussed here are graded provisionally for the strength of the findings in the literature, safety and tolerability, and likely utility of use in patients with bipolar disorder. Successful long-term treatment of bipolar depression is critical to preventing illness-related morbidity, disability, cognitive decline, suicide, and premature loss of years of life expectancy largely from the excess medical mortality associated with cardiovascular disorders.

  12. Au impact on GaAs epitaxial growth on GaAs (111){sub B} substrates in molecular beam epitaxy

    SciTech Connect

    Liao, Zhi-Ming; Chen, Zhi-Gang; Xu, Hong-Yi; Guo, Ya-Nan; Sun, Wen; Zhang, Zhi; Yang, Lei; Lu, Zhen-Yu; Chen, Ping-Ping; Lu, Wei; Zou, Jin

    2013-02-11

    GaAs growth behaviour under the presence of Au nanoparticles on GaAs {l_brace}111{r_brace}{sub B} substrate is investigated using electron microscopy. It has been found that, during annealing, enhanced Ga surface diffusion towards Au nanoparticles leads to the GaAs epitaxial growth into {l_brace}113{r_brace}{sub B} faceted triangular pyramids under Au nanoparticles, governed by the thermodynamic growth, while during conventional GaAs growth, growth kinetics dominates, resulting in the flatted triangular pyramids at high temperature and the epitaxial nanowires growth at relatively low temperature. This study provides an insight of Au nanoparticle impact on GaAs growth, which is critical for understanding the formation mechanisms of semiconductor nanowires.

  13. Passivated ambipolar black phosphorus transistors.

    PubMed

    Yue, Dewu; Lee, Daeyeong; Jang, Young Dae; Choi, Min Sup; Nam, Hye Jin; Jung, Duk-Young; Yoo, Won Jong

    2016-07-01

    We report the first air-passivated ambipolar BP transistor formed by applying benzyl viologen, which serves as a surface charge transfer donor for BP flakes. The passivated BP devices exhibit excellent stability under both an ambient atmosphere and vacuum; their transistor performance is maintained semi-permanently. Unlike their intrinsic p-type properties, passivated BP devices present advantageous ambipolar properties with much higher electron mobility up to ∼83 cm(2) V(-1) s(-1) from 2-terminal measurement at 300 K, compared to other reported studies on n-type BP transistors. On the basis of the n-type doping effect that originated from benzyl viologen, we also systematically investigated the BP thickness dependence of our devices on electrical properties, in which we found the best electron transport performance to be attained when an ∼10 nm thick BP flake was used. PMID:27283027

  14. High current gain transistor laser.

    PubMed

    Liang, Song; Qiao, Lijun; Zhu, Hongliang; Wang, Wei

    2016-06-10

    A transistor laser (TL), having the structure of a transistor with multi-quantum wells near its base region, bridges the functionality gap between lasers and transistors. However, light emission is produced at the expense of current gain for all the TLs reported up to now, leading to a very low current gain. We propose a novel design of TLs, which have an n-doped InP layer inserted in the emitter ridge. Numerical studies show that a current flow aperture for only holes can be formed in the center of the emitter ridge. As a result, the common emitter current gain can be as large as 143.3, which is over 15 times larger than that of a TL without the aperture. Besides, the effects of nonradiative recombination defects can be reduced greatly because the flow of holes is confined in the center region of the emitter ridge.

  15. High current gain transistor laser

    NASA Astrophysics Data System (ADS)

    Liang, Song; Qiao, Lijun; Zhu, Hongliang; Wang, Wei

    2016-06-01

    A transistor laser (TL), having the structure of a transistor with multi-quantum wells near its base region, bridges the functionality gap between lasers and transistors. However, light emission is produced at the expense of current gain for all the TLs reported up to now, leading to a very low current gain. We propose a novel design of TLs, which have an n-doped InP layer inserted in the emitter ridge. Numerical studies show that a current flow aperture for only holes can be formed in the center of the emitter ridge. As a result, the common emitter current gain can be as large as 143.3, which is over 15 times larger than that of a TL without the aperture. Besides, the effects of nonradiative recombination defects can be reduced greatly because the flow of holes is confined in the center region of the emitter ridge.

  16. High current gain transistor laser

    PubMed Central

    Liang, Song; Qiao, Lijun; Zhu, Hongliang; Wang, Wei

    2016-01-01

    A transistor laser (TL), having the structure of a transistor with multi-quantum wells near its base region, bridges the functionality gap between lasers and transistors. However, light emission is produced at the expense of current gain for all the TLs reported up to now, leading to a very low current gain. We propose a novel design of TLs, which have an n-doped InP layer inserted in the emitter ridge. Numerical studies show that a current flow aperture for only holes can be formed in the center of the emitter ridge. As a result, the common emitter current gain can be as large as 143.3, which is over 15 times larger than that of a TL without the aperture. Besides, the effects of nonradiative recombination defects can be reduced greatly because the flow of holes is confined in the center region of the emitter ridge. PMID:27282466

  17. GaAs VLSI for aerospace electronics

    NASA Technical Reports Server (NTRS)

    Larue, G.; Chan, P.

    1990-01-01

    Advanced aerospace electronics systems require high-speed, low-power, radiation-hard, digital components for signal processing, control, and communication applications. GaAs VLSI devices provide a number of advantages over silicon devices including higher carrier velocities, ability to integrate with high performance optical devices, and high-resistivity substrates that provide very short gate delays, good isolation, and tolerance to many forms of radiation. However, III-V technologies also have disadvantages, such as lower yield compared to silicon MOS technology. Achieving very large scale integration (VLSI) is particularly important for fast complex systems. At very short gate delays (less than 100 ps), chip-to-chip interconnects severely degrade circuit clock rates. Complex systems, therefore, benefit greatly when as many gates as possible are placed on a single chip. To fully exploit the advantages of GaAs circuits, attention must be focused on achieving high integration levels by reducing power dissipation, reducing the number of devices per logic function, and providing circuit designs that are more tolerant to process and environmental variations. In addition, adequate noise margin must be maintained to ensure a practical yield.

  18. Implantation of carbon in GaAs

    SciTech Connect

    Moll, A.J.

    1992-03-01

    Carbon implanted into GaAs and thermally annealed typically exhibits very low (<3%) electrical activity. It has been demonstrated that the electrical activity of C can be significantly enhanced by co-implantation with Ga. Improved activation may result from either additional damage of the crystal lattice or from stoichiometric changes, forcing the C atoms onto As sites. To determine the relative importance of each of these effects, I have undertaken a systematic study of carbon activation in GaAs. A range of co-implants have been used: group III (B, Ga), group V (N, P, As) and noble gases (Ar, Kr). The damage introduced to the substrate will depend on the mass of the ion implanted. The group III and group V co-implants will affect the crystal stoichiometry. The results indicate that both lattice damage and crystal stoichiometry are important for high electrical activity of C. Increasing the damage will increase the activation due to the increased number of As vacancies but maximum activation can be obtained only by a co-implant which not only damages the lattice but also forces the C to occupy an As site.

  19. Phonon thermoelectric transistors and rectifiers

    NASA Astrophysics Data System (ADS)

    Jiang, Jian-Hua; Kulkarni, Manas; Segal, Dvira; Imry, Yoseph

    2015-07-01

    We describe nonlinear phonon-thermoelectric devices where charge current and electronic and phononic heat currents are coupled, driven by voltage and temperature biases, when phonon-assisted inelastic processes dominate the transport. Our thermoelectric transistors and rectifiers can be realized in a gate-tunable double quantum-dot system embedded in a nanowire which is realizable within current technology. The inelastic electron-phonon scattering processes are found to induce pronounced charge, heat, and cross rectification effects, as well as a thermal transistor effect that, remarkably, can appear in the present model even in the linear-response regime without relying on the onset of negative differential thermal conductance.

  20. Programmable, automated transistor test system

    NASA Technical Reports Server (NTRS)

    Truong, L. V.; Sundburg, G. R.

    1986-01-01

    A programmable, automated transistor test system was built to supply experimental data on new and advanced power semiconductors. The data will be used for analytical models and by engineers in designing space and aircraft electric power systems. A pulsed power technique was used at low duty cycles in a nondestructive test to examine the dynamic switching characteristic curves of power transistors in the 500 to 1000 V, 10 to 100 A range. Data collection, manipulation, storage, and output are operator interactive but are guided and controlled by the system software.

  1. Redistribution of constituent elements in Pd/Ge contacts to n-type GaAs using rapid thermal annealing

    NASA Astrophysics Data System (ADS)

    Lai, Jiun Tsuen; Lee, Joseph Ya-Min

    1994-08-01

    Pd/Ge contact to n-type GaAs is performed by using electron-beam evaporation and rapid thermal annealing. The rapid thermal annealing is performed at 400-500 C for various time durations. Low specific contact resistivity on the order of 10(exp -6) Ohm, sq cm is obtained from measurements based on the transmission line model method. The contact depth profiles are analyzed by secondary ion mass spectrometry (SIMS). A very shallow ohmic contact is achieved. The redistribution of constituent elements after heat treatment is examined. A gallium SIMS signal bump is detected in the contact layer and is correlated with good ohmic contact behavoir. A model based on Ga vacanies is utilized to fabricate GaAs/AlGaAs and GaAs/InGaAs/AlGaAs negative resistance field-effect transistors, for which shallow ohmic contact is critical.

  2. The development of integrated chemical microsensors in GaAs

    SciTech Connect

    CASALNUOVO,STEPHEN A.; ASON,GREGORY CHARLES; HELLER,EDWIN J.; HIETALA,VINCENT M.; BACA,ALBERT G.; HIETALA,S.L.

    1999-11-01

    Monolithic, integrated acoustic wave chemical microsensors are being developed on gallium arsenide (GaAs) substrates. With this approach, arrays of microsensors and the high frequency electronic components needed to operate them reside on a single substrate, increasing the range of detectable analytes, reducing overall system size, minimizing systematic errors, and simplifying assembly and packaging. GaAs is employed because it is both piezoelectric, a property required to produce the acoustic wave devices, and a semiconductor with a mature microelectronics fabrication technology. Many aspects of integrated GaAs chemical sensors have been investigated, including: surface acoustic wave (SAW) sensors; monolithic SAW delay line oscillators; GaAs application specific integrated circuits (ASIC) for sensor operation; a hybrid sensor array utilizing these ASICS; and the fully monolithic, integrated SAW array. Details of the design, fabrication, and performance of these devices are discussed. In addition, the ability to produce heteroepitaxial layers of GaAs and aluminum gallium arsenide (AlGaAs) makes possible micromachined membrane sensors with improved sensitivity compared to conventional SAW sensors. Micromachining techniques for fabricating flexural plate wave (FPW) and thickness shear mode (TSM) microsensors on thin GaAs membranes are presented and GaAs FPW delay line and TSM resonator performance is described.

  3. Silicon on insulator self-aligned transistors

    DOEpatents

    McCarthy, Anthony M.

    2003-11-18

    A method for fabricating thin-film single-crystal silicon-on-insulator (SOI) self-aligned transistors. Standard processing of silicon substrates is used to fabricate the transistors. Physical spaces, between the source and gate, and the drain and gate, introduced by etching the polysilicon gate material, are used to provide connecting implants (bridges) which allow the transistor to perform normally. After completion of the silicon substrate processing, the silicon wafer is bonded to an insulator (glass) substrate, and the silicon substrate is removed leaving the transistors on the insulator (glass) substrate. Transistors fabricated by this method may be utilized, for example, in flat panel displays, etc.

  4. Field dependent emission rates in radiation damaged GaAs

    SciTech Connect

    Fleming, R. M.; Myers, S. M.; Wampler, W. R.; Lang, D. V.; Seager, C. H.; Campbell, J. M.

    2014-07-07

    We have measured the temperature and field dependence of emission rates from five traps in electron damaged GaAs. Four of the traps have previously been identified as radiation defects. One of the traps, seen in higher doped diodes, has not been previously identified. We have fit the data to a multiphonon emission theory that allows recombination in GaAs to be characterized over a broad range of temperature and electric field. These results demonstrate an efficient method to calculate field-dependent emission rates in GaAs.

  5. Photocurrent Spectroscopy of Single Wurtzite GaAs Nanowires

    SciTech Connect

    Kim, D. C.; Ahtapodov, L.; Boe, A. B.; Moses, A. F.; Dheeraj, D. L.; Fimland, B. O.; Weman, H.; Choi, J. W.; Ji, H.; Kim, G. T.

    2011-12-23

    Photocurrent of single wurtzite GaAs nanowires grown by Au-assisted molecular beam epitaxy is measured at room and low temperature (10 K). At room temperature a high photo-response with more than two orders of magnitude increase of current is observed. The wavelength dependence of the photocurrent shows a sharp change near the zinc blende GaAs band gap. The absence of the free exciton peak in the low temperature photocurrent spectrum, and problems related to determining the exact position of the energy bandgap of wurtzite GaAs from the observed data are discussed.

  6. Analysing organic transistors based on interface approximation

    SciTech Connect

    Akiyama, Yuto; Mori, Takehiko

    2014-01-15

    Temperature-dependent characteristics of organic transistors are analysed thoroughly using interface approximation. In contrast to amorphous silicon transistors, it is characteristic of organic transistors that the accumulation layer is concentrated on the first monolayer, and it is appropriate to consider interface charge rather than band bending. On the basis of this model, observed characteristics of hexamethylenetetrathiafulvalene (HMTTF) and dibenzotetrathiafulvalene (DBTTF) transistors with various surface treatments are analysed, and the trap distribution is extracted. In turn, starting from a simple exponential distribution, we can reproduce the temperature-dependent transistor characteristics as well as the gate voltage dependence of the activation energy, so we can investigate various aspects of organic transistors self-consistently under the interface approximation. Small deviation from such an ideal transistor operation is discussed assuming the presence of an energetically discrete trap level, which leads to a hump in the transfer characteristics. The contact resistance is estimated by measuring the transfer characteristics up to the linear region.

  7. Developmental staging models in bipolar disorder.

    PubMed

    Passos, Ives C; Jansen, Karen; Kapczinski, Flavio

    2015-12-01

    The previous contribution of Duffy and colleagues suggests that a chain of behavioral events starting during childhood precedes the development of full-blown bipolar disorder. In this vein, the recent contribution of Keown-Stoneman and colleagues brings a new perspective to the study of prodromal symptoms of bipolar disorder.

  8. Screening for bipolar disorder during pregnancy.

    PubMed

    Merrill, Lindsay; Mittal, Leena; Nicoloro, Jennifer; Caiozzo, Christina; Maciejewski, Paul K; Miller, Laura J

    2015-08-01

    Bipolar disorder is a high-risk condition during pregnancy. In women receiving prenatal care, this study addresses the proportion screening positive for bipolar disorder with or without also screening positive for depression. This is a pilot study using chart abstraction of Edinburgh Postnatal Depression Scale (EPDS) and Mood Disorder Questionnaire (MDQ) scores from patients' initial prenatal visits. Among 342 participants, 289 (87.1 %) completed the EPDS, 277 (81.0 %) completed the MDQ, and 274 (80.1 %) completed both. Among EPDS screens, 49 (16.4 %) were positive. Among MDQ screens, 14 (5.1 %) were positive. Nine (21.4 %) of the 42 participants with a positive EPDS also had a positive MDQ. Of the 14 patients with a positive MDQ, five (35.7 %) had a negative EPDS. The prevalence of positive screens for bipolar disorder in an obstetric population is similar to gestational diabetes and hypertension, which are screened for routinely. Without screening for bipolar disorder, there is a high risk of misclassifying bipolar depression as unipolar depression. If only women with current depressive symptoms are screened for bipolar disorder, approximately one third of bipolar disorder cases would be missed. If replicated, these findings support simultaneous screening for both depression and bipolar disorder during pregnancy.

  9. Bipolar Disorder and Cognitive Therapy: A Commentary

    ERIC Educational Resources Information Center

    Riskind, John H.

    2005-01-01

    This article comments on the three articles (Leahy, 2005; Newman, 2005; and Reilly-Harrington & Knauz, 2005) that deal with the applications of cognitive therapy to treatment of bipolar disorder. They focus on the uses of cognitive therapy in treating three important facets of the special problems of bipolar patients: rapid cycling, severe…

  10. Swimming in Deep Water: Childhood Bipolar Disorder

    ERIC Educational Resources Information Center

    Senokossoff, Gwyn W.; Stoddard, Kim

    2009-01-01

    The authors focused on one parent's struggles in finding a diagnosis and intervention for a child who had bipolar disorder. The authors explain the process of identification, diagnosis, and intervention of a child who had bipolar disorder. In addition to the personal story, the authors provide information on the disorder and outline strategies…

  11. Bipolar Disorder in School-Age Children

    ERIC Educational Resources Information Center

    Olson, Patricia M.; Pacheco, Mary Rae

    2005-01-01

    This article examines the individual components of bipolar disorder in children and the behaviors that can escalate as a result of misdiagnosis and treatment. The brain/behavior relationship in bipolar disorders can be affected by genetics, developmental failure, or environmental influences, which can cause an onset of dramatic mood swings and…

  12. Temperature-Programmed Scattering (TPS) Study on Reactivity Difference of GaAs and GaAs Oxide Surfaces

    NASA Astrophysics Data System (ADS)

    Sasaki, Masahiro; Yoshida, Seikoh; Yamada, Chikashi

    1993-10-01

    The reactivity of GaAs and GaAs oxide surfaces to trimethylgallium (TMG) was studied by temperature-programmed scattering (TPS) through the energy accommodation coefficient (EAC). The substrate temperature was increased at a constant rate while the scattered TMG was being measured under a constant flux of TMG supplied to the substrate by a cryo-shrouded quadrupole mass spectrometer. Since the detection efficiency of the spectrometer is inversely proportional to the translational velocity of scattered TMG, the observed intensity variation represents the change in translational velocity of reflected TMG during the temperature increase. The variation of the signal intensities was least-squares analyzed to yield the EAC, which is a measure of the surface reactivity. The thus-obtained reactivity of photo-oxidized GaAs to TMG is smaller than that of dark-oxidized GaAs, which is even smaller than that of a bare GaAs surface. This difference in the reactivity is discussed in relation to the mechanism of selective area growth of GaAs using GaAs oxide as a mask.

  13. GaAs VLSI technology and circuit elements for DSP

    NASA Astrophysics Data System (ADS)

    Mikkelson, James M.

    1990-10-01

    Recent progress in digital GaAs circuit performance and complexity is presented to demonstrate the current capabilities of GaAs components. High density GaAs process technology and circuit design techniques are described and critical issues for achieving favorable complexity speed power and cost tradeoffs are reviewed. Some DSP building blocks are described to provide examples of what types of DSP systems could be implemented with present GaAs technology. DIGITAL GaAs CIRCUIT CAPABILITIES In the past few years the capabilities of digital GaAs circuits have dramatically increased to the VLSI level. Major gains in circuit complexity and power-delay products have been achieved by the use of silicon-like process technologies and simple circuit topologies. The very high speed and low power consumption of digital GaAs VLSI circuits have made GaAs a desirable alternative to high performance silicon in hardware intensive high speed system applications. An example of the performance and integration complexity available with GaAs VLSI circuits is the 64x64 crosspoint switch shown in figure 1. This switch which is the most complex GaAs circuit currently available is designed on a 30 gate GaAs gate array. It operates at 200 MHz and dissipates only 8 watts of power. The reasons for increasing the level of integration of GaAs circuits are similar to the reasons for the continued increase of silicon circuit complexity. The market factors driving GaAs VLSI are system design methodology system cost power and reliability. System designers are hesitant or unwilling to go backwards to previous design techniques and lower levels of integration. A more highly integrated system in a lower performance technology can often approach the performance of a system in a higher performance technology at a lower level of integration. Higher levels of integration also lower the system component count which reduces the system cost size and power consumption while improving the system reliability

  14. Bipolar Ag-Zn battery

    NASA Technical Reports Server (NTRS)

    Giltner, L. John

    1994-01-01

    The silver-zinc (AgZn) battery system has been unique in its ability to safely satisfy high power demand applications with low mass and volume. However, a new generation of defense, aerospace, and commercial applications will impose even higher power demands. These new power demands can be satisfied by the development of a bipolar battery design. In this configuration the power consuming, interelectrode current conductors are eliminated while the current is then conducted via the large cross-section electrode substrate. Negative and positive active materials are applied to opposite sides of a solid silver foil substrate. In addition to reducing the weight and volume required for a specified power level, the output voltage performance is also improved as follows. Reduced weight through: elimination of the plastic cell container; elimination of plate leads and intercell connector; and elimination of internal plate current collector. Increased voltage through: elimination of resistance of current collector; elimination of resistance of plate lead; and elimination of resistance of intercell connector. EPI worked previously on development of a secondary bipolar silver zinc battery. This development demonstrated the electrical capability of the system and manufacturing techniques. One difficulty with this development was mechanical problems with the seals. However, recent improvements in plastics and adhesives should eliminate the major problem of maintaining a seal around the periphery of the bipolar module. The seal problem is not as significant for a primary battery application or for a requirement for only a few discharge cycles. A second difficulty encountered was with activation (introducing electrolyte into the cell) and with venting gas from the cell without loss of electrolyte. During previous work, the following projections for energy density were made from test data for a high power system which demonstrated in excess of 50 discharge/charge cycles. Projected

  15. Localized corrosion of GaAs surfaces and formation of porous GaAs

    SciTech Connect

    Schmuki, P.; Vitus, C.M.; Isaacs, H.S.; Fraser, J.; Graham, M.J.

    1995-12-01

    The present work deals with pitting corrosion of p- and n-type GaAs (100). Pit growth can be electrochemically initiated on both conduction types in chloride-containing solutions and leads after extended periods of time to the formation of a porous GaAs structure. In the case of p-type material, localized corrosion is only observed if a passivating film is present on the surface, otherwise -- e.g. in acidic solutions -- the material suffers from a uniform attack (electropolishing) which is independent of the anion present. In contrast, pitting corrosion of n-type material can be triggered independent of the presence of an oxide film. This is explained in terms of the different current limiting factor for the differently doped materials (oxide film in the case of the p- and a space charge layer in the case of the n-GaAs). The porous structure was characterized by SEM, EDX and AES, and consists mainly of GaAs. From scratch experiments it is clear that the pit initiation process is strongly influenced by surface defects. For n-type material, AFM investigations show that light induced roughening of the order of several hundred nm occurs under non-passivating conditions. This nm- scale roughening however does not affect the pitting process.

  16. Small signal model parameters analysis of GaN and GaAs based HEMTs over temperature for microwave applications

    NASA Astrophysics Data System (ADS)

    Alim, Mohammad A.; Rezazadeh, Ali A.; Gaquiere, Christophe

    2016-05-01

    Thermal and small-signal model parameters analysis have been carried out on 0.5 μm × (2 × 100 μm) AlGaAs/GaAs HEMT grown on semi-insulating GaAs substrate and 0.25 μm × (2 × 100 μm) AlGaN/GaN HEMT grown on SiC substrate. Two different technologies are investigated in order to establish a detailed understanding of their capabilities in terms of frequency and temperature using on-wafer S-parameter measurement over the temperature range from -40 to 150 °C up to 50 GHz. The equivalent circuit parameters as well as their temperature-dependent behavior of the two technologies were analyzed and discussed for the first time. The principle elevation or degradation of transistor parameters with temperature demonstrates the great potential of GaN device for high frequency and high temperature applications. The result provides some valuable insights for future design optimizations of advanced GaN and a comparison of this with the GaAs technology.

  17. Electronic properties of GaAs, InAs and InP nanowires studied by terahertz spectroscopy.

    PubMed

    Joyce, Hannah J; Docherty, Callum J; Gao, Qiang; Tan, H Hoe; Jagadish, Chennupati; Lloyd-Hughes, James; Herz, Laura M; Johnston, Michael B

    2013-05-31

    We have performed a comparative study of ultrafast charge carrier dynamics in a range of III-V nanowires using optical pump-terahertz probe spectroscopy. This versatile technique allows measurement of important parameters for device applications, including carrier lifetimes, surface recombination velocities, carrier mobilities and donor doping levels. GaAs, InAs and InP nanowires of varying diameters were measured. For all samples, the electronic response was dominated by a pronounced surface plasmon mode. Of the three nanowire materials, InAs nanowires exhibited the highest electron mobilities of 6000 cm² V⁻¹ s⁻¹, which highlights their potential for high mobility applications, such as field effect transistors. InP nanowires exhibited the longest carrier lifetimes and the lowest surface recombination velocity of 170 cm s⁻¹. This very low surface recombination velocity makes InP nanowires suitable for applications where carrier lifetime is crucial, such as in photovoltaics. In contrast, the carrier lifetimes in GaAs nanowires were extremely short, of the order of picoseconds, due to the high surface recombination velocity, which was measured as 5.4 × 10⁵  cm s⁻¹. These findings will assist in the choice of nanowires for different applications, and identify the challenges in producing nanowires suitable for future electronic and optoelectronic devices.

  18. Fundamentals of bipolar high-frequency surgery.

    PubMed

    Reidenbach, H D

    1993-04-01

    In endoscopic surgery a very precise surgical dissection technique and an efficient hemostasis are of decisive importance. The bipolar technique may be regarded as a method which satisfies both requirements, especially regarding a high safety standard in application. In this context the biophysical and technical fundamentals of this method, which have been known in principle for a long time, are described with regard to the special demands of a newly developed field of modern surgery. After classification of this method into a general and a quasi-bipolar mode, various technological solutions of specific bipolar probes, in a strict and in a generalized sense, are characterized in terms of indication. Experimental results obtained with different bipolar instruments and probes are given. The application of modern microprocessor-controlled high-frequency surgery equipment and, wherever necessary, the integration of additional ancillary technology into the specialized bipolar instruments may result in most useful and efficient tools of a key technology in endoscopic surgery.

  19. Black phosphorus nonvolatile transistor memory.

    PubMed

    Lee, Dain; Choi, Yongsuk; Hwang, Euyheon; Kang, Moon Sung; Lee, Seungwoo; Cho, Jeong Ho

    2016-04-28

    We demonstrated nanofloating gate transistor memory devices (NFGTMs) using mechanically-exfoliated few-layered black phosphorus (BP) channels and gold nanoparticle (AuNPs) charge trapping layers. The resulting BP-NFGTMs exhibited excellent memory performances, including the five-level data storage, large memory window (58.2 V), stable retention (10(4) s), and cyclic endurance (1000 cycles). PMID:27074903

  20. 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.

  1. Viruses, schizophrenia, and bipolar disorder.

    PubMed Central

    Yolken, R H; Torrey, E F

    1995-01-01

    The hypothesis that viruses or other infectious agents may cause schizophrenia or bipolar disorder dates to the 19th century but has recently been revived. It could explain many clinical, genetic, and epidemiologic aspects of these diseases, including the winter-spring birth seasonality, regional differences, urban birth, household crowding, having an older sibling, and prenatal exposure to influenza as risk factors. It could also explain observed immunological changes such as abnormalities of lymphocytes, proteins, autoantibodies, and cytokines. However, direct studies of viral infections in individuals with these psychiatric diseases have been predominantly negative. Most studies have examined antibodies in blood or cerebrospinal fluid, and relatively few studies have been done on viral antigens, genomes, cytopathic effect on cell culture, and animal transmission experiments. Viral research on schizophrenia and bipolar disorder is thus comparable to viral research on multiple sclerosis and Parkinson's disease: an attractive hypothesis with scattered interesting findings but no clear proof. The application of molecular biological techniques may allow the identification of novel infectious agents and the associations of these novel agents with serious mental diseases. PMID:7704891

  2. GaAs Films Prepared by RF-Magnetron Sputtering

    SciTech Connect

    L.H. Ouyang; D.L. Rode; T. Zulkifli; B. Abraham-Shrauner; N. Lewis; M.R. Freeman

    2001-08-01

    The authors reported on the optical absorption, adhesion, and microstructure of RF-magnetron sputtered films of hydrogenated amorphous and microcrystalline GaAs films for the 1 to 25 {micro}m infrared wavelength rate. Sputtering parameters which were varied include sputtering power, temperature and pressure, and hydrogen sputtering-gas concentration. TEM results show a sharp transition from purely amorphous GaAs to a mixture of microcrystalline GaAs in an amorphous matrix at 34 {+-} 2 C. By optimizing the sputtering parameters, the optical absorption coefficient can be decreased below 100 cm{sup -1} for wavelengths greater than about 1.25 {micro}m. These results represent the lowest reported values of optical absorption for sputtered films of GaAs directly measured by spectrophotometry for the near-infrared wavelength region.

  3. GaAs monolithic RF modules for SARSAT distress beacons

    NASA Technical Reports Server (NTRS)

    Cauley, Michael A.

    1991-01-01

    Monolithic GaAs UHF components for use in SARSAT Emergency Distress beacons are under development by Microwave Monolithics, Inc., Simi Valley, CA. The components include a bi-phase modulator, driver amplifier, and a 5 watt power amplifier.

  4. Interfacial Ga-As suboxide: Structural and electronic properties

    SciTech Connect

    Colleoni, Davide Pasquarello, Alfredo

    2015-07-20

    The structural and electronic properties of Ga-As suboxide representative of the transition region at the GaAs/oxide interface are studied through density functional calculations. Two amorphous models generated by quenches from the melt are taken under consideration. The absence of As–O bonds indicates that the structure is a mixture of GaAs and Ga-oxide, in accordance with photoemission experiments. The band edges of the models are found to be closely aligned to those of GaAs. The simulation of charging and discharging processes leads to the identification of an As-related defect with an energy level at ∼0.7 eV above the GaAs valence band maximum, in good agreement with the experimental density of interface states.

  5. Crystal Growth of Device Quality Gaas in Space

    NASA Technical Reports Server (NTRS)

    Gatos, H. C.

    1985-01-01

    The GaAs research evolves about these key thrust areas. The overall program combines: (1) studies of crystal growth on novel approaches to engineering of semiconductor material (i.e., GaAs and related compounds); (2) investigation and correlation of materials properties and electronic characteristics on a macro- and microscale; and (3) investigation of electronic properties and phenomena controlling device applications and device performance. This effort is aimed at the essential ground-based program which would insure successful experimentation with and eventually processing of GaAs in near zero gravity environment. It is believed that this program addresses in a unique way materials engineering aspects which bear directly on the future exploitation of the potential of GaAs and related materials in device and systems applications.

  6. Crystal growth of device quality GaAs in space

    NASA Technical Reports Server (NTRS)

    Gatos, H. C.; Lagowski, J.

    1983-01-01

    GaAs device technology has recently reached a new phase of rapid advancement, made possible by the improvement of the quality of GaAs bulk crystals. At the same time, the transition to the next generation of GaAs integrated circuits and optoelectronic systems for commercial and government applications hinges on new quantum steps in three interrelated areas: crystal growth, device processing and device-related properties and phenomena. Special emphasis is placed on the establishment of quantitative relationships among crystal growth parameters-material properties-electronic properties and device applications. The overall program combines studies of crystal growth on novel approaches to engineering of semiconductor material (i.e., GaAs and related compounds); investigation and correlation of materials properties and electronic characteristics on a macro- and microscale; and investigation of electronic properties and phenomena controlling device applications and device performance.

  7. Characteristics of GaAs with inverted thermal conversion

    NASA Technical Reports Server (NTRS)

    Kang, C. H.; Lagowski, J.; Gatos, H. C.

    1987-01-01

    GaAs crystals exhibiting inverted thermal conversion (ITC) of resistivity were investigated in conjunction with standard semiinsulating (SI) GaAs regarding characteristics important in device processing. It was established that dislocation density and Si implant activation are unaffected by transformation to the ITC state. However, in ITC GaAs the controlled increase of the EL2 (native midgap donor) concentration during annealing makes it possible to attain resistivities one order of magnitude greater (e.g., about 10 to the 9th ohm cm of 300 K) than those attained in standard SI GaAs (e.g., 10 to the 7th-10 to the 8th ohm cm).

  8. Ultrafast spectroscopy of GaAs under magnetic field

    SciTech Connect

    Mycek, M.A.; Siegner, U.; Glutsch, S.

    1995-03-01

    Surprising and novel results are obtained for both the linear and the nonlinear optical response of GaAs under magnetic field. Using a variety of spectroscopic techniques, we measure field dependent effects due to Coulomb correlation.

  9. GaAs solar cells for space applications

    NASA Technical Reports Server (NTRS)

    Conway, E. J.; Walker, G. H.; Heinbockel, J. H.

    1980-01-01

    GaAs solar cells offer substantial advantages for space photovoltaic power over Si solar cells in the areas of efficiency, elevated temperature operation, and radiation damage stability. A mission cost comparison is made for GaAs and Si solar cells. For Si cell arrays, the total mission cost is found to be a minimum for a solar concentration of 2.9. For GaAs, modes of operation and construction are investigated. Modes having lower mission costs than the minimum Si mission cost are defined. These include higher concentrations, lightweight cells, and simultaneous power generation and annealing. The technological progress necessary for GaAs to operate in these modes is identified.

  10. Interfacial Ga-As suboxide: Structural and electronic properties

    NASA Astrophysics Data System (ADS)

    Colleoni, Davide; Pasquarello, Alfredo

    2015-07-01

    The structural and electronic properties of Ga-As suboxide representative of the transition region at the GaAs/oxide interface are studied through density functional calculations. Two amorphous models generated by quenches from the melt are taken under consideration. The absence of As-O bonds indicates that the structure is a mixture of GaAs and Ga-oxide, in accordance with photoemission experiments. The band edges of the models are found to be closely aligned to those of GaAs. The simulation of charging and discharging processes leads to the identification of an As-related defect with an energy level at ˜0.7 eV above the GaAs valence band maximum, in good agreement with the experimental density of interface states.

  11. [Dislocation-disassembly of bipolar hip arthroplasty--case report].

    PubMed

    Gagała, Jacek; Blacha, Jan

    2005-01-01

    Bipolar hip arthroplasty dislocation is rare. A case of bipolar hip arthroplasty dislocation in patient treated because of femoral neck fracture was described. Patient had neurological problems. The arthroplasty was made with posterolateral approach. Disassembly of bipolar prosthesis occurred during closed reduction. Open reduction with bipolar head exchange was necessary. To avoid this complication reduction should be made in anesthesia with muscles relaxation.

  12. GaAs Hall devices produced by local ion implantation

    NASA Astrophysics Data System (ADS)

    Pettenpaul, E.; Huber, J.; Weidlich, H.; Flossmann, W.; von Borcke, U.

    1981-08-01

    GaAs Hall devices were produced by complete planar technology using two selective silicon ion implantation steps. The fundamental characteristics of these devices with respect to reproducible implantation dose and geometry of cross-shaped elements are obtained both by experiment and calculation. The prominent properties of the GaAs Hall elements presented are high sensitivity and linearity, small temperature dependence of sensitivity and resistance, and low residual voltage.

  13. Novel GAA mutations in patients with Pompe disease.

    PubMed

    Turaça, Lauro Thiago; de Faria, Douglas Oliveira Soares; Kyosen, Sandra Obikawa; Teixeira, Valber Dias; Motta, Fabiana Louise; Pessoa, Juliana Gilbert; Rodrigues E Silva, Marina; de Almeida, Sandro Soares; D'Almeida, Vânia; Munoz Rojas, Maria Verônica; Martins, Ana Maria; Pesquero, João Bosco

    2015-04-25

    Pompe disease is an autosomal recessive disorder linked to GAA gene that leads to a multi-system intralysosomal accumulation of glycogen. Mutation identification in the GAA gene can be very important for early diagnosis, correlation between genotype-phenotype and therapeutic intervention. For this purpose, peripheral blood from 57 individuals susceptible to Pompe disease was collected and all exons of GAA gene were amplified; the sequences and the mutations were analyzed in silico to predict possible impact on the structure and function of the human protein. In this study, 46 individuals presented 33 alterations in the GAA gene sequence, among which five (c.547-67C>G, c.547-39T>G, p.R437H, p.L641V and p.L705P) have not been previously described in the literature. The alterations in the coding region included 15 missense mutations, three nonsense mutations and one deletion. One insertion and other 13 single base changes were found in the non-coding region. The mutation p.G611D was found in homozygosis in a one-year-old child, who presented low levels of GAA activity, hypotonia and hypertrophic cardiomyopathy. Two patients presented the new mutation p.L705P in association with c.-32-13T>G. They had low levels of GAA activity and developed late onset Pompe disease. In our study, we observed alterations in the GAA gene originating from Asians, African-Americans and Caucasians, highlighting the high heterogeneity of the Brazilian population. Considering that Pompe disease studies are not very common in Brazil, this study will help to better understand the potential pathogenic role of each change in the GAA gene. Furthermore, a precise and early molecular analysis improves genetic counseling besides allowing for a more efficient treatment in potential candidates.

  14. Characterisation of semi-insulating GaAs

    NASA Technical Reports Server (NTRS)

    Walukiewicz, W.; Pawlowicz, L.; Lagowski, J.; Gatos, H. C.

    1982-01-01

    Hole and electron mobilities as functions of temperature and ionised impurity concentration are calculated for GaAs. It is shown that these calculations, when used to analyse electrical properties of semi-insulating GaAs, enable an assessment of the Fermi energy position and ionised impurity concentration to be made. In contrast to previous work, the analysis does not require any phenomenological assumptions.

  15. Bipolar plates for PEM fuel cells

    NASA Astrophysics Data System (ADS)

    Middelman, E.; Kout, W.; Vogelaar, B.; Lenssen, J.; de Waal, E.

    The bipolar plates are in weight and volume the major part of the PEM fuel cell stack, and are also a significant contributor to the stack costs. The bipolar plate is therefore a key component if power density has to increase and costs must come down. Three cell plate technologies are expected to reach targeted cost price levels, all having specific advantages and drawbacks. NedStack has developed a conductive composite materials and a production process for fuel cell plates (bipolar and mono-polar). The material has a high electric and thermal conductivity, and can be processed into bipolar plates by a proprietary molding process. Process cycle time has been reduced to less than 10 s, making the material and process suitable for economical mass production. Other development work to increase material efficiency resulted in thin bipolar plates with integrated cooling channels, and integrated seals, and in two-component bipolar plates. Total thickness of the bipolar plates is now less than 3 mm, and will be reduced to 2 mm in the near future. With these thin integrated plates it is possible to increase power density up to 2 kW/l and 2 kW/kg, while at the same time reducing cost by integrating other functions and less material use.

  16. Bipolar Janus particle assembly in microdevice.

    PubMed

    Hossan, Mohammad R; Gopmandal, Partha P; Dillon, Robert; Dutta, Prashanta

    2015-03-01

    In recent years, there are significant interests in the manipulation of bipolar Janus particles. In this article, we investigate the transient behavior of the electro-orientation process and particle-particle interaction of ellipsoidal bipolar Janus particles in the presence and absence of a DC electric field. The bipolar particle dynamics is modeled with a body force term in the fluid flow equations based on the Maxwell stress tensor. This force is due to presence of bipolar surface charges on the particles as well as their interactions with an imposed field. An interface resolved numerical scheme that consider the finite size of the particle is adopted for computation of the electric and flow fields. Our numerical results show that in the absence of an electric field, particles can undergo self-orientation to reach an equilibrium position. The time taken to reach a stable orientation depends on the initial configuration and inter-particle separation distance. Bipolar particles experience forces only on their polar ends, a phenomena that is difficult to capture with noninterface resolved methods. When bipolar particles are exposed to an external electric field, they rotate to align along the external electric field direction. Depending upon the initial configuration, particles orient via clockwise or counter clockwise rotations to form head to tail chains. The time required to form particle assembly strongly depends on particle size and bipolar charge density. The present numerical algorithm can be applied to a wider class of dual-faced Janus particles.

  17. Brief Report: A Family Risk Study Exploring Bipolar Spectrum Problems and Cognitive Biases in Adolescent Children of Bipolar Parents

    ERIC Educational Resources Information Center

    Espie, Jonathan; Jones, Steven H.; Vance, Yvonne H.; Tai, Sara J.

    2012-01-01

    Children of parents with bipolar disorder are at increased risk of bipolar spectrum diagnoses. This cross-sectional study explores cognitive factors in the prediction of vulnerability to bipolar disorder. Adolescents at high-risk (with a parent with bipolar disorder; n = 23) and age and gender matched adolescents (n = 24) were recruited. Parent…

  18. 1.1-μm InAs/GaAs quantum-dot light-emitting transistors grown by molecular beam epitaxy.

    PubMed

    Wu, Cheng-Han; Chen, Hsuan-An; Lin, Shih-Yen; Wu, Chao-Hsin

    2015-08-15

    In this Letter, we report the enhanced radiative recombination output from an AlGaAs/GaAs heterojunction bipolar transistor with InAs quantum dots embedded in the base region to form a quantum-dot light-emitting transistor (QDLET) grown by molecular beam epitaxy systems. For the device with a 100  μm×100  μm emitter area, we demonstrate the dual output characteristics with an electrical output and an optical output when the device is operating in the common-emitter configuration. The quantum-dot light-emitting transistor exhibits a base recombination radiation in the near-infrared spectral range with a dominant peak at λ of 1100 nm.

  19. AlGaAs/GaAs/InGaAs pnp-type vertical-cavity surface-emitting transistor-lasers.

    PubMed

    Xiang, Y; Reuterskiöld-Hedlund, C; Yu, X; Yang, C; Zabel, T; Hammar, M; Akram, M N

    2015-06-15

    We report on the design, fabrication and analysis of vertical-cavity surface-emitting transistor-lasers (T-VCSELs) based on the homogeneous integration of an InGaAs/GaAs VCSEL and an AlGaAs/GaAs pnp-heterojunction bipolar transistor (HBT). Epitaxial regrowth confinement, modulation doping, intracavity contacting and non-conducting mirrors are used to ensure a low-loss structure, and a variety of design variations are investigated for a proper internal biasing and current injection to ensure a wide operating range. Optimized devices show mW-range output power, mA-range base threshold current and high-temperature operation to at least 60°C with the transistor in its active mode of operation for base currents well beyond threshold. Current confinement schemes based on pnp-blocking layers or a buried tunnel junction are investigated as well as asymmetric current injection for reduced extrinsic resistances.

  20. The Integration and Applications of Organic Thin Film Transistors and Ferroelectric Polymers

    NASA Astrophysics Data System (ADS)

    Hsu, Yu-Jen

    Organic thin film transistors and ferroelectric polymer (polyvinylidene difluoride) sheet material are integrated to form various sensors for stress/strain, acoustic wave, and Infrared (heat) sensing applications. Different from silicon-based transistors, organic thin film transistors can be fabricated and processed in room-temperature and integrated with a variety of substrates. On the other hand, polyvinylidene difluoride (PVDF) exhibits ferroelectric properties that are highly useful for sensor applications. The wide frequency bandwidth (0.001 Hz to 10 GHz), vast dynamic range (100n to 10M psi), and high elastic compliance (up to 3 percent) make PVDF a more suitable candidate over ceramic piezoelectric materials for thin and flexible sensor applications. However, the low Curie temperature may have impeded its integration with silicon technology. Organic thin film transistors, however, do not have the limitation of processing temperature, hence can serve as transimpedance amplifiers to convert the charge signal generated by PVDF into current signal that are more measurable and less affected by any downstream parasitics. Piezoelectric sensors are useful for a range of applications, but passive arrays suffer from crosstalk and signal attenuation which have complicated the development of array-based PVDF sensors. We have used organic field effect transistors, which are compatible with the low Curie temperature of a flexible piezoelectric polymer,PVDF, to monolithically fabricate transimpedance amplifiers directly on the sensor surface and convert the piezoelectric charge signal into a current signal which can be detected even in the presence of parasitic capacitances. The device couples the voltage generated by the PVDF film under strain into the gate of the organic thin film transistors (OFET) using an arrangement that allows the full piezoelectric voltage to couple to the channel, while also increasing the charge retention time. A bipolar detector is created by

  1. SEU In An Advanced Bipolar Integrated Circuit

    NASA Technical Reports Server (NTRS)

    Zoutendyk, John A.; Secrest, Elaine C.; Berndt, Dale F.

    1989-01-01

    Report summarizes investigation of single-event upsets (SEU) in bipolar integrated-circuit set of flip-flops (memory cells). Device tested made by advanced digital bipolar silicon process of Honeywell, Inc. Circuit chip contained 4 cells. Construction enabled study of effect of size on SEU behavior. Each cell externally biased so effect of bias current on SEU behavior. Results of study provides important information for optimal design of devices fabricated using buried-layer bipolar process operating in heavy-ion SEU environments. Designers use information to provide required levels of suppression of SEU in specific applications via combinations of size and/or cell-current scaling.

  2. A Rare Case of Bipolar Clavicle Fracture

    PubMed Central

    Hoy, Gregory A.

    2016-01-01

    Segmental or bipolar fractures of the clavicle generally refer to a concomitant ipsilateral distal clavicle and midshaft clavicle fracture. These injuries are exceedingly rare and are generally secondary to higher energy injuries. We report a case of a 38-year-old male who sustained a left bipolar clavicle fracture after falling from a push bike while riding recreationally which unusually involved the medial and lateral ends of the clavicle and not the midshaft as previously reported in other patients. The patient's exact fracture configuration was not immediately apparent highlighting the need for careful examination of the whole clavicle in order to not miss a bipolar fracture. PMID:27051546

  3. Backgating effect in GaAs FETs with a channel—semi-insulating substrate boundary

    NASA Astrophysics Data System (ADS)

    Chaouki Megherbi, Ahmed; Benramache, Said; Guettaf, Abderrazak

    2014-03-01

    This study focuses on modeling the effects of deep hole traps, mainly the effect of the substrate (backgating effect) in a GaAs transistor MESFT. This effect is explained by the existence, at the interface, of a space charge zone. Any modulation in this area leads to response levels trapping the holes therein to the operating temperature. We subsequently developed a model treating the channel substrate interface as an N—P junction, allowing us to deduce the time dependence of the component parameters of the total resistance Rds, the pinch-off voltage VP, channel resistance, fully open Rco and the parasitic series resistance RS to bind the effect trap holes H1 and H0. When compared with the experimental results, the values of the RDS (tS) model for both traps show that there is an agreement between theory and experiment; it has inferred parameter traps, namely the density and the time constant of the trap. This means that a space charge region exists at the channel—substrate interface and that the properties can be approximated to an N—P junction.

  4. Magnetotransport Properties of Epitaxial Ge/AlAs Heterostructures Integrated on GaAs and Silicon.

    PubMed

    Hudait, Mantu K; Clavel, Michael; Goley, Patrick S; Xie, Yuantao; Heremans, Jean J

    2015-10-14

    The magnetotransport properties of epitaxial Ge/AlAs heterostructures with different growth conditions and substrate architectures have been studied under ±9 T magnetic field and at 390 mK temperature. Systematic mobility measurements of germanium (Ge) epilayers grown on GaAs substrates at growth temperatures from 350 to 450 °C allow us to extract a precise growth window for device-quality Ge, corroborated by structural and morphological properties. Our results on Si substrate using a composite metamorphic AlAs/GaAs buffer at 400 °C Ge growth temperature, show that the Ge/AlAs system can be tailored to have a single carrier transport while keeping the charge solely in the Ge layer. Single carrier transport confined to the Ge layer is demonstrated by the weak-localization quantum correction to the conductivity observed at low magnetic fields and 390 mK temperature. The weak localization effect points to a near-absence of spin-orbit interaction for carriers in the electronically active layer and is used here for the first time to pinpoint Ge as this active layer. Thus, the epitaxial Ge grown on Si using AlAs/GaAs buffer architecture is a promising candidate for next-generation energy-efficient fin field-effect transistor applications.

  5. Noise characteristics of stroboscopic transducers built with GaAs microcircuit integration

    NASA Astrophysics Data System (ADS)

    Staroselskiy, V. I.

    1985-10-01

    Stroboscopic transducers are used for measuring electric signals over a wide frequency range, the sensitivity of these devices being largely determined by the equivalent input noise voltage. The internal noise level can be appreciably lowered and the performance of such a transducer correspondingly improved by GaAs microcircuit integration of the input stage. A chip of 1x1 sq mm area can carry a mixer bridge of four Schottky-barrier diodes, a storing capacitor with discharge circuit, and a voltage repeater on Schottky-gate field-effect transistors, shot noise in the mixer diodes, and flicker noise in the diodes as well as in the voltage repeater. Two noise mechanisms are identified, corresponding to the two modes of transducer operation: mixer noise alone during strobing, mixer noise with noise in the discharge circuit and in the voltage repeater during measurement of widened pulses. The resultant spectral noise density is calculated on the basis of these identifications and corresponding equivalent circuit diagrams. During strobing the flicker noise appears as a multiplicative component and its deviation from the 1/omega law determines its lower frequency limit. During measurement of a widened pulse the noise is limited to the pass band of the output amplifier-integrator stage and a low-pass filter before this stage becomes desirable.

  6. Single-transistor-clocked flip-flop

    DOEpatents

    Zhao, Peiyi; Darwish, Tarek; Bayoumi, Magdy

    2005-08-30

    The invention provides a low power, high performance flip-flop. The flip-flop uses only one clocked transistor. The single clocked transistor is shared by the first and second branches of the device. A pulse generator produces a clock pulse to trigger the flip-flop. In one preferred embodiment the device can be made as a static explicit pulsed flip-flop which employs only two clocked transistors.

  7. Coaxial inverted geometry transistor having buried emitter

    NASA Technical Reports Server (NTRS)

    Hruby, R. J.; Cress, S. B.; Dunn, W. R. (Inventor)

    1973-01-01

    The invention relates to an inverted geometry transistor wherein the emitter is buried within the substrate. The transistor can be fabricated as a part of a monolithic integrated circuit and is particularly suited for use in applications where it is desired to employ low actuating voltages. The transistor may employ the same doping levels in the collector and emitter, so these connections can be reversed.

  8. Principles of an atomtronic transistor

    NASA Astrophysics Data System (ADS)

    Caliga, Seth C.; Straatsma, Cameron J. E.; Zozulya, Alex A.; Anderson, Dana Z.

    2016-01-01

    A semiclassical formalism is used to investigate the transistor-like behavior of ultracold atoms in a triple-well potential. Atom current flows from the source well, held at fixed chemical potential and temperature, into an empty drain well. In steady-state, the gate well located between the source and drain is shown to acquire a well-defined chemical potential and temperature, which are controlled by the relative height of the barriers separating the three wells. It is shown that the gate chemical potential can exceed that of the source and have a lower temperature. In electronics terminology, the source-gate junction can be reverse-biased. As a result, the device exhibits regimes of negative resistance and transresistance, indicating the presence of gain. Given an external current input to the gate, transistor-like behavior is characterized both in terms of the current gain, which can be greater than unity, and the power output of the device.

  9. Black phosphorus nonvolatile transistor memory

    NASA Astrophysics Data System (ADS)

    Lee, Dain; Choi, Yongsuk; Hwang, Euyheon; Kang, Moon Sung; Lee, Seungwoo; Cho, Jeong Ho

    2016-04-01

    We demonstrated nanofloating gate transistor memory devices (NFGTMs) using mechanically-exfoliated few-layered black phosphorus (BP) channels and gold nanoparticle (AuNPs) charge trapping layers. The resulting BP-NFGTMs exhibited excellent memory performances, including the five-level data storage, large memory window (58.2 V), stable retention (104 s), and cyclic endurance (1000 cycles).We demonstrated nanofloating gate transistor memory devices (NFGTMs) using mechanically-exfoliated few-layered black phosphorus (BP) channels and gold nanoparticle (AuNPs) charge trapping layers. The resulting BP-NFGTMs exhibited excellent memory performances, including the five-level data storage, large memory window (58.2 V), stable retention (104 s), and cyclic endurance (1000 cycles). Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr02078j

  10. The thermodynamics of bipolarity: a bifurcation model of bipolar illness and bipolar character and its psychotherapeutic applications.

    PubMed

    Sabelli, H C; Carlson-Sabelli, L; Javaid, J I

    1990-11-01

    Two models dominate current formulations of bipolar illness: the homeostatic model implicit in Freud's psychodynamics and most neuroamine deficit/excess theories; and the oscillatory model of exaggerated biological rhythms. The homeostatic model is based on the closed systems approach of classic thermodynamics, while the oscillatory model requires the open systems approach of modern thermodynamics. Here we present a thermodynamic model of bipolarity that includes both homeostatic and oscillatory features and adds the most important feature of open systems thermodynamics: the creation of novel structures in bifurcation processes. According to the proposed model, bipolarity is the result of exaggerated biological energy that augments homeostatic, oscillatory and creative psychological processes. Only low-energy closed systems tend to rest ("point attractor") and entropic disorder. Open processes containing and exchanging energy fluctuate between opposite states ("periodic attractors"); they are characteristic of most physiological rhythms and are exaggerated in bipolar subjects. At higher energies, their strong fluctuations destroy pre-existing patterns and structures, produce turbulence ("chaotic attractors"), which sudden switches between opposite states, and create new and more complex structures. Likewise, high-energy bipolars develop high spontaneity, great fluctuations between opposite moods, internal and interpersonal chaos, and enhanced creativity (personal, artistic, professional) as well as psychopathology (personality deviations, psychotic delusions). Offered here is a theoretical explanation of the dual--creative and destructive--nature of bipolarity in terms of the new enantiodromic concept of entropy generalized by process theory. Clinically, this article offers an integrative model of bipolarity that accounts for many clinical features and contributes to a definition of the bipolar personality.

  11. Bipolar Disorder: A Daughter's Experience.

    PubMed

    Khare, Satya Rashi

    2016-09-01

    My father suffered from bipolar disorder. His illness placed an enormous strain on our relationship which, for the most part, was filled with turbulence. Although our family physician played an integral role in supporting my parents throughout the disease, I did not receive the same support and suffered as a consequence. In this essay, I describe my father's manic and major depressive episodes, as well as my emotions that resulted from the experience. Treating mental illness goes beyond just treating the patient but rather encompasses the family as a whole. My relationship with my father may have been different had I learned effective coping strategies through the support of my family physician. PMID:27621165

  12. Composite substrate for bipolar electrodes

    DOEpatents

    Tekkanat, Bora; Bolstad, James J.

    1992-12-22

    Substrates for electrode systems, particularly those to be used for bipolar electrodes in zinc-bromine batteries, are disclosed. The substrates preferably include carbon-black as a conductive filler in a polymeric matrix, with reinforcing materials such as glass fibers. Warpage of the zinc-bromine electrodes which was experienced in the prior art and which was believed to be caused by physical expansion of the electrodes due to bromine absorption by the carbon-black, is substantially eliminated when new substrate fabrication techniques are employed. In the pesent invention, substrates are prepared using a lamination process known as glass mat reinforced thermoplastics technology or, in an alternate embodiment, the substrate is made using a slurry process.

  13. Antidepressant chronotherapeutics for bipolar depression

    PubMed Central

    Benedetti, Francesco

    2012-01-01

    Chronotherapeutics refers to treatments based on the principles of circadian rhythm organization and sleep physiology, which control the exposure to environmental stimuli that act on biological rhythms, in order to achieve therapeutic effects in the treatment of psychiatric conditions. It includes manipulations of the sleep-wake cycle such as sleep deprivation and sleep phase advance, and controlled exposure to light and dark. The antidepressant effects of chronotherapeutics are evident in difficult-to-treat conditions such as bipolar depression, which has been associated with extremely low success rates of antidepressant drugs in naturalistic settings and with stable antidepressant response to chronotherapeutics in more than half of the patients. Recent advances in the study of the effects of chronotherapeutics on neurotransmitter systems, and on the biological clock machinery, allow us to pinpoint its mechanism of action and to transform it from a neglected or “orphan” treatment to a powerful clinical instrument in everyday psychiatric practice. PMID:23393416

  14. Composite substrate for bipolar electrodes

    DOEpatents

    Tekkanat, B.; Bolstad, J.J.

    1992-12-22

    Substrates for electrode systems, particularly those to be used for bipolar electrodes in zinc-bromine batteries, are disclosed. The substrates preferably include carbon-black as a conductive filler in a polymeric matrix, with reinforcing materials such as glass fibers. Warpage of the zinc-bromine electrodes which was experienced in the prior art and which was believed to be caused by physical expansion of the electrodes due to bromine absorption by the carbon-black, is substantially eliminated when new substrate fabrication techniques are employed. In the present invention, substrates are prepared using a lamination process known as glass mat reinforced thermoplastics technology or, in an alternate embodiment, the substrate is made using a slurry process. 4 figs.

  15. Comorbidity in pediatric bipolar disorder.

    PubMed

    Joshi, Gagan; Wilens, Timothy

    2009-04-01

    The growing literature shows the pervasiveness and importance of comorbidity in youth with bipolar disorder (BPD). For instance, up to 90% of youth with BPD have been described to manifest comorbidity with attention-deficit hyperactivity disorder. Multiple anxiety, substance use, and disruptive behavior disorders are the other most commonly reported comorbidities with BPD. Moreover, important recent data highlight the importance of obsessive-compulsive and pervasive developmental illness in the context of BPD. Data suggest that not only special developmental relationships are operant in the context of comorbidity but also that the presence of comorbid disorders with BPD results in a more severe clinical condition. Moreover, the presence of comorbidity has therapeutic implications for the treatment response for both BPD and the associated comorbid disorder. Future longitudinal studies to address the relationship and the impact of comorbid disorders on course and therapeutic response over time are required in youth with BPD. PMID:19264265

  16. Antidepressant chronotherapeutics for bipolar depression.

    PubMed

    Benedetti, Francesco

    2012-12-01

    Chronotherapeutics refers to treatments based on the principles of circadian rhythm organization and sleep physiology, which control the exposure to environmental stimuli that act on biological rhythms, in order to achieve therapeutic effects in the treatment of psychiatric conditions. It includes manipulations of the sleep-wake cycle such as sleep deprivation and sleep phase advance, and controlled exposure to light and dark. The antidepressant effects of chronotherapeutics are evident in difficult-to-treat conditions such as bipolar depression, which has been associated with extremely low success rates of antidepressant drugs in naturalistic settings and with stable antidepressant response to chronotherapeutics in more than half of the patients. Recent advances in the study of the effects of chronotherapeutics on neurotransmitter systems, and on the biological clock machinery, allow us to pinpoint its mechanism of action and to transform it from a neglected or "orphan" treatment to a powerful clinical instrument in everyday psychiatric practice.

  17. Miniature Bipolar Electrostatic Ion Thruster

    NASA Technical Reports Server (NTRS)

    Hartley, Frank T.

    2006-01-01

    The figure presents a concept of a bipolar miniature electrostatic ion thruster for maneuvering a small spacecraft. The ionization device in the proposed thruster would be a 0.1-micron-thick dielectric membrane with metal electrodes on both sides. Small conical holes would be micromachined through the membrane and electrodes. An electric potential of the order of a volt applied between the membrane electrodes would give rise to an electric field of the order of several mega-volts per meter in the submicron gap between the electrodes. An electric field of this magnitude would be sufficient to ionize all the molecules that enter the holes. In a thruster-based on this concept, one or more propellant gases would be introduced into such a membrane ionizer. Unlike in larger prior ion thrusters, all of the propellant molecules would be ionized. This thruster would be capable of bipolar operation. There would be two accelerator grids - one located forward and one located aft of the membrane ionizer. In one mode of operation, which one could denote the forward mode, positive ions leaving the ionizer on the backside would be accelerated to high momentum by an electric field between the ionizer and an accelerator grid. Electrons leaving the ionizer on the front side would be ejected into free space by a smaller accelerating field. The equality of the ion and electron currents would eliminate the need for an additional electron- or ion-emitting device to keep the spacecraft charge-neutral. In another mode of operation, which could denote the reverse mode, the polarities of the voltages applied to the accelerator grids and to the electrodes of the membrane ionizer would be the reverse of those of the forward mode. The reversal of electric fields would cause the ion and electrons to be ejected in the reverse of their forward mode directions, thereby giving rise to thrust in the direction opposite that of the forward mode.

  18. Terahertz responsivity of field-effect transistors under arbitrary biasing conditions

    NASA Astrophysics Data System (ADS)

    Földesy, Péter

    2013-09-01

    Current biased photoresponse model of long channel field-effect transistor (FET) detectors is introduced to describe the low frequency behavior in complex circuit environment. The model is applicable in all FET working regions, including subthreshold, linear, saturated modes, includes bulk potential variations, and handles the simultaneous gate-source and drain-source detection or source-driven topologies. The model is based on the phenomenological representation that links the photoresponse to the gate transconductance over drain current ratio (gm/ID) and circuit theory. A derived method is provided to analyze the detector behavior, to characterize existing antenna coupled detectors, and to predict the photoresponse in a complex circuit. The model is validated by measurements of 180 nm gate length silicon and GaAs high electron mobility FETs.

  19. Complementary junction heterostructure field-effect transistor

    DOEpatents

    Baca, A.G.; Drummond, T.J.; Robertson, P.J.; Zipperian, T.E.

    1995-12-26

    A complimentary pair of compound semiconductor junction heterostructure field-effect transistors and a method for their manufacture are disclosed. The p-channel junction heterostructure field-effect transistor uses a strained layer to split the degeneracy of the valence band for a greatly improved hole mobility and speed. The n-channel device is formed by a compatible process after removing the strained layer. In this manner, both types of transistors may be independently optimized. Ion implantation is used to form the transistor active and isolation regions for both types of complimentary devices. The invention has uses for the development of low power, high-speed digital integrated circuits. 10 figs.

  20. Complementary junction heterostructure field-effect transistor

    DOEpatents

    Baca, Albert G.; Drummond, Timothy J.; Robertson, Perry J.; Zipperian, Thomas E.

    1995-01-01

    A complimentary pair of compound semiconductor junction heterostructure field-effect transistors and a method for their manufacture are disclosed. The p-channel junction heterostructure field-effect transistor uses a strained layer to split the degeneracy of the valence band for a greatly improved hole mobility and speed. The n-channel device is formed by a compatible process after removing the strained layer. In this manner, both types of transistors may be independently optimized. Ion implantation is used to form the transistor active and isolation regions for both types of complimentary devices. The invention has uses for the development of low power, high-speed digital integrated circuits.

  1. Transport Properties of III-N Hot Electron Transistors

    NASA Astrophysics Data System (ADS)

    Suntrup, Donald J., III

    Unipolar hot electron transistors (HETs) represent a tantalizing alternative to established bipolar transistor technologies. During device operation electrons are injected over a large emitter barrier into the base where they travel along the device axis with very high velocity. Upon arrival at the collector barrier, high-energy electrons pass over the barrier and contribute to collector current while low-energy electrons are quantum mechanically reflected back into the base. Designing the base with thickness equal to or less than the hot electron mean free path serves to minimize scattering events and thus enable quasi-ballistic operation. Large current gain is achieved by increasing the ratio of transmitted to reflected electrons. Although III-N HETs have undergone substantial development in recent years, there remain ample opportunities to improve key device metrics. In order to engineer improved device performance, a deeper understanding of the operative transport physics is needed. Fortunately, the HET provides fertile ground for studying several prominent electron transport phenomena. In this thesis we present results from several studies that use the III-N HET as both emitter and analyzer of hot electron momentum states. The first provides a measurement of the hot electron mean free path and the momentum relaxation rate in GaN; the second relies on a new technique called electron injection spectroscopy to investigate the effects of barrier height inhomogeneity in the emitter. To supplement our analysis we develop a comprehensive theory of coherent electron transport that allows us to model the transfer characteristics of complex heterojunctions. Such a model provides a theoretical touchstone with which to compare our experimental results. While these studies are of potential interest in their own right, we interpret the results with an eye toward improving next-generation device performance.

  2. High-Power, High-Frequency Si-Based (SiGe) Transistors Developed

    NASA Technical Reports Server (NTRS)

    Ponchak, George E.

    2002-01-01

    Future NASA, DOD, and commercial products will require electronic circuits that have greater functionality and versatility but occupy less space and cost less money to build and integrate than current products. System on a Chip (SOAC), a single semiconductor substrate containing circuits that perform many functions or containing an entire system, is widely recognized as the best technology for achieving low-cost, small-sized systems. Thus, a circuit technology is required that can gather, process, store, and transmit data or communications. Since silicon-integrated circuits are already used for data processing and storage and the infrastructure that supports silicon circuit fabrication is very large, it is sensible to develop communication circuits on silicon so that all the system functions can be integrated onto a single wafer. Until recently, silicon integrated circuits did not function well at the frequencies required for wireless or microwave communications, but with the introduction of small amounts of germanium into the silicon to make silicon-germanium (SiGe) transistors, silicon-based communication circuits are possible. Although microwavefrequency SiGe circuits have been demonstrated, there has been difficulty in obtaining the high power from their transistors that is required for the amplifiers of a transmitter, and many researchers have thought that this could not be done. The NASA Glenn Research Center and collaborators at the University of Michigan have developed SiGe transistors and amplifiers with state-of-the-art output power at microwave frequencies from 8 to 20 GHz. These transistors are fabricated using standard silicon processing and may be integrated with CMOS integrated circuits on a single chip. A scanning electron microscope image of a typical SiGe heterojunction bipolar transistor is shown in the preceding photomicrograph. This transistor achieved a record output power of 550 mW and an associated power-added efficiency of 33 percent at 8

  3. [Bipolar patients, structured psychotherapeutic treatment and approaches].

    PubMed

    Bonvalot, Thierry; Mazouni, Rabbah; Rivallan, Armel; Lassignardie, Hélène

    2010-01-01

    The current development of structured psychotherapy has brought gradual improvements to the treatment provided to bipolar patients. This psychotherapy may be either carried out individually or in a group. In this context, psychotherapeutic meditation seems beneficial.

  4. Bipolar disorder: causes, contexts, and treatments.

    PubMed

    Leahy, Robert L

    2007-05-01

    Bipolar disorder is a chronic and often devastating illness that may go undiagnosed because of its complex and diverse presentation. Clinicians can provide psychological treatments, in conjunction with pharmacotherapy, that can reduce the frequency, severity, and duration of manic and depressive episodes. Because bipolar disorder is characterized by high degrees of comorbidity and high rates of medical complications, the clinician will frequently need to implement other treatments targeted to comorbid conditions, such as panic, generalized anxiety, substance abuse, and personality disorders. This article introduces the issue of Journal of Clinical Psychology: In Session devoted to the treatment of bipolar disorder. We describe the cognitive styles and personal vulnerabilities that pose greater risk for bipolar disorder. Three evidence-based psychological treatments (interpersonal social rhythm therapy, family-focused treatment, and cognitive-behavioral therapy) and current pharmacological treatments are examined and illustrated. Finally, we review the effectiveness and practice implications of a variety of treatments for this severe and underresearched disorder.

  5. Spectroscopy of GaAs quantum wells

    SciTech Connect

    West, L.C.

    1985-07-01

    A new type of optical dipole transition in GaAs quantum wells has been observed. The dipole occurs between two envelope states of the conduction band electron wavefunction, and is called a quantum well envelope state transition (QWEST). The QWEST is observed by infrared absorption in three different samples with quantum well thicknesses 65, 82, and 92 A and resonant energies of 152, 121, and 108 MeV, respectively. The oscillator strength is found to have values of over 12, in good agreement with prediction. The linewidths are seen as narrow as 10 MeV at room temperature and 7 MeV at low temperature, thus proving a narrow line resonance can indeed occur between transitions of free electrons. Techniques for the proper growth of these quantum well samples to enable observation of the QWEST have also been found using (AlGa)As compounds. This QWEST is considered to be an ideal material for an all optical digital computer. The QWEST can be made frequency matched to the inexpensive Carbon Dioxide laser with an infrared wavelength of 10 microns. The nonlinearity and fast relaxation time of the QWEST indicate a logic element with a subpicosecond switch time can be built in the near future, with a power level which will eventually be limited only by the noise from a lack of quanta to above approximately 10 microwatts. 64 refs., 35 figs., 6 tabs.

  6. Optimising the management of bipolar disorder.

    PubMed

    MsAbda Mahmood; Ebmeler, Klaus R

    2015-05-01

    NICE recommends that when adults present in primary care with depression, they should be asked about previous periods of overactivity or disinhibited behaviour. If this behaviour lasted for four or more days referral for a specialist mental health assessment should be considered. Although depressive episodes are not necessary for a diagnosis of bipolar disorder, they are common and dominate the lifetime pattern of the condition: 50% of the time is spent in a euthymic (well) state, 38% in a depressed and 12% in a manic state. If there have only been depressive symptoms, it is not possible to exclude bipolar disorder. A diagnosis of bipolar disorder is supported by diagnostic criteria and usually confirmed by a psychiatrist. If the GP suspects mania or severe depression, or if patients are a danger to themselves or others, an urgent referral should be made for a specialist mental health assessment. If a manic episode has been present during the history the diagnosis is bipolar I disorder, while a hypomanic episode is indicative of bipolar disorder. The patient's care plan should include current health status, social situation, social support, co-ordination arrangements with secondary care, details of early warning signs, and the patient's preferred course of action in the event of a clinical relapse. Physical health checks should focus on cardiovascular disease, diabetes, obesity and respiratory disease given the heightened risk for these illnesses in bipolar disorder. PMID:27254890

  7. Optimising the management of bipolar disorder.

    PubMed

    MsAbda Mahmood; Ebmeler, Klaus R

    2015-05-01

    NICE recommends that when adults present in primary care with depression, they should be asked about previous periods of overactivity or disinhibited behaviour. If this behaviour lasted for four or more days referral for a specialist mental health assessment should be considered. Although depressive episodes are not necessary for a diagnosis of bipolar disorder, they are common and dominate the lifetime pattern of the condition: 50% of the time is spent in a euthymic (well) state, 38% in a depressed and 12% in a manic state. If there have only been depressive symptoms, it is not possible to exclude bipolar disorder. A diagnosis of bipolar disorder is supported by diagnostic criteria and usually confirmed by a psychiatrist. If the GP suspects mania or severe depression, or if patients are a danger to themselves or others, an urgent referral should be made for a specialist mental health assessment. If a manic episode has been present during the history the diagnosis is bipolar I disorder, while a hypomanic episode is indicative of bipolar disorder. The patient's care plan should include current health status, social situation, social support, co-ordination arrangements with secondary care, details of early warning signs, and the patient's preferred course of action in the event of a clinical relapse. Physical health checks should focus on cardiovascular disease, diabetes, obesity and respiratory disease given the heightened risk for these illnesses in bipolar disorder.

  8. The use of bipolar technology in hysteroscopy.

    PubMed

    Calabrese, Stefania; DE Alberti, Davide; Garuti, Giancarlo

    2016-04-01

    Bipolar technology was introduced in the hysteroscopic clinical use in 1999, by the design of both loop electrodes addressed to resectoscopic surgery and miniaturized electrodes adaptable to small-size hysteroscopes. The need of an electrolytic solution as distension medium and the spatial relationships between the active and return bipolar electrode avoid, by definition, the risks of severe electrolyte imbalance syndromes and unpredictable electrical burns, sometimes complicating monopolar surgery. The true revolution in the hysteroscopy care has achieved through the availability of mini-hysteroscopes not requiring cervical dilatation, thus limiting uterine wall damages and allowing surgeons to manage several endometrial pathologies by mini-invasive procedures using an effective electrosurgical bipolar instrumentation. Many surgical interventions, traditionally accomplished by the resectoscope in a surgical room theatre, can be now carried out in an outpatient setting without any support from anesthesia. The patients' avoidance of surgical room access and the quick return to daily activities lead to an obvious - but not fully demonstrated - improvement in the medical and social costs associated to outpatient operative hysteroscopy. In the field of resectoscopy, bipolar electrodes are clinically as effective as monopolar devices. Randomized trials showed that bipolar resectoscopic technology prevents the electrolyte imbalance observed after monopolar surgery. However, in daily clinical practice the assumedly safer profile of bipolar with respect to monopolar resectoscopy has not been demonstrated yet.

  9. The development of lurasidone for bipolar depression.

    PubMed

    Loebel, Antony; Xu, Jane; Hsu, Jay; Cucchiaro, Josephine; Pikalov, Andrei

    2015-11-01

    Bipolar disorder is a chronic, recurrent illness that ranks among the top 10 causes of disability in the developed world. As the illness progresses, major depressive episodes increasingly predominate. However, few treatment options are available that have demonstrated efficacy in the treatment of bipolar depression, either as monotherapy or adjunctive therapy in combination with mood stabilizers. Lurasidone is an atypical antipsychotic drug that was initially developed for the treatment of schizophrenia. Since no previous atypical antipsychotic development program had proceeded directly from work on schizophrenia to bipolar depression, the decision to focus on this indication represented an innovation in central nervous system drug development and was designed to address a clinically significant unmet need. The current review summarizes key results of a clinical development program undertaken to characterize the efficacy and safety of lurasidone in patients diagnosed with bipolar depression. Lurasidone is currently the only treatment for bipolar depression approved in the United States as both a monotherapy and an adjunctive therapy with lithium or valproate. The approval of lurasidone expands available treatment options for patients with bipolar depression and provides a therapy with an overall favorable risk-benefit profile. PMID:26771990

  10. All-optical transistor- and diode-action and logic gates based on anisotropic nonlinear responsive liquid crystal.

    PubMed

    Wang, Cheng-Yu; Chen, Chun-Wei; Jau, Hung-Chang; Li, Cheng-Chang; Cheng, Chiao-Yu; Wang, Chun-Ta; Leng, Shi-Ee; Khoo, Iam-Choon; Lin, Tsung-Hsien

    2016-08-05

    In this paper, we show that anisotropic photosensitive nematic liquid crystals (PNLC) made by incorporating anisotropic absorbing dyes are promising candidates for constructing all-optical elements by virtue of the extraordinarily large optical nonlinearity of the nematic host. In particular, we have demonstrated several room-temperature 'prototype' PNLC-based all-optical devices such as optical diode, optical transistor and all primary logic gate operations (OR, AND, NOT) based on such optical transistor. Owing to the anisotropic absorption property and the optical activity of the twist alignment nematic cell, spatially non-reciprocal transmission response can be obtained within a sizeable optical isolation region of ~210 mW. Exploiting the same mechanisms, a tri-terminal configuration as an all-optical analogue of a bipolar junction transistor is fabricated. Its ability to be switched by an optical field enables us to realize an all-optical transistor and demonstrate cascadability, signal fan-out, logic restoration, and various logical gate operations such as OR, AND and NOT. Due to the possibility of synthesizing anisotropic dyes and wide ranging choice of liquid crystals nonlinear optical mechanisms, these all-optical operations can be optimized to have much lower thresholds and faster response speeds. The demonstrated capabilities of these devices have shown great potential in all-optical control system and photonic integrated circuits.

  11. All-optical transistor- and diode-action and logic gates based on anisotropic nonlinear responsive liquid crystal

    PubMed Central

    Wang, Cheng-Yu; Chen, Chun-Wei; Jau, Hung-Chang; Li, Cheng-Chang; Cheng, Chiao-Yu; Wang, Chun-Ta; Leng, Shi-Ee; Khoo, Iam-Choon; Lin, Tsung-Hsien

    2016-01-01

    In this paper, we show that anisotropic photosensitive nematic liquid crystals (PNLC) made by incorporating anisotropic absorbing dyes are promising candidates for constructing all-optical elements by virtue of the extraordinarily large optical nonlinearity of the nematic host. In particular, we have demonstrated several room-temperature ‘prototype’ PNLC-based all-optical devices such as optical diode, optical transistor and all primary logic gate operations (OR, AND, NOT) based on such optical transistor. Owing to the anisotropic absorption property and the optical activity of the twist alignment nematic cell, spatially non-reciprocal transmission response can be obtained within a sizeable optical isolation region of ~210 mW. Exploiting the same mechanisms, a tri-terminal configuration as an all-optical analogue of a bipolar junction transistor is fabricated. Its ability to be switched by an optical field enables us to realize an all-optical transistor and demonstrate cascadability, signal fan-out, logic restoration, and various logical gate operations such as OR, AND and NOT. Due to the possibility of synthesizing anisotropic dyes and wide ranging choice of liquid crystals nonlinear optical mechanisms, these all-optical operations can be optimized to have much lower thresholds and faster response speeds. The demonstrated capabilities of these devices have shown great potential in all-optical control system and photonic integrated circuits. PMID:27491391

  12. All-optical transistor- and diode-action and logic gates based on anisotropic nonlinear responsive liquid crystal

    NASA Astrophysics Data System (ADS)

    Wang, Cheng-Yu; Chen, Chun-Wei; Jau, Hung-Chang; Li, Cheng-Chang; Cheng, Chiao-Yu; Wang, Chun-Ta; Leng, Shi-Ee; Khoo, Iam-Choon; Lin, Tsung-Hsien

    2016-08-01

    In this paper, we show that anisotropic photosensitive nematic liquid crystals (PNLC) made by incorporating anisotropic absorbing dyes are promising candidates for constructing all-optical elements by virtue of the extraordinarily large optical nonlinearity of the nematic host. In particular, we have demonstrated several room-temperature ‘prototype’ PNLC-based all-optical devices such as optical diode, optical transistor and all primary logic gate operations (OR, AND, NOT) based on such optical transistor. Owing to the anisotropic absorption property and the optical activity of the twist alignment nematic cell, spatially non-reciprocal transmission response can be obtained within a sizeable optical isolation region of ~210 mW. Exploiting the same mechanisms, a tri-terminal configuration as an all-optical analogue of a bipolar junction transistor is fabricated. Its ability to be switched by an optical field enables us to realize an all-optical transistor and demonstrate cascadability, signal fan-out, logic restoration, and various logical gate operations such as OR, AND and NOT. Due to the possibility of synthesizing anisotropic dyes and wide ranging choice of liquid crystals nonlinear optical mechanisms, these all-optical operations can be optimized to have much lower thresholds and faster response speeds. The demonstrated capabilities of these devices have shown great potential in all-optical control system and photonic integrated circuits.

  13. All-optical transistor- and diode-action and logic gates based on anisotropic nonlinear responsive liquid crystal.

    PubMed

    Wang, Cheng-Yu; Chen, Chun-Wei; Jau, Hung-Chang; Li, Cheng-Chang; Cheng, Chiao-Yu; Wang, Chun-Ta; Leng, Shi-Ee; Khoo, Iam-Choon; Lin, Tsung-Hsien

    2016-01-01

    In this paper, we show that anisotropic photosensitive nematic liquid crystals (PNLC) made by incorporating anisotropic absorbing dyes are promising candidates for constructing all-optical elements by virtue of the extraordinarily large optical nonlinearity of the nematic host. In particular, we have demonstrated several room-temperature 'prototype' PNLC-based all-optical devices such as optical diode, optical transistor and all primary logic gate operations (OR, AND, NOT) based on such optical transistor. Owing to the anisotropic absorption property and the optical activity of the twist alignment nematic cell, spatially non-reciprocal transmission response can be obtained within a sizeable optical isolation region of ~210 mW. Exploiting the same mechanisms, a tri-terminal configuration as an all-optical analogue of a bipolar junction transistor is fabricated. Its ability to be switched by an optical field enables us to realize an all-optical transistor and demonstrate cascadability, signal fan-out, logic restoration, and various logical gate operations such as OR, AND and NOT. Due to the possibility of synthesizing anisotropic dyes and wide ranging choice of liquid crystals nonlinear optical mechanisms, these all-optical operations can be optimized to have much lower thresholds and faster response speeds. The demonstrated capabilities of these devices have shown great potential in all-optical control system and photonic integrated circuits. PMID:27491391

  14. Terahertz pulse detection by the GaAs Schottky diodes

    NASA Astrophysics Data System (ADS)

    Laperashvili, Tina; Kvitsiani, Orest; Imerlishvili, Ilia; Laperashvili, David

    2010-06-01

    We present the results of experimental studies of physical properties of the detection process of GaAs Schottky diodes for terahertz frequency radiation. The development of technology in the THz frequency band has a rapid progress recently. Considered as an extension of the microwave and millimeter wave bands, the THz frequency offers greater communication bandwidth than is available at microwave frequencies. The Schottky barrier contact has an important role in the operation of many GaAs devices. GaAs Schottky diodes have been the primary nonlinear device used in millimeter and sub millimeter wave detectors and receivers. GaAs Schottky diodes are especially interesting due to their high mobility transport characteristics, which allows for a large reduction of the resistance-capacitance (RC) time constant and thermal noise. In This work are investigated the electrical and photoelectric properties of GaAs Schottky diodes. Samples were obtained by deposition of different metals (Au, Ni, Pt, Pd, Fe, In, Ga, Al) on semiconductor. For fabrication metal-semiconductor (MS) structures is used original method of metal electrodepositing. In this method electrochemical etching of semiconductor surface occurs just before deposition of metal from the solution, which contains etching material and metal ions together. For that, semiconductor surface cleaning processes and metal deposition carries out in the same technological process. In the experiments as the electrolyte was used aqueous solution of chlorides. Metal deposition was carried out at room temperature.

  15. Nondestructive tribochemistry-assisted nanofabrication on GaAs surface

    PubMed Central

    Song, Chenfei; Li, Xiaoying; Dong, Hanshan; Yu, Bingjun; Wang, Zhiming; Qian, Linmao

    2015-01-01

    A tribochemistry-assisted method has been developed for nondestructive surface nanofabrication on GaAs. Without any applied electric field and post etching, hollow nanostructures can be directly fabricated on GaAs surfaces by sliding a SiO2 microsphere under an ultralow contact pressure in humid air. TEM observation on the cross-section of the fabricated area shows that there is no appreciable plastic deformation under a 4 nm groove, confirming that GaAs can be removed without destruction. Further analysis suggests that the fabrication relies on the tribochemistry with the participation of vapor in humid air. It is proposed that the formation and breakage of GaAs-O-Si bonding bridges are responsible for the removal of GaAs material during the sliding process. As a nondestructive and conductivity-independent method, it will open up new opportunities to fabricate defect-free and well-ordered nucleation positions for quantum dots on GaAs surfaces. PMID:25761910

  16. The effect of aperture layout design on the multi-GHz operation of light-emitting transistors

    NASA Astrophysics Data System (ADS)

    Chou, Peng-Hao; Wang, Hsiao-Lun; Wu, Chao-Hsin

    2012-11-01

    The base current (IB) plays a key role in the transistor since its discovery (16 December 1947, Bardeen and Brattain). It separates the low impedance input (emitter) from the high impedance output (collector), thus yielding a "transfer resistor." Recently, III-V semiconductor material has been fabricated as a heterojunction bipolar transistor (HBT) which can operate as a high speed device. The HBT can be modified and operated as a three-port light-emitting device (an electrical input, electrical output, and a third port optical output) by incorporating one or more quantum wells in the base region, thus becoming a heterojunction bipolar light-emitting transistor (LET). In the present work, we have designed different sizes of emitter diameter DE and base diameter DB of InGaP/GaAs LETs in aperture layout design. Through different layout designs, the LETs exhibit different electrical current gain (β= IC/IB) and optical light output due to different carrier recombination processes in the transistor base region. By reducing the lateral emitter size from 18 to 13 μm, β increases due to the higher injection current densities and better confinement of the radiative recombination in the base region. Moreover, β increases when reducing the base diameter from 27 to 22 μm with fixed emitter diameter. The effective carrier recombination lifetime, τrec, can be estimated from dc analysis and rf measurement (small-signal modulation).We have obtained multi-GHz spontaneous light modulation of LETs, and the device performance is closely related to different layout designs with different device parasitics.

  17. An excellent enzymatic lactic acid biosensor with ZnO nanowires-gated AlGaAs/GaAs high electron mobility transistor.

    PubMed

    Ma, Siwei; Liao, Qingliang; Liu, Hanshuo; Song, Yu; Li, Ping; Huang, Yunhua; Zhang, Yue

    2012-10-21

    An excellent biosensor with ZnO nanowires-gated AlGaAs/GaAs high electron mobility transistor (HEMT) was used to detect lactic acid. Due to the new structure, addition of the Si-doped GaAs cap layer, the HEMT biosensor could detect a wide range of lactic acid concentrations from 0.03 nM to 300 mM. The novel biosensor exhibiting good performance along with fast response, high sensitivity, wide detection range, and long-term stability, can be integrated with a commercially available transmitter to realize lactic acid detection. PMID:22951602

  18. An excellent enzymatic lactic acid biosensor with ZnO nanowires-gated AlGaAs/GaAs high electron mobility transistor

    NASA Astrophysics Data System (ADS)

    Ma, Siwei; Liao, Qingliang; Liu, Hanshuo; Song, Yu; Li, Ping; Huang, Yunhua; Zhang, Yue

    2012-09-01

    An excellent biosensor with ZnO nanowires-gated AlGaAs/GaAs high electron mobility transistor (HEMT) was used to detect lactic acid. Due to the new structure, addition of the Si-doped GaAs cap layer, the HEMT biosensor could detect a wide range of lactic acid concentrations from 0.03 nM to 300 mM. The novel biosensor exhibiting good performance along with fast response, high sensitivity, wide detection range, and long-term stability, can be integrated with a commercially available transmitter to realize lactic acid detection.

  19. Clinical, Demographic, and Familial Correlates of Bipolar Spectrum Disorders among Offspring of Parents with Bipolar Disorder

    ERIC Educational Resources Information Center

    Goldstein, Benjamin I.; Shamseddeen, Wael; Axelson, David A.; Kalas, Cathy; Monk, Kelly; Brent, David A.; Kupfer, David J.; Birmaher, Boris

    2010-01-01

    Objective: Despite increased risk, most offspring of parents with bipolar disorder (BP) do not manifest BP. The identification of risk factors for BP among offspring could improve preventive and treatment strategies. We examined this topic in the Pittsburgh Bipolar Offspring Study (BIOS). Method: Subjects included 388 offspring, ages 7-17 years,…

  20. Subcortical Gray Matter Volume Abnormalities in Healthy Bipolar Offspring: Potential Neuroanatomical Risk Marker for Bipolar Disorder?

    ERIC Educational Resources Information Center

    Ladouceur, Cecile D.; Almeida, Jorge R. C.; Birmaher, Boris; Axelson, David A.; Nau, Sharon; Kalas, Catherine; Monk, Kelly; Kupfer, David J.; Phillips, Mary L.

    2008-01-01

    A study is conducted to examine the extent to which bipolar disorder (BD) is associated with gray matter volume abnormalities in brain regions in healthy bipolar offspring relative to age-matched controls. Results show increased gray matter volume in the parahippocampus/hippocampus in healthy offspring at genetic risk for BD.