Sample records for gaas bipolar transistor

  1. Dose rate and total dose 1/f noise performance of GaAs heterojunction bipolar transistors

    SciTech Connect

    Hiemstra, D.M. [SPAR Environmental Systems, Brampton, Ontario (Canada)] [SPAR Environmental Systems, Brampton, Ontario (Canada)

    1996-12-01

    In this paper, for the first time to the authors` knowledge, dose rate and total dose 1/f noise performance of GaAs heterojunction bipolar transistors is presented. These devices are being investigated for use in amplifiers for sensor readout in an experimental fusion reactor. Here, GaAs heterojunction bipolar transistor 1/f noise performance is demonstrated to be unaffected by dose rate and total dose. This is believed to be due to shielding provided by the N{sup +} collector from the GaAs substrate.

  2. Significant Effect of Emitter Area on the Efficiency, Stability and Reliability of Picosecond Switching in a GaAs Bipolar Transistor Structure

    Microsoft Academic Search

    Sergey N. Vainshtein; Valentin S. Yuferev; Juha T. Kostamovaara; Marina M. Kulagina; Hannu T. Moilanen

    2010-01-01

    A drastic reduction in the residual voltage (from ~ 100 V to a few volts) and a significant (factor of ~ 2) increase in the dU\\/dt switching rate is demonstrated experimentally in the superfast ( ~ 200 ps) avalanche switching of a GaAs bipolar junction transistor with increased emitter area. This result is not a trivial one as only a

  3. A GaAs heterojunction bipolar transistor with 106 V breakdown

    SciTech Connect

    Baca, A.G.; Klem, J.F.; Ashby, C.I.; Martin, D.C.

    2000-01-11

    A high voltage GaAs HBT with an open-base collector breakdown voltage of 106 V and an open-emitter breakdown voltage of 134 V has been demonstrated. A high quality 9.0 {micro}m thick collector doped to 2.0{times}10{sup 15} cm{sup {minus}3} grown by MBE on a doped GaAs substrate is the key to achieving this breakdown. These results were achieved for HBTs with 4{times}40 {micro}m{sup 2} emitters. DC current gain of 38 at 6,000 A/cm{sup 2} was measured.

  4. 25-42 GHz GaAs heterojunction bipolar transistor low phase noise push-push VCOs

    Microsoft Academic Search

    D. M. Smith; J. C. Canyon; D. L. Tait

    1989-01-01

    Two push-push thin-film VCOs (voltage-controlled oscillators) utilizing GaAs-AlGaAs heterojunction bipolar transistors that cover the 25-42 GHz frequency range are presented. Key features of the designs are: greater than 33% continuous tuning bandwidth, SSB phase noise less than -70 dBc\\/Hz at 100 kHz offset, and better than -90-dBc fundamental spur suppression. Over 10 GHz of tunability has been achieved using this

  5. Bipolar Junction Transistors

    NSDL National Science Digital Library

    Kuphaldt, Tony R.

    All About Circuits is a website that â??provides a series of online textbooks covering electricity and electronics.â? Written by Tony R. Kuphaldt, the textbooks available here are wonderful resources for students, teachers, and anyone who is interested in learning more about electronics. This specific section, Bipolar Junction Transistors, is the fourth chapter in Volume III â??Semiconductors. A few of the topics covered in this chapter include: The Transistor as a Switch, Active Mode Operation, and Input and Output Coupling. Diagrams and detailed descriptions of concepts are included throughout the chapter to provide users with a comprehensive lesson. Visitors to the site are also encouraged to discuss concepts and topics using the All About Circuits discussion forums (registration with the site is required to post materials).

  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. GaAs-based heterojunction bipolar transistors for very high performance electronic circuits

    Microsoft Academic Search

    PETER M. ASBECK; FRANK MAU-CHUNG CHANG; KEH-CHUNG WANG; GERARD J. SULLIVAN; DEREK T. CHEUNG

    1993-01-01

    This paper reviews the principles and status of AlGaAs\\/GaAs heterojunction bipolar transistor technology. Comparisons of this technology with Si bipolar transistor and GaAs field-effect transistor technologies are made. Epitaxial materials, fabrication processes, transistor DC and RF characteristics, and modeling of AlGaAs\\/GaAs HBT's are described. Key areas of HBT application are also highlighted

  8. 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

  9. Vertical bipolar charge plasma transistor with buried metal layer.

    PubMed

    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 · f(T) 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. THz Bipolar Transistor Circuits: Technical Feasibility, Technology Development,

    E-print Network

    Rodwell, Mark J. W.

    THz Bipolar Transistor Circuits: Technical Feasibility, Technology Development, Integrated Circuit Scientific Abstract--We examine the feasibility of developing bipolar transistors with current-gain and power-frequency performance limits of InP-based bipolar transistors, and their potential for operation at low THz frequencies

  11. Scaling of SiGe Heterojunction Bipolar Transistors

    E-print Network

    Rieh, Jae-Sung

    Scaling of SiGe Heterojunction Bipolar Transistors JAE-SUNG RIEH, SENIOR MEMBER, IEEE, DAVID-century. This paper inves- tigates the impacts of scaling on SiGe heterojunction bipolar tran- sistors (HBTs), which and operation current density. Bipolar transistor scaling rules are reviewed and compared with accumulated

  12. 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??m, 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

  13. Electrothermal stability of bipolar transistors at medium-and high-current operation regimes

    E-print Network

    Technische Universiteit Delft

    Electrothermal stability of bipolar transistors at medium- and high-current operation regimes N Naples, Italy Abstract -- Electrothermal behavior of single- and two- finger bipolar transistors. Index Terms -- Bipolar devices, bipolar modeling and simulation, electrothermal behavior, electrothermal

  14. Vertical scaling in heterojunction bipolar transistors with nonequilibrium base transport

    E-print Network

    Levi, Anthony F. J.

    -p-n heterojunction bipolar transistors. It is empirically established that extreme nonequilibrium electron transport electron transport. In a classical n-p-n homojunction (and graded-juno tion) bipolar transistor, electrons that this behavior is re- lated to nondiffusive electron transport in the base. Single crystal, Ab.4,1no.szAs/Ina53G

  15. Single-event burnout of epitaxial bipolar transistors

    SciTech Connect

    Kuboyama, S.; Sugimoto, K.; Shugyo, S.; Matsuda, S. [National Space Development Agency of Japan, Tsukuba, Ibaraki (Japan)] [National Space Development Agency of Japan, Tsukuba, Ibaraki (Japan); Hirao, T. [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan)] [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan)

    1998-12-01

    Single-Event Burnout (SEB) of bipolar junction transistors (BJTs) has been observed nondestructively. It was revealed that all the NPN BJTs, including small signal transistors, with thinner epitaxial layers were inherently susceptible to the SEB phenomenon. It was demonstrated that several design parameters of BJTs were responsible for SEB susceptibility. Additionally, destructive and nondestructive modes of SEB were identified.

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

    NASA Astrophysics Data System (ADS)

    Mimila-Arroyo, J.

    2013-11-01

    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.

  17. Impact of emitter resistance mismatch on base and collector current matching in bipolar transistors

    E-print Network

    McNeill, John A.

    Impact of emitter resistance mismatch on base and collector current matching in bipolar transistors rue des Martyrs, 38016 Grenoble, France ABSTRACT Bipolar transistor matching is characterized the bipolar transistor matching in medium and high current zones. We demonstrate the preponderant impact

  18. IEEE BCTM 2.1 On the Feasibility of few-THz Bipolar Transistors

    E-print Network

    Rodwell, Mark J. W.

    IEEE BCTM 2.1 On the Feasibility of few-THz Bipolar Transistors Mark Rodwell, E. Lind, Z. Griffith the limits faced in scaling of InP-based bipolar transistors for increased device bandwidth. Emitter and baseGe technologies. 250 nm Indium Phosphide (InP) heterojunction bipolar transistors (HBTs) have demonstrated 416 GHz

  19. Measurement of the electron ionization coefficient at low electric fields in GaAs-based heterojunction bipolar transistors

    Microsoft Academic Search

    Claudio Canali; Federico Capasso; Roger Malik; Andrea Neviani; Paolo Pavan; Carlo Tedesco; Enrico Zanoni

    1994-01-01

    Values of the electron ionization coefficient ?n in ?100? GaAs extending the previously available data by two orders of magnitude, down to 1 cm-1, are presented. The data are directly extracted from the multiplication factor, M-1, measured in lightly doped collector n-p-n AlGaAs\\/GaAs heterojunction bipolar transistors (HBT's). It is shown that the sensitivity of the technique is limited by the

  20. RF Model of Lateral Bipolar Junction Transistor on Silicon-on-Insulator Substrate

    E-print Network

    Ng, Wai Tung

    RF Model of Lateral Bipolar Junction Transistor on Silicon-on-Insulator Substrate Dora Lee and I-Shan Michael Sun and Wai Tung Ng Abstract- A methodology for modelling a novel high- frequency lateral bipolar] in the lateral bipolar transistor (LBJT) indicate that there is a drive to better integrate bipolar devices

  1. 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.

  2. Low noise fast bipolar transistors for detector preamplifiers

    SciTech Connect

    Morii, M.M.; Taniguchi, T.; Fuhushima, Y.

    1989-02-01

    The noise parameters of several species of microwave bipolar transistors were measured using a common base amplifier. The base spread resistance r/sub bb'/ of the transistors were determined from the measured noise parameters. Some species were found to have r/sub bb'/ of less than 30..cap omega... For the low noise preamplifier applications in high energy physics, the series noise contribution from these values of r/sub bb'/ is negligibly small compared with that due to the emitter resistance r/sub e/. A simple relation between the structure of transistors and their r/sub bb'/ was found.

  3. 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…

  4. Silicon carbide and silicon carbide:germanium heterostructure bipolar transistors

    E-print Network

    Kolodzey, James

    Silicon carbide and silicon carbide:germanium heterostructure bipolar transistors K. J. Roe,a) G HBTs based on silicon carbide SiC and a silicon carbide:germanium SiC:Ge alloy. The SiC:Ge base alloy: 10.1063/1.1358851 Silicon carbide has garnered considerable attention as a promising material for use

  5. 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…

  6. Design, Simulation and Modeling of Insulated Gate Bipolar Transistor 

    E-print Network

    Gupta, Kaustubh

    2013-07-09

    The market for Insulated Gate Bipolar Transistor (IGBT) is growing and there is a need for techniques to improve the design, modeling and simulation of IGBT. In this thesis, we first developed a new method to optimize the layout and dimensions...

  7. Analysis of magnetic proportional drive circuits for bipolar junction transistors

    Microsoft Academic Search

    R. L. Avant; W. T. Michael; D. J. Shortt; R. E. Palma

    1985-01-01

    A comparison is presented of some advantages and disadvantages of three popular magnetic proportional drive circuits for bipolar junction transistors (BJT) used in spacecraft switched mode power supplies (SMPS). A generic classification of these drives is introduced. A novel adaptation of one of these drives, the multiple mode proportional drive (MMPD), is developed to provide a total proportional drive for

  8. High Current Analog Bipolar Junction Transistor Amplifier Integrated Circuit Development

    E-print Network

    Texas at Arlington, University of

    (considering push-pull, class AB, common emitter and emitter follower designs) A. Comparison of circuit, common emitter and emitter follower designs C. Circuits - procedures for and determination of practicalHigh Current Analog Bipolar Junction Transistor Amplifier Integrated Circuit Development Statement

  9. Current-driven instabilities and high-injection phenomena in heterojunction bipolar transistors

    NASA Astrophysics Data System (ADS)

    Posse, Vladimir A.

    A comprehensive numerical investigation of the carrier transport in bipolar transistor collectors at high levels of injection is undertaken with the primary purpose of designing a novel GaAs-based heterojunction bipolar transistor (HBT) capable of intrinsic transferred-electron induced current oscillations. The behavior of III-V HBTs at high collector currents is found to depend on the intricate interplay between the transferred-electron (Gunn-Hilsum) and base widening (Kirk) phenomena arising at similar current levels. While all the conditions for the emergence of Gunn oscillations can be readily met in GaAs transistor collectors, the HBT intrinsic stability under the DC conditions is ensured by the base widening creating the collector field profile detrimental to the nucleation of Gunn charge domains. Under transient conditions, we determine that the onset of base widening upon bias switching is associated with a time delay caused by the slow diffusive influx of carriers in the forming current-induced base region. The ways to utilize the Kirk effect transient phenomenon to enhance silicon transistors high-frequency characteristics are discussed. We develop the improved large-signal models, for both silicon and GaAs transistors, compatible with the standard CAD tools and taking into account the base widening onset delay. During this delay, propagating charge domains are formed in the III-V HBT collectors. The impact of the transferred-electron effect in III-V HBTs on the Kirk effect threshold conditions and the device transient behavior is discussed. We then demonstrate that proper engineering of the collector field profile greatly increases the base widening onset delay and leads to the intrinsic collector current instabilities, similar to those in Gunn diodes. Further modification of the collector doping profile and judicious choice of bias conditions may result in the appearance of the sustainable microwave or millimeter wave current oscillations in III-V transistor structures. The principles of design, operation, and industrial application, as well as technological advantages, of the proposed device are discussed and demonstrated by numerical simulations. The novel three-terminal bipolar transferred electron oscillator (BTEO) can combine signal generation and modulation stages in a single device.

  10. Development of a RF Bipolar Transistor in a Standard 0.35m CMOS Technology

    E-print Network

    Ng, Wai Tung

    Development of a RF Bipolar Transistor in a Standard 0.35µm CMOS Technology I-Shan Michael Sun-0021, Japan ABSTRACT A RF Bipolar Transistor integrated to a standard 0.35µm CMOS process is presented compared to previously published BiCMOS technologies. Key Words 0.35µm CMOS Technology, RF Silicon Bipolar

  11. The Effects of Aging and Hydrogen on the Radiation Response of Gated Lateral PNP Bipolar Transistors

    Microsoft Academic Search

    David. R. Hughart; Ronald D. Schrimpf; Daniel M. Fleetwood; X. Jie Chen; Hugh J. Barnaby; Keith E. Holbert; Ronald L. Pease; Dale G. Platteter; Blair R. Tuttle; Sokrates T. Pantelides

    2009-01-01

    Complex interplay between hydrogen-related defect formation and passivation is observed in irradiated bipolar transistors. Hydrogen soaking experiments are performed to evaluate the dependence of defect buildup and annealing in gated lateral bipolar transistors on hydrogen exposure. Comparisons of the radiation responses of transistors tested in 2009 to identical devices from the same wafer tested in 2003 show that aging has

  12. A gallium phosphide high-temperature bipolar junction transistor

    Microsoft Academic Search

    T. E. Zipperian; L. R. Dawson; R. J. Caffin

    1981-01-01

    Preliminary results are reported on the development of a high-temperature (> 350°C) gallium phosphide bipolar junction transistor (BJT) for goethermal and other energy applications. This four-layer p\\/sup +\\/n⁻pp\\/sup +\\/ structure was fromed 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

  13. AlGaN\\/GaN heterojunction bipolar transistor

    Microsoft Academic Search

    L. S. McCarthy; P. Kozodoy; M. J. W. Rodwell; S. P. DenBaars; U. K. Mishra

    1999-01-01

    We demonstrate the first GaN bipolar transistor. An AlGaN\\/GaN HBT structure was grown by MOCVD on c-plane sapphire substrate. The emitter was grown with an Al0.1Ga0.9N barrier to increase the emitter injection efficiency. Cl2 RIE was used to pattern the emitter mesa, and selectively regrown base contact pads were implemented to reduce a contact barrier associated with RIE etch damage

  14. Bipolar transistor scaling for minimum switching delay and energy dissipation

    Microsoft Academic Search

    J. M. C. Stork

    1988-01-01

    A novel figure-of-merit to guide in the scaling of high-speed bipolar transistors is proposed. A method is described to relate the gate delay of a ring-oscillator to measurable device parameters analytically. The closed-form solution for an unloaded ECL (emitter coupled logic) gate agrees very well with published data of the past several years and with the results of circuit simulation.

  15. Investigation of the tunneling emitter bipolar transistor as spin-injector into silicon

    E-print Network

    Van Veenhuizen, Marc Julien

    2010-01-01

    In this thesis is discussed the tunneling emitter bipolar transistor as a possible spin-injector into silicon. The transistor has a metallic emitter which as a spin-injector will be a ferromagnet. Spin-polarized electrons ...

  16. Local bipolar-transistor gain measurement for VLSI devices

    NASA Astrophysics Data System (ADS)

    Bonnaud, O.; Chante, J. P.

    1981-08-01

    A method is proposed for measuring the gain of a bipolar transistor region as small as possible. The measurement then allows the evaluation particularly of the effect of the emitter-base junction edge and the technology-process influence of VLSI-technology devices. The technique consists in the generation of charge carriers in the transistor base layer by a focused laser beam in order to bias the device in as small a region as possible. To reduce the size of the conducting area, a transversal reverse base current is forced through the base layer resistance in order to pinch in the emitter current in the illuminated region. Transistor gain is deduced from small signal measurements. A model associated with this technique is developed, and this is in agreement with the first experimental results.

  17. A comparison between bipolar transistor and nanowire field effect transistor biosensors

    NASA Astrophysics Data System (ADS)

    Zafar, Sufi; Khater, Marwan; Jain, Vibhor; Ning, Tak

    2015-02-01

    Important performance metrics, such as sensitivity and signal to noise ratio (SNR) of bipolar transistor based biosensors, are compared to those for nanowire field effect transistor (FET) sensors. The sensor consists of a heterojunction bipolar transistor (HBT) with silicon germanium base connected to a sensing surface in contact with the solution. The measured sensitivity is ?2 times and SNR is >20 times higher in comparison to those for nanowire FET sensors. More importantly, the HBT biosensor sensitivity is constant over the sensing range of ˜5 decades and depends only on the temperature. In comparison, the nanowire FET sensor sensitivity varies in a complex manner over the sensing range and exhibits significant fabrication induced sensor to sensor variations. Consequently, HBT sensors would require minimal calibration for quantitative sensing studies. Furthermore, the bipolar transistor SNR is not only significantly higher but is also constant over the sensing range. In comparison, the nanowire FET sensor SNR varies with the peak value confined over a narrow sensing range. Hence, HBT sensor has <20 times lower detection limit that remains constant over the sensing range. In summary, HBT sensors are demonstrated to have superior performance metrics and are better suited for quantitative studies. Lastly, these HBT sensors also provide simultaneous temperature measurement.

  18. Proposal and design of a new SiC-emitter lateral NPM Schottky collector bipolar transistor on

    E-print Network

    Kumar, M. Jagadesh

    Proposal and design of a new SiC-emitter lateral NPM Schottky collector bipolar transistor on SOI for VLSI applications M. Jagadesh Kumar and D.V. Rao Abstract: A novel bipolar transistor structure, namely, a SiC emitter lateral NPM Schottky collector bipolar transistor (SCBT) with a silicon-on-insulator (SOI

  19. The equivalence of displacement damage in silicon bipolar junction transistors

    NASA Astrophysics Data System (ADS)

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

    2012-06-01

    The current gain degradation in silicon bipolar junction transistors (BJTs) is examined under the irradiation with heavy ions. To characterize the radiation damage of the BJTs, the ionizing dose Di and displacement dose Dd verse the chip depth in the BJTs have been calculated for heavy ions. Based on the irradiation testing and calculation results, an approach to evaluate the equivalence of displacement damage in silicon BJTs is given, which could optimize the non-ionizing energy loss (NIEL) methodology and normalize the displacement damage caused by heavy ions.

  20. Single-event burnout of power bipolar junction transistors

    SciTech Connect

    Titus, J.L. (Naval Weapons Support Center, Crane, IN (United States)); Johnson, G.H.; Schrimpf, R.D.; Galloway, K.F. (Arizona Univ., Tucson, AZ (United States). 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.

  1. SiGe bipolar junction transistors for microwave power applications

    Microsoft Academic Search

    Gregory N. Henderson; Matthew F. O'Keefe; Timothy E. Boles; P. Noonan; J. M. Sledziewski; B. M. Brown

    1997-01-01

    High-efficiency silicon germanium (SiGe) bipolar junction transistors have been developed for 5-10 V, 1.88 GHz power amplifier applications. Class A-B biased common base parts have demonstrated a power gain Gp=16 dB, one-dB compression point P1dB=25 dBm and power-added-efficiency PAE(P1dB)=53% at Vc=5 V and >1 W output power with >15 dB gain and >50% PAE at Vc=10 V. Common-emitter measurements (Vc=7

  2. IEEE BCTM 12.3 Distribution ofthe Collector Resistance ofPlanar Bipolar Transistors

    E-print Network

    Technische Universiteit Delft

    IEEE BCTM 12.3 Distribution ofthe Collector Resistance ofPlanar Bipolar Transistors: Impact Abstract We investigate the relevance ofthe distribution ofthe extrinsic collector resistance of a bipolar results are relevant to compact modeling, bipolar device technology de- velopment and characterization

  3. 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.

  4. Evaluation of the Radiation Tolerance of SiGe Heterojunction Bipolar Transistors Under

    E-print Network

    California at Santa Cruz, University of

    current than the other transistors, and a large number of additional transistors used in shaping sectionsEvaluation of the Radiation Tolerance of SiGe Heterojunction Bipolar Transistors Under 24GeV Proton-For the potential use in future high luminosity applications in High Energy Physics (HEP) (e.g. the Large Hadron

  5. Theoretical values of various parameters in the Gummel-Poon model of a bipolar junction transistor

    NASA Technical Reports Server (NTRS)

    Benumof, R.; Zoutendyk, J.

    1986-01-01

    Various parameters in the Gummel-Poon model of a bipolar junction transistor are expressed in terms of the basic structure of a transistor. A consistent theoretical approach is used which facilitates an understanding of the foundations and limitations of the derived formulas. The results enable one to predict how changes in the geometry and composition of a transistor would affect performance.

  6. Noise behavior of GaAs field-effect transistors with short gate lengths

    Microsoft Academic Search

    W. Baechtold; W. V. Munch; N. Kawamura; D. Shinoda; R. Igarashi; H. Muta; Y. Seki

    1972-01-01

    The noise behavior of the GaAs Schottky-barrier gate field-effect transistor has been investigated theoretically and experimentally. It has been found that an additional noise source has to be taken into account in GaAs FET's biased in the pinchoff region: the intervalley scattering noise. This noise source has been investigated and a new transistor noise model is proposed. Measured and calculated

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

    SciTech Connect

    Kennedy, E.J. (Tennessee Univ., Knoxville, TN (USA) Oak Ridge National Lab., TN (USA)); Alley, G.T.; Britton, C.L. Jr. (Oak Ridge National Lab., TN (USA)); Skubic, P.L. (Oklahoma Univ., Norman, OK (USA)); Gray, B.; Wu, A. (Tennessee Univ., Knoxville, TN (USA))

    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.

  8. Bendable GaAs metal-semiconductor field-effect transistors formed with printed GaAs wire arrays on plastic substrates

    E-print Network

    Rogers, John A.

    Bendable GaAs metal-semiconductor field-effect transistors formed with printed GaAs wire arrays Micro/nanowires of GaAs with integrated ohmic contacts have been prepared from bulk wafers by metal of these wires at low temperatures onto plastic substrates yield high-quality bendable metal-semiconductor field

  9. Bipolar junction transistor models for circuit simulation of cosmic-ray-induced soft errors

    NASA Technical Reports Server (NTRS)

    Benumof, R.; Zoutendyk, J.

    1984-01-01

    This paper examines bipolar junction transistor models suitable for calculating the effects of large excursions of some of the variables determining the operation of a transistor. Both the Ebers-Moll and Gummel-Poon models are studied, and the junction and diffusion capacitances are evaluated on the basis of the latter model. The most interesting result of this analysis is that a bipolar junction transistor when struck by a cosmic particle may cause a single event upset in an electronic circuit if the transistor is operated at a low forward base-emitter bias.

  10. Microwave power heterojunction bipolar transistors fabricated with thermal shunt bathtub

    SciTech Connect

    Bozada, C.A.; Barlage, D.W.; Barrette, J.P. [and others

    1995-12-31

    Heterojunction bipolar transistor devices and circuits were fabricated using thermal shunt and bathtub thermal management techniques. Broadband cascode MMICs exhibited 10 - 14 dB gain at an output power of 2.5 - 3.0 Watts across 7 - 11 GHz. A 200 {mu}m{sup 2} common-emitter unit cell achieved 7 - 8 dB linear power gain and 40% power-added efficiency at a noise power ratio (NPR) of 18 dBc at 12 GHz. Under single tone measurements at 12 GHz, the unit cell achieved 52% power-added efficiency, with 9.5 dB linear gain, 8 dB power gain and 240 mW output power at 5 V bias.

  11. 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.

  12. Enhanced breakdown voltage and reduced self-heating effects in thin-film lateral bipolar transistors: Design and

    E-print Network

    Kumar, M. Jagadesh

    Enhanced breakdown voltage and reduced self-heating effects in thin-film lateral bipolar bipolar transistor (CT-SLBT) on silicon-on-insulator (SOI), which shows enhanced breakdown voltage as high as 80% when compared with that of the conventional uniformly doped lateral bipolar transistor (LBT

  13. 1376 IEEE TRANSACTIONS ON ELECTRON DEVICES, VOL. 52, NO. 7, JULY 2005 Lateral High-Speed Bipolar Transistors

    E-print Network

    Ng, Wai Tung

    1376 IEEE TRANSACTIONS ON ELECTRON DEVICES, VOL. 52, NO. 7, JULY 2005 Lateral High-Speed Bipolar--This paper introduces a novel silicon-on-insulator (SOI) lateral radio-frequency (RF) bipolar transistor for lateral bipolar junction transistors (LBJT) so far. As for the high-voltage device, the measured max of 12

  14. Silicon Nanomembrane Bipolar Junction Transistors for Microwave Frequency Applications

    NASA Astrophysics Data System (ADS)

    Bavier, John; Ballarotto, Vince; Cumings, John

    2014-03-01

    Silicon nanomembranes (SiNMs) are a promising material for flexible semiconductor devices due to their high carrier mobility and compatibility with standard CMOS processing. Previous studies have reported SiNM field-effect transistors with operating frequencies as high as 12 GHz. In order to expand the utility of SiNM devices, a method for the fabrication of monocrystalline microwave frequency silicon bipolar junction transistors (BJTs) will be presented. High-temperature processing of SiNM BJT devices is performed on a Silicon-on-Insulator (SOI) wafer. Using angled ion implantation, conformal chemical vapor deposition and anisotropic reactive ion etching, a poly-silicon sidewall spacer is formed. This spacer defines a base region approximately 200nm wide without the use of electron beam lithography. Devices are then released using selective wet etching in HF and transferred to alternate flexible substrates. Microwave frequency data will be presented, and the effects of the transfer process on device performance will be discussed.

  15. Gallium phosphide high-temperature bipolar junction transistor

    SciTech Connect

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

    1981-03-01

    Preliminary results are reported on the development of a high-temperature (> 350/sup 0/C) gallium phosphide bipolar junction transistor (BJT) for goethermal and other energy applications. This four-layer p/sup +/n/sup -/pp/sup +/ structure was fromed 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 gallium phosphide BJT is observed to have a common-emitter current gain peaking in the range of 6 to 10 (for temperatures from 20/sup 0/C to 400/sup 0/C) and a room-temperature, punchthrough-limited, collector-emitter breakdown voltage of approximately -6V. Other parameters of interest include an f/sub/ = 400 KHz (at 20/sup 0/C) and a collector base leakage current = 200 ..mu..A (at 350/sup 0/C).

  16. Impact of polysilicon emitter interfacial layer engineering on the 1\\/f noise of bipolar transistors

    Microsoft Academic Search

    Eddy Simoen; Stefaan Decoutere; Alan Cuthbertson; Cor L. Claeys; Ludo Deferm

    1996-01-01

    To optimize the electrical characteristics of polysilicon emitter bipolar transistors, the poly emitter interface needs careful engineering. In this paper, bipolar transistors of a 0.5 ?m BiCMOS process have been fabricated with intentionally grown oxides in an LPCVD cluster for precise control over the interfacial oxide thickness and uniformity. The trade off between current gain enhancement and increased 1\\/f noise

  17. Location of low-frequency noise sources in submicrometer bipolar transistors

    Microsoft Academic Search

    Theo G. M. Kleinpenning

    1992-01-01

    Expressions are derived for the low-frequency noise (1\\/f noise, shot noise, Nyquist noise) in bipolar transistors. Particular attention has been paid to the influence of the internal base and emitter series resistance. The expressions have been compared with experimental results from submicrometer silicon bipolar transistors. It is found at low forward currents that the 1\\/f noise is dominated by 1\\/f

  18. The impact of non-equilibrium transport on breakdown and transit time in bipolar transistors

    Microsoft Academic Search

    E. F. Crabbe; J. M. C. Stork; G. Baccarani; M. V. Fischetti; S. E. Laux

    1990-01-01

    Impact ionization and velocity overshoot in the base-collector junction of bipolar transistors are studied using Monte Carlo simulation and the hydrodynamic energy-balance equation. For advanced bipolar transistors, the carrier energy lags the electric field; therefore, the maximum impact ionization rate occurs deep into the junction. A simplified solution of the energy-balance equation can accurately model this nonlocal behavior. Excellent agreement

  19. Small-signal and noise model extraction technique for heterojunction bipolar transistor at microwave frequencies

    Microsoft Academic Search

    J. P. Roux; L. Escotte; R. Plana; J. Graffeuil; S. L. Delage; H. Blanck

    1995-01-01

    The increasing use of Heterojunction Bipolar Transistors (HBT's) in microwave analog circuits requires a valid description of these devices by means of an equivalent circuit including noise sources in an extended bias and frequency range. This paper describes a technique to extract the elements of the equivalent circuit from simultaneous noise and S-parameter measurements. Additionally, the conventional high frequency bipolar

  20. Evaluation of temperature-enhanced gain degradation of verticle npn and lateral pnp bipolar transistors

    SciTech Connect

    Witczak, S.C.; Lacoe, R.C. [Aerospace Corp., Los Angeles, CA (United States). Electronics Technology Center; Galloway, K.F. [Vanderbilt Univ., Nashville, TN (United States). Dept. of Electrical and Computer Engineering] [and others

    1997-03-01

    The effect of dose rate on radiation-induced gain degradation is compared for verticle npn and lateral pnp bipolar transistors. High dose rate irradiations at elevated temperatures are more effective at simulating low dose rate degradation in the lateral pnp transistors.

  1. Silicon-germanium base heterojunction bipolar transistors by molecular beam epitaxy

    Microsoft Academic Search

    S. S. Iyer; G. L. Patton; S. S. Delage; S. Tiwari; J. M. C. Stork

    1987-01-01

    We report the first SiGe base heterojunction Bipolar Transistors (HBT) The devices were fabricated using Molecular Beam Epitaxy (MBE), low temperature processing and different germanium contents. The transistors demonstrate current gain and show the expected increase in collector current as a result of reduced bandgap due to Ge incorporation in the base. A 6 times increase in collector current was

  2. On noise sources in hot electron-degraded bipolar junction transistors

    Microsoft Academic Search

    P. Llinares; G. Ghibaudo; J. A. Chroboczek

    1997-01-01

    The effects of electrical stress on static characteristics and power spectral density, SIb, of base current, Ib, fluctuations at low frequencies, f<1 kHz, have been studied in quasiself-aligned bipolar n-p-n junction. In as-fabricated devices SIb?1\\/AE, where AE is the transistor emitter area, whereas in strongly degraded transistors Sib?1\\/PE, where PE is the transistor perimeter. The latter demonstrates directly that hot

  3. Transistor-based measurements of electron injection currents in p -type GaAs doped 10 sup 18 --10 sup 20 cm sup minus 3

    SciTech Connect

    Klausmeier-Brown, M.E.; Melloch, M.R.; Lundstrom, M.S. (School of Electrical Engineering, Purdue University, West Lafayette, Indiana 47907 (US))

    1990-01-08

    Measurements of electron currents injected into {ital p}{sup +}-GaAs are presented for molecular beam epitaxially grown material doped from 2{times}10{sup 18} to 8{times}10{sup 19} cm{sup {minus}3} with Be. The collector current versus base-emitter voltage characteristics of {ital n}-{ital p}{sup +}-{ital n} GaAs homojunction bipolar transistors are analyzed, and the results are interpreted in terms of the quantity ({ital n}{sub 0}{ital D}{sub {ital n}}), where {ital n}{sub 0} is the equilibrium minority-carrier concentration and {ital D}{sub {ital n}} is the minority-carrier diffusion coefficient. The results are consistent with earlier measurements of ({ital n}{sub 0}{ital D}{sub {ital n}}) made using metalorganic chemical vapor deposited {ital p}{sup +}-{ital n} GaAs solar cells, Zn doped as heavily as 1{times}10{sup 19} cm{sup {minus}3}. The large electron injection currents observed are interpreted as evidence for significant effective band-gap shrinkage. These effects must be accounted for in the modeling and design of GaAs-based heterojunction bipolar transistors and solar cells.

  4. GaAs metaloxidesemiconductor field-effect transistor with nanometer-thin dielectric grown by atomic layer deposition

    E-print Network

    Ye, Peide "Peter"

    GaAs metal­oxide­semiconductor field-effect transistor with nanometer- thin dielectric grown, New Jersey 07974 Received 27 January 2003; accepted 7 May 2003 A GaAs metal­oxide­semiconductor field. © 2003 American Institute of Physics. DOI: 10.1063/1.1590743 GaAs metal­oxide­semiconductor field

  5. Phosphidization of GaAs by a remote phosphine plasma process and its application to surface passivation of GaAs metal-semiconductor field-effect transistors

    NASA Astrophysics Data System (ADS)

    Sugino, Takashi; Nozu, Satoshi; Nakajima, Shigeru

    1999-05-01

    Surface passivation of GaAs due to phosphidization is investigated. GaAs surfaces are treated with a remote plasma of phosphine (PH3) diluted with Ar. X-ray photoelectron spectroscopy analysis reveals that the PH3 plasma treatment removes native oxide from GaAs surfaces and that generation of As oxide is suppressed on phosphidized surfaces. Photoluminescence intensity is enhanced for phosphidized GaAs. The PH3 plasma treatment is applied to surface passivation of GaAs metal-semiconductor field-effect transistors. A significant increase of the drain current and the transconductance is achieved. These results strongly suggest that the surface states have been passivated.

  6. Graded-SiGe-base, poly-emitter heterojunction bipolar transistors

    Microsoft Academic Search

    G. L. Patton; D. L. Harame; J. M. C. Stork; B. S. Meyerson; G. J. Scilla; E. Ganin

    1989-01-01

    Si\\/Si1-xGex heterojunction bipolar transistors (HBTs) fabricated using a low-temperature epitaxial technique to form the SiGe graded-bandgap base layer are discussed. These devices were fabricated on patterned substrates and subjected to annealing cycles used in advanced bipolar processing. These devices, which have base widths under 75 mm, were found to have excellent junction qualities. Due to the small bandgap of SiGe,

  7. Current gain rolloff in graded-base SiGe heterojunction bipolar transistors

    SciTech Connect

    Crabbe, E.F.; Cressler, J.D.; Patton, G.L.; Stork, J.M.C.; Comfort, J.H.; Sun, J.Y.C. (Thomas J. Watson Research Center, Yorktown Heights, NY (United States))

    1993-04-01

    The authors report the experimental observation of a novel effect in SiGe heterojunction bipolar transistors (HBT's) with graded bases which results in a significant emitter-base bias dependence of the current gain. The nonideal collector current is caused by the interaction of the bias dependence of the emitter-base space-charge region width and the exponential dependence of the collector current on the germanium concentration at the edge of the space-charge region. The resulting current gain rolloff must be taken into account for accurate modeling of bipolar transistors with bandgap grading in the base.

  8. Abstract --Design guidelines are provided to improve the thermal stability of three-finger bipolar transistors. Experiments

    E-print Network

    Technische Universiteit Delft

    Abstract -- Design guidelines are provided to improve the thermal stability of three-finger bipolar non-adjacent fingers, a `hexagonal' topography is proposed. INDEX TERMS -- Aluminum nitride, bipolar applications, transistors have to be designed to handle an appreciable amount of current. In bipolar junction

  9. Horizontal current bipolar transistor (HCBT) process variations for future RF BiCMOS applications

    Microsoft Academic Search

    T. Suligoj; J. K. O. Sin; K. L. Wang

    2005-01-01

    Two different process designs of horizontal current bipolar transistor (HCBT) technology suitable for future RF BiCMOS circuits are presented. The active transistor region is built in the defect-free sidewall of 900-nm-wide n-hills on a [110] wafer. The collector n-hill region is partially etched at the extrinsic base-collector periphery, whereas the extrinsic base is self-protected, resulting in reduced collector-base capacitance (CBC)

  10. Collector region design and optimization in Horizontal Current Bipolar Transistor (HCBT)

    Microsoft Academic Search

    T. Suligoj; M. Koricic; H. Mochizuki; S. Morita; K. Shinomura; H. Imai

    2010-01-01

    Three different types of the n-collector region of Horizontal Current Bipolar Transistor (HCBT) are analyzed and compared. The optimum n-collector profile suppresses the charge sharing effect between the intrinsic and extrinsic base regions, resulting in the uniform base width and electric field in the intrinsic transistor. This implies a maximum BVCEO and an optimum fTBVCEO product among compared structures. The

  11. An IGBT and MOSFET gated SiC bipolar junction transistor

    Microsoft Academic Search

    Huijie Yu; Jason Lai; X. Li; Y. Luo; L. Fursin; J. H. Zhao; P. Alexandrov; B. Wright; M. Weiner

    2002-01-01

    A high voltage 4H-SiC bipolar junction transistor (BJT) has been developed with 16 A, 600 V rating. This paper presents a new base drive structure for the SiC BJT for inverter application. The driver consists of one IGBT and one MOSFET to help turn-on and turn-off of the SiC BJT transistor in a Darlington like configuration. Instead of using conventional

  12. Silicon on insulator bipolar junction transistors for flexible microwave applications

    NASA Astrophysics Data System (ADS)

    Bavier, John McGoldrick

    Microwave frequency flexible electronic devices require a high quality semiconducting material and a set of fabrication techniques that are compatible with device integration onto flexible polymer substrates. Over the past ten years, monocrystalline silicon nanomembranes (SiNMs) have been studied as a flexible semiconducting material that is compatible with industrial Si processing. Fabricated from commercial silicon on insulator (SOI) wafers, SiNMs can be transferred to flexible substrates using a variety of techniques. Due to their high carrier mobilities, SiNMs are a promising candidate for flexible microwave frequency devices. This dissertation presents fabrication techniques for flexible SiNM devices in general, as well as the progress made towards the development of a microwave frequency SiNM bipolar junction transistor (BJT). In order to overcome previous limitations associated with adhesion, novel methods for transfer printing of metal films and SiNMs are presented. These techniques enable transfer printing of a range of metal films and improve the alignment of small transfer printed SiNM devices. Work towards the development of a microwave frequency BJT on SOI for SiNM devices is also described. Utilizing a self-aligned polysilicon sidewall spacer technique, a BJT with an ultra-narrow base region is fabricated and tested. Two regimes of operation are identified and characterized under DC conditions. At low base currents, devices exhibited forward current gain as high as betaF = 900. At higher base current values, a transconductance of 59 mS was observed. Microwave scattering parameters were obtained for the BJTs under both biasing conditions and compared to unbiased measurements. Microwave frequency gain was not observed. Instead, bias-dependent non-reciprocal behavior was observed and examined. Limitations associated with the microwave impedance-matched electrode configuration are presented. High current densities in the narrow electrodes cause localized heating, which leads to electrode material damage and ultimately dopant diffusion in the BJT. Finally, device design improvements are proposed to address the problem of localized heating and increase device lifetime under testing conditions. High values for DC current gain suggest that future modifications should improve microwave frequency performance and measurement reproducibility.

  13. Thermal resistance measurements for AlGaAs/GaAs heterojunction bipolar transistors

    NASA Astrophysics Data System (ADS)

    Adlerstein, Michael G.; Zaitlin, Mark P.

    1991-06-01

    A method for the measurement of the thermal resistance of heterojunction bipolar transistors (HBTs) has been developed. The measurement technique is described and its application is illustrated. Results for single-emitter HBTs are explained with the help of a model for HBT thermal resistance. Measured values agree with the predictions of the model for heat flow for single-emitter HBTs.

  14. Suppression of boron transient enhanced diffusion in SiGe heterojunction bipolar transistors by carbon incorporation

    E-print Network

    Suppression of boron transient enhanced diffusion in SiGe heterojunction bipolar transistors the outdiffusion of boron from the base under postgrowth implantation and annealing procedures. Without the base sheet resistance using base boron doping levels greater than 1020 cm 3 .1 However, high boron

  15. Identification of 1\\/f diffusion and recombination noise sources in bipolar transistors

    Microsoft Academic Search

    S. Decoutere; L. Deferm; G. Vanhorebeek; C. Claeys; G. Declerck

    1990-01-01

    A method is proposed to identify 1\\/f noise sources in bipolar transistors related to mobility fluctuations in the base and collector current and to recombination at the surface of the emitter\\/base depletion region. It is shown that the physical location of the 1\\/f noise sources plays a key role in interpreting noise data. Excellent agreement between theory and measurements is

  16. Base Resistance Distribution in Bipolar Transistors: Relevance to Compact Noise Modeling and Extraction from Admittance Parameters.

    E-print Network

    Technische Universiteit Delft

    by calculating the transfer of internal noise sources to the terminal of the device. In prac- tice this is done, to predict the noise for complex devices (i.e. devices having both passive and active parts) from a detailedBase Resistance Distribution in Bipolar Transistors: Relevance to Compact Noise Modeling

  17. Effect of threading dislocations on AlGaNGaN heterojunction bipolar transistors

    E-print Network

    Rodwell, Mark J. W.

    and detectors.8 GaN is desirable for electronics ap- plications due to saturated electron velocities of 2 107 cm 2001 We demonstrate an AlGaN/GaN heterojunction bipolar transistor on a substrate grown using.1063/1.1358358 The past several years have seen a dramatic increase in research of GaN materials and devices. Progress has

  18. 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…

  19. Identification of failure precursor parameters for Insulated Gate Bipolar Transistors (IGBTs)

    Microsoft Academic Search

    N. Patil; D. Das; K. Goebel; M. Pecht

    2008-01-01

    Insulated Gate Bipolar Transistors (IGBTs) are used in applications such as the switching of automobile and train traction motors, high voltage power supplies, and in aerospace applications such as switch mode power supplies (SMPS) to regulate DC voltage. The failure of these switches can reduce the efficiency of the system or lead to system failure. By identifying failure precursor parameters

  20. Analysis of a novel drive circuit for bipolar transistor switches in dc-dc converters

    Microsoft Academic Search

    R. Osabe; H. Matsuo

    2003-01-01

    When employing a bipolar transistor as a main switch in the dc-dc converter, the driving circuit with the current transformer is widely used to improve the power efficiency. However, it is also known that there exists low limit of the turn on time of the main switch in this conventional driving circuit. In this paper, a novel driving circuit for

  1. EE 321 BJT 2 Fall 2008 Bipolar Junction Transistors, Part II

    E-print Network

    Wedeward, Kevin

    will investigate two bipolar junction transistor (BJT) amplifiers. The Common Emitter Amplifier The amplifier. Vin OV 2N3904 RE Q2 VEE = -15V VCC = +15V 3.3K 270 RS Figure 2. The Emitter Follower Amplifier 4. When the input signal is applied to the base and the output is taken at the emitter (Figure 2) the amplifier

  2. Current gain collapse in microwave multifinger heterojunction bipolar transistors operated at very high power densities

    Microsoft Academic Search

    William Liu; Steve Nelson; Darrell G. Hill; Ali Khatibzadeh

    1993-01-01

    The rapid development of heterojunction bipolar transistor (HBT) technologies has led to the demonstration of high power single-chip microwave amplifiers. Because HBTs are operated at high power densities, the ultimate limits on the performance of HBTs are imposed by thermal considerations. The authors address a thermal phenomenon observed when a multifinger power HBT is operating at high power densities. This

  3. The origin of 1\\/f PM and AM noise in bipolar junction transistor amplifiers

    Microsoft Academic Search

    F. L. Walls; E. S. Ferre-Pikal; S. R. Jefferts

    1995-01-01

    In this paper we report the results of extensive research on phase modulation (PM) and amplitude modulation (AM) noise in linear bipolar junction transistor (BJT) amplifiers. BJT amplifiers exhibit 1\\/f PM and AM noise about a carrier signal that is much larger than the amplifier's thermal noise at those frequencies in the absence of the carrier signal. Our work shows

  4. Origin of 1\\/f PM and AM noise in bipolar junction transistor amplifiers

    Microsoft Academic Search

    F. L. Walls; E. S. Ferre-Pikal; S. R. Jefferts

    1997-01-01

    In this paper we report the results of extensive research on phase modulation (PM) and amplitude modulation (AM) noise in linear bipolar junction transistor (BJT) amplifiers. BJT amplifiers exhibit 1\\/f PM and AM noise about a carrier signal that is much larger than the amplifiers thermal noise at those frequencies in the absence of the carrier signal. Our work shows

  5. SiGe-base heterojunction bipolar transistors: physics and design issues

    Microsoft Academic Search

    G. L. Patton; J. M. C. Stork; J. H. Comfort; E. F. Crabbe; B. S. Meyerson; D. L. Harame; J. Y.-C. Sun

    1990-01-01

    It has been shown that SiGe technology has the capability to extend the performance of Si bipolar transistors at both high and low current levels. The ability to tailor the bandgap, independently of the doping profile design, provides considerable flexibility for optimizing cutoff frequency, intrinsic base resistance, and junction capacitances for a given application. It is concluded that, when combined

  6. Theory of semiconductor magnetic bipolar transistors M. E. Flattea)

    E-print Network

    Flatte, Michael E.

    device suggestions. These include a ``spin filter,'' 2 ``spin-resonant-tunneling-diode,'' 3 ``unipolar spin transistor,'' 4 ``magnetic Zener tunnel diode,'' 5 and ``mag- netic p-n diode.'' 6 At the same

  7. 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.

  8. Low-frequency noise sources in bipolar junction transistors

    Microsoft Academic Search

    R. C. Jaeger; A. J. Brodersen

    1970-01-01

    Low-frequency noise measurements are made on specially fabricated silicon tetrode planar transistors. The measurements show the existence of three distinct sources of excess noise: a 1\\/fnoise source associated with the surface; a l\\/fnoise source associated with the active base region; and an anomalous burst noise source associated with the forward-biased emitter-base junction. Burst noise which is present in many transistors

  9. 2734 IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, VOL. 55, NO. 12, DECEMBER 2007 Integrated Heterojunction Bipolar Transistor

    E-print Network

    Choi, Woo-Young

    P heterojunction bipolar transistor (HBT), monolithic microwave integrated circuit (MMIC), optical injection integrated circuit (MMIC) oscillator and demonstrate 30-GHz bi-directional data trans- mission. The HBT MMIC

  10. ECE 417/ECE517 Basic Semiconductor Devices Catalog Description: Theory and physical principles of bipolar junction and field-effect transistors.

    E-print Network

    of bipolar junction and field-effect transistors. Credits: 4 Terms Offered: Winter Prerequisites: ECE 416 and physical principles of bipolar junction transistors · Theory and physical principles of field-effect transistors · Modeling and simulation of semiconductor devices using computer aided design/analysis software

  11. Demonstration of npn InAs bipolar transistors with inverted base doping

    SciTech Connect

    Dodd, P.E.; Lovejoy, M.L. [Sandia National Labs., Albuquerque, NM (United States)] [Sandia National Labs., Albuquerque, NM (United States); Lundstrom, M.S.; Melloch, M.R.; Woodall, J.M. [Purdue Univ., West Lafayette, IN (United States)] [Purdue Univ., West Lafayette, IN (United States); Pettit, D. [IBM, Yorktown Heights, NY (United States). T.J. Watson Research Center] [IBM, Yorktown Heights, NY (United States). T.J. Watson Research Center

    1996-04-01

    The authors demonstrate np{sup +}n InAs bipolar transistors that operate under room temperature and cryogenic conditions. InAs transistors on an InP substrate were characterized as a function of temperature and exhibited good room temperature and low temperature common-emitter characteristics. Although the base doping density exceeded the emitter doping density by a factor of 20, current gains of 30 were achieved at room temperature. Junction leakage currents and contact resistance were identified as problems to address.

  12. Bipolar transistor modeling of avalanche generation for computer circuit simulation

    Microsoft Academic Search

    R. W. Dutton

    1975-01-01

    An avalanche generation model is developed and incorporated into computer circuit analysis programs SLIC and NICAP. A modified form of Miller's empirical expression for generation is found to agree well with measured data for Western Electric and commercial n-p-n transistors. Measurement techniques and parameter determination for the three model coefficients are discussed. Equation constraints appropriate for computer implementation are presented.

  13. Thermal properties and thermal instabilities of InP-based heterojunction bipolar transistors

    Microsoft Academic Search

    William Liu; Hin-Fai Chau; Edward Beam

    1996-01-01

    We investigate the physical parameters which are critical to the understanding of the thermal phenomena in InP-based heterojunction bipolar transistors. These parameters include thermal resistance, thermal-electric feedback coefficient, current gain, and base-collector leakage current. We examine the thermal instability behavior in multi-finger HBTs, and observe for the first time the collapse of current gain in InP-based HBTs. Based on both

  14. Response of SOI Bipolar Transistors Exposed to -Rays Under Different Dose Rate and Bias Conditions

    Microsoft Academic Search

    Lodovico Ratti; Massimo Manghisoni; Enrico Oberti; V. Re; V. Speziali; G. Traversi; G. Fallica; R. Modica

    2005-01-01

    This work is devoted to the analysis of$gamma$-ray effects on the behavior of bipolar junction transistors belonging to a silicon on insulator technology. Such a process is currently being investigated in order to assess its suitability for use in radiation-resistant applications, namely in the design of readout electronics for radiation detectors in high energy physics experiments and for operation in

  15. Hardness Assurance Guidelines for Moderate Neutron Environment Effects in Bipolar Transistors and Integrated Circuits

    Microsoft Academic Search

    Robert A. Berger; Joseph L. Azarewicz; Harvey Eisen

    1978-01-01

    This paper sets forth procedures which provide effective means of obtaining semiconductor devices whose neutron-induced response is within known, acceptable limits. These Hardness Assurance (HA) procedures can be applied to bipolar transistors, TTL (54\\/74 series) digital integrated circuits, and operational amplifiers (such as the 741). HA is implemented by imposing two control levels on the supplier and\\/or two quality levels

  16. Modeling the variation of the low-frequency noise in polysilicon emitter bipolar junction transistors

    Microsoft Academic Search

    Martin Sandén; Ognian Marinov; M. Jamal Deen; Mikael Östling

    2001-01-01

    The variation of the low-frequency noise in polysilicon emitter bipolar junction transistors (BJTs) was investigated as a function of emitter area (AE). For individual BJTs with submicron-sized A E, the low-frequency noise strongly deviated from a 1\\/f-dependence. The averaged noise varied as 1\\/f, with a magnitude proportional to AE-1, while the variation in the noise level was found to vary

  17. Low-frequency noise in TFSOI lateral n-p-n bipolar transistors

    Microsoft Academic Search

    Jeffrey A. Babcock; Dieter K. Schroder; Wen-Ling Margaret Huang; Jenny M. Ford

    2001-01-01

    Low-frequency (1\\/f) noise is characterized as a function of base current density (JB) on thin-film-silicon-on-insulator (TFSOI) lateral bipolar transistors. In the low injection region of operation, the noise power spectral density was proportional to JB 1.8 for JB<0.4 ?A\\/?m2, which suggest that the noise in these devices is primarily dominated by a uniform distribution of noise sources across the emitter-base

  18. Laterally etched undercut (LEU) technique to reduce base-collector capcitances in heterojunction bipolar transistors

    SciTech Connect

    Liu, W.; Hill, D.; Chau, H.F. [and others

    1995-12-31

    The authors report a novel fabrication process aimed at reducing the parasitic junction capacitance of AlGaAs/GaAs heterojunction bipolar transistors. The process, named as the Laterally Etched Undercut (LEU) process, physically removes the extrinsic base-collector junction area and results in a cantilever structure. The d.c., small-signal, and large-signal performances of the LEU devices are compared to those obtained from the conventional devices.

  19. Laterally etched undercut (LEU) technique to reduce base-collector capacitances in heterojunction bipolar transistors

    Microsoft Academic Search

    William Liu; Darrell Hill; Hin-Fai Chau; Jim Sweder; Tom Nagle; J. Delaney

    1995-01-01

    We report a novel fabrication process aimed at reducing the parasitic junction capacitance of AlGaAs-GaAs heterojunction bipolar transistors. The process, named as the Laterally Etched Undercut (LEU) process, physically removes the extrinsic base-collector junction area and results in a cantilever structure. The DC, small-signal, and large-signal performances of the LEU devices are compared to those obtained from the conventional devices

  20. Hot-electron electroluminescence in AlGaAs\\/GaAs heterojunction bipolar transistors

    Microsoft Academic Search

    Enrico Zanoni; Loris Vendrame; Paolo Pavan; Manfredo Manfredi; Stefano Bigliardi; Roger Malik; Claudio Canali

    1993-01-01

    When biased in the active region at high collector voltages, AlGaAs\\/GaAs single heterojunction bipolar transistors have been observed to emit light in the 1.1–2.5 eV energy range. The spectral distribution of the emitted radiation results from the superimposition of (i) two peaks at about 1.4 and 2.1 eV, due to band-to-band recombination of cold electrons and holes, and (ii) a

  1. The effect of external factors on the gain characteristics of a bipolar transistor

    Microsoft Academic Search

    V. A. Gusev; I. A. Iliushkin; V. A. Isaev

    1985-01-01

    The gain factor of a bipolar silicon transistor irradiated by fast neutrons is analyzed with allowance for the dependence of the factor of radiation-induced change of lifetime on the injection level. A two-dimensional model is developed and used to investigate the degradation of the gain factor as a function of current and radiation. It is found that a narrow-strip emitter

  2. Degradation of InGaAs\\/InP double heterojunction bipolar transistors under electron irradiation

    Microsoft Academic Search

    A. Bandyopadhyay; S. Subramanian; S. Chandrasekhar; Andrew G. Dentai; Stephen M. Goodnick

    1999-01-01

    The dc characteristics of InGaAs\\/InP double heterojunction bipolar transistors (DHBTs) are studied under high-energy (~1 MeV) electron irradiation up to a fluence of 14.8×1015 electrons\\/cm 2. The devices show an increase in common-emitter current gain (hfe) at low levels of dose (<1015 electrons\\/cm2) and a gradual decrease in hfe and an increase in output conductance for higher doses. The decrease

  3. Application of insulated gate bipolar transistor to zero-current switching converters

    Microsoft Academic Search

    R. Rangan; DAN Y. CHEN; Jian Yang; JOHN LEE

    1989-01-01

    The problems associated with insulated-gate bipolar transistor (IGBT) devices in PWM converters, such as turn-off current tailing and turn-off latching, are largely avoided in zero-current switching resonant converters. Phenomena induced by dv\\/dt, such as the power losses and latching, are identified as the predominant problems in using IGBT devices for very-high-frequency resonant operations. The discussion and the verification of the

  4. Comparison of hot-carrier and radiation induced increases in base current in bipolar transistors

    Microsoft Academic Search

    R. L. Pease; S. L. Kosier; R. D. Schrimpf; W. E. Combs; M. Davey; M. Delaus; D. M. Fleetwood

    1994-01-01

    A comparison was made between hot-carrier stress induced and ionizing-radiation induced increases in the base current of bipolar linear microcircuit transistors from two process technologies. The comparison was made on the basis of a failure stress in seconds and a failure dose in rad(SiO2) for a failure criterion of ?I B=2 nA measured at an IC of 1 ?A and

  5. Neutron irradiation effects in InP\\/InGaAs single heterojunction bipolar transistors

    Microsoft Academic Search

    Alexei Shatalov; S. Subramanian; Andrew Dentai

    2000-01-01

    In this paper we report the effects of epi-thermal and high energy neutron irradiation on the DC characteristics of InP\\/InGaAs heterojunction bipolar transistors. Significant current gain degradation and collector-emitter offset voltage VCE,off shift are the two predominant effects observed on the devices irradiated up to ~1015 n\\/cm2. The current gain degradation is attributed to the increasing base current due to

  6. Low cost fast switch using a stack of bipolar transistors as a pockel cell driver

    Microsoft Academic Search

    A. K. Dharmadhikari; J. A. Dharmadhikari; K. P. Adhi; N. Y. Mehendale; R. C. Aiyer

    1996-01-01

    A fast high voltage switch to discharge a capacitive load using a stack of bipolar junction transistors is described. The switch operating at a voltage of 3.5 kV has a fall time (90%â10%) of â¼2 ns. With a capacitive load (pockel cell) the pulse fall time increases to 6 ns. The life of the stack is <50 million shots. {copyright}

  7. Low cost fast switch using a stack of bipolar transistors as a pockel cell driver

    Microsoft Academic Search

    A. K. Dharmadhikari; J. A. Dharmadhikari; K. P. Adhi; N. Y. Mehendale; R. C. Aiyer

    1996-01-01

    A fast high voltage switch to discharge a capacitive load using a stack of bipolar junction transistors is described. The switch operating at a voltage of 3.5 kV has a fall time (90%–10%) of ?2 ns. With a capacitive load (pockel cell) the pulse fall time increases to 6 ns. The life of the stack is >50 million shots.

  8. Low cost fast switch using a stack of bipolar transistors as a pockel cell driver

    NASA Astrophysics Data System (ADS)

    Dharmadhikari, A. K.; Dharmadhikari, J. A.; Adhi, K. P.; Mehendale, N. Y.; Aiyer, R. C.

    1996-12-01

    A fast high voltage switch to discharge a capacitive load using a stack of bipolar junction transistors is described. The switch operating at a voltage of 3.5 kV has a fall time (90%-10%) of ˜2 ns. With a capacitive load (pockel cell) the pulse fall time increases to 6 ns. The life of the stack is >50 million shots.

  9. Experimental studies of frequency response and related properties of small-signal bipolar junction transistor amplifiers

    Microsoft Academic Search

    A. Motayed; T. E. Browne; A. I. Onuorah; S. N. Mohammad

    2001-01-01

    Small-signal bipolar junction transistor (BJT) amplifiers, including common-emitter (C-E), common-base, and common-collector amplifiers, are the basic building blocks of many analog integrated circuits. An experimental investigation of the physical analysis of the frequency response and related parameters of these amplifiers have been performed in some details. The analysis uncovers fundamental reasons underlying the frequency response of the amplifiers. It indicates

  10. Hardness assurance testing of bipolar junction transistors at elevated irradiation temperatures

    Microsoft Academic Search

    S. C. Witczakl; R. D. Schrimpfz; D. M. Fleetwood; K. F. Galloway; R. C. Lacoel; D. C. Mayer; J. M. Puhl; R. L. Pease; J. S. Suehle

    1997-01-01

    The effect of dose rate on radiation-induced current gain degradation was quantified for radiation-hardened poly-Si emitter n-p-n bipolar transistors over the range of 0.005 to 294 rad(Si)\\/s. Degradation increases sharply with decreasing dose rate and saturates near 0.005 rad(Si)\\/s. The amount of degradation enhancement at low dose rates decreases monotonically with total dose. In addition, the effect of ambient temperature

  11. Vertical profile optimization of very high frequency epitaxial Si and SiGe-base bipolar transistors

    Microsoft Academic Search

    E. F. Crabbe; B. S. Meyerson; J. M. C. Stork; D. L. Harame

    1993-01-01

    Bipolar transistors with phosphorus-doped emitters and sub-50 nm epitaxial bases have been fabricated in a low thermal-cycle process to explore the trade-offs between cutoff frequency, breakdown voltage and Early voltage. Record peak fTs of 73 GHz for a Si BJT and 113 GHz for a SiGe HBT with respective ?VA products of 630 and 48,400 V were obtained for intrinsic

  12. 75GHz fT SiGe-base heterojunction bipolar transistors

    Microsoft Academic Search

    GARY L. PATTON; JAMES H. COMFORT; BERNARD S. MEYERSON; E. F. Crabbe; G. J. Scilla; E. de Fresart; J. M. C. Stork; J. Y.-C. Sun; D. L. Harame; J. N. Burghartz

    1990-01-01

    The fabrication of silicon heterojunction bipolar transistors which have a record unity-current-gain cutoff frequency (fT) of 75 GHz for a collector-base bias of 1 V, an intrinsic base sheet resistance (Rbi) of 17 k?\\/□, and an emitter width of 0.9 ?m is discussed. This performance level, which represents an increase by almost a factor of 2 in the speed of

  13. High Performance 0.1 m GaAs Pseudomorphic High Electron Mobility Transistors with Si Pulse-Doped Cap Layer for 77 GHz Car Radar Applications

    E-print Network

    Seo, Kwang Seok

    , radar, smart weapon, electronic warfare and radiometry system applications. Significant progress hasHigh Performance 0.1 m GaAs Pseudomorphic High Electron Mobility Transistors with Si Pulse double-recessed T-gate GaAs pseudomorphic high electron mobility transistors (PHEMT's), in which an In

  14. A New Bipolar Type Transistor Created Based on Interface Effects of Integrated All Perovskite Oxides

    NASA Astrophysics Data System (ADS)

    Xia, Feng-Jin; Wu, Hao; Fu, Yue-Ju; Xu, Bo; Yuan, Jie; Zhu, Bei-Yi; Qiu, Xiang-Gang; Cao, Li-Xin; Li, Jun-Jie; Jin, Ai-Zi; Wang, Yu-Mei; Li, Fang-Hua; Liu, Bao-Ting; Xie, Zhong; Zhao, Bai-Ru

    2012-10-01

    Oxide transistor is the basic device to construct the oxide electronic circuit that is the backing to develop integrated oxide electronics with high efficiency and low power consumption. By growing the perovskite oxide integrated layers and tailoring them to lead semiconducting functions at their interfaces, the development of oxide transistors may be able to perform. We realize a kind of p-i-n type integrated layers consisting of an n-type cuprate superconductor, p-type colossal magnetoresistance manganite, and a ferroelectric barrier (i). From this, bipolar transistors were fabricated at the back-to-back p-i-n junctions, for which the Schottky emission and p-n junction barriers, as well as the ferroelectric polarization, were integrated into the interfaces to control the transport properties; a preliminary but distinct current gain greater than 1.6 at input current of microampers order was observed. These results present a real possibility to date for developing bipolar all perovskite oxide transistors.

  15. An approximate HSPICE model for orbit low noise analog bipolar NPN transistors

    SciTech Connect

    Zimmerman, T.

    1991-07-01

    Vertical bipolar NPN transistors can be fabricated cheaply through MOSIS by using the Orbit 2 um Low Noise Analog CMOS process. The collector is formed from an N-well, the base from a p-base diffusion, and the emitter from an N-diffusion. However, since this is a CMOS process there is no buried layer in the collector. Therefore the collector resistance is quite large. Also, the minimum emitter size is 8 um {times} 8 um, which is substantially larger than many fast bipolar processes. For certain applications, though, such as common base or emitter follower amplifiers, the performance of this transistor may be quite acceptable. However, no AC SPICE model is published for this device. This paper describes a simple approximate measurement method that was used at Fermilab to formulate an HSPICE model for these transistor. This method requires only a fast pulse generator and a good digitizing oscilloscope with an active FET probe for the AC measurements. Model parameters for two transistors of different size are then given. 1 ref., 1 fig.

  16. 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. PMID:20211771

  17. 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.

  18. Performance enhancement of a heterojunction bipolar transistor (HBT) by two-step passivation

    NASA Astrophysics Data System (ADS)

    Fu, Ssu-I.; Lai, Po-Hsien; Tsai, Yan-Ying; Hung, Ching-Wen; Yen, Chih-Hung; Cheng, Shiou-Ying; Liu, Wen-Chau

    2006-09-01

    An interesting two-step passivation (with ledge structure and sulphide based chemical treatment) on base surface, for the first time, is demonstrated to study the temperature-dependent DC characteristics and noise performance of an InGaP/GaAs heterojunction bipolar transistor (HBT). Improved transistor behaviors on maximum current gain ?max, offset voltage ? VCE, and emitter size effect are obtained by using the two-step passivation. Moreover, the device with the two-step passivation exhibits relatively temperature-independent and improved thermal stable performances as the temperature is increased. Therefore, the two-step passivationed device can be used for high-temperature and low-power electronics applications.

  19. 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.

  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. 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.

  2. 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.

  3. Origin of 1/f PM and AM noise in bipolar junction transistor amplifiers.

    PubMed

    Walls, F L; Ferre-Pikal, E S; Jefferts, S R

    1997-01-01

    In this paper we report the results of extensive research on phase modulation (PM) and amplitude modulation (AM) noise in linear bipolar junction transistor (BJT) amplifiers. BJT amplifiers exhibit 1/f PM and AM noise about a carrier signal that is much larger than the amplifiers thermal noise at those frequencies in the absence of the carrier signal. Our work shows that the 1/f PM noise of a BJT based amplifier is accompanied by 1/f AM noise which can be higher, lower, or nearly equal, depending on the circuit implementation. The 1/f AM and PM noise in BJTs is primarily the result of 1/f fluctuations in transistor current, transistor capacitance, circuit supply voltages, circuit impedances, and circuit configuration. We discuss the theory and present experimental data in reference to common emitter amplifiers, but the analysis can be applied to other configurations as well. This study provides the functional dependence of 1/f AM and PM noise on transistor parameters, circuit parameters, and signal frequency, thereby laying the groundwork for a comprehensive theory of 1/f AM and PM noise in BJT amplifiers. We show that in many cases the 1/f PM and AM noise can be reduced below the thermal noise of the amplifier. PMID:18244130

  4. The collapse of current gain in multi-finger heterojunction bipolar transistors: its substrate temperature dependence, instability criteria, and modeling

    Microsoft Academic Search

    William Liu; Ali Khatibzadeh

    1994-01-01

    One undesirable phenomenon observed when AlGaAs\\/GaAs heterojunction bipolar transistors (HBT's) are operated under high power density is the collapse (of current gain). The collapse manifests itself by a distinct abrupt decrease of collector current in the transistor common-emitter current-voltage (I-V) characteristics. In this investigation, we study the substrate temperature dependence of the collapse. A unified equation is introduced to relate

  5. 73GHz self-aligned SiGe-base bipolar transistors with phosphorus-doped polysilicon emitters

    Microsoft Academic Search

    E. F. Crabbe; James H. Comfort; Wai Lee; John D. Cressler; Bernard S. Meyerson; Andrew C. Megdanis; Jack Y.-C. Sun; Johannes M. C. Stork

    1992-01-01

    The authors report a thermal-cycle emitter process using phosphorus for the fabrication of self-aligned SiGe-base heterojunction bipolar transistors. The low thermal cycle results in extremely, narrow basewidths and preservation of lightly doped spacers in both the emitter-base and base-collector junctions for improved breakdown. Transistors with 35-nm basewidths were obtained with low emitter-base reverse leakage and a peak cutoff frequency of

  6. Magnesium as p dopant in InGaAs/InP heterojunction bipolar transistors grown by metalorganic vapor phase epitaxy

    NASA Astrophysics Data System (ADS)

    Dildey, F.; Schier, M.; Ebbinghaus, G.

    1992-04-01

    Magnesium has been used as p dopant for the base in InGaAs/InP heterojunction bipolar transistors during growth by metalorganic vapor phase epitaxy. Very sharp and well controlled Mg profiles were achieved resulting in excellent dc-characteristics of the device. With a layer sequence suitable for high frequency applications, the transistors show a common emitter current gain of about 100 with very weak dependence on collector current, low offset voltage, low output conductance, and high breakdown voltage.

  7. 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 ?W 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.

  8. Radiation-induced surface degradation of GaAs and high electron mobility transistor structures

    SciTech Connect

    Bobyl, A. V.; Konnikov, S. G.; Ustinov, V. M.; Baidakova, M. V.; Maleev, N. A.; Sakseev, D. A. [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation); Konakova, R. V., E-mail: konakova@isp.kiev.ua; Milenin, V. V.; Prokopenko, I. V. [National Academy of Sciences of Ukraine, Lashkaryov Institute of Semiconductor Physics (Ukraine)

    2012-06-15

    Transistor heterostructures with high-carrier-mobility have been studied. It is shown that, as the {gamma}-irradiation dose {Phi} increases, their degradation occurs in the following sequence. (i) At {Phi} < 10{sup 7} rad, the GaAs surface layer is damaged to a depth of 10 nm due to a >0.2-eV decrease in the diffusion energy of intrinsic defects and, probably, atmospheric oxygen. (ii) At {Phi} > 10{sup 7} rad, highly structurally disordered regions larger than 1 {mu}m are formed near microscopic defects or dislocations. (iii) At {Phi} > 10{sup 8} rad, there occurs degradation of the internal AlGaAs/InGaAs/GaAs interfaces and the working channel. An effective method for studying the degradation processes in heterostructures is to employ a set of structural diagnostic methods to analyze processes of radiation-induced and aging degradation, in combination with theoretical simulation of the occurring processes.

  9. Simple Fabrication Technique of Symmetrical Emitter-Collector Zinc-doped Planar Ga1-xAlxAs/GaAs/Ga1-yAlyAs Double Heterojunction Bipolar Transistors

    NASA Astrophysics Data System (ADS)

    Deesirapipat, Yuparwadee; Thainoi, Supachok; Ratanathammaphan, Somchai; Antarasena, Choompol

    2001-04-01

    Symmetrical emitter-collector planar Ga1-xAlxAs/GaAs/Ga1-yAlyAs double heterojunction bipolar transistors have been designed and fabricated. Crystal growth and doping are carried out using liquid phase epitaxy (LPE) technique. Five layers consisting of collector, base, emitter, emitter contact and mask layer, Ga0.6Al0.4As, have been grown consecutively by LPE on GaAs (n+) substrate. After etching the mask layer to open a region for base diffusion, the sample was carried back to the LPE furnace to grow the Zn-doped Ga0.6Al0.4As in order to diffuse Zn to the p-type base. After the process, both the diffusion layer and the mask layer were selectively etched. Ohmic contacts were then made. Finally, the DC characteristics of the transistors were measured to show their symmetrical behaviors.

  10. Analysis of heterojunction bipolar transistor\\/resonant tunneling diode logic for low-power and high-speed digital applications

    Microsoft Academic Search

    C. E. Chang; Peter M. Asbeck; Keh-Chung Wang; Elliott R. Brown

    1993-01-01

    A high-speed digital logic family based on heterojunction bipolar transistors (HBTs) and resonant tunneling diodes (RTDs) is proposed. The negative differential resistance of RTDs is used to significantly decrease the static power dissipation. SPICE simulations indicate that propagation delay time below 150 ps at 0.09-mW static power per gate should be obtainable

  11. A novel double-gate Trench Insulated Gate Bipolar transistor with ultra-low on-state voltage

    Microsoft Academic Search

    Wesley Chih-Wei Hsu; Florin Udrea; Ho-Tai Chen; Wei-Chieh Lin

    2009-01-01

    In this paper, a new Trench Insulated Gate Bipolar Transistor (TIGBT) which features a double-gate (DG) structure is presented. The new DG-TIGBT can enhance the excess carrier density near the emitter side of the IGBTs so that the conductivity modulation in the N- drift region is stronger than that presents in the conventional IGBTs. In addition, these excess holes can

  12. 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.

  13. p-buffer layer dependent drift mobility profiles in GaAs metal-semiconductor field-effect transistors

    Microsoft Academic Search

    K. Steiner; Naotaka Uchitomi

    2008-01-01

    Mobility profiles in WNâ-LDD (lightly doped drain region) and WNâ-BPLDD (buried p-type buffer lightly doped drain region) GaAs metal-semiconductor field-effect transistor (MESFET) with various p-buffer layers are discussed. The mobility profiles are evaluated using frequency dependent admittance studies. A slightly doped p-buffer layer seems to have no influence on the carrier concentration while there is a significant modification of the

  14. The Gate-Bias Dependency of Breakdown Location in GaAs Metal Semiconductor Field Effect Transistors (MESFETs)

    Microsoft Academic Search

    Jayne M. Ashworth; Norbert Arnold

    1991-01-01

    The breakdown behaviour of refractory metal self-aligned GaAs metal semiconductor field effect transistors (MESFETs) has been studied by two-dimensional simulation using a drift-diffusion transport model and emission microscopy. Exact quantitative simulation of the device characteristics has been achieved for a device with a four fold implant scheme. The location of breakdown, as defined as the area of high avalanche generation

  15. Analysis of Gate Lag in GaAs Metal-Semiconductor Field-Effect Transistor Using Light Illumination

    Microsoft Academic Search

    Hajime Sasaki; Hiroto Matsubayashi; Osamu Ishihara; Ryosuke Konishi; Koshi Ando

    1995-01-01

    We have developed a novel method for analyzing the gate lag effect in gallium arsenide (GaAs) metal-semiconductor field-effect transistor (MESFET) using light illumination. It is estimated that the density of trapped electrons at the surface of an active channel layer is above 6×1011 cm-2 from the dependence on photon flux density. Photon energy dependence shows that the electrons are mainly

  16. 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.

  17. Investigation of proton irradiation effects on InP/InGaAs double heterojunction bipolar transistors

    NASA Astrophysics Data System (ADS)

    Liu, Min; Zhang, Yuming; Lu, Hongliang; Zhang, Yimen; Zhang, Jincan; Ren, Xiaotang

    2015-07-01

    In this article, 3 MeV proton irradiation-induced degradation in InP/InGaAs double heterojunction bipolar transistors (DHBTs) is studied, the fluence up to 5 × 1012 protons/cm2, meanwhile 10 MeV proton irradiation is investigated in order to compare the differences induced by different proton energy irradiation. The devices exhibit good tolerance up to 5 × 1011 protons/cm2. The concentration of vacancies at different proton fluences can be calculated from SRIM. Being donor-like defects, the In and Ga vacancies act as compensation center while As vacancy acts as an acceptor-like defect. Adding the vacancies model into Sentaurus device simulator, simulation results match well with the trends of measured data.

  18. 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.

  19. Base profile design for high-performance operation of bipolar transistors at liquid-nitrogen temperature

    SciTech Connect

    Stork, J.M.C.; Harame, D.L.; Meyerson, B.S.; Nguyen, T.N. (International Business Machines Corp., Yorktown Heights, NY (USA). Thomas J. Watson Research Center)

    1989-08-01

    The base profile requirements of Si bipolar junction transistors (BJT's) high-performance operation at liquid-nitrogen temperature are examined. Measurements of thin epitaxial-base polysilicon-emitter n-p-n transistors with increasing base doping show the effects of bandgap narrowing, mobility changes, and carrier freezeout. At room temperature the collector current at low injection is proportional to the integrated base charge, independent of the impurity distribution. At temperatures below 150 {Kappa}, however, minority injection is dominated by the peak base doping because of the greater effectiveness of bandgap narrowing. When the peak doping in the base approaches 10/sup 19/ cm/sup -3/, the bandgap difference between emitter and base is sufficiently small that the current gain no longer monotonically decreases with lower temperature but instead shows a maximum as low as 180 {Kappa}. The device design window appears limited at the low-current end by increased base-emitter leakage due to tunneling and by resistance control at the high-current end. Using the measured dc characteristics, circuit delay calculations are made to estimate the performance of an ECL ring oscillator at room and liquid-nitrogen temperatures. It is shown that if the base doping can be raised to 10/sup 19/ cm/sup -3/ while keeping the base thickness constant, the minimum delay at liquid nitrogen can approach the delay of optimized devices at room temperature.

  20. Silicon germanium heterojunction bipolar technology: the next leap in silicon?

    Microsoft Academic Search

    John D. Cressler; D. L. Harame; J. H. Comfort; Johannes M. C. Stork; Bernard S. Meyerson; Thomas E. Tice

    1994-01-01

    SiGe heterostructure bipolar transistor (HBT) technology will allow circuit designers to combine the performance historically associated with compound semiconductor technologies such as GaAs with the integration levels, yield, and cost associated with conventional Si processing. At present, unloaded SiGe ECL circuits switch at sub20ps speeds, transistors exhibit cutoff frequencies in excess of 100GHz, and integration levels high enough to realize

  1. Note: cryogenic low-noise dc-coupled wideband differential amplifier based on SiGe heterojunction bipolar transistors.

    PubMed

    Beev, Nikolai; Kiviranta, Mikko

    2012-06-01

    Silicon-germanium heterojunction bipolar transistors can be used to construct low-noise cryogenic amplifiers. We present a dc-coupled differential amplifier capable of operating down to 10 K. In this temperature regime it has bandwidth of 15 MHz and noise temperature as low as 1.3 K. When operated at liquid nitrogen temperature of 77 K, the measured noise temperature is lower than 3 K. The amplifier is based on the commercially available transistors NESG3031 and operational amplifier OPA836 and is capable of standalone operation without any additional stages at room temperature. PMID:22755673

  2. Note: Cryogenic low-noise dc-coupled wideband differential amplifier based on SiGe heterojunction bipolar transistors

    NASA Astrophysics Data System (ADS)

    Beev, Nikolai; Kiviranta, Mikko

    2012-06-01

    Silicon-germanium heterojunction bipolar transistors can be used to construct low-noise cryogenic amplifiers. We present a dc-coupled differential amplifier capable of operating down to 10 K. In this temperature regime it has bandwidth of 15 MHz and noise temperature as low as 1.3 K. When operated at liquid nitrogen temperature of 77 K, the measured noise temperature is lower than 3 K. The amplifier is based on the commercially available transistors NESG3031 and operational amplifier OPA836 and is capable of standalone operation without any additional stages at room temperature.

  3. Investigation and Application of Neutron Damage to Bipolar Transistors in Light Water Reactor Dosimetry.

    NASA Astrophysics Data System (ADS)

    Roknizadeh, Mansour

    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 ECG-196 and ECG-184 transistors have been calibrated for neutron fluences ranging from 1.0E10 n(1MeV)/ {rm cm}^2 to 1.0E12 n(1MeV)/{rm cm}^2. PN2222A transistors have been calibrated for neutron fluences ranging from 1.0E12 to 2.0E15 n(1MeV)/cm^2 . 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)/{rm cm}^2. The departure from linearity has been represented by a quadratic function. 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. This has been proven to be due to the fact that low energy neutron effects are not correctly accounted for when using the silicon displacement kerma to calculate 1-MeV equivalent neutron fluence. Therefore, a model has been developed by which the damage response is corrected in order to account for the low energy neutron effects. 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% {rm cm}^2 /m(1MeV).Sec. This supports the theory that base transit time is a parameter from which the neutron vulnerability in a nuclear radiation environment can be determined. The developed techniques have been used in five reactor dosimetry experiments. Four of these experiments were conducted at reactor buildings of Unit-I and Unit-II of the Arkansas Nuclear One power plant. Another experiment was performed at the nuclear reactor laboratory of University of Illinois. In these experiments, the 1-MeV equivalent fluence rates for several irradiation positions have been calculated.

  4. Degradation of DC characteristics of InGaAs\\/InP single heterojunction bipolar transistors under electron irradiation

    Microsoft Academic Search

    A. Bandyopadhyay; S. Subramanian; S. Chandrasekhar; Andrew G. Dentai; Stephen M. Goodnick

    1999-01-01

    The effects of high-energy (~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 <1015\\/cm2. 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

  5. Neutron, proton, and electron irradiation effects in InGaP\\/GaAs single heterojunction bipolar transistors

    Microsoft Academic Search

    Soujanya Vuppala; Chyishiun Li; P. Zwicknagl; S. Subramanian

    2003-01-01

    Neutron, proton, and electron irradiation effects in InGaP\\/GaAs single heterojunction bipolar transistors are investigated. Devices with different emitter sizes and grown by two different growth techniques are studied. At low fluences of proton and neutron irradiation, a small gain increase is observed at low base currents. At higher fluences, gain degradation is observed whose magnitude depends on the nature and

  6. Low-frequency noise sources in polysilicon emitter bipolar transistors: Influence of hot-electron-induced degradation

    Microsoft Academic Search

    A. Mounib; F. Balestra; N. Mathieu; J. Brini; G. Ghibaudo; A. Chovet; A. Chantre; A. Nouailhat

    1993-01-01

    The noise properties of polysilicon emitter bipolar transistors are studied. The influences of the various chemical treatments and annealing temperatures, prior and after polysilicon deposition, on the noise magnitude are shown. The impact of hot-electron-induced degradation and post-stress recovery on the base and collector current fluctuations are also investigated in order to determine the main noise sources of these devices.

  7. Degradation of InGaAs\\/InP single heterojunction bipolar transistors under high energy electron irradiation

    Microsoft Academic Search

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

    1999-01-01

    The d.c. characteristics of InGaAs\\/InP single heterojunction bipolar transistors (SHBTs) were studied for the first time under high energy (?1 MeV) electron radiation of cumulative dose up to 5.4×1015 electrons\\/cm2. No degradation was observed for electron doses below 1015\\/cm2. For electron doses greater than 1015\\/cm2 the following degradation effects were observed: (1) decrease in collector current; (2) decrease in current

  8. Evaluation of the Radiation Tolerance of SiGe Heterojunction Bipolar Transistors Under 24GeV Proton Exposure

    Microsoft Academic Search

    J. Metcalfe; D. E. Dorfan; A. A. Grillo; A. Jones; D. Lucia; F. Martinez-McKinney; M. Mendoza; M. Rogers; H. F.-W. Sadrozinski; A. Seiden; E. Spencer; M. Wilder; J. D. Cressler; G. Prakash; A. Sutton

    2006-01-01

    For the potential use in future high luminosity applications in high energy physics (HEP) [e.g., the Large Hadron Collider (LHC) upgrade], we evaluated the radiation tolerance of a candidate technology for the front-end of the readout application-specific integrated circuit (ASIC) for silicon strip detectors. The devices investigated were first-generation silicon-germanium (SiGe) heterojunction bipolar transistors (HBTs). The current gain as a

  9. Monolithic Integration of Heterojunction Bipolar Transistor and Grating-Outcoupled Surface Emitting Laser Electronic-Photonic Integrated Circuit

    Microsoft Academic Search

    W. A. Jones; S. McWilliams; C. Boehme; Haijun Zhu; P. Pinsukanjana; T. Masood; Linglin Jiang; V. Amarasinghe; M. Achtenhagen; G. A. Evans

    2007-01-01

    This paper reports on the design, growth, fabrication, and processing of an integrated Grating-Outcoupled Surface Emitting (GSE) semiconductor laser and a Double Heterojunction Bipolar Transistor (DHBT) driver. The GSE laser has a 380 mum long gain section, 15 mum long out-coupler, and 200 mum long distributed Bragg reflectors (DBRs). The design of the DHBT includes an InP emitter and collector

  10. Base Transport and Vertical Profile Engineering in SILICON\\/SILICON(1-X) Germanium(x)\\/silicon Heterojunction Bipolar Transistors

    Microsoft Academic Search

    Erwin Josef Prinz

    1992-01-01

    Recent advances in low-temperature epitaxial growth of strained silicon-germanium alloys on silicon substrates allow bandgap engineering in silicon-based devices, with profound consequences for device design. In this thesis the improved control by Rapid Thermal Chemical Vapor Deposition of the vertical profile of a Si\\/Si_{1-x}Ge _{x}\\/Si heterojunction bipolar transistor (HBT) is used to study the effect of the shape of the

  11. Root-Cause Analysis and Statistical Process Control of Epilayers for SiGe:C HeteroStructure Bipolar Transistors

    Microsoft Academic Search

    Qianghua Xie; Erika Duda; Mike Kottke; Wentao Qin; Xiangdong Wang; Shifeng Lu; Martha Erickson; Heather Kretzschmar; Linda Cross; Sharon Murphy

    2003-01-01

    The SiGe:C hetero-structure bipolar transistor (HBT) has turned into a key technology for wireless communication. This paper describes various critical analytical techniques to bring up and maintain the SiGe:C epi-process. Two types of analysis are critical, (1) routine monitoring SiGe base and Si cap thickness, doping dose, Ge composition profile, and their uniformity across the wafer; and (2) root-cause analysis

  12. Comparative study of phase and amplitude noise of CE, CE-CB and CC-CB bipolar transistor amplifiers

    Microsoft Academic Search

    T. I. Boldyreva

    1998-01-01

    Results of development of an algorithm for theoretical calculations both wideband and 1\\/f PM and AM noise in common emitter (CE), common emitter-common base (CE-CB) and common collector-common base (CC-CB) amplifiers are presented. The algorithm is based on using hybrid pi model of a bipolar junction transistor (BJT). An influence of wideband noise sources is calculated basing on well known

  13. Thermal stability analysis of AlGaAs\\/GaAs heterojunction bipolar transistors with multiple emitter fingers

    Microsoft Academic Search

    L. L. Liou; B. Bayraktaroglu

    1994-01-01

    A numerical electro-thermal model was developed for AlGaAs\\/GaAs heterojunction bipolar transistors (HBT's) to describe the base current, current gain and output power dependence on junction temperature. The model is applied to microwave HBT devices with multi-emitter fingers. The calculated results of the common-emitter, current-voltage characteristics in the linear active region show a “current crush” effect due to inherent nonuniform junction

  14. On the optimum design of the front-end PIN-heterojunction bipolar transistor optoelectronic integrated circuit photoreceiver

    Microsoft Academic Search

    N. R. Das; M. J. Deen

    2002-01-01

    In this article, a detailed analysis of the performance of an integrated front-end PIN-heterojunction bipolar transistor photoreceiver has been given and optimum designs are suggested for maximum gain-bandwidth product (GB) and gain-bandwidth-sensitivity measure (GBS) of the device. The present SPICE-based analysis requires the equivalent circuit model of the receiver components. An expression for the impulse response of a PIN photodiode

  15. 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., E-mail: shestakov@thermo.isp.nsc.ru; Zhuravlev, K. S. [Russian Academy of Sciences, Rzhanov Institute of Semiconductor Physics, Siberian Branch (Russian Federation)

    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.

  16. Hot-electron mean free path of ErAs thin films grown on GaAs determined by metal-base transistor ballistic electron emission spectroscopy

    E-print Network

    Russell, Kasey

    Hot-electron mean free path of ErAs thin films grown on GaAs determined by metal-base transistor of the hot-electron mean free path in ErAs thin films grown on GaAs. Using an Al/Al2O3/Al tunnel junction as a hot-electron source for ballistic electron emission spectros- copy, we investigate ErAs films

  17. 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??m and nickel powder with grain size of 10 and 25??m 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

  18. 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.

  19. Heat removal from bipolar transistor by loop heat pipe with nickel and copper porous structures.

    PubMed

    Nemec, Patrik; 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 ?m and nickel powder with grain size of 10 and 25 ?m 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

  20. 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).

  1. 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. [Sandia National Labs., Albuquerque, NM (United States); Enquist, P.M. [Research Triangle Inst., Research Triangle Park, NC (United States)

    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.

  2. 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

  3. Optical detection of hot-electron spin injection into GaAs from a magnetic tunnel transistor source.

    PubMed

    Jiang, X; Wang, R; van Dijken, S; Shelby, R; Macfarlane, R; Solomon, G S; Harris, J; Parkin, S S P

    2003-06-27

    Injection of spin-polarized hot-electron current from a magnetic tunnel transistor into GaAs is demonstrated by the observation of polarized light emission from a GaAs/In(0.2)Ga(0.8)As multiple quantum well light-emitting diode. Electroluminescence from the quantum wells shows a polarization of approximately 10% after subtraction of a linear background polarization. The polarization shows a strong dependence on the bias voltage across the diode, which may originate from changes in the electron spin relaxation rate in the quantum wells under varying bias conditions. PMID:12857153

  4. Self-aligned GaAs p-channel enhancement mode MOS heterostructure field-effect transistor

    Microsoft Academic Search

    Matthias Passlack; Jonathan K. Abrokwah; Ravi Droopad; Zhiyi Yu; Corey Overgaard; Sang In Yi; M. Hale; J. Sexton; A. C. Kummel

    2002-01-01

    Self-aligned GaAs enhancement mode MOS heterostructure field-effect transistors (MOS-HFET) have been successfully fabricated for the first time. The MOS devices employ a Ga2O3 gate oxide, an undoped Al0.75Ga0.25As spacer layer, and undoped In0.2Ga0.8As as channel layer. The p-channel devices with a gate length of 0.6 ?m exhibit a maximum DC transconductance gm of 51 mS\\/mm which is an improvement of

  5. 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.

  6. Improvement of GaAs metal–semiconductor field-effect transistor drain–source breakdown voltage by oxide surface passivation grown by atomic layer deposition

    Microsoft Academic Search

    P. D. Ye; G. D. Wilk; B. Yang; S. N. G. Chu; K. K. Ng; J. Bude

    2005-01-01

    Oxide surface passivation grown by atomic layer deposition (ALD) has been applied to GaAs metal–semiconductor field-effect transistors (MESFETs). The breakdown characteristic of a MESFET is greatly improved by both Al2O3 and HfO2 passivation. Three-terminal transistor breakdown voltage is improved to a maximum level of 20V with Al2O3 passivation from 11V without any surface passivation. With the removal of native oxide

  7. 63-75 GHz fT SiGe-base heterojunction bipolar technology

    Microsoft Academic Search

    G. L. Patton; J. H. Comfort; B. S. Meyerson; E. F. Crabbe; G. J. Scilla; E. de Fresart; J. M. C. Stork; J. Y.-C. Sun; D. L. Harame; J. Burghartz

    1990-01-01

    Experimental results for maximum cut-off frequency (fT) values of 75 and 52 GHz were achieved for SiGe-base and Si-base bipolar transistors with intrinsic base sheet resistances in the 10-17 k?\\/square range. These results extend the speed of silicon bipolar devices into a regime previously reserved to GaAs and other compound semiconductor technologies. Excellent junction characteristics were also obtained for devices

  8. Effect of parasitic series resistances and spurious currents on the extracted temperature of a bipolar junction transistor.

    PubMed

    Mimila-Arroyo, J

    2013-12-01

    Verster's proposition to directly extract the temperature of a bipolar junction transistor using its collector current is widely used. However, the resulting temperature is low accurate even when calibrated. Here, it is demonstrated that the misuse of the emitter current instead of the collector one, because of the presence of spurious currents other than the injection-diffusion one and transistor parasitic series resistances both contribute to the observed inaccuracy. Particularly parasitic series resistances increase the inaccuracy and introduce a strong dependence of the extracted temperature on the collector currents used to extract the temperature; the higher those resistances the higher the inaccuracy. A proposition is made to reduce the effect of those resistances on the inaccuracy of this thermometric element, which allows obtaining a more accurate value on a wider range of the collector probe currents. PMID:24387455

  9. Lateral carrier diffusion and current gain in terahertz InGaAs/InP double-heterojunction bipolar transistors

    NASA Astrophysics Data System (ADS)

    Chiang, Han-Wei; Rode, Johann C.; Choudhary, Prateek; Rodwell, Mark J. W.

    2014-01-01

    The DC current gain in In0.53Ga0.47As/InP double-heterojunction bipolar transistors is computed based on a drift-diffusion model, and is compared with experimental data. Even in the absence of other scaling effects, lateral diffusion of electrons to the base Ohmic contacts causes a rapid reduction in DC current gain as the emitter junction width and emitter-base contact spacing are reduced. The simulation and experimental data are compared in order to examine the effect of carrier lateral diffusion on current gain. The impact on current gain due to device scaling and approaches to increase current gain are discussed.

  10. Low-frequency noise in InP-based NnPnN double heterojunction bipolar transistors

    NASA Astrophysics Data System (ADS)

    Su, Y. K.; Shei, S. C.; Chen, C. H.

    1992-09-01

    This letter deals with the low-frequency noise in an InGaAs(P)/InP double heterojunction bipolar transistor at room temperature. The recombination is mainly responsible for the noise. The current dependence of the base noise with floating collector was of the form IB3 and the shot noise of base current corresponding to 3.2×10-24 A2/Hz for f=10 Hz. The current dependence of the collector noise with high frequency short circuited was of the form Ic1.55 and the shot noise of collector current corresponding to 3.2×10-24 A2/Hz for f=10 Hz.

  11. A comparison of the effects of gamma irradiation on SiGe HBT and GaAs HBT technologies

    Microsoft Academic Search

    Shiming Zhang; Guofu Niu; John D. Cressler; Suraj J. Mathew; Usha Gogineni; Steven D. Clark; Peter Zampardi; Richard L. Pierson

    2000-01-01

    A comparison of the effects of gamma irradiation on silicon-germanium (SiGe) heterojunction bipolar transistor (HBT) and gallium-arsenide (GaAs) HBT technologies is reported, DC and radiofrequency (RF) performance as well as the low frequency noise are investigated for gamma doses up to 1 Mrad(Si). The results indicate that both SiGe and GaAs HBT technologies are tolerant to gamma irradiation

  12. Transistors

    NSDL National Science Digital Library

    Mr. Blackburn

    2004-07-05

    How does a transistor work ? History of semi-conductors Visit the museum of how the transistor was developed. Transistor history The Transistor Museum How stuff works Visit this site and follow through a short course on how a semi-conductor works. How stuff works PBS site Visit the PBS site of transistors and semi-conductors. Watch shorth videos on the development of the transistor. Timeline pbs ...

  13. Indium Phosphide Heterojunction Bipolar Transistors with Emitter Regrowth by Molecular Beam Epitaxy

    NASA Astrophysics Data System (ADS)

    Scott, Dennis W.

    A novel InP-based heterojunction bipolar transistor (HBT) technology using molecular beam epitaxy (MBE) regrowth to form the emitter-base heterojunction and emitter capping layers is presented in this dissertation. The motivation for this work is to combining the positive attributes of the SiGe HBT device structure and fabrication technology with the superior attributes of III-V material systems. The intention of this work is to provide initial investigations into the required material properties as well as initial demonstrations of devices with regrown emitters. Low-resistance polycrystalline InAs (poly-InAs) deposited onto silicon nitride (SiNx) dielectric is demonstrated, and an investigation into material property dependencies on deposition conditions is presented. Low-resistance poly-InAs may be used as an emitter capping material in an InP HBT with regrown emitter where the emitter contact material is wider than the base-emitter junction area. An emitter contact area larger than the emitter junction allows scaling of the device to reduce parasitic capacitances without introducing detrimental parasitics to the emitter contact resistance. Such an HBT could be produced using a patterned base-collector template covered in SiNx with openings in the dielectric in areas where emitter junctions are desired. Areas where the base semiconductor is exposed to emitter regrowth would produce a monocrystalline emitter, and areas where deposition occurs onto SiNx would produce polycrystalline material. A graded InAlAs emitter with InAs emitter cap was used in the initial demonstrations of the regrown emitter HBT. Large-area devices were used to successfully demonstrate proof-of-concept devices and to make the first-order improvements required for a small-area RF device demonstration. The first small-area regrown emitter InP HBT with emitter contact area wider than the 0.7 x 8 mum2 base-emitter junction demonstrated 160 GHz peak ft and simultaneous 140 GHz fmax. Further studies into the base-collector template surface preparation process produced an improved regrowth surface with near-epitaxial smoothness. A simplified, abrupt InP emitter regrowth onto this surface produces regrowth similar to what is observed for growth onto epi-ready InP substrates. The improved regrown emitter HBT with 0.7 x 8 mum2 InP emitter area is used to demonstrate a simultaneous 183 GHz ft and 165 GHz fmax.

  14. Electron Transport Behavior on Gate Length Scaling in Sub-50 nm GaAs Metal Semiconductor Field Effect Transistors

    SciTech Connect

    Han, Jaeheon [Department of Electronic Engineering, Kangnam University, 111 Gugal-dong, Giheung-gu, Yongin-city, Gyeonggi-do, Korea 446-702 (Korea, Republic of)

    2011-12-23

    Short channel GaAs Metal Semiconductor Field Effect Transistors (MESFETs) have been fabricated with gate length to 20 nm, in order to examine the characteristics of sub-50 nm MESFET scaling. Here the rise in the measured transconductance is mainly attributed to electron velocity overshoot. For gate lengths below 40 nm, however, the transconductance drops suddenly. The behavior of velocity overshoot and its degradation is investigated and simulated by using a transport model based on the retarded Langevin equation (RLE). This indicates the existence of a minimum acceleration length needed for the carriers to reach the overshoot velocity. The argument shows that the source resistance must be included as an internal element, or appropriate boundary condition, of relative importance in any model where the gate length is comparable to the inelastic mean free path of the carriers.

  15. \\\\Proc. IEEE 2004 Int. Conference on MicroelectronicTest Structures, Vol 17, March 2004. 127 A New Test Circuit for the Matching Characterization of npn Bipolar Transistors

    E-print Network

    McNeill, John A.

    the forcelsense method a common emitter line is wiring all bipolar transistor pairs in series. Collector and base for the statistical analysis. Matching parameters are given for collector current, current gain, and base-emitter. An example is the offset voltage of an operational amplifier. The offset voltage is partially caused

  16. Lateral carrier diffusion and current gain in terahertz InGaAs/InP double-heterojunction bipolar transistors

    SciTech Connect

    Chiang, Han-Wei; Rode, Johann C.; Choudhary, Prateek; Rodwell, Mark J. W. [Department of Electrical and Computer Engineering, University of California, Santa Barbara, California 93106 (United States)

    2014-01-21

    The DC current gain in In{sub 0.53}Ga{sub 0.47}As/InP double-heterojunction bipolar transistors is computed based on a drift-diffusion model, and is compared with experimental data. Even in the absence of other scaling effects, lateral diffusion of electrons to the base Ohmic contacts causes a rapid reduction in DC current gain as the emitter junction width and emitter-base contact spacing are reduced. The simulation and experimental data are compared in order to examine the effect of carrier lateral diffusion on current gain. The impact on current gain due to device scaling and approaches to increase current gain are discussed.

  17. 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.

  18. 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.

  19. Measurements of Electroluminescence Intensity Distribution in the Direction of Gate Width of n+ Self-Aligned Gate GaAs Metal-Semiconductor Field-Effect Transistors

    Microsoft Academic Search

    Hiroyuki Niwa; Yutaka Ohno; Shigeru Kishimoto; Koichi Maezawa; Takashi Mizutani; Hajime Yamazaki; Toru Taniguchi

    1999-01-01

    We studied electroluminescence (EL) intensity distributions in the direction of gate width of n+ self-aligned gate GaAs metal-semiconductor field-effect transistors (MESFETs). Nonuniform EL was observed along the gate-width direction, suggesting the nonuniform high-field formation in the direction of the gate. It has also been found that the EL at the source side shows gentler distribution than that at the drain

  20. Dry etch damage in GaAs metal-semiconductor field-effect transistors exposed to inductively coupled plasma and electron cyclotron resonance Ar plasmas

    Microsoft Academic Search

    F. Ren; J. W. Lee; C. R. Abernathy; S. J. Pearton; C. Constantine; C. Barratt; R. J. Shul

    1997-01-01

    The effects of Ar plasma exposure on transconductance, channel sheet resistance, output resistance, and gate contact ideality factor of GaAs metal-semiconductor field-effect transistors (MESFETs) were investigated using two different high-density plasma sources, namely inductively coupled plasma and electron resonance plasma. Ion-induced damage is found to be reduced at moderate source powers (â¼200W) because of the reduction in cathode dc self-bias

  1. DLTS study of deep level defects in Li-ion irradiated bipolar junction transistor

    NASA Astrophysics Data System (ADS)

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

    2007-01-01

    Commercial npn transistor (2N 2219A) irradiated with 50 MeV Li 3+-ions with fluences ranging from 3.1 × 10 13 ions cm -2 to 12.5 × 10 13 ions cm -2, is studied for radiation induced gain degradation and minority carrier trap levels or recombination centers. The properties such as activation energy, trap concentration and capture cross section of induced deep levels are studied by deep level transient spectroscopy (DLTS) technique. Minority carrier trap levels with energies ranging from 0.237 eV to 0.591 eV were observed in the base-collector junction of the transistor. In situ I- V measurements were made to study the gain degradation as a function of ion fluence. Ion induced energy levels result in increase in the base current through Shockley Read Hall (SRH) or multi-phonon recombination and subsequent transistor gain degradation.

  2. A Physically Based Analytical Model of the Collector Charge of Ill-V Heterojunction Bipolar Transistors

    E-print Network

    Technische Universiteit Delft

    's equation' for $ in this equation, E is the dielectric constant, q. the electron charge, N the dopantA Physically Based Analytical Model of the Collector Charge of Ill-V Heterojunction Bipolar, charge and capacitance in the collector of a Ill- V HBT. The model consistently takes into ac- count

  3. Ballistic versus diffusive base transport in the high-frequency characteristics of bipolar transistors

    E-print Network

    Luryi, Serge

    Ballistic versus diffusive base transport in the high-frequency characteristics of bipolar a universal character both in the diffusion limit ( W)Z,,) and the ballistic limit (I,,. IV). In the latter ("ballistic") limit Z& W, the second term in Eqs. (4) and (5) is negligible 2770 Appl. Phys. Lett. 60 (22), 1

  4. Parasitic capacitance extraction in bipolar junction transistor for arbitrarily shaped diffusion 

    E-print Network

    Hassan, Mehedi

    1992-01-01

    . . 15 II. I EXISTIiNG POLYGONAL STRUCTURES . . 15 11. 2 SUPER POLYGONAL S'I'HUCTURES . . 11. '3 TRAU!SFORMATIOiN FROM POLYGONAL GDF TO SUPER POI. YCONAL GDF . III I'OLYGON AND LINE GEOlvIETRICS . 24 III. I A13EA AND PERIMETI'. H 1)LeTI, H, 'if... Transistor 10 6 Cross-sectional View of Lateral pnp Transistor 7 Various Parasitic Capacitances 8 A Ring Shaped Structure Described by Two Polygons . 14 17 9 Typical Geometric Structures . 10 Transformation of Polygonal GDF to Super Polygonal GDF . 11...

  5. Uniform junction temperature AIGaAs/GaAs power heterojunction bipolar transistors on silicon substrates

    E-print Network

    spreadacrossthe entire deviceareais about I "C. The deviceexhibits a common emitter current gain of 20, a maximum-power microwave amplifiers. Power levelsof 2.5 W at C band and 2.5 W at X bandhave already been demonstrated in devices on GaAs sub- strates."* Power densities of up to 4 W/mm of emitter length in continuous wave (cw

  6. e bipolar junction transistor (BJT) is historically the first solid-state analog amplifier and digital switch, and formed the basis of integrated circuits (IC) in the 1970s. Starting in the early 1980s, the

    E-print Network

    Wilamowski, Bogdan Maciej

    transistor back into high-volume commercial production, mainly for the now widespread wire- less and wire spaced PN junctions connected back to back sharing the same p-type region, as shown in Figure 9.1a. e...........................................................................9-12 Thermal Sensitivity · Second Order Effects · SPICE Model of the Bipolar Transistor 9.8 Si

  7. DC and microwave noise transient behavior of InP\\/InGaAs double heterojunction bipolar transistor (DHBT) with polyimide passivation

    Microsoft Academic Search

    Yong Zhong Xiong; Geok-Ing Ng; Hong Wang; J. S. Fu

    2001-01-01

    DC and microwave noise transient behavior of InP\\/InGaAs double heterojunction bipolar transistor (DHBT) with polyimide passivation is reported in this paper for the first time. The base transient current is believed to be due to the change of surface potential near the base-emitter junction perimeter at the polyimide\\/emitter interface resulting from a decrease in the amount of trapped electrons in

  8. Low-Frequency Noise Sources in Polysilicon Emiter Bipolar Transistors: Influence of Hot-Electron-Induced Degradation and Post-Stress Recovery

    Microsoft Academic Search

    A. Mounib; F. Balestra; N. Mathieu; J. Brini; G. Ghibaudo; A. Chovet; A. Chantre; A. Nouailhat

    1993-01-01

    The noise properties of polysilicon emitter bipolar transistors are studied. The influences of the various chemical treatments and annealing temperatures, prior and after polysilicon deposition, on the noise magnitude are shown. The impact of hot-electron-induced degradation and post-stress recovery on the base and collector current fluctuations are also investigated in order to determine the main noise sources of these devices.

  9. Neutron irradiation induced degradation of the collector-emitter offset voltage in InP\\/InGaAs single heterojunction bipolar transistors

    Microsoft Academic Search

    Alexei Shatalov; S. Subramanian; A. Dentai; S. Chadrasekhar; S. M. Goodnick

    2000-01-01

    In this article, we report the results of our investigation of neutron irradiation effects on the collector-emitter offset voltage of InP\\/InGaAs single heterojunction bipolar transistors. We find that the offset voltage of these devices increases by more than 0.1 V for neutron doses ~6×1014 cm-2. We present an analysis of the forward and inverse Gummel plots that clearly shows that

  10. Low-frequency noise characterization of self-aligned AlGaAs-GaAs heterojunction bipolar transistors with a noise corner frequency below 3 kHz

    Microsoft Academic Search

    Jin-Ho Shin; Jiyoung Kim; Yujin Chung; Joonwoo Lee; Youngsuk Suh; Kyu Hwan Ahn; Bumman Kim

    1998-01-01

    To find dominant 1\\/f noise sources, generalized noise analyses have been performed for self-aligned AlGaAs\\/GaAs heterojunction bipolar transistors (HBT's). For shorted base-emitter condition, the resistance fluctuation 1\\/f noise is dominant, while for open base-emitter condition, the base-emitter current 1\\/f noise is dominant. The collector-emitter 1\\/f current noise, though generally considered an important noise source, is negligible. The resistance 1\\/f noise

  11. Reverse Conducting Double Gate Lateral Insulated Gate Bipolar Transistor in SOI Based Technology

    Microsoft Academic Search

    F. Udrea; U. N. K. Udugampola; T. Trajkovic; G. A. J. Amaratunga

    2007-01-01

    In this paper we report a lateral insulated gate bipolar device with an embedded anti-parallel diode (body diode) for use in half bridge or full bridge configurations. The device offers ultra-fast switching speed and low on-state resistance and is based on an SOI proprietary process earlier reported by us (F. Udrea, et. al., 2004). The device features double CMOS gates

  12. Silicon-germanium base heterojunction bipolar transistors by molecular beam epitaxy

    Microsoft Academic Search

    GARY L. PATTON; SUBRAMANIAN S. IYER; SYLVAIN L. DELAGE; S. Tiwari; J. M. C. Stork

    1988-01-01

    The devices were fabricated using molecular-beam epitaxy (MBE), low-temperature processing, and germanium concentrations of 0, 6%, and 12%. The transistors demonstrate current gain, and show the expected increase in collector current as a result of reduced bandgap due to Ge incorporation in the base. For a 1000-Å base device containing 12% Ge, a six-times increase in collector current was measured

  13. A gate driver based soft-switching SiC bipolar junction transistor

    Microsoft Academic Search

    Huijie Yu; Jason Lai; Xudong Huang; Jian H. Zhao; Jianhui Zhang; Xiangyang Hu; John Carter; Leonid Fursin

    2003-01-01

    This paper presented a new soft-switching concept that the soft transition is achieved based on gate driver control. A new soft-switched IGBT and MOSFET Gated Transistor (SS-IMGT) base drive structure is proposed for high power SiC BJT. The proposed base scheme can proportionally drive SiC BJT into near-saturate region. In addition, the zero voltage turn-on for BJT can be adaptively

  14. The temperature dependence of the DC base and collector currents in silicon bipolar transistors

    Microsoft Academic Search

    RAMON C. MARTINELLI

    1976-01-01

    Detailed measurements have been made of the base and collector-current characteristics of both n-p-n and p-n-p silicon transistors as a function of temperature. The collector current shows ideal behavior over the temperature range -60 to 150°C in thatI_{C} infin exp (eV_{BE}\\/kT). On the other hand, the base current is nonideal:I_{B} infin exp (eV_{BE}\\/nkT), wheren > 1.0. The nonideality of IBis

  15. Non-ideal effect in 4H–SiC bipolar junction transistor with double Gaussian-doped base

    NASA Astrophysics Data System (ADS)

    Yuan, Lei; Zhang, Yu-Ming; Song, Qing-Wen; Tang, Xiao-Yan; Zhang, Yi-Men

    2015-06-01

    The non-ideal effect of 4H–SiC bipolar junction transistor (BJT) with a double Gaussian-doped base is characterized and simulated in this paper. By adding a specific interface model between SiC and SiO2, the simulation results are in good agreement with the experiment data. An obvious early effect is found from the output characteristic. As the temperature rises, the early voltage increases, while the current gain gradually decreases, which is totally different from the scenario of silicon BJT. With the same effective Gummel number in the base region, the double Gaussian-doped base structure can realize higher current gain than the single base BJT due to the built-in electric field, whereas the early effect will be more salient. Besides, the emitter current crowding effect is also analyzed. Due to the low sheet resistance in the first highly-doped base epilayer, the 4H–BJT with a double base has more uniform emitter current density across the base-emitter junction, leading to better thermal stability. Project supported by the National Natural Science Foundation of China (Grant Nos. 60876061 and 61234006), the Natural Science Foundation of Shaanxi Province, China (Grant No. 2013JQ8012), and the Doctoral Fund of the Ministry of Education of China (Grant Nos. 20130203120017 and 20110203110010).

  16. A 65-kV insulated gate bipolar transistor switch applied in damped AC voltages partial discharge detection system

    NASA Astrophysics Data System (ADS)

    Jiang, J.; Ma, G. M.; Luo, D. P.; Li, C. R.; Li, Q. M.; Wang, W.

    2014-02-01

    Damped AC voltages detection system (DAC) is a productive way to detect the faults in power cables. To solve the problems of large volume, complicated structure and electromagnetic interference in existing switches, this paper developed a compact solid state switch based on electromagnetic trigger, which is suitable for DAC test system. Synchronous electromagnetic trigger of 32 Insulated Gate Bipolar Transistors (IGBTs) in series was realized by the topological structure of single line based on pulse width modulation control technology. In this way, external extension was easily achieved. Electromagnetic trigger and resistor-capacitor-diode snubber circuit were optimized to reduce the switch turn-on time and circular layout. Epoxy encapsulating was chosen to enhance the level of partial discharge initial voltage (PDIV). The combination of synchronous trigger and power supply is proposed to reduce the switch volume. Moreover, we have overcome the drawback of the electromagnetic interference and improved the detection sensitivity of DAC by using capacitor storage energy to maintain IGBT gate driving voltage. The experimental results demonstrated that the solid-state switch, with compact size, whose turn-on time was less than 400 ns and PDIV was more than 65 kV, was able to meet the actual demands of 35 kV DAC test system.

  17. Simulation of energy and fluence dependence of heavy ion induced displacement damage factor in bipolar junction transistor

    NASA Astrophysics Data System (ADS)

    Kulkarni, S. R.; Ravindra, M.; Joshi, G. R.; Damle, R.

    2004-05-01

    This article presents the theoretical calculation of the variation of displacement damage factors as a function of energy and rad equivalent fluence in bipolar junction transistor for various particulate radiation viz ., He, Si, Cl, Ti, Ni, Br, Ag, I, and Au. The calculation is based on the experimental data on gamma-ray induced gain degradation in a commercial space borne BJT (2N3019). The method involves the calculation of gamma-ray dose (rad(Si)) equivalent of effective particle fluence. The linear energy transfer (LET) in silicon for different particle radiation obtained from TRIM calculation has been used for the conversion of gamma-dose into fluence of various particles. The estimation predicts a smooth increase in the displacement damage factor as the mass of the ion increases. Further, the displacement damage factor reaches a maximum at the same value of energy, which corresponds to maximum LET for all heavy ions. The maximum value of damage factor marginally decreases with increasing ion fluence for an ion of given energy. The results are compared with the data available in the literature for proton, deuteron, and helium induced displacement damage.

  18. 3-D simulation of angled strike heavy-ion induced charge collection in silicon-germanium heterojunction bipolar transistors

    NASA Astrophysics Data System (ADS)

    Jinxin, Zhang; Hongxia, Guo; Lin, Wen; Qi, Guo; Jiangwei, Cui; Xin, Wang; Wei, Deng; Qiwen, Zhen; Xue, Fan; Yao, Xiao

    2014-04-01

    This paper presents 3-D simulation of angled strike heavy-ion induced charge collection in domestic silicon-germanium heterojunction bipolar transistors (SiGe HBTs). 3D damaged model of SiGe HBTs single-event effects (SEE) is built by TCAD simulation tools to research ions angled strike dependence. We select several different strike angles at variously typical ions strike positions. The charge collection mechanism for each terminal is identified based on analysis of the device structure and simulation results. Charge collection induced by angled strike ions presents a complex situation. Whether the location of device ions enters, as long as ions track through the sensitive volume, it will cause vast charge collection. The amount of charge collection of SiGe HBT is not only related to length of ions track in sensitive volume, but also influenced by STI and distance between ions track and electrodes. The simulation model is useful to research the practical applications of SiGe HBTs in space, and provides a theoretical basis for the further radiation hardening.

  19. Fabrication of InAlAs/InGaAsSb/InGaAs double heterojunction bipolar transistors

    SciTech Connect

    Lo, C. F. [University of Florida; Ren, F. [University of Florida; Chang, C. Y. [University of Florida; Pearton, S. J. [University of Florida; Chen, Shu-han [National Central University, Taiwan; Chyi, Jen-inn [National Central University, Taiwan; Wang, Sheng-yu [National Central University, Taiwan; Kravchenko, Ivan I [ORNL

    2011-01-01

    A trilevel resist system was employed to fabricate self-aligned, submicron emitter finger In0.52Al0.48As/ In0.42Ga0.58As0.77Sb0.23 / In0.53Ga0.47As double heterojunction bipolar transistors DHBTs. Selective wet-etchants were used to define the emitter fingers and to form an InGaAs guard-ring around the emitter fingers. Due to the low energy bandgap of the InGaAsSb base layer and type II base-collector junction, a low turn-on voltage of 0.38 V at 1 A/cm2 and a high dc current gain of 123.8 for a DHBT with a 0.658.65 m2 emitter area were obtained. A unity gain cutoff frequency fT of 260 GHz and a maximum oscillation frequency fmax of 485 GHz at JC =302 kA/cm2 were achieved.

  20. Performance of Pd\\/Ge\\/Au\\/Pd\\/Au ohmic contacts and its application to GaAs metal-semiconductor field-effect transistors

    Microsoft Academic Search

    Jong-Won Lim; Jae-Kyoung Mun; Myeong-Hyeon Kwak; Jae-Jin Lee

    1999-01-01

    Pd\\/Ge\\/Au\\/Pd\\/Au ohmic contacts have been studied for application to GaAs metal-semiconductor field-effect transistors (MESFETs). The interfacial reaction of the Pd\\/Ge\\/Au\\/Pd\\/Au ohmic contact is investigated using X-ray diffraction, Auger depth profile, and scanning electron microscopy. The good Pd\\/Ge\\/Au\\/Pd\\/Au ohmic contact with the lowest contact resistivity of ?2×10?6 ?cm2 is obtained after annealing at 400°C. This is due to formation of AuGa

  1. 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

  2. Surface passivation effects of As sub 2 S sub 3 glass on self-aligned AlGaAs/GaAs heterojunction bipolar transistors

    SciTech Connect

    Chuang, H.L.; Carpenter, M.S.; Melloch, M.R.; Lundstrom, M.S. (School of Electrical Engineering, Purdue University, West Lafayette, Indiana 47907 (USA)); Yablonovitch, E.; Gmitter, T.J. (Bell Communications Research, Navesink Research Center, Red Bank, NJ (USA))

    1990-11-12

    A recently developed As{sub 2}S{sub 3} chemical treatment was used to passivate the perimeters of self-aligned heterojunction bipolar transistors (HBTs). The As{sub 2}S{sub 3} chemical treatment significantly lowered the base current resulting in a two order of magnitude reduction in the collector current density at which dc current gain was observed ({beta}=1). No degradation with time has been observed in the electrical characteristics of the chemically treated HBTs. This absence of degradation is attributed to the impermeability to oxygen of the As{sub 2}S{sub 3} glass which coats the perimeter of the HBT after chemical treatment.

  3. A comparison of low-frequency noise characteristics and noise sources in NPN and PNP InP-based heterojunction bipolar transistors

    Microsoft Academic Search

    Shawn S. H. Hsu; Dimitris Pavlidis

    2003-01-01

    Low-frequency noise characteristics of NPN and PNP InP-based heterojunction bipolar transistors (HBTs) were investigated. NPN HBTs showed a lower base noise current level (3.85 × 10-17 A2\\/Hz) than PNP HBTs (3.10 × 10-16 A2\\/Hz), but higher collector noise current level (7.16 × 10-16 A2\\/Hz) than PNP HBTs (1.48 × 10-16 A2\\/Hz) at 10 Hz under IC=1 mA, VC=1 V. The

  4. 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.

  5. Bendable GaAs metal-semiconductor field-effect transistors formed with printed GaAs wire arrays on plastic substrates

    Microsoft Academic Search

    Yugang Sun; Seiyon Kim; Ilesanmi Adesida; John A. Rogers

    2005-01-01

    Micro\\/nanowires of GaAs with integrated ohmic contacts have been prepared from bulk wafers by metal deposition and patterning, high-temperature annealing, and anisotropic chemical etching. These wires provide a unique type of material for high-performance devices that can be built directly on a wide range of unusual device substrates, such as plastic or paper. In particular, transfer printing organized arrays of

  6. ELDRS in Bipolar Linear Circuits: A Review

    Microsoft Academic Search

    Ronald L. Pease; Ronald D. Schrimpf; Daniel M. Fleetwood

    2009-01-01

    Enhanced Low Dose Rate Sensitivity (ELDRS) in bipolar linear transistors was first identified in bipolar microcircuit transistors in 1991 and demonstrated in bipolar linear circuits in 1994. Since then it has been a major topic of research, characterization and analysis. Data compendia of low dose rate enhancement factors were presented in 1996, 2001 and 2008, identifying 30 unique widely used

  7. Common-base multi-finger submicron InGaAs/InP double heterojunction bipolar transistor with fmax of 305 GHz

    NASA Astrophysics Data System (ADS)

    Jin, Z.; Su, Y.; Cheng, W.; Liu, X.; Xu, A.; Qi, M.

    2008-11-01

    A layout of a common-base four-finger InGaAs/InP double heterostructure bipolar transistor (DHBT) has been designed and the corresponding DHBT has been fabricated successfully by using planarization technology. The area of each emitter finger was 1 × 15 ?m2. The breakdown voltage was more than 7 V, the current could be more than 100 mA. The maximum output power can be more than 80 mW derived from the DC characteristics. The maximum oscillation frequency was as high as 305 GHz at IC = 50 mA and VCB = 1.5 V. The DHBT is thus promising for the medium power amplifier and voltage controlled oscillator (VCO) applications at W band and higher frequencies.

  8. Refractory WNx\\/W Self-Aligned Gate GaAs Power Metal-Semiconductor Field-Effect Transistor for 1.9GHz Digital Mobile Communication System Operating with a Single Low-Voltage Supply

    Microsoft Academic Search

    Masami Nagaoka; Kenji Ishida; Tokuhiko Matsunaga; Kazuya Nishihori; Takashi Hashimoto; Misao Yoshimura; Yoshikazu Tanabe; Masakatsu Mihara; Yoshiaki Kitaura; Naotaka Uchitomi

    1994-01-01

    We have developed a refractory WN x\\/W self-aligned gate GaAs power metal-semiconductor field-effect transistor (MESFET) for use in L-band digital mobile communication systems. This power MESFET operates with high efficiency and low distortion at a gate bias of 0 V and a low drain bias of 2.7 V, because of its small drain knee voltage, high transconductance and sufficient breakdown

  9. Vertical electron transistor (VET) in GaAs with a heterojunction (AlGaAs-GaAs) cathode

    NASA Astrophysics Data System (ADS)

    Mishra, U.; Maki, P. A.; Wendt, J. R.; Schaff, W.; Kohn, E.; Eastman, L. F.

    1984-02-01

    The successful fabrication of submicrometer channel length (0.75 micron) and gate length (0.15 micron) vertical electron transistors with AlGaAs cathodes is reported. Lack of electron velocity enhancement has been proposed to be due to high operating channel temperatures, and low temperature measurements were hindered by carrier freeze-out.

  10. All-silicon nonlinear transmission line integrated into a Si\\/SiGe heterostructure bipolar transistor process

    Microsoft Academic Search

    M. Birk; D. Behammer; H. Schumacher

    2000-01-01

    Summary form only given. Nonlinear Transmission Lines (NLTL) have been fabricated so far on GaAs substrates only. Recently, we were able to demonstrate a working nonlinear transmission line for the first time on high resistivity silicon proving the applicability of the NLTL concept to silicon millimeter wave integrated circuits (SIMMWICs). We have significantly improved our previous results by integrating the

  11. Ultra High Speed Heterojunction Bipolar Transistor Technology M. Urteaga, D. Scott, M. Dahlstrom, Y. Betser, S. Lee, S. Krishnan

    E-print Network

    Rodwell, Mark J. W.

    ( f ) and power gain ( maxf ) cutoff frequencies is summarized. Key bandwidth limits include scaling transistors (HBTs) find important applications in complex high frequency ICs. In the commercial arena, ICs for multi-gigabit optical fiber transmission are of major current interest. In military applications, fast

  12. AbstractAn indium-phosphide (InP) double-heterojunction bipolar transistor (DHBT) based suite of terahertz monolithic

    E-print Network

    Rodwell, Mark J. W.

    demonstrate the capability of 256nm InP DHBT technology to enable sophisticated single-chip heterodyne their use in many applications. During the 1970's, the development of the microwave monolithic integrated circuit (MMIC) enabled the implementation of complex transistor-based microwave circuits monolithically

  13. Critical appraisal of thermo-mechanical reliability of medium-power heterojunction bipolar transistors for base station and military applications mounted in SOIC-8 leadframe based plastic overmold packages with conductive silver epoxy

    Microsoft Academic Search

    Satbir Madra

    2005-01-01

    Medium power GaInP\\/GaAs heterojunction bipolar transistors (HBTs) operating up to 2.5 Watts of dc dissipation have been evaluated vis-a-vis thermo-mechanical reliability when packaged into SOIC-8 leadframe packages with conductive silver-based epoxy. Thermo-mechanical analyses (TMA) was used to characterize the glass transition temperature (TG) of the molding compound, and detailed finite difference analysis (FDA) based thermal models were generated to characterize

  14. Transport and noise in GaAs\\/AlGaAs heterojunction bipolar transistors. II - Noise and gain at low frequencies

    Microsoft Academic Search

    Shao Cheng Jue; Derek J. Day; Agnes Margittai; Mikelis N. Svilans

    1989-01-01

    Low-frequency noise measured in high-current-gain GaAs\\/AlGaAs double-heterojunction transistors is shown to originate from noise processes in the base. High base resistance associated with high current gain causes Johnson noise to be dominant at high frequencies and low bias, while at low frequencies interface 1\\/f and generation-recombination noise exceed Johnson noise over a bandwidth that increases with base current. At high

  15. Effects of heavy impurity doping on electron injection in p/sup +/-n GaAs diodes

    SciTech Connect

    Klausmeier-Brown, M.E.; Lundstrom, M.S.; Melloch, M.R.; Tobin, S.P.

    1988-06-27

    Measurements of electron injection currents in p/sup +/-n diodes are presented for a range of p-type dopant concentrations. A successive etch technique was used to characterize the electron injection current in terms of the product (n/sub o/D/sub n/). Measurements are presented for Zn-doped GaAs solar cells with p-layer hole concentrations in the range 6.3 x 10/sup 17/-1.3 x 10/sup 19/ cm/sup -3/. The results demonstrate that so-called band-gap narrowing effects substantially increase the injected electron current in heavily doped p-type GaAs. These heavy doping effects must be accounted for in the modeling and design of GaAs solar cells and heterostructure bipolar transistors.

  16. Fabrication of InP-based Optoelectronic Integrated Circuit (OEIC) Photoreceivers Using Shared Layer Integration of Heterojunction Bipolar Transistors and Refracting-Facet Photodiodes

    NASA Astrophysics Data System (ADS)

    Lee, Bangkeun; Yang, Kyounghoon

    2004-04-01

    InP-based monolithic photoreceivers have been fabricated using a shared layer integration scheme of refracting-facet photodiodes (RFPDs) and heterojunction bipolar transistors (HBTs). An HBT was fabricated using a self-aligned emitter-base process and nonalloyed metallization of the emitter, base and collector ohmic contacts. The fabricated 2× 10 ?m2 emitter HBT exhibited a maximum current gain of 40. The maximum cutoff frequencies of this HBT were measured to be fT=79 GHz and fmax=143 GHz at IC=19 mA and VCE=1.5 V, respectively. An RFPD was fabricated using the base-collector junction layers of the HBT based on the selective wet chemical etching characteristics of InP and InGaAs layers. The fabricated RFPD showed a 37% increased optical responsivity of 0.48 A/W compared to the fabricated surface-illuminated photodiode using the same photoreceiver epitaxial layer. The full width at half maximum (FWHM) of the fabricated RFPD was determined to be 24 ps using the standard 50 ? system load. The fabricated three-stage transimpedance amplifier (TIA) showed a transimpedance gain of 46 dB? and a -3 dB bandwidth of 12 GHz. The fabricated monolithic RFPD/HBT photoreceiver has demonstrated a -3 dB optical bandwidth of 6.9 GHz.

  17. Growth, Electrical Characterization, and Electroluminescence of GaN/SiC Heterojunction Diodes and Bipolar Transistors Fabricated on SiC Off-Axis Substrates

    NASA Astrophysics Data System (ADS)

    Miyake, Hiroki; Amari, Koichi; Kimoto, Tsunenobu; Suda, Jun

    2013-12-01

    The growth, electrical characterization, and electroluminescence (EL) of GaN/SiC heterojunction bipolar transistors (HBTs) are presented. GaN grown on off-axis SiC by molecular beam epitaxy showed step bunching owing to the large off-angle of SiC substrates, which contributed to the annihilation of edge dislocations. We investigated the impact of base doping concentration and SiC polytype (4H and 6H) on the characteristics of GaN/SiC heterojunction diodes. By utilizing a reduced doping concentration of 1×1018 cm-3 instead of 1×1019 cm-3, we suppressed the tunneling current via interface traps, resulting in an improved rectifying behavior in the diodes. Capacitance-voltage (C-V) and EL characteristics revealed that the band lineup of GaN/SiC is of type II, and 6H-SiC is better for electron injection. In accordance with diode characteristics, the fabricated GaN/SiC HBTs showed an improved common-base current gain of 0.03 by employing a reduced base doping concentration of 1×1018 cm-3 and 6H-SiC, whereas a current gain below 1×10-4 was obtained in the HBTs with a base doping concentration of 1×1019 cm-3.

  18. Hardness assurance testing and radiation hardening by design techniques for silicon-germanium heterojunction bipolar transistors and digital logic circuits

    NASA Astrophysics Data System (ADS)

    Sutton, Akil K.

    Hydrocarbon exploration, global navigation satellite systems, computed tomography, and aircraft avionics are just a few examples of applications that require system operation at an ambient temperature, pressure, or radiation level outside the range covered by military specifications. The electronics employed in these applications are known as "extreme environment electronics." On account of the increased cost resulting from both process modifications and the use of exotic substrate materials, only a handful of semiconductor foundries have specialized in the production of extreme environment electronics. Protection of these electronic systems in an extreme environment may be attained by encapsulating sensitive circuits in a controlled environment, which provides isolation from the hostile ambient, often at a significant cost and performance penalty. In a significant departure from this traditional approach, system designers have begun to use commercial off-the-shelf technology platforms with built in mitigation techniques for extreme environment applications. Such an approach simultaneously leverages the state of the art in technology performance with significant savings in project cost. Silicon-germanium is one such commercial technology platform that demonstrates potential for deployment into extreme environment applications as a result of its excellent performance at cryogenic temperatures, remarkable tolerance to radiation-induced degradation, and monolithic integration with silicon-based manufacturing. In this dissertation the radiation response of silicon-germanium technology is investigated, and novel transistor-level layout-based techniques are implemented to improve the radiation tolerance of HBT digital logic.

  19. The use of CBr 4 and SiBr 4 doping in MOMBE and application to InP-based heterojunction bipolar transistor structures

    NASA Astrophysics Data System (ADS)

    Beam, E. A.; Chau, H. F.

    1996-07-01

    The use of silicon tetrabromide and carbon tetrabromide for n- and p-type doping respectively of In 0.53Ga 0.47As and InP materials grown by metalorganic molecular beam epitaxy (MOMBE) has been investigated. Controllable n-type doping concentrations from 1 × 10 16cm -3 to 6 × 10 19cm -3 have been obtained in InP using SiBr 4 and tertiarybutylphosphine (TBP). Silicon doping concentrations from n = 1 × 10 16cm -3 to 1 × 10 19cm -3 have been obtained in InGaAs grown using tertiarybutylarsine (TBA). Slightly lower concentrations were obtained when using tris-dimethylaminoarsenic (DMAAs) as the arsenic source. A memory effect has been observed when transitioning from heavily to lightly doped layers, and is attributed to accumulated SiBr 4 evaporating from uncooled surfaces in the growth chamber. Carbon doping of InGaAs to carrier concentrations of 8 × 10 19cm -3 have been obtained with CBr 4 and TBA; however, significantly lower p-type doping levels are obtained when DMAAs is used as the arsenic source. We attribute this behavior to the DMAAs decomposition products reacting with carbon on the wafer surface. Secondary ion mass spectroscopy (SIMS) profiling of heavily Si- and C-doped materials indicates that bromine incorporation is below the detection level of our instrument (< 10 15cm -3). These dopant sources have been used for the growth of InP-based heterojunction bipolar transistor (HBT) structures. Both single- and double-heterojunction device structures have been produced with ft of 69-91 GHz and fmax of 163-166 GHz, which are comparable to the same structures grown using conventional dopant sources.

  20. Metal-sulfur-based air-stable passivation of GaAs with very low surface-state densities

    NASA Astrophysics Data System (ADS)

    Ashby, Carol I. H.; Zavadil, Kevin R.; Baca, Albert G.; Chang, P.-C.; Hammons, B. E.; Hafich, M. J.

    2000-01-01

    An air-stable electronic surface passivation for GaAs and other III-V compound semiconductors that employs sulfur and a suitable metal ion, e.g., Zn, and that is robust towards plasma dielectric deposition has been developed. Initial improvements in photoluminescence are twice that of S-only treatments and have been preserved for >11 months with SiOxNy dielectric encapsulation. Photoluminescence and x-ray photoelectron spectroscopies indicate that the passivation consists of two major components with one being stable for >2 years in air. This process improves heterojunction bipolar transistor current gain for both large and small area devices.

  1. Novel Metal-Sulfur-Based Air-Stable Passivation of GaAs with Very Low Surface State Densities

    SciTech Connect

    Ashby, Carol I.H.; Baca, Albert G.; Chang, P.-C; Hafich, M.J.; Hammons, B.E.; Zavadil, Kevin R.

    1999-08-09

    A new air-stable electronic surface passivation for GaAs and other III-V compound semiconductors that employs sulfur and a suitable metal ion, e.g., Zn, and that is robust towards plasma dielectric deposition has been developed. Initial improvements in photoluminescence are twice that of S-only treatments and have been preserved for >11 months with SiO{sub x}N{sub y} dielectric encapsulation. Photoluminescence and X-ray photoelectron spectroscopies indicate that the passivation consists of two major components with one being stable for >2 years in air. This process improves heterojunction bipolar transistor current gain for both large and small area devices.

  2. Direct-current and radio-frequency characterizations of GaAs metal-insulator-semiconductor field-effect transistors enabled by

    E-print Network

    Ye, Peide "Peter"

    hysteresis-free Ids-Vgs characteristics and low flicker noise indicate that a high-quality SAND-GaAs MISFETs. We observe high-quality in- terface between SAND and GaAs by characterizing low fre- quency noiseDirect-current and radio-frequency characterizations of GaAs metal-insulator-semiconductor field

  3. IEEE ELECTRON DEVICE LETTERS, VOL. 18, NO. 11, NOVEMBER 1997 553 High InP Double Heterojunction Bipolar

    E-print Network

    Yang, Kyounghoon

    Bipolar Transistors with Chirped InGaAs/InP Superlattice Base­Collector Junction Grown by CBE Kyounghoon- erojunction Bipolar Transistors (DHBT's) with a chirped In- GaAs/InP superlattice B­C junction grown by CBE -emitter DHBT. I. INTRODUCTION RECENTLY, InP-based heterojunction bipolar transistors have demonstrated

  4. A fiber-optically triggered avalanche transistor

    Microsoft Academic Search

    R. J. Baker; G. T. Perryman; P. W. Watts

    1991-01-01

    A silicon bipolar transistor operating in the avalanche region was optically triggered into secondary breakdown. This transistor has been given the name fiber-optically triggered avalanche transistor (FOTAT). The FOTAT acts as an optical power discriminator. That is, secondary breakdown occurs when the triggering optical power exceeds the triggering threshold of the FOTAT. This secondary breakdown is seen as a negative

  5. BIPOLAR TRANSISTORS Erwin Jasef Prinz

    E-print Network

    -xGex material can be fabricated using processes compatible with standard silicon technology. Graded-base ~i with the concurrent degradation of the electrical performance of the devices. This deleterious effect is especially a fun placeto work. Peter M. Garone insta.l1edthe RTCVD reactor and provided the initial growth rec

  6. The Schottky-gated hall-effect transistor and its application to carrier concentration and mobility profiling in GaAs MESFET's

    Microsoft Academic Search

    Craig Wayne Farley; Ben G. Streetman

    1987-01-01

    A special four-terminal MESFET (HFET) is employed in a unique way to characterize carrier concentration and mobility profiles of channel implants into GaAs. This device allows measurement of carrier concentration and mobility under forward gate bias so that the near surface region within the zero bias depletion width can be profiled. From the carrier concentration and mobility profiles, surface and

  7. Implementation and operational investigations of bipolar gate drivers

    E-print Network

    Boyer, Edmond

    Implementation and operational investigations of bipolar gate drivers Jean-Christophe CREBIER with the investigation of simple implementation and design of bipolar gate driver for high side power transistor control. Bipolar gate signals are usually preferred for high switching dynamic control and power device shielding

  8. Electrical degradation mechanisms of RF power GaAs PHEMTs

    E-print Network

    Villanueva, Anita A. (Anita Ariel), 1978-

    2007-01-01

    GaAs Pseudomorphic High-Electron Mobility Transistors (PHEMTs) are widely used in RF power applications. Since these devices typically operate at high power levels and under high voltage biasing, their electrical reliability ...

  9. InGaP/GaAs/InGaP double-heterojunction bipolar transistors grown by solid-source molecular-beam epitaxy with a valved phosphorus cracker

    E-print Network

    Woodall, Jerry M.

    -beam epitaxy with a valved phosphorus cracker T. P. Chin, J. C. P. Chang, and J. M. Woodall School equipped with a valved phosphorus cracker. Various designs of base­collector (B­C) junction are used-quality phosphorus-containing compounds.1­4 The growth of high-performance InGaP/ GaAs and InGaAs/InP single

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

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

    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 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 Technical Reports Server (NTRS)

    Simons, Rainee N.

    1987-01-01

    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. 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.

  13. 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. [Fraunhofer Institute for Applied Solid-State Physics (IAF), Tullastrasse 72, 79108 Freiburg (Germany)

    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.

  14. Plasma nitridation of thin Si layers for GaAs dielectrics D. M. Diatezua,b)

    E-print Network

    Rockett, Angus

    ­insulator­ semiconductor MIS field-effect transistors FETs .1 Initial work growing Si3N4 directly on GaAs by variousPlasma nitridation of thin Si layers for GaAs dielectrics Z. Wang,a) D. M. Diatezua,b) D-G. Park ICL were deposited on GaAs epitaxial layers on GaAs substrates. These were then nitrided by exposure

  15. D-MOS transistor for microwave applications

    Microsoft Academic Search

    HANS J. SIGG; GEORGE D. VENDELIN; THOMAS P. CAUGE; JOSEPH KOCSIS

    1972-01-01

    A new n-channel silicon MOS transistor is described that can be fabricated with channel lengths of less than 1 µ by using a double-diffusion process similar to that used in bipolar transistor fabrication. The dimensional tolerances are not tighter than those used in the processing of conventional MOS transistors. This device (called D-MOST) shows gain in the GHz range and

  16. Characteristics enhancement of a GaAs based heterostructure field-effect transistor with an electrophoretic deposition (EPD) surface treated gate structure

    NASA Astrophysics Data System (ADS)

    Chen, Chun-Chia; Chen, Huey-Ing; Liu, I.-Ping; Chou, Po-Cheng; Liou, Jian-Kai; Tsai, Yu-Ting; Liu, Wen-Chau

    2015-06-01

    A Pt/AlGaAs/InGaAs/GaAs heterostructure field-effect transistor (HFET), prepared by an electrophoretic deposition (EPD) approach on gate Schottky contact region, is fabricated and studied. The EPD-based Pt-gates with three different molar ratios (?0) are examined by scanning electron microscopy (SEM) image. Good Pt-gate coverage with effective reduction of thermal-induced defects at Pt/AlGaAs interface is achieved through a low temperature EPD approach. Experimentally, for a gate dimension of 1 ?m × 100 ?m, a lower gate current of 1.9 × 10-2 mA/mm, a higher turn-on voltage of 0.85 V, a higher maximum drain saturation current of 319.3 mA/mm, and a higher maximum extrinsic transconductance of 146.8 mS/mm are obtained for an EPD-based HFET at 300 K. Moreover, comparable microwave characteristics of an EPD-based HFET are demonstrated at different temperature ambiences. Therefore, based on the improved DC performance and inherent benefits of low cost, simple apparatus, flexible deposition on varied substrates, and adjustable alloy grain size, the proposed EPD approach shows the promise to fabricate high-performance electronic devices.

  17. Metal-sulfur-based air-stable passivation of GaAs with very low surface-state densities

    SciTech Connect

    Ashby, Carol I. H. [Sandia National Laboratories, Albuquerque, New Mexico 87185-0603 (United States)] [Sandia National Laboratories, Albuquerque, New Mexico 87185-0603 (United States); Zavadil, Kevin R. [Sandia National Laboratories, Albuquerque, New Mexico 87185-0603 (United States)] [Sandia National Laboratories, Albuquerque, New Mexico 87185-0603 (United States); Baca, Albert G. [Sandia National Laboratories, Albuquerque, New Mexico 87185-0603 (United States)] [Sandia National Laboratories, Albuquerque, New Mexico 87185-0603 (United States); Chang, P.-C. [Sandia National Laboratories, Albuquerque, New Mexico 87185-0603 (United States)] [Sandia National Laboratories, Albuquerque, New Mexico 87185-0603 (United States); Hammons, B. E. [Sandia National Laboratories, Albuquerque, New Mexico 87185-0603 (United States)] [Sandia National Laboratories, Albuquerque, New Mexico 87185-0603 (United States); Hafich, M. J. [Sandia National Laboratories, Albuquerque, New Mexico 87185-0603 (United States)] [Sandia National Laboratories, Albuquerque, New Mexico 87185-0603 (United States)

    2000-01-17

    An air-stable electronic surface passivation for GaAs and other III-V compound semiconductors that employs sulfur and a suitable metal ion, e.g., Zn, and that is robust towards plasma dielectric deposition has been developed. Initial improvements in photoluminescence are twice that of S-only treatments and have been preserved for >11 months with SiO{sub x}N{sub y} dielectric encapsulation. Photoluminescence and x-ray photoelectron spectroscopies indicate that the passivation consists of two major components with one being stable for >2 years in air. This process improves heterojunction bipolar transistor current gain for both large and small area devices. (c) 2000 American Institute of Physics.

  18. Formation and characterization of nanometer scale metal-oxide-semiconductor structures on GaAs using low-temperature

    E-print Network

    Ye, Peide "Peter"

    Formation and characterization of nanometer scale metal-oxide-semiconductor structures on GaAs semiconductors and is used as gate dielectric for GaAs and GaN metal-oxide-semiconductor field-effect transistors to fabricate nanometer scale metal-oxide-semiconductor structures on GaAs using newly developed low

  19. Bipolar disorder

    Microsoft Academic Search

    Gérard Emilien; Lucia Septien; Claudine Brisard; Emmanuelle Corruble; Michel Bourin

    2007-01-01

    Bipolar disorder is a pathological disturbance of mood, characterized by waxing and waning manic, depressive and, sometimes distinctly mixed states. A diagnosis of bipolar disorder can only be made with certainty when the manic syndrome declares itself. Most individuals who are diagnosed with this disorder will experience both poles of the illness recurrently, but depressive episodes are the commonest cause

  20. 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…

  1. 64K dynamic 1\\/N fractional device bipolar memory

    Microsoft Academic Search

    J. Selleck; R. Kenyon; D. Gaffney; F. Wiedman; A. Bhattacharyya; P. Mollier

    1980-01-01

    This report will cover a 1\\/N fractional device bipolar memory cell - the FET one-device memory cell equivalent - noting that by reversing the orientation of the transistor and capacitor, the density, thin dielectric and polysilicon techniques of FET technology can be combined with the speed of bipolar technology,

  2. GaAs phase noise characteristics in high frequency synthesizer prescalers

    Microsoft Academic Search

    Jaime A. Borras

    1988-01-01

    The phase noise of GaAs dividers has been suggested to be 20-30 dB worse than for bipolar ECL dividers. The author investigates this suggestion and its implications for microwave frequency synthesizers. The single-sideband phase noise (SSBN) spectral density of a GaAs prescaler using source-coupled FET logic was found to be better (lower) than that of a bipolar diode-load emitter-coupled logic

  3. Characterization of enhanced low dose rate sensitivity (ELDRS) effects using Gated Lateral PNP transistor structures

    Microsoft Academic Search

    Ronald L. Pease; Dale G. Platteter; G. W. Dunham; J. E. Seiler; H. J. Barnaby; R. D. Schrimpf; Marty R. Shaneyfelt; M. C. Maher; R. N. Nowlin

    2004-01-01

    The high and low dose rate responses of bipolar transistors in a bipolar linear circuit process technology have been studied with specially designed gated lateral pnp test transistors that allow for the extraction of the oxide trapped charge (Not) and interface trap (Nit) densities. The buildup of Not and Nit with total dose is investigated as a function of the

  4. 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.

  5. Cryogenic measurements of aerojet GaAs n-JFETs

    Microsoft Academic Search

    John H. Goebel; Theodore T. Weber

    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

  6. Manufacturing Methods and Technology (MMT) measure for fabrication of silicon transcalent transistor

    Microsoft Academic Search

    M. F. Devito; S. W. Kessler; R. E. Reed; D. R. Trout

    1980-01-01

    The design of a silicon transcalent transistor, its fabrication and its evaluation are detailed. The transcalent transistor, type J15381, is a triple diffused, bipolar NPN silicon transistor assembly mounted in a ruggedized, heat pipe cooled military package with integral fins for forced air cooling. Both high voltage and high current capabilities are achieved in small size, light weight assembly that

  7. Hot Electron Transistors on Silicon Substrate (HESS)--A Computational Prototyping

    E-print Network

    Dutton, Robert W.

    electron transistors. The first type is similar to a bipolar transistor. However, the carrier injection electrons. In the first implementation by CHINT (CHarge INjection Transistor)[5], the electrons used in CHINT, where carrier heating is achieved through the space­charge­limited current and barrier

  8. Effects of Radiation on the Noise Performance of Transistors

    Microsoft Academic Search

    Peter O. Lauritzen

    1972-01-01

    The predominant transistor noise sources are surveyed and related to both surface and bulk permanent damage radiation effects. The medium and high frequency noise performance of FET and bipolar transistors is not strongly affected by radiation until the devices themselves begin to fail. Low frequency 1\\/f noise is affected by relatively light radiation doses, but only with the junction FET

  9. High-frequency equivalent circuit of GaAs FETs for large-signal applications

    Microsoft Academic Search

    Manfred Berroth; Roland Bosch

    1991-01-01

    The application of GaAs field effect transistors in digital circuits requires a valid description by an equivalent circuit at all possible gate and drain bias voltages for all frequencies from DC up to the gigahertz range. An equivalent circuit is presented which takes into account the gate current of positively biased transistors as well as the symmetrical nature of the

  10. 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. PMID:23843205

  11. Thermoelectric Effects in Bipolar Devices: Internally Cooled Semiconductor Lasers

    E-print Network

    Thermoelectric Effects in Bipolar Devices: Internally Cooled Semiconductor Lasers Kevin P. Pipe of Technology and * Jack Baskin School of Engineering, UC Santa Cruz Heating in semiconductor lasers 10µm from the bottom contact to the 100µm-thick GaAs substrate. A temperature difference

  12. 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.

  13. 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.

  14. 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

  15. 2364 IEEE TRANSACTIONS ON ELECTRON DEVICES, VOL. 53, NO. 9, SEPTEMBER 2006 New Schottky-Gate Bipolar-Mode Field-Effect

    E-print Network

    Kumar, M. Jagadesh

    -Gate Bipolar-Mode Field-Effect Transistor (SBMFET): Design and Analysis Using Two-Dimensional Simulation M. Jagadesh Kumar, Senior Member, IEEE, and Harsh Bahl Abstract--A new Schottky-gate bipolar-mode field importance in medium-power high-current switching applications. Index Terms--Bipolar-mode field

  16. 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.

  17. Assessment of interatomic potentials for molecular dynamics simulations of GaAs deposition D. A. Murdick,* X. W. Zhou, and H. N. G. Wadley

    E-print Network

    Wadley, Haydn

    , lasers, infrared detectors, and solar cells.1 Metal semi- conductor field effect transistors MESFETs avoidance and phased array radars.2 GaAs thin films doped with transition metals, such as manganese, have re

  18. Experimental verification of the parasitic bipolar amplification effect in PMOS single event transients

    NASA Astrophysics Data System (ADS)

    He, Yi-Bai; Chen, Shu-Ming

    2014-07-01

    The contribution of parasitic bipolar amplification to SETs is experimentally verified using two P-hit target chains in the normal layout and in the special layout. For PMOSs in the normal layout, the single-event charge collection is composed of diffusion, drift, and the parasitic bipolar effect, while for PMOSs in the special layout, the parasitic bipolar junction transistor cannot turn on. Heavy ion experimental results show that PMOSs without parasitic bipolar amplification have a 21.4% decrease in the average SET pulse width and roughly a 40.2% reduction in the SET cross-section.

  19. Optimum noise source impedance determination for GaAs FETs at room and cryogenic temperatures

    Microsoft Academic Search

    R. CLARK ROBERTSON; TRI T. HA

    1987-01-01

    An analytical technique is developed to determine the optimum noise source impedance for an extrinsic, or packaged, gallium arsenide field-effect transistor (GaAs FET) using only the small-signal s-parameters and the minimum noise figures available from the manufacturer's data sheet. The procedure is then modified to treat the special case of the intrinsic, or chip, GaAs FET as well. The technique

  20. GaAs FET and HFET on InP substrate

    Microsoft Academic Search

    A. Clei; R. Azoulay; N. Draida; S. Biblemont; C. Joly

    1990-01-01

    GaAs FET and HFET structures have been grown by mismatched MOVPE epitaxy on InP substrates and processed using conventionnal technology. These transistors exhibit characteristics comparable to those measured on GaAs substrate. Ft and Fmax values of 12 and 30 GHz are measured on 1¿m MESFET. Intrinsic transconductance greater than 250 mS\\/mm have been extracted for 1¿m gatelength DMT.

  1. A new structure of back contact solar cell improved by transistor effect

    Microsoft Academic Search

    J. C. Jimeno; R. Gutierrez; F. Hernando; K. Varner; V. Rodriguez; S. Uriarte; C. Ikaran; I. Petrina

    2005-01-01

    This work presents a new structure of back contact solar cell. This structure, denominated transistor wrap through, TWT, collects the photogenerated current in their front surface, having a pn junction placed there. To transport this current to the back emitter TWT includes several localized bipolar transistors. An analytical model, including their electrical equivalent circuit has been developed. Manufacturing of TWT

  2. TUDE ET RALISATION D'AMPLIFICATEUR A TRANSISTOR A EFFET DE CHAMP A L'AsGa REFROIDI

    E-print Network

    Boyer, Edmond

    un facteur de bruit 0,25 dB. Abstract. 2014 Minimum noise figure and optimum source impedance of GaAs to the physical changes of the material. Amplifiers using GaAs field-effect transistors (NE 244 and Gat 1) were field-effect tran- sistors cooled at cryogenic temperatures are computed. Noise characteristics

  3. Intermodulation distortion of a bipolar common-emitter amplifier with arbitrary emitter impedance and input matching network

    Microsoft Academic Search

    G. A. M. Hurkx; Edwin van der Heijden

    2004-01-01

    In this paper, concise formulas for the intermodulation distortion of a bipolar common-emitter amplifier stage with arbitrary emitter impedance and input matching network are presented. These expressions provide quantitative insight in the influence of transistor properties, emitter degeneration and input power matching on distortion. Only a small set of measurable transistor parameters is needed. As examples, IIP3 is calculated for

  4. Switching Transistor

    NASA Technical Reports Server (NTRS)

    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.

  5. Novel WSi/Au T-shaped gate GaAs metal-semiconductor field-effect-transistor fabrication process for super low-noise microwave monolithic integrated circuit amplifiers

    SciTech Connect

    Takano, H.; Hosogi, K.; Kato, T. [Mitsubishi Electric Corp., Itami (Japan)] [and others] [Mitsubishi Electric Corp., Itami (Japan); and others

    1995-05-01

    A fully ion-implanted self-aligned T-shaped gate Ga As metal-semiconductor field-effect transistor (MESFET) with high frequency and extremely low-noise performance has been successfully fabricated for super low-noise microwave monolithic integrated circuit (MMIC) amplifiers. A subhalf-micrometer gate structure composed of WSi/Ti/Mo/Au is employed to reduce gate resistance effectively. This multilayer gate structure is formed by newly developed dummy SiON self-alignment technology and a photoresist planarization process. At an operating frequency of 12 GHz, a minimum noise figure of 0.87 dB with an associated gain of 10.62 dB has been obtained. Based on the novel FET process, a low-noise single-stage MMIC amplifier with an excellent low-noise figure of 1.2 dB with an associated gain of 8 dB in the 14 GHz band has been realized. This is the lowest noise figure ever reported at this frequency for low-noise MMICs based on ion-implanted self-aligned gate MESFET technology. 14 refs., 9 figs.

  6. Experimental study on energy injection damage of a GaAs low noise amplifier with and without DC bias

    Microsoft Academic Search

    Changchun Chai; Yintang Yang; Bing Zhang; Yang Yang; Peng Leng; Wei Rao

    2008-01-01

    An experimental study on energy injection induced damage by a pulse-modulated carrier with 300 MHz radio frequency (RF) signal source to a GaAs bipolar low noise amplifier (LNA) with and without DC bias is presented in this paper based on the measurement of the noise figure and gain variation of GaAs LNA prior to and after the energy injection. Experimental

  7. Orientation-dependent perimeter recombination in GaAs diodes

    SciTech Connect

    Stellwag, T.B.; Melloch, M.R.; Lundstrom, M.S.; Carpenter, M.S.; Pierret, R.F. (School of Electrical Engineering, Purdue University, West Lafayette, Indiana 47907 (USA))

    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.

  8. Electronic states of GaAs and GaAs +

    NASA Astrophysics Data System (ADS)

    Balasubramanian, K.

    1987-03-01

    Complete active space MCSCF (CASSCF) followed by first-order configuration interaction (FOCI) calculations are carried out on low-lying electronic states of GaAs and GaAs+. Among the 12 electronic states of GaAs considered here, six of them are bound and their spectroscopic properties are calculated. The ground state of GaAs is found to be 3?- with a 3? state only 1569 cm-1 above the 3?- state. The ground state of GaAs+ is found to be 4?- state. The vertical ionization potential of GaAs is calculated to be 5.91 eV. Our calculations predict the electronic spectra of GaAs and GaAs+ which are yet to be observed.

  9. Low dark current GaAs metal-semiconductor-metal (MSM) photodiodes using WSi(x) contacts

    Microsoft Academic Search

    M. Ito; O. Wada

    1986-01-01

    The fabrication and characterization of metal-semiconductor-metal (MSM) photodiodes using the same undoped GaAs layer that is used as a buffer layer in the epitaxial structure for GaAs field effect transistors (FET's) is presented. To study the dark current mechanism, various metal electrodes used for Schottky contacts are examined. A drastic V-shape relationship between the dark current of the MSM photodiode

  10. Modeling of Low-Level Rectification RFI in Bipolar Circuitry

    Microsoft Academic Search

    Robert Richardson

    1979-01-01

    This paper discusses the rectification response exhibited by low-frequency bipolar transistors when microwave energy is injected. A circuit-analysis model for calculating low-frequency small-signal RFI response is outlined and applied in analyzing RFI behavior ofa 741 op amp. Principal results from the RFI-device model are 1) RFI is due basically to nonlinearity of the emitter-base characteristic, and also to ac crowding

  11. Broadband cryogenic preamplifiers incorporating GaAs MESFETs for use with low-temperature particle detectors

    SciTech Connect

    Lee, A.T. (Physics Department, Stanford University, Stanford, California 94305 (US))

    1989-10-01

    Two voltage-sensitive preamplifier designs are presented for operation at 1.6 K. Both designs incorporate GaAs MESFETs (Plessy P35-1101). The first design has two stages including a common-source gain stage and a source follower stage. The noise performance, particularly with the low-frequency noise, was found to improve with cooling. The white-noise level at low temperature is 1 nV/Hz{sup 1/2}, and the low-frequency noise corner occurs at approximately 1 MHz. The voltage gain into 50 {Omega} is 7.0 dB, with the {minus}3-dB point occuring at 10 MHz. The noise of the first stage was found to dominate the total noise at the output of a low-noise room-temperature post amplifier. The output impedance of the preamplifier is 50 {Omega}. The second design incorporates one cold FET, dissipating 1 mW, in cascode with a room-temperature bipolar transistor. The noise of this design was found to be approximately equal to that of the two-cold-stage design except for a bulge in the voltage noise centered at 13 MHz due to impedance mismatching of the line to room temperature. The gain of this design is 21 dB, with the {minus}3-dB point at 2 MHz. Cryogenic semiconductor operation is discussed, design parameters of the two preamplifiers are discussed in detail, noise measurements are presented along with a discussion of the different temperature- and bias-dependent noise sources, and an analysis of the signal-to-noise ratio and rise time for the present detection scheme is made.

  12. Temperature enhancement of terahertz responsivity of plasma field effect transistors

    NASA Astrophysics Data System (ADS)

    Klimenko, Oleg A.; Knap, Wojciech; Iniguez, Benjamin; Coquillat, Dominique; Mityagin, Yury A.; Teppe, Frederic; Dyakonova, Nina; Videlier, Hadley; But, Dmitry; Lime, Francois; Marczewski, Jacek; Kucharski, Krzysztof

    2012-07-01

    Temperature dependence of THz detection by field effect transistors was investigated in a wide range of temperatures from 275 K down to 5 K. The important increase of the photoresponse following 1/T functional dependence was observed when cooling from room temperature down to 30 K. At the temperatures below ˜30 K, the THz response saturated and stayed temperature independent. Similar behavior was observed for GaAs, GaN, and Si based field effect transistors. The high temperature data were successfully interpreted using recent theory of overdamped plasma excitation in field effect transistors. The low temperature saturation of the photoresponse was tentatively explained by the change of the transport regime from diffusive to ballistic or traps governed one. Our results clearly show that THz detectors based on field effect transistors may improve their responsivity with lowering temperature but in the lowest temperatures (below ˜30 K) further improvement is hindered by the physics of the electron transport itself.

  13. Delta- (°-) doping in MBE-grown GaAs: Concept and device application

    NASA Astrophysics Data System (ADS)

    Ploog, Klaus

    1987-02-01

    The implementation of °-function-like doping profiles during molecular beam epitaxy (MBE) of GaAs by using Si donors and Be acceptors is employed to generate V-shaped potential wells with a quasi-two-dimensional electron (hole) gas and to create a new GaAs sawtooth doping superlattice with strongly reduced energy gap. Three examples for application of °-doped n-type GaAs are given; (i) as electron supplying layer in selectively doped asymmetric GaAs/Al xGa 1- xAs quantum well heterostructures, (ii) as thin tunneling barrier for non-alloyed ohmic contacts on n-GaAs, and (iii) as Schottky gate °-doped field effect transistor. GaAs sawtooth doping superlattices are attractive for application in photonic devices due to the significant red-shift of their luminescence.

  14. Bipolar disorder in women.

    PubMed

    Miller, Laura J; Ghadiali, Nafisa Y; Larusso, Elizabeth M; Wahlen, Kelly J; Avni-Barron, Orit; Mittal, Leena; Greene, Judy A

    2015-01-01

    This article summarizes research pertinent to the clinical care of women with bipolar disorder. With bipolar disorder, female gender correlates with more depressive symptoms and different comorbidities. There is a high risk of symptom recurrence postpartum and possibly during perimenopause. Women with bipolar disorder have increased risk of sexually transmitted diseases, unplanned pregnancies, excessive weight gain, metabolic syndrome, and cardiovascular disease. Mood stabilizing medications, specific psychotherapies, and lifestyle changes can stabilize mood and improve functioning. Pharmacologic considerations include understanding interactions between mood stabilizing medications and contraceptive agents and risks and benefits of mood stabilizing medication during pregnancy and lactation. PMID:25315819

  15. Supergain transistors on high-purity float-zone silicon substrate

    NASA Astrophysics Data System (ADS)

    Han, D. J.; Batignani, G.; Guerra, A. Del.

    2003-08-01

    Since float-zone (FZ) silicon has lower contamination and longer minority carrier lifetime than those in Czochralski silicon and other semiconductor materials, it has potential advantages to fabricate a bipolar junction transistor on the FZ substrate to achieve high gain at very low current levels. In this report, the authors present preliminary experimental results on supergain bipolar junction transistors fabricated on unusual FZ refined high-resistivity silicon substrate and by ion implantation technology. A phosphorus-doped polycrystalline silicon backside gettering layer has been employed to preserve the long carrier lifetime of the high-purity FZ silicon. Bipolar junction transistors have demonstrated high current gain, more than 3300 for ultralow base current levels of 10 pA in this study. Possible applications of high-purity FZ silicon on some advanced semiconductor devices and circuits are discussed in this letter.

  16. Bipolar thermoelectric devices

    E-print Network

    Pipe, Kevin P. (Kevin Patrick), 1976-

    2004-01-01

    The work presented here is a theoretical and experimental study of heat production and transport in bipolar electrical devices, with detailed treatment of thermoelectric effects. Both homojunction and heterojunction devices ...

  17. Molecular beam epitaxy growth of InAs and In0.8Ga0.2As channel materials on GaAs substrate for metal oxide semiconductor field effect

    E-print Network

    Woodall, Jerry M.

    Molecular beam epitaxy growth of InAs and In0.8Ga0.2As channel materials on GaAs substrate for metal oxide semiconductor field effect transistor applications Ning Li,a Eric S. Harmon, and David B velocities. Using them as the metal oxide semiconductor field effect transistor MOSFET channel materials

  18. A novel high voltage bipolar technology featuring trench-isolated base

    Microsoft Academic Search

    H. Kim; J. Jin; C. Jeoun; Y. Choi; B. Kwon; S. Lim; K. Choi

    1994-01-01

    In this paper, we present a novel bipolar technology featuring the trench-isolated base. When employed for a conventional 2 ?m process, the trench isolation reduces both the surface leakage and current gain of the parasitic lateral pnp transistor by at least one order, which results in the improvement of the punchthrough-induced breakdown behavior by almost a factor of two. The

  19. Staging Bipolar Disorder

    Microsoft Academic Search

    Eduard Vieta; M. Reinares; A. R. Rosa

    2011-01-01

    The purpose of this study was to analyze the evidence supporting a staging model for bipolar disorder. The authors conducted\\u000a an extensive Medline and Pubmed search of the published literature using a variety of search terms (staging, bipolar disorder,\\u000a early intervention) to find relevant articles, which were reviewed in detail. Only recently specific proposals have been made\\u000a to apply clinical

  20. Structural properties and band offset determination of p-channel mixed As/Sb type-II staggered gap tunnel field-effect transistor structure

    E-print Network

    Yener, Aylin

    field scattering in AlGaN/AlN/GaN heterostructure field-effect transistors Appl. Phys. Lett. 101, 113501-channel staggered gap In0.7Ga0.3As/ GaAs0.35Sb0.65 heterostructure tunnel field-effect transistor (TFET) grown tunnel field-effect transistor structure Y. Zhu, N. Jain, D. K. Mohata, S. Datta, D. Lubyshev et al

  1. A silicon nanocrystal tunnel field effect transistor

    SciTech Connect

    Harvey-Collard, Patrick, E-mail: P.Collard@USherbrooke.ca [Département de Physique, Université de Sherbrooke, 2500 Boulevard de l'Université, Sherbrooke, Quebec J1K 2R1 (Canada); Institut Interdisciplinaire d'Innovation Technologique (3IT), Université de Sherbrooke, 3000 Boulevard de l'Université, Sherbrooke, Quebec J1K 0A5 (Canada); Laboratoire Nanotechnologies Nanosystèmes (LN2)–CNRS UMI-3463, Université de Sherbrooke, 3000 Boulevard de l'Université, Sherbrooke, Quebec J1K 0A5 (Canada); Drouin, Dominique [Institut Interdisciplinaire d'Innovation Technologique (3IT), Université de Sherbrooke, 3000 Boulevard de l'Université, Sherbrooke, Quebec J1K 0A5 (Canada); Laboratoire Nanotechnologies Nanosystèmes (LN2)–CNRS UMI-3463, Université de Sherbrooke, 3000 Boulevard de l'Université, Sherbrooke, Quebec J1K 0A5 (Canada); Pioro-Ladrière, Michel [Département de Physique, Université de Sherbrooke, 2500 Boulevard de l'Université, Sherbrooke, Quebec J1K 2R1 (Canada); CIFAR Program in Quantum Information Science, Canadian Institute for Advanced Research (CIFAR), Toronto, Ontario M5G 1Z8 (Canada)

    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/?m 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. Gated Conductance of Thin Indium Tin Oxide - The Simplest Transistor

    E-print Network

    Jiang, Jie; Sun, Jia; Dou, Wei; Zhang, Qing

    2012-01-01

    Transistors are the fundamental building block of modern electronic devices. So far, all transistors are based on various types of semiconductor junctions. The most common bipolar-junction transistors and metal-oxide-semiconductor field-effect transistors contain p-n junctions to control the current, depending on applied biases across the junctions. Thin-film transistors need metal-semiconductor junctions for injecting and extracting electrons from their channels. Here, by coating a heavily-doped thin indium-tin-oxide (ITO) film through a shadow mask onto a biopolymer chitosan/ITO/glass substrate, we can have a high-performance junctionless transparent organic-inorganic hybrid thin film transistor. This could be the simplest transistor in the world, to our knowledge, not only in its structure, but also its fabrication process. In addition, the device performance is found to be greatly enhanced using a reinforced chitosan/SiO2 hybrid bilayer dielectric stack. Our results clearly show that this architecture can...

  3. Outlook and emerging semiconducting materials for ambipolar transistors.

    PubMed

    Bisri, Satria Zulkarnaen; Piliego, Claudia; Gao, Jia; Loi, Maria Antonietta

    2014-02-26

    Ambipolar or bipolar transistors are transistors in which both holes and electrons are mobile inside the conducting channel. This device allows switching among several states: the hole-dominated on-state, the off-state, and the electron-dominated on-state. In the past year, it has attracted great interest in exotic semiconductors, such as organic semiconductors, nanostructured materials, and carbon nanotubes. The ability to utilize both holes and electrons inside one device opens new possibilities for the development of more compact complementary metal-oxide semiconductor (CMOS) circuits, and new kinds of optoelectronic device, namely, ambipolar light-emitting transistors. This progress report highlights the recent progresses in the field of ambipolar transistors, both from the fundamental physics and application viewpoints. Attention is devoted to the challenges that should be faced for the realization of ambipolar transistors with different material systems, beginning with the understanding of the importance of interface modification, which heavily affects injections and trapping of both holes and electrons. The recent development of advanced gating applications, including ionic liquid gating, that open up more possibility to realize ambipolar transport in materials in which one type of charge carrier is highly dominant is highlighted. Between the possible applications of ambipolar field-effect transistors, we focus on ambipolar light-emitting transistors. We put this new device in the framework of its prospective for general lightings, embedded displays, current-driven laser, as well as for photonics-electronics interconnection. PMID:24591008

  4. Perturbation of Au-assisted planar GaAs nanowire growth by p-type dopant impurities

    E-print Network

    Li, Xiuling

    to be promising materials for many applications including solar cells, light emitting diodes, transistors, and lasers. Self-aligned, twin-plane-defect free, planar GaAs NWs can be grown by metalorganic chemical vapor-up assembly of large-area nanowire resonator arrays," Nat. Nanotechnol. 3(2), 88­92 (2008). 5. S. A. Fortuna

  5. GaAs IC technology for wireless communications applications

    SciTech Connect

    Nair, V. [Phoenix Corporate Research Labs., Tempe, AZ (United States)

    1995-12-31

    Present day wireless communication products require low power consumption receivers and high efficiency transmitters. Long battery life, light weight, small size and low cost are few of the key parameters that determine the success of a portable communication product. The size and weight of wireless products can be drastically reduced by decreasing the number of battery cells. RF power amplifiers are the highest energy consumption component of portable communication equipment. The introduction of GaAs MESFET, HFET, and HBT into wireless communications equipment increased the performance level of RF power functions. A significant improvement in DC to RF conversion efficiency over the previous bipolar RF power amplifiers was achieved. In order to meet the customer demand for longer talk time, low power receiver ICs and high efficiency power amplifiers are being designed into wireless communications products. Semiconductor devices with better noise figure-gain performance and higher efficiency are needed to maintain the same RF performance at lower voltages. Linearity of the device is also very important for the transmitter and receiver applications. GaAs device and IC technology has many salient features that make it an ideal candidate for wireless communication applications. GaAs IC receivers lead to a reduction in the number of parts and interconnects and, hence, the size and weight. In this paper we will discuss the principles of GaAs device and IC design, with emphasis on the active and passive devices, circuit design and applications. GaAs Microwave Monolithic Integrated Circuits (MMICs) design principles and examples will also be discussed.

  6. Fabrication, testing and reliability modeling of copper\\/titanium-metallized GaAs MESFETs and HEMTs for low-noise applications

    Microsoft Academic Search

    Ting Feng

    1999-01-01

    Today, GaAs based field effect transistors (FETs) have been used in a broad range of high-speed electronic military and commercial applications. However, their reliability still needs to be improved. Particularly the hydrogen induced degradation is a large remaining issue in the reliability of GaAs FETs, because hydrogen can easily be incorporated into devices during the crystal growth and virtually every

  7. Bipolar clavicular dislocation.

    PubMed

    Argintar, Evan; Holzman, Michael; Gunther, Stephen

    2011-07-01

    Bipolar clavicular dislocation rarely occurs. Although referred to by several different names (panclavicular dislocation, bifocal clavicle dislocation, traumatic floating clavicle, and periarticular clavicle dislocation), knowledge regarding appropriate treatment of this condition is limited. Conservative therapy remains the gold standard in asymptomatic individuals. In younger individuals with higher functional demands, or individuals with persistent pain or instability, open reduction with internal fixation of the acromioclavicular joint has also proven successful. In situations with continued medial instability, internal fixation can be used at both the acromioclavicular joint and sternoclavicular joint.Chronic bipolar dislocation may require total claviculectomy, especially when chronic dislocation has led to nonviable acromioclavicular and sternoclavicular joint viability. This article presents a chronic case of bipolar dislocation treated by complete claviculectomy. PMID:21717997

  8. Bipolar disorder therapeutics: maintenance treatment

    Microsoft Academic Search

    Gary S Sachs; Michael E Thase

    2000-01-01

    Although most of the care received by bipolar patients occurs during the maintenance phase, relatively little empirical data is available to guide long-term treatment decisions. We review literature pertaining to key questions related to use of pharmacotherapy in the maintenance phase of bipolar disorder. The few double-blind trials with a reasonable sample size are restricted to bipolar I patients and

  9. 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.

  10. Integration of front-end electronics with GaAs pixel detectors: Experimental and feasibility analysis

    SciTech Connect

    Bertuccio, G.; Longoni, A.; De Geronimo, G. [Politecnico di Milano (Italy)] [Politecnico di Milano (Italy); Canali, C. [Dipt. di Scienze dell`Ingegeneria and INFM, Modena (Italy)] [Dipt. di Scienze dell`Ingegeneria and INFM, Modena (Italy); Lanzieri, C. [Alenia, Roma (Italy)] [Alenia, Roma (Italy); Nava, F. [Dipt. di Fisica and INFN Bologna, Modena (Italy)] [Dipt. di Fisica and INFN Bologna, Modena (Italy)

    1999-08-01

    This work aims to study the feasibility of the integration, on the same chip, of GaAs pixel detectors and frontend electronics employing GaAs metal semiconductor FET`s (MESFET`s) or high electron mobility transistors (HEMT`s). The interest of fully integrated GaAs systems lies in X and {gamma}-ray spectroscopy and Imaging for scientific, industrial, and medical applications. The system design criteria and the prediction of the performance have been derived on the basis of recent experimental results on semi-insulating GaAs pixel detectors. Measurements of the relevant parameters of GaAs FET`s suitable for the stringent requirements of a specroscopy-grade frontend amplifier are analyzed. It is shown that an optimized GaAs integrated system can reach an electronic noise level below 100 electrons rms (<1 keV FWHM) even at room temperature. Some open problems regarding the detector-electronics integration are highlighted and discussed.

  11. Oxidation of the GaAs semiconductor at the Al2O3/GaAs junction.

    PubMed

    Tuominen, Marjukka; Yasir, Muhammad; Lång, Jouko; Dahl, Johnny; Kuzmin, Mikhail; Mäkelä, Jaakko; Punkkinen, Marko; Laukkanen, Pekka; Kokko, Kalevi; Schulte, Karina; Punkkinen, Risto; Korpijärvi, Ville-Markus; Polojärvi, Ville; Guina, Mircea

    2015-03-14

    Atomic-scale understanding and processing of the oxidation of III-V compound-semiconductor surfaces are essential for developing materials for various devices (e.g., transistors, solar cells, and light emitting diodes). The oxidation-induced defect-rich phases at the interfaces of oxide/III-V junctions significantly affect the electrical performance of devices. In this study, a method to control the GaAs oxidation and interfacial defect density at the prototypical Al2O3/GaAs junction grown via atomic layer deposition (ALD) is demonstrated. Namely, pre-oxidation of GaAs(100) with an In-induced c(8 × 2) surface reconstruction, leading to a crystalline c(4 × 2)-O interface oxide before ALD of Al2O3, decreases band-gap defect density at the Al2O3/GaAs interface. Concomitantly, X-ray photoelectron spectroscopy (XPS) from these Al2O3/GaAs interfaces shows that the high oxidation state of Ga (Ga2O3 type) decreases, and the corresponding In2O3 type phase forms when employing the c(4 × 2)-O interface layer. Detailed synchrotron-radiation XPS of the counterpart c(4 × 2)-O oxide of InAs(100) has been utilized to elucidate the atomic structure of the useful c(4 × 2)-O interface layer and its oxidation process. The spectral analysis reveals that three different oxygen sites, five oxidation-induced group-III atomic sites with core-level shifts between -0.2 eV and +1.0 eV, and hardly any oxygen-induced changes at the As sites form during the oxidation. These results, discussed within the current atomic model of the c(4 × 2)-O interface, provide insight into the atomic structures of oxide/III-V interfaces and a way to control the semiconductor oxidation. PMID:25686555

  12. How Does A Transistor Work? No, How Do They Really Work?

    NSDL National Science Digital Library

    A simple explanation of how a transistor works. Most introductory textbooks do a very poor job of explaining the details of how transistors work. First they assume that the Base current is somehow controlling the Collector current, then they try to explain how one current can affect another. These explanations always fail because Bipolar transistors, like FETs, are voltage-controlled devices. One current doesn't affect another. Instead, the Base-Emitter voltage controls the thickness of an insulating "depletion layer" which lies in the path of both the Collector current and the Base current.

  13. Transistors: The Field Effect

    NSDL National Science Digital Library

    The Concord Consortium

    2011-12-11

    Transistors are the building blocks of modern electronic devices. Your cell phones, iPods, and computers all depend on them to operate. Thanks to today's microfabrication technology, transistors can be made very tiny and be massively produced. You are probably using billions of them while working with this activity now--as of 2006, a dual-core Intel microprocessor contains 1.7 billion transistors. The field effect transistor is the most common type of transistor. So we will focus on it in this activity.

  14. A novel interpretation of transistor S-parameters by poles and zeros for RF IC circuit design

    Microsoft Academic Search

    Shey-Shi Lu; T.-W. Chen; H.-C. Chen; C.-C. Meng

    2001-01-01

    In this paper, we have developed an interpretation of transistor S-parameters by poles and zeros. The results from our proposed method agreed well with experimental data from GaAs FETs and Si MOSFETs. The concept of source-series feedback was employed to analyze a transistor circuit set up for the measurement of the S-parameters. Our method can describe the frequency responses of

  15. Bipolar fuel cell

    Microsoft Academic Search

    McElroy

    1989-01-01

    This patent describes an improvement in a fuel cell stack comprising two or more fuel cells each having a catalytic anode and a catalytic cathode in contact with opposite surfaces of an ion transporting membrane, a wet-proofed carbon paper bonded to the cathode surface opposite the membrane, a bipolar separator in contact with the wet-proofed carbon paper and forming an

  16. GaAs JFET front-end MMICs for L-band personal communications

    Microsoft Academic Search

    Takahiro Ohgihara; Shigeo Kusunoki; Masaru Wada; Yoshikazu Murakami

    1993-01-01

    The development of GaAs JFET (junction field-effect transistor) low noise and low distortion amplifier and mixer MMICs (monolithic microwave integrated circuits) for front-end use in L-band personal communications is discussed. These MMICs can be operated by a 3.0-V single biasing supply with a very low current dissipation of 4.0 mA. In order to achieve excellent low intermodulation distortion, a current-mirror

  17. Scaling Effect Of GaAs pHEMTs Small Signal And Noise Model

    Microsoft Academic Search

    S. C. Huang; W. Y. Lin; Y. M. Hsin

    2009-01-01

    In this work, small-signal and noise model with gate-width scaling of GaAs pseudomorphic high electron mobility transistors (pHEMT) are presented. The scaling effect of the model parameters are derived from an accurate small-signal and noise equivalent circuit model for the different gate widths of pHEMTs. The experimental and model results show that noise coefficients are not dependant on the gate

  18. Photoemission studies on heterostructure bipolar transistors Fritz Schuermeyera,

    E-print Network

    Asbeck, Peter M.

    , and low noise are of importance. These transis- tors can also be used as fast photodetectors [1 characteristics. The emitter base barrier increases the threshold voltage in n-p-n HBTs and reduces the uniformity, such as the evaluation of the temperature dependence of the current voltage behavior of diodes, capacitance voltage

  19. Handout 2 for EE-203 Bipolar Junction Transistor (BJT)

    E-print Network

    Iqbal, Sheikh Sharif

    "" is common emitter current gain constant for a particular BJT "" is common base current gain iE iC iB+ 1+ i Modes of operation ForwardForward ReverseReverse Switch ReverseForwardAmplifier CBJEBJApplication VBE operate as "Amplifier" or as "Switch" · Voltage between the two terminals is used to control the current

  20. 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.

  1. Bipolar transistor circuit analysis using the Lambert W-function

    Microsoft Academic Search

    T. C. Banwell

    2000-01-01

    The generalized diode equation describes conduction in a diode with series resistance. An analytical solution for the generalized diode equation has been elusive; however, one was found based on the transcendental equation w=ln(x\\/w). The solution of this equation; w=W(x), is traditionally referred to as the Lambert W-function. This function provides a long sought after natural continuity between exponential diode and

  2. Thermodynamic stability of Ga2O3(Gd2O3)/GaAs interface

    NASA Astrophysics Data System (ADS)

    Huang, Y. L.; Chang, P.; Yang, Z. K.; Lee, Y. J.; Lee, H. Y.; Liu, H. J.; Kwo, J.; Mannaerts, J. P.; Hong, M.

    2005-05-01

    Ga2O3(Gd2O3)/GaAs heterostructures have been annealed up to ˜780°C. Studies using x-ray reflectivity and high-resolution transmission electron microscopy have shown that the samples annealed under ultrahigh vacuum have maintained smooth and abrupt interfaces with the interfacial roughness being less than 0.2nm. The oxide remains amorphous, an important parameter for device consideration. Current-voltage and capacitance-voltage measurements have shown low leakage currents (10-8-10-9A/cm2), a high dielectric constant of 15, and a low interfacial density of states (Dit) between gate dielectrics and GaAs. The attainment of a smooth interface between the gate dielectric and GaAs, even after high temperature annealing for activating implanted dopant, is a must to ensure the low (Dit) and to maintain a high carrier mobility in the channel of the metal-oxide-semiconductor field-effect transistor.

  3. ACUTE: a high performance analog complementary polysilicon emitter bipolar technology utilizing SOI\\/trench full dielectric isolation

    Microsoft Academic Search

    R. C. Jerome; I. R. C. Post; T. G. Travnicek; G. M. Wodek; K. E. Huffstater; D. R. Williams

    1993-01-01

    The advantages of using full dielectric isolation, in the form of SOI substrates and trench isolation, are well known, namely the reduction of substrate parasitic currents due to high voltage, high temperature or harsh radiation environments. Moreover, high voltage analog bipolar transistors can also benefit from full dielectric isolation in terms of limiting substrate capacitance and providing the means to

  4. Statistical modeling of radiation-induced proton transport in silicon: deactivation of dopant acceptors in bipolar devices

    Microsoft Academic Search

    S. N. Rashkeev; D. M. Fleetwood; R. D. Schrimpf; S. T. Pantelides

    2003-01-01

    We show that radiation-induced dopant deactivation in MOS capacitors that simulate the base oxides of silicon bipolar transistors is due primarily to direct neutralization by protons. The strong dependence of the deactivation process on electric field is related to the transport of H+ in the depletion region. The probability of acceptor neutralization near the Si surface is higher for small

  5. Microstructure characterization of Cu,Ge/n-type GaAs ohmic contacts M. 0. Aboelfotoh, S. Oktyabrsky, and J. Narayan

    E-print Network

    Woodall, Jerry M.

    to the Ge/Pd contacts,' and that n-channel GaAs metal- semiconductor field-effect transistors using the q of the heterostructure we deduce the optimum concentration of Ge to be 30 at. % for formation of low-resistance ohmic

  6. HfO2 and Al2O3 gate dielectrics on GaAs grown by atomic layer deposition Martin M. Franka

    E-print Network

    Garfunkel, Eric

    HfO2 and Al2O3 gate dielectrics on GaAs grown by atomic layer deposition Martin M. Franka IBM Semiconductor Research and Development Center (SRDC), Thomas J. Watson Research Center, Yorktown Heights, New; published online 4 April 2005 High-performance metal-oxide-semiconductor field effect transistors MOSFETs

  7. Characteristics of in situ deposited GaAs metal-insulator-semiconductor structures

    NASA Astrophysics Data System (ADS)

    Reed, J.; Tao, M.; Park, D. G.; Botchkarev, A.; Fan, Z.; Suzue, S. K.; Li, D.; Gao, G. B.; Mohammad, S. N.; Chey, S. J.; van Nostrand, J. E.; Cahill, D. G.; Morkoç, H.

    1995-07-01

    GaAs based metal-insulator-semiconductor structures utilizing a pseudomorphic Si interface layer were investigated. Deposition involved molecular beam epitaxy for GaAs and remote plasma enhanced chemical vapor epitaxy for Si and insulator (Si 3N 4) layers, all without exposure to air. As determined by the conductance method, interface trap densities in the upper 10 10 eV -1 cm -2 were obtained, with samples withstanding high temperature rapid thermal annealing. Frequency dispersion and hysteresis of under 100 mV indicate the quality of the interface and bulk layers. Bulk trap density in the insulator appears to be below 10 12 cm -2. Metal-insulator-semiconductor field-effect-transistors were fabricated and investigated. With GaAs channels, excess channel conduction which vanished at low temperatures was observed. Addition of as low as 5% InAs in the channel eliminated this excess channel current. A similar observation was made when a Ge interface layer was grown on GaAs prior to the Si layer. The excess current is attributed to interfacial traps below the midgap. Transconductances as high as 160 and 170 mS/mm have been obtained with about 2.5 ?m gate length in GaAs and InGaAs channels, respectively.

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

    PubMed Central

    2011-01-01

    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 × 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.

  9. Flexible transistor matrix (FTM)

    Microsoft Academic Search

    King C. Ho; Sarma Sastry

    1991-01-01

    This paper describes a new layout style called the Flexible Transistor Matrix (FTM) for large scale CMOS module generation. FTM uses two layers of metal. Compared to Gate Matrix, FTM can generate significantly better results. In addition, the algorithm can control the aspect ratio, 1\\/0 pin positions and different transistor sizes.

  10. Implementation of RF\\/microwave receiver components on a semi-custom silicon bipolar array

    Microsoft Academic Search

    Kevin J. Negus; J. N. Wholey

    1990-01-01

    The analog transistor array starCHIP-1 has been developed for rapid, cost-effective design and delivery of many RF\\/microwave components for applications to 5 GHz. The array is based on silicon bipolar devices with 10-GHz fT. and 20-GHz fmax and thin-film polysilicon resistors with low parasitic capacitance and excellent matching. An overview of the array topology and technology is presented. The implementation

  11. Analysis and control of floating-body bipolar effects in fully depleted submicrometer SOI MOSFET's

    Microsoft Academic Search

    Jin-Young Choi; Jerry G. Fossum

    1991-01-01

    Floating-body effects triggered by impact ionization in fully depleted submicrometer silicon-on-insulator (SOI) MOSFETs are analyzed based on two-dimensional device simulations. The parasitic bipolar junction transistor (BJT) effects are emphasized, but the kink effect and its disappearance in the fully depleted device are first explained physically to provide a basis for the BJT analysis. The results of simulations of the BJT-induced

  12. The effectiveness of stress relief etching for improving bipolar device characteristics

    E-print Network

    Reed, Lynn Gillespie

    1975-01-01

    the number of dislocations formed during thermal cycling. An optimum etch time is found, and bipolar devices are built on Sirtl etched starting material. Measurements are made of the breakdown voltages, leakage currents, current gains and minority carrier... Voltage Leakage Current Minority Carrier Lifetime Transistor Gain Page 16 16 17 21 22 26 27 29 29 31 31 38 Devices Produced At Texas Instruments . 38 V. CONCLUSIONS AND RECOMMENDATIONS BIBLIOGRAPHY, APPENDIX A. 41 43 45 Vl Test...

  13. Gigahertz operation in flexible transistors on plastic substrates

    NASA Astrophysics Data System (ADS)

    Sun, Yugang; Menard, Etienne; Rogers, John A.; Kim, Hoon-Sik; Kim, Seiyon; Chen, Guang; Adesida, Ilesanmi; Dettmer, Ross; Cortez, Rebecca; Tewksbury, Alan

    2006-05-01

    The combined use of GaAs wires with Ohmic contacts formed from bulk wafers, soft lithographic transfer printing techniques, and optimized device designs enables mechanically flexible transistors to be formed on low-cost plastic substrates, with individual device speeds in the gigahertz range and with high degrees of mechanical bendability. These high-speed devices incorporate materials in simple layouts that can be fabricated with modest lithographic patterning resolution and registration. This letter describes their electrical and mechanical characteristics. The results have the potential to be important to certain large-area, "macroelectronic" systems that can provide for high-speed communication and processing capabilities.

  14. Managing bipolar depression.

    PubMed

    Pary, Raymond; Matuschka, Paul R; Lewis, Susan; Lippmann, Steven

    2006-02-01

    What should the clinician do when confronted with a patient who has depressive symptoms? Seek the proper diagnosis. Question the patient about depressive symptoms over a two-week course that interferes with social and/or occupational functioning. Determine if there is any history of mania or hypomania. Information from a significant other is extremely useful as well. Coexisting diagnoses, such as substance abuse, posttraumatic stress disorder, or medical conditions, must be ruled in or out. It is critical to include a suicide risk assessment in the evaluation. Lithium is still the gold standard for bipolar patients with its suicide preventative effects. Lamotrigine appears to have the advantage of efficacy against bipolar depression without high risk for inducing mania. Experts recommend that a mood stabilizer be used in combination with antidepressants. The tricyclic antidepressants and the monoamine oxidase inhibitors appear to have the highest risk for mania and are best avoided. Atypical antipsychotic medications are best utilized for psychotic symptoms and as adjuncts to existing antidepressants. Cognitive behavioral therapy may complement pharmacotherapy. PMID:21103153

  15. Bipolar pulse forming line

    DOEpatents

    Rhodes, Mark A. (Pleasanton, CA)

    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.

  16. Humidity resistance of GaAs ICs

    Microsoft Academic Search

    W. J. Roesch; R. Winters; A. L. Rubalcava; B. Ingle

    1994-01-01

    A series of investigations into reliability effects of moisture on GaAs structures have lead to the conclusion that GaAs devices have resistance to degradation effects of humidity. This not only provides evidence that GaAs devices are ready for low-cost non-hermetic packages, but that GaAs ICs may have superior reliability performance compared to silicon devices under accelerated humidity conditions.

  17. Nickel-Silicided Schottky Junction CMOS Transistors With Gate-All-Around Nanowire Channels

    Microsoft Academic Search

    E. J. Tan; K. L. Pey; N. Singh; G. Q. Lo; D. Z. Chi; Y. K. Chin; L. J. Tang; P. S. Lee; C. K. F. Ho

    2008-01-01

    We demonstrate high-performance Schottky CMOS transistors with NiSi source\\/drain and gate-all-around (GAA) silicon nanowire (~5 nm) channels. The transistors exhibit good I on\\/I off characteristics, along with fully controlled shortchannel effects revealed by low drain-induced barrier lowering (~10 mV\\/V) and near-ideal subthreshold swing (~60 mV\\/dec). Although the N-MOSFET required dopant segregation to suppress the ambipolar behavior, excellent P-MOSFET characteristics could

  18. Bipolar II Depression with Melancholic Features

    Microsoft Academic Search

    Franco Benazzi

    2000-01-01

    Bipolar II depression with melancholic features has been understudied. The aims of the present study were to find the prevalence of melancholic features in bipolar II depression and in unipolar depression, and to compare melancholic with nonmelancholic bipolar II\\/ unipolar depression in private practice. One hundred and sixty two consecutive unipolar and bipolar II depressed outpatients were interviewed with the

  19. Fracture mechanics evaluation of GaAs

    NASA Technical Reports Server (NTRS)

    Chen, C. P.

    1984-01-01

    A data base of mechanical and fracture properties for GaAs was generated. The data for single crystal GaAs will be used to design reusable GaAs solar modules. Database information includes; (1) physical property characterizations; (2) fracture behavior evaluations; and (3) strength of cells determined as a function of cell processing and material parameters.

  20. 35-GHz monolithic GaAs FET power amplifiers

    NASA Astrophysics Data System (ADS)

    Ho, T.; Phelleps, F.; Hegazi, G.; Pande, K.; Huang, H.; Rice, P.; Pages, P.

    A state-of-the-art 35-GHz monolithic GaAs power amplifier, based on metal semiconductor field-effect transistor (MESFET) technology, is developed for millimeter-wave communications and seeker applications. Both single-ended and balanced amplifier configurations, with on-chip dc-block and bias networks, are designed and evaluated. A cascaded four-stage amplifier exhibited 14.6 dB of linear gain and 300 mW of saturated output power at 35 GHz. These MMIC chips are very flexible and can easily be combined/cascaded to achieve even higher gains and greater output power using low-loss off-chip power combiner/dividers. These amplifiers are suitable for future military millimeter-wave systems applications.

  1. A rapid optoelectronic half-adder logic composed of a pair of GaAs metal-semiconductor-metal photodetectors

    Microsoft Academic Search

    Kazutoshi Nakajima; Takashi Iida; Ken-Ichi Sugimoto; Hirofumi Kan; Yoshihiko Mizushima

    1990-01-01

    A novel optoelectronic half-adder logic, composed of only two GaAs metal-semiconductor-metal photodetectors (MSM-PDs), is reported. The optoelectronic logic utilizes the features of the MSM-PD for both polarities of electrical bias (positive and negative). Without any other active devices such as transistors, the output delay time is short, less than 100 ps for the entire half-adder operation, which assures a very

  2. Microwave operation of GaN\\/AlGaN-doped channel heterostructure field effect transistors

    Microsoft Academic Search

    M. Asif Khan; Q. Chen; J. W. Yang; Michael S. Shur; B. T. Dermott; J. A. Higgins

    1996-01-01

    We report on the microwave operation of 1 ?m gate AlGaN\\/GaN doped channel heterostructure field effect transistors (DC-HFET's) with the cutoff frequency fT of 18.3 GHz. These devices exhibit the cutoff frequency-gate length product in excess of 18 GHz·?m, comparable to that of the state-of-the-art GaAs MESFET's. We explain these improvements in the device performance by the increased sheet carrier

  3. Surface photovoltage spectroscopy of epitaxial structures for high electron mobility transistors

    E-print Network

    Shapira, Yoram

    for low-noise applications. InGaAs/GaAs pseudomorphic HEMTs PHEMTs are the current ``work horses,'' widelyGaN/GaN high electron mobility transistor, AlGaAs/InGAs/GaAs pseudomorphic HEMT, and InAlAs/InGaAs metamorphic- cillation frequencies2,3 together with low-cost GaAs sub- strates make metamorphic HEMTs MHEMTs attractive

  4. Voltage Gain in GaAs-Based Lateral Single-Electron Transistors Having Schottky Wrap Gates

    Microsoft Academic Search

    Yoshihiro Satoh; Hiroshi Okada; Kei-ichiroh Jinushi; Hajime Fujikura; Hideki Hasegawa

    1999-01-01

    Gain characteristics of GaAs-based lateral single-electron transistors (SETs)formed by putting two- or three-wrap gates (WPGs) on etched GaAs quantum wirewere investigated in detail theoretically and experimentally. The computersimulation of potential distribution showed that the three-WPG SET allowsindependent control of the dot geometry and the tunneling barrier profile and thatthe three-gate device realizes much tighter control of the dot potential and

  5. A back-gated high electron mobility transistor utilizing a p-type doped layer

    Microsoft Academic Search

    A. C. Churchill; M. P. Grimshaw; D. A. Ritchie; E. H. Linfield; G. A. C. Jones

    1993-01-01

    A technique for fabricating back-gated high electron mobility transistors (HEMTS) with large low-temperature mobilities is reported. The device consists of a normal MBE-grown two-dimensional electron gas structure (2DEG), optimized for low-temperature transport, grown on top of a p-type doped GaAs back-gate, the two layers being separated by an AlGaAs barrier. After optical lithography to define a mesa, standard n- and

  6. The Transistor Game

    NSDL National Science Digital Library

    In this game, your job working at a Transistor Recycling Centre is to ensure that only items containing transistors are sent to the recycling machine. Goods enter the recycling machine via a conveyer belt, and you must remove all the items that do not contain transistors. You are awarded one point for each item that you correctly remove from the belt. If you mistakenly remove an item with a transistor, two points will be deducted from your total score. The game has an infinite number of levels, and you will be evaluated at the end of each level. When you have completed one level you can move onto the next, in which the belt moves faster and there will be new items to sort. If you're really skilled you could become this month's super recycler!

  7. Printed inorganic transistors

    E-print Network

    Ridley, Brent (Brent Alan), 1974-

    2003-01-01

    Forty years of exponential growth of semiconductor technology have been predicated on the miniaturization of the transistors that comprise integrated circuits. While complexity has greatly increased within a given area of ...

  8. Spin Hall effect transistor.

    PubMed

    Wunderlich, Jörg; Park, Byong-Guk; Irvine, Andrew C; Zârbo, Liviu P; Rozkotová, Eva; Nemec, Petr; Novák, Vít; Sinova, Jairo; Jungwirth, Tomás

    2010-12-24

    The field of semiconductor spintronics explores spin-related quantum relativistic phenomena in solid-state systems. Spin transistors and spin Hall effects have been two separate leading directions of research in this field. We have combined the two directions by realizing an all-semiconductor spin Hall effect transistor. The device uses diffusive transport and operates without electrical current in the active part of the transistor. We demonstrate a spin AND logic function in a semiconductor channel with two gates. Our study shows the utility of the spin Hall effect in a microelectronic device geometry, realizes the spin transistor with electrical detection directly along the gated semiconductor channel, and provides an experimental tool for exploring spin Hall and spin precession phenomena in an electrically tunable semiconductor layer. PMID:21205664

  9. The resonant gate transistor

    Microsoft Academic Search

    HARVEY C. NATHANSON; WILLIAM E. NEWELL; ROBERT A. WICKSTROM

    1967-01-01

    A device is described which permits high-Qfrequency selection to be incorporated into silicon integrated circuits. It is essentially an electrostatically excited tuning fork employing field-effect transistor \\

  10. Genetics of bipolar disorder

    PubMed Central

    Kerner, Berit

    2014-01-01

    Bipolar disorder is a common, complex genetic disorder, but the mode of transmission remains to be discovered. Many researchers assume that common genomic variants carry some risk for manifesting the disease. The research community has celebrated the first genome-wide significant associations between common single nucleotide polymorphisms (SNPs) and bipolar disorder. Currently, attempts are under way to translate these findings into clinical practice, genetic counseling, and predictive testing. However, some experts remain cautious. After all, common variants explain only a very small percentage of the genetic risk, and functional consequences of the discovered SNPs are inconclusive. Furthermore, the associated SNPs are not disease specific, and the majority of individuals with a “risk” allele are healthy. On the other hand, population-based genome-wide studies in psychiatric disorders have rediscovered rare structural variants and mutations in genes, which were previously known to cause genetic syndromes and monogenic Mendelian disorders. In many Mendelian syndromes, psychiatric symptoms are prevalent. Although these conditions do not fit the classic description of any specific psychiatric disorder, they often show nonspecific psychiatric symptoms that cross diagnostic boundaries, including intellectual disability, behavioral abnormalities, mood disorders, anxiety disorders, attention deficit, impulse control deficit, and psychosis. Although testing for chromosomal disorders and monogenic Mendelian disorders is well established, testing for common variants is still controversial. The standard concept of genetic testing includes at least three broad criteria that need to be fulfilled before new genetic tests should be introduced: analytical validity, clinical validity, and clinical utility. These criteria are currently not fulfilled for common genomic variants in psychiatric disorders. Further work is clearly needed before genetic testing for common variants in psychiatric disorders should be established. PMID:24683306

  11. High Electron Mobility Transistors

    Microsoft Academic Search

    Vassil Palankovski; Rüdiger Quay

    \\u000a High Electron Mobility Transistors(HEMTs) [340] are an advanced modification of the simple bulk FET, such as the MEtal Semiconductors\\u000a Field Effect Transistor (MESFET). Typically, a semiconductor material (barrier) with a comparably wider bandgap is grown on\\u000a top of a semiconductor material with a higher mobility and comparably lower bandgap. If the bandgap alignment of the two materials\\u000a is appropriately chosen,

  12. 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.

  13. 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

  14. Impact of ?110? uniaxial strain on n-channel In0.15Ga0.85As high electron mobility transistors

    E-print Network

    del Alamo, Jesus A.

    This letter reports on a study of the impact of ?110? uniaxial strain on the characteristics of InGaAs high electron mobility transistors (HEMT) by bending GaAs chips up to a strain level of 0.4%. Systematic changes in ...

  15. Impact of 110 uniaxial strain on n-channel In0.15Ga0.85As high electron mobility transistors

    E-print Network

    Xia, Ling

    This letter reports on a study of the impact of ?110? uniaxial strain on the characteristics of InGaAs high electron mobility transistors (HEMT) by bending GaAs chips up to a strain level of 0.4%. Systematic changes in the ...

  16. Monolithic cryogenic preamplifiers based on large gate-area GaAs MESFETs

    SciTech Connect

    Camin, D.V.; Fedyakin, N.; Pessina, G.; Previtali, E. [Dipartimento di Fisica dell`Universita, Milano (Italy)] [Dipartimento di Fisica dell`Universita, Milano (Italy); [Inst. Nazionale di Fisica Nucleare, Milano (Italy)

    1995-08-01

    Monolithic preamplifiers using large gate-area Gallium-Arsenide Metal-Semiconductor Field-Effect Transistors (GaAs MESFETs) at the input have been designed and fabricated using an ion-implanted GaAs process. Large gate-area is necessary to obtain low series noise. A differential voltage-sensitive preamplifier has at the input two MESFETs with a gate width W = 6,000 {micro}m, it is fully DC coupled, has a large common-mode rejection ratio (CMRR) and dissipates low power at 4 K. Dual current-sensitive preamplifiers using at the input MESFETs with W = 24,000 {micro}m, designed for the readout of noble liquid calorimeters, have been integrated in a single chip. Recent tests with a LAr calorimeter prototype demonstrated strong noise reduction compared to previous state-of-the-art hybrid readout circuits. Radiation damage tests have been performed at cold on the current-sensitive preamplifier chips.

  17. 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., E-mail: pekka.laukkanen@utu.fi; Kokko, K. [Department of Physics and Astronomy, University of Turku, FI-20014 Turku (Finland)] [Department of Physics and Astronomy, University of Turku, FI-20014 Turku (Finland); Kuzmin, M. [Department of Physics and Astronomy, University of Turku, FI-20014 Turku (Finland) [Department of Physics and Astronomy, University of Turku, FI-20014 Turku (Finland); Ioffe Physical-Technical Institute, Russian Academy of Sciences, St. Petersburg 194021 (Russian Federation); Korpijärvi, V.-M.; Polojärvi, V.; Guina, M. [Optoelectronics Research Centre, Tampere University of Technology, FI-33101 Tampere (Finland)] [Optoelectronics Research Centre, Tampere University of Technology, FI-33101 Tampere (Finland)

    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.

  18. Hydrodynamic Models of Bipolar Semiconductors Best Asymptotic Profiles

    E-print Network

    Hydrodynamic Models of Bipolar Semiconductors Best Asymptotic Profiles Convergence to Stationary Waves Asymptotic Profiles for Bipolar Hydrodynamic System of Semiconductors Ming Mei Champlain College for Bipolar Hydrodynamic System of Semicon #12;Hydrodynamic Models of Bipolar Semiconductors Best Asymptotic

  19. Dislocation Velocities in GaAs

    Microsoft Academic Search

    Sun Keun Choi; Minoru Mihara; Toshiyuki Ninomiya

    1977-01-01

    Dislocation velocities in undoped n-type (n{=}1× 1017 cm-3) and Zn-doped p-type (p{=}3× 1018 cm-3) GaAs have been determined by the double-etch technique. In n-type GaAs, alpha dislocations are about 102 times faster than beta dislocations; in p-type GaAs, beta dislocations are about 2 to 10 times faster than alpha dislocations. The velocities of alpha dislocations in n- and p-type GaAs

  20. BIPOLAR COXETER GROUPS Pierre-Emmanuel Capracea

    E-print Network

    Caprace, Pierre-Emmanuel

    BIPOLAR COXETER GROUPS Pierre-Emmanuel Capracea & Piotr Przytyckib a Universit´e catholique de these Coxeter groups bipolar. They include the virtually Poincar´e dual- ity Coxeter groups, the pseudo-manifold Coxeter groups and the infinite irreducible 2-spherical ones. We show in a geometric way that a bipolar

  1. Handling bipolar knowledge with imprecise probabilities

    E-print Network

    Paris-Sud XI, Université de

    Handling bipolar knowledge with imprecise probabilities Sébastien Destercke December 15, 2011 Abstract Information is said to be bipolar when it has a positive and a negative part. The problem of representing and processing such bipolar information has recently received a lot of attention in uncertainty

  2. Is bipolar always bipolar? Understanding the controversy on bipolar disorder in children

    PubMed Central

    Grimmer, Yvonne; Hohmann, Sarah

    2014-01-01

    Dramatically increasing prevalence rates of bipolar disorder in children and adolescents in the United States have provoked controversy regarding the boundaries of manic symptoms in child and adolescent psychiatry. The serious impact of this ongoing debate on the treatment of affected children is reflected in the concomitant increase in prescription rates for antipsychotic medication. A key question in the debate is whether this increase in bipolar disorder in children and adolescents is based on a better detection of early-onset bipolar disorder—which can present differently in children and adolescents—or whether it is caused by an incorrect assignment of symptoms which overlap with other widely known disorders. So far, most findings suggest that the suspected symptoms, in particular chronic, non-episodic irritability (a mood symptom presenting with easy annoyance, temper tantrums and anger) do not constitute a developmental presentation of childhood bipolar disorder. Additional research based on prospective, longitudinal studies is needed to further clarify the developmental trajectories of bipolar disorder and the diagnostic status of chronic, non-episodic irritability. PMID:25580265

  3. 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.

  4. Receiver Video Transistor Amplifiers

    Microsoft Academic Search

    R. G. Salaman

    1958-01-01

    The development of the transistor has progressed to the point where practical video amplifiers of quality comparable to those of vacuum tubes can be designed. Limitations such as collector-emitter voltage, power, and alpha cut-off frequency continue to pose problems in designing a one stage video amplifier.

  5. A stereophonic transistor preamplifier

    Microsoft Academic Search

    W. Steiger

    1961-01-01

    Designed to drive two transistor-power amplifiers previously described, this preamplifier contains all the controls necessary for stereophonic and monophonic programs. The first two of the three stages form a complementary circuit readily adaptable for the various input sources, which provides the necessary gain and equalization for low-level phonograph and tape inputs, guard voltages to reduce the capacitive effects of the

  6. Transistorized communications receiver

    Microsoft Academic Search

    S. Schwartz

    1956-01-01

    The purpose of this project was to use silicon transistors in place of vacuum tubes in all sections following the mixer stage of a military type communication receiver. The hybrid receiver built, while keeping the desirable characteristics of the vacuum tube receiver also provided for an increase of audio power and a reduction of battery power drain.

  7. Reconfigurable silicon nanowire transistors.

    PubMed

    Heinzig, André; Slesazeck, Stefan; Kreupl, Franz; Mikolajick, Thomas; Weber, Walter M

    2012-01-11

    Over the past 30 years electronic applications have been dominated by complementary metal oxide semiconductor (CMOS) devices. These combine p- and n-type field effect transistors (FETs) to reduce static power consumption. However, CMOS transistors are limited to static electrical functions, i.e., electrical characteristics that cannot be changed. Here we present the concept and a demonstrator of a universal transistor that can be reversely configured as p-FET or n-FET simply by the application of an electric signal. This concept is enabled by employing an axial nanowire heterostructure (metal/intrinsic-silicon/metal) with independent gating of the Schottky junctions. In contrast to conventional FETs, charge carrier polarity and concentration are determined by selective and sensitive control of charge carrier injections at each Schottky junction, explicitly avoiding the use of dopants as shown by measurements and calculations. Besides the additional functionality, the fabricated nanoscale devices exhibit enhanced electrical characteristics, e.g., record on/off ratio of up to 1 × 10(9) for Schottky transistors. This novel nanotransistor technology makes way for a simple and compact hardware platform that can be flexibly reconfigured during operation to perform different logic computations yielding unprecedented circuit design flexibility. PMID:22111808

  8. Paper field effect transistor

    Microsoft Academic Search

    E. Fortunato; Nuno Correia; Pedro Barquinha; Cláudia Costa; Luís Pereira; Gonçalo Gonçalves; Rodrigo Martins

    2009-01-01

    In this paper we report the use of a sheet of cellulose fiber-based paper as the dielectric layer used in oxide based semiconductor thin film field-effect transistors (FETs). In this new approach we are using the cellulose fiber-based paper in an \\

  9. A Matterwave Transistor Oscillator

    E-print Network

    Caliga, Seth C; Zozulya, Alex A; Anderson, Dana Z

    2012-01-01

    A triple-well atomtronic transistor combined with forced RF evaporation is used to realize a driven matterwave oscillator circuit. The transistor is implemented using a metalized compound glass and silicon substrate. On-chip and external currents produce a cigar-shaped magnetic trap, which is divided into transistor source, gate, and drain regions by a pair of blue-detuned optical barriers projected onto the magnetic trap through a chip window. A resonant laser beam illuminating the drain portion of the atomtronic transistor couples atoms emitted by the gate to the vacuum. The circuit operates by loading the source with cold atoms and utilizing forced evaporation as a power supply that produces a positive chemical potential in the source, which subsequently drives oscillation. High-resolution in-trap absorption imagery reveals gate atoms that have tunneled from the source and establishes that the circuit emits a nominally mono-energetic matterwave with a frequency of 23.5(1.0) kHz by tunneling from the gate, ...

  10. Bipolar electrodissection tonsillectomy in children

    Microsoft Academic Search

    Tayfun Kirazli; Cem Bilgen; Rasit Midilli; Fatih Ögüt; Meltem Uyar; Aysegül Kedek

    2005-01-01

    The purpose of this study was to compare bipolar electrodissection tonsillectomy with traditional cold dissection tonsillectomy in the pediatric population. Forty children with recurrent tonsillitis and\\/or obstructive symptoms were included in the study. The study population was randomly divided into two groups, and the two techniques were compared with regard to operative time, intraoperative and postoperative bleeding and postoperative pain.

  11. Deep level analysis in heterostructure field-effect transistors by means of the photo-FET method

    Microsoft Academic Search

    Michael Heuken; Klaus Heime; Lutz Loreck; Klaus Ploog; Winfried Schlapp; G. Weimann

    1986-01-01

    The photo-FET method, a fast and simple room-temperature method for deep level analysis, was applied to heterostructure field-effect transistors for the first time. Well-known donor-like and several unknown acceptor-like levels were detected. By comparing heterostructures and homogeneously doped AlGaAs layers, GaAs- and AlGaAs-related traps could be separated. For comparison, similar samples were investigated independently by photocapacitance- and by low-frequency noise

  12. Spectroscopy of a GaAs Double Dot Qubit with Dispersive Readout

    NASA Astrophysics Data System (ADS)

    Colless, James; Mahoney, Alice; Croot, Xanthe; Hornibrook, John; Doherty, Andrew; Stace, Tom; Lu, Hong; Gossard, Art; Reilly, David

    2013-03-01

    We report microwave spectroscopy of a GaAs double dot qubit device using the dispersive gate sensor (DGS) readout technique. In contrast to charge sensing methods based on quantum point contacts (QPCs) or single electron transistors (SETs), the DGS detection method senses the tunneling of charge between states that are near degenerate in energy. Microwave excitation applied to the surface gates enables this readout approach to resolve low energy spectroscopic features not apparent in transport or standard charge sensing measurements. We discuss the origin of these features and the use of this technique for characterizing semiconductor qubit systems. We report microwave spectroscopy of a GaAs double dot qubit device using the dispersive gate sensor (DGS) readout technique. In contrast to charge sensing methods based on quantum point contacts (QPCs) or single electron transistors (SETs), the DGS detection method senses the tunneling of charge between states that are near degenerate in energy. Microwave excitation applied to the surface gates enables this readout approach to resolve low energy spectroscopic features not apparent in transport or standard charge sensing measurements. We discuss the origin of these features and the use of this technique for characterizing semiconductor qubit systems. We acknowledge funding from the U.S. Intelligence Advanced Research Projects Activity (IARPA), through the U.S. Army Research Office and the Australian Research Council Centre of Excellence Scheme (Grant No. EQuS CE110001013).

  13. Cryogenically Cooled GaAs FET Amplifier with a Noise Temperature Under 70 K at 5.0 GHz (Short Papers)

    Microsoft Academic Search

    J. Pierro

    1976-01-01

    A 4.5-5.0-GHz gallium arsenide field-effect transistor (GaAs FET) amplifier cryogenically cooled to approximately 70 K is described. A noise temperature of under 70 K is achieved over the hand. Power gain for the two-stage amplifier is 20 dB. A noise analysis is performed to predict noise-temperature dependence on the temperature of the amplifier.

  14. 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.

  15. 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.

  16. Transistorized Distributed Amplifier

    Microsoft Academic Search

    Charles W. McMullen

    1959-01-01

    Some analytical and experimental results are given for a transistorized distributed amplifier using the common emitter configuration. The characteristic impedances of the base and collector transmission lines are both 43.4?. A 4-section amplifier stage yields a mid-frequency gain of 5.1 db and an upper half-power frequency of 290 Mc. The low-frequency response is reasonably constant down to 10 cps.

  17. Transistorized Distributed Amplifier

    Microsoft Academic Search

    Charles W. McMullen

    1959-01-01

    Some analytical and experimental results are given for a transistorized ; distributed amplifier using the common emitter configuration. The characteristic ; impedances of the base and collector transmission lines are both 43.4 OMEGA . A ; 4-section amplifier stage yields a mid-frequency gain of 5.1 db and an upper half-; power frequency of 290 Mc. The low-frequency response is reasonably

  18. In situ passivation of GaAs surface with aluminum oxide with MOVPE

    NASA Astrophysics Data System (ADS)

    Terada, Yuki; Deura, Momoko; Shimogaki, Yukihiro; Sugiyama, Masakazu; Nakano, Yoshiaki

    2008-11-01

    In situ passivation of GaAs surface subsequent to the growth in a metalorganic vapor phase epitaxy (MOVPE) reactor has been made possible using trimethylaluminum (TMAl). The adsorption layer on GaAs, presumably consisting of aluminum and the decomposition product of TMAl, was oxidized upon exposure to air to form thin AlO x layer. TMAl supply of only 0.5 monolayer completely prevented the oxidation of As on the surface, as confirmed by XPS. The passivation layer mostly prevented the oxidation of As upon O 2 annealing for 5 min at 250 °C. For the successful passivation, complete desorption of excess As on the GaAs surface was essential prior to the injection of TMAl. Otherwise, AlAs layer was formed and arsenic oxide was inevitably formed. The optimum length of H 2 purge to desorb As was determined to be 2 min with in situ surface monitoring using reflectance anisotropy spectroscopy (RAS). This passivation method, combined with the succeeding deposition of Al 2O 3 as a gate dielectric in a different reactor, provides the GaAs/gate interface without As-oxide. The method is applicable to the MOVPE growth of electron channel layers containing As for III-V metal-insulator-semiconductor field effect transistors (MISFETs).

  19. Modulating the morphology and electrical properties of GaAs nanowires via catalyst stabilization by oxygen.

    PubMed

    Han, Ning; Yang, Zaixing; Wang, Fengyun; Yip, SenPo; Dong, Guofa; Liang, Xiaoguang; Hung, TakFu; Chen, Yunfa; Ho, Johnny C

    2015-03-11

    Nowadays, III-V compound semiconductor nanowires (NWs) have attracted extensive research interest because of their high carrier mobility favorable for next-generation electronics. However, it is still a great challenge for the large-scale synthesis of III-V NWs with well-controlled and uniform morphology as well as reliable electrical properties, especially on the low-cost noncrystalline substrates for practical utilization. In this study, high-density GaAs NWs with lengths >10 ?m and uniform diameter distribution (relative standard deviation ? ? 20%) have been successfully prepared by annealing the Au catalyst films (4-12 nm) in air right before GaAs NW growth, which is in distinct contrast to the ones of 2-3 ?m length and widely distributed of ? ? 20-60% of the conventional NWs grown by the H2-annealed film. This air-annealing process is found to stabilize the Au nanoparticle seeds and to minimize Ostwald ripening during NW growth. Importantly, the obtained GaAs NWs exhibit uniform p-type conductivity when fabricated into NW-arrayed thin-film field-effect transistors (FETs). Moreover, they can be integrated with an n-type InP NW FET into effective complementary metal oxide semiconductor inverters, capable of working at low voltages of 0.5-1.5 V. All of these results explicitly demonstrate the promise of these NW morphology and electrical property controls through the catalyst engineering for next-generation electronics. PMID:25700210

  20. Carbon Nanotube Transistors

    NASA Astrophysics Data System (ADS)

    Datta, Supriyo

    2003-03-01

    Carbon nanotube transistors (CNTFETs) with performance greatly exceeding silicon MOSFETs have recently been demonstrated. In order to explore potential applications of CNT technologies in future nanoelectronic systems, it is important to understand the device physics and evaluate the upper limit for the performance of CNTFETs. We will present a theoretical evaluation of ballistic CNTFET's using both (1) a detailed atomistic model and (2) a simple, phenomenological model. CNTFETs present the possibility of achieving both the ballistic and quantum capacitance limits, leading to several interesting effects. For example, the transconductance, gm, is identical to the channel conductance, GD, and quantized in units of 4e^2/h. An analysis of recent experiments indicates that present-day CNTFET's still operate well below their performance limit due to parasitic resistance and scattering. Possible approaches for improving the performance will be discussed. References: [1] Jing Guo, Supriyo Datta, and Mark Lundstrom, Markus Brink and Paul McEuen, Ali Javey, Hongjie Dai, Hyoungsub Kim, and Paul McIntyre,"Assessment of Silicon MOS and Carbon Nanotube FET Performance LimitsUsing a General Theory of Ballistic Transistors", to appear in IEDM Proceedings, 2002. [2] Jing Guo, Sebastien Goasguen, Mark Lundstrom, and Supriyo Datta, "Metal-insulator-semiconductor electrostatics of carbon nanotubes" Appl. Phys. Lett., 81, 1486 (2002). [3] Jing Guo, Mark Lundstrom, and Supriyo Datta, "Performance Projections for Ballistic Carbon Nanotube Field-Effect Transistors", Appl. Phys. Lett., 80, 3192 (2002).

  1. Neurocognition in Bipolar Disorder and Juvenile Bipolar Disorder

    PubMed Central

    Cahill, Catherine M.; Walter, Garry; Malhi, Gin S.

    2009-01-01

    Introduction: In the ongoing quest for improved diagnostic markers of bipolar illness, the focus of research has gradually shifted to examining the onset of mood difficulties early in life and investigating the potential corollaries of such early onset such as cognitive impairment, disruption of social and emotional functioning, and constriction of quality of life. This article considers the disruptions to cognitive functioning that accompany bipolar disorder and compares adult and child profiles to ascertain the likelihood of identifying a neurocognitive biomarker of the illness. Methods: A succinct review of the literature pertaining to cognition in both adult and childhood populations is synthesised following Medline and PsychINFO searches using key-terms including ‘cognition’, ‘bipolar disorder’, ‘neurocognitive’ ‘child’, ‘adolescent’ and a range of neuropsychological domain names. In addition, literature known to the authors was scrutinised and relevant references further pursued. Results: Findings from the literature are contextualised and key findings are summarised and provide a basis for future recommendations. Conclusion: A number of deficits have been consistently identified in both adolescent and adult populations that perhaps reflect disease traits. Future research needs to focus on these and employ multimodal tests in pristine patient groups, with a view to identifying reliable biomarkers. PMID:19718423

  2. Depression and Bipolar Support Alliance

    NSDL National Science Digital Library

    Living and coping with depression or bipolar disorder can be difficult, but there are a number of high-quality online resources that can be very useful to those with these conditions, or for those who work directly with these individuals. The homepage of the Depression and Bipolar Support Alliance (DBSA) can be of great help in this area, as their site includes everything from their "Real Recovery" podcasts to such basics as factsheets on both diseases. A good place to start here would be with any of the five primary sections, which include crisis intervention resources and recovery steps. Visitors can also view many of these materials in Spanish and they may also wish to sign up to receive the DBSA's electronic newsletter.

  3. Depression and Bipolar Support Alliance

    NSDL National Science Digital Library

    Living and coping with depression or bipolar disorder can be difficult, but there are a number of high-quality online resources that can be very useful to those with these conditions, or for those who work directly with these individuals. The homepage of the Depression and Bipolar Support Alliance (DBSA) can be of great help in this area, as their site includes everything from their �Real Recovery� podcasts to such basics as factsheets on both diseases. A good place to start here would be with any of the five primary sections, which include crisis intervention resources and recovery steps. Visitors can also view many of these materials in Spanish and they may also wish to sign up to receive the DBSA�s electronic newsletter.

  4. Bipolar spintronics: Fundamentals and applications

    Microsoft Academic Search

    Igor Zutic; Jaroslav Fabian; Steven C. Erwin

    2006-01-01

    By incorporating spin-dependent properties and magnetism in semiconductor structures, new applications can be considered which go beyond magnetoresistive effects in metallic systems. Notwithstanding the prospects for spin\\/magnetism-enhanced logic in semiconductors, many important theoretical, experimental, and materials challenges remain. Here we discuss the challenges for realizing a particular class of associated applications and our proposal for bipolar spintronic devices in which

  5. Treatment-resistant bipolar disorder

    Microsoft Academic Search

    M Gitlin

    2006-01-01

    Despite the remarkable increase in medications validated as effective in bipolar disorder, treatment is still plagued by inadequate response in acute manic or depressive episodes or in long-term preventive maintenance treatment. Established first-line treatments include lithium, valproate and second-generation antipsychotics (SGAs) in acute mania, and lithium and valproate as maintenance treatments. Recently validated treatments include extended release carbamazapine for acute

  6. Am2900 Bipolar Microprocessor family

    Microsoft Academic Search

    John R. Mick

    1975-01-01

    The Am2900 Bipolar Microprocessor family provides LSI building blocks applicable to numerous high-speed system configurations. The building blocks in this family handle the data path signals, the microprogram control functions, the input\\/output bus interconnections and the interrupt and timing\\/control requirements applicable to most digital systems. These building blocks are well suited for computer or central processor emulation, peripheral controllers, communications

  7. 15-year outcome of treated bipolar disorder

    Microsoft Academic Search

    Shang-Ying M Tsai; Chiao-Chicy Chen; Chian-Jue Kuo; Ju-Chin Lee; Hsin-Chien Lee; Stephen M Strakowski

    2001-01-01

    Background: Prior reports suggested that bipolar patients in Taiwan had comparable long-term outcome to Western patients despite markedly lower rates of co-occurring substance use disorders. Thus, predictors of long-term outcome identified from Taiwanese bipolar samples may be less influenced by substance abuse. Methods: One hundred and one patients with bipolar disorder (DSM-III-R) having been naturalistically treated for at least 15

  8. Mutant Mouse Models of Bipolar Disorder

    Microsoft Academic Search

    Anneloes Dirks; Lucianne Groenink; Berend Olivier

    Bipolar disorder (also known as manic-depressive illness) is distinctive among psychiatric illnesses in that it is characterized\\u000a by spontaneously alternating episodes of depression and mania. Over the years, extensive research into the pathophysiology\\u000a of bipolar disorder has resulted in a growing understanding of the cellular, biochemical, and molecular changes associated\\u000a with bipolar disorder and its treatment. However, given its unique

  9. Is there validity to the bipolar prodrome?

    PubMed

    Singh, Manpreet K

    2015-05-01

    Bipolar disorder is a debilitating chronic psychiatric disorder with high likelihood of progression to multiple morbidities and early mortality. It is deserving of rigorous research efforts to understand the mechanisms and risk factors for developing the disorder in order to prevent its onset and progression. There are a number of studies that have now identified key clinical risk factors for developing bipolar disorder, including, most consistently, a family history of bipolar disorder. PMID:26035200

  10. Lay Theories of Bipolar Disorder: the Causes, Manifestations and Cures for Perceived Bipolar Disorder

    Microsoft Academic Search

    Adrian Furnham; Elizabeth Anthony

    2010-01-01

    This study aimed to investigate lay theories of the cause and treatment of bipolar disorder, and the recognition of its symptoms. This questionnaire-based study included vignette descriptions of mental disorders and 70 items relating to bipolar disorder. It was completed by 173 participants. Bipolar disorder was recognized less than depression but at the same rate as schizophrenia. Contrary to previous

  11. 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…

  12. Emitter bypassing in transistor circuits

    Microsoft Academic Search

    R. Murray

    1957-01-01

    The emitter bypass capacitor has probably become as commonplace in transistor circuitry as its vacuum tube counterpart, the cathode bypass capacitor. An equivalent circuit analysis of the common-emitter amplifier yields a simple relation that may be used for the determination of the approximate value of the capacitor in terms of the required low-frequency response and the circuit and transistor parameters.

  13. Superconducting Field-Effect Transistors

    NASA Technical Reports Server (NTRS)

    Bhasin, Kul; Romanofsky, Robert R.; Tabib-Azar, Massood

    1995-01-01

    Devices offer switching speeds greater than semiconducting counterparts. High-Tc superconducting field-effect transistors (SUPEFETs) investigated for use as electronic switches in delay-line-type microwave phase shifters. Resemble semiconductor field-effect transistors in some respects, but their operation based on different principle; namely, electric-field control of transition between superconductivity and normal conductivity.

  14. 2001 GaAs IC symposium, Baltimore, Maryland, October 21-24. Abstract --We report InP/InGaAs/InP Double

    E-print Network

    Rodwell, Mark J. W.

    . Results Fig. 1 shows the common emitter DC characteristic of a device with 0.5×8 µm2 emitter and 1 µA 0 1 2 0 2 4 6 8 I C (mA) V CE (V) I b step = 20 µA Fig. 1. ­ Common Emitter DC characteristics Heterojunction Bipolar Transistors (DHBT) will enable high-power amplifiers at 94 and 180 GHz, microwave analog

  15. 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.

  16. 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

  17. Optimization of Vertical Double-Diffused Metal-Oxide Semiconductor (VDMOS) Power Transistor Structure for Use in High Frequencies and Medical Devices

    PubMed Central

    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

  18. Spin noise spectroscopy in GaAs.

    PubMed

    Oestreich, M; Römer, M; Haug, R J; Hägele, D

    2005-11-18

    We observe the noise spectrum of electron spins in bulk GaAs by Faraday-rotation noise spectroscopy. The experimental technique enables the undisturbed measurement of the electron-spin dynamics in semiconductors. We measure exemplarily the electron-spin relaxation time and the electron Landé g factor in -doped GaAs at low temperatures and find good agreement of the measured noise spectrum with a theory based on Poisson distribution probability. PMID:16384167

  19. Nanoscale Transistors: Device Physics, Modeling and Simulation

    Microsoft Academic Search

    Mark Lundstrom; Jing Guo

    2006-01-01

    The continuous scaling of transistors in the last half of century has been the driving force for electronics. The channel length of the transistors in production today is below 100nm. A wide variety of devices are also being explored to complement or even replace silicon transistors at molecular scales. Similarities between nanoscale and micronscale transistors exist, but nanotransistors also behave

  20. Ion-implanted GaAs JFETs with f{sub t} {gt} 45 GHz for low-power electronics

    SciTech Connect

    Zolper, J.C.; Baca, A.G.; Hietala, V.M.; Shul, R.J. [Sandia National Labs., Albuquerque, NM (United States); Sherwin, M.E. [Sandia National Labs., Albuquerque, NM (United States)]|[Microwave Signal, Clarksburg, MD (United States)

    1996-12-31

    GaAs Junction Field Effect Transistors (JFETs) are reported with gate lengths down to 0.3 micrometers. The structure is fully self-aligned and employs all ion implantation doping. p[sup +]-gate regions are formed with either Zn or Cd implants along with a P coimplantation to reduce diffusion. The source and rain implants are engineered with Si or SiF implants to minimize short channel effects. JFETs with 0.3 micrometer gate length are demonstrated with a sub-threshold slope of 110 mV/decade along with an intrinsic unity current gain cutoff frequency as high as 52 GHz.

  1. Cryogenic noise performance of InGaAs/InAlAs HEMTs grown on InP and GaAs substrate

    NASA Astrophysics Data System (ADS)

    Schleeh, J.; Rodilla, H.; Wadefalk, N.; Nilsson, P. Å.; Grahn, J.

    2014-01-01

    We present a comparative study of InGaAs/InAlAs high electron mobility transistors (HEMTs), intended for cryogenic ultra-low noise amplifiers (LNAs) and fabricated on different substrate and buffer technologies. The first was pseudomorphically grown on InP (InP pHEMT) while the second was grown on a linearly graded metamorphic InAlAs buffer on top of a GaAs substrate (GaAs mHEMT). Both HEMTs had identical active epitaxial regions. When integrated in a 4-8 GHz 3-stage LNA at 300 K, the measured average noise temperature was 45 K for the InP pHEMT and 49 K (9% higher) for the GaAs mHEMT. When cooled down to 10 K, the InP pHEMT LNA was improved to 1.7 K whereas the GaAs mHEMT LNA was only reduced to 4 K (135% higher). The observed superior cryogenic noise performance of the HEMTs grown on InP is believed to be due to a higher carrier confinement within the channel. Microscopy analysis suggested this was related to defects from the metamorphic buffer of the GaAs mHEMT.

  2. The use of organometallic group-V sources for the metalorganic molecular beam epitaxy growth of In 0.48Ga 0.52P/GaAs and In 0.53Ga 0.47As/InP heterojunction bipolar device structures

    NASA Astrophysics Data System (ADS)

    Beam, E. A.; Chau, H. F.; Henderson, T. S.; Liu, W.; Seabaugh, A. C.

    1994-03-01

    This paper describes the use of tertiarybutylarsine (TBA) and tertiarybutylphosphine (TBP) as replacements for arsine and phosphine in MOMBE/CBE for the production of device structures with state-of-the-art performance. The growth system used for this work is based on the use of elemental group-III and dopant sources, and employs thermal crackers for the low pressure precracking of TBA and TBP. Device structures fabricated in the In 0.48Ga 0.52P/GaAs materials system include single- and double-heterojunction bipolar transistors (SHBTs and DHBTs). Current gains as high as 2690 have been obtained with these transistors. Deep level transient spectroscopy (DLTS) measurements of the emitter-base junctions of these transistors reveals the absence of deep level traps, in contrast to similar devices fabricated using AlGaAs/GaAs. Device structures fabricated in the In 0.53Ga 0.47As/InP materials system include SHBTs, DHBTs, and resonant tunneling bipolar transistors (RTBTs). In 0.53Ga 0.47As/InP SHBTs with record maximum oscillation frequencies (ƒ max) of > 180 GHz have been produced with high breakdown voltages BV CEO and BV CBO of 8.1 and 17 V, respectively. In addition, DHBTs with ƒ T=134 GHz and ƒ max=137 GHz have been fabricated. Resonant tunneling bipolar transistors, consisting of a structured AlAs/In xGa 1- xAs resonant tunneling double barrier vertically integrated into the emitter of an InP/InGaAs double heterojunction bipolar transistor structure, have been demonstrated. These transistors have room temperature peak-to-valley current ratio of approximately 20, current gain of 100, and breakdown voltage exceeding 5 V, allowing the demonstration of the first room temperature resonant tunneling transistor integrated circuits.

  3. 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

  4. Field-effect tunneling transistor based on vertical graphene heterostructures.

    PubMed

    Britnell, L; Gorbachev, R V; Jalil, R; Belle, B D; Schedin, F; Mishchenko, A; Georgiou, T; Katsnelson, M I; Eaves, L; Morozov, S V; Peres, N M R; Leist, J; Geim, A K; Novoselov, K S; Ponomarenko, L A

    2012-02-24

    An obstacle to the use of graphene as an alternative to silicon electronics has been the absence of an energy gap between its conduction and valence bands, which makes it difficult to achieve low power dissipation in the OFF state. We report a bipolar field-effect transistor that exploits the low density of states in graphene and its one-atomic-layer thickness. Our prototype devices are graphene heterostructures with atomically thin boron nitride or molybdenum disulfide acting as a vertical transport barrier. They exhibit room-temperature switching ratios of ?50 and ?10,000, respectively. Such devices have potential for high-frequency operation and large-scale integration. PMID:22300848

  5. Adjunctive Psychotherapy for Bipolar Disorder

    PubMed Central

    Miklowitz, David J.

    2008-01-01

    Objective Psychotherapy has long been recommended as adjunctive to pharmacotherapy for bipolar disorder, but it is unclear which interventions are effective for which patients, over what intervals, and for what domains of outcome. This article reviews randomized trials of adjunctive psychotherapy for bipolar disorder. Method Eighteen trials of individual and group psychoeducation, systematic care, family therapy, interpersonal therapy, and cognitive-behavioral therapy are described. Relevant outcome variables include time to recovery, recurrence, duration of episodes, symptom severity, and psychosocial functioning. Results The effects of the treatment modalities varied according to the clinical condition of patients at the time of random assignment and the polarity of symptoms at follow-up. Family therapy, interpersonal therapy, and systematic care appeared to be most effective in preventing recurrences when initiated after an acute episode, whereas cognitive-behavioral therapy and group psychoeducation appeared to be most effective when initiated during a period of recovery. Individual psychoeducational and systematic care programs were more effective for manic than depressive symptoms, whereas family therapy and cognitive-behavioral therapy were more effective for depressive than manic symptoms. Conclusions Adjunctive psychotherapy enhances the symptomatic and functional outcomes of bipolar disorder over 2-year periods. The various modalities differ in content, structure, and associated mediating mechanisms. Treatments that emphasize medication adherence and early recognition of mood symptoms have stronger effects on mania, whereas treatments that emphasize cognitive and interpersonal coping strategies have stronger effects on depression. The placement of psychotherapy within chronic care algorithms and its role as a preventative agent in the early stages of the disorder deserve investigation. PMID:18794208

  6. Current steering detection scheme of three terminal antenna-coupled terahertz field effect transistor detectors.

    PubMed

    Földesy, Péter

    2013-08-01

    An antenna-coupled field effect transistor (FET) as a plasma wave terahertz detector is used with the current steering to record separately the gate-source and gate-drain photoresponses and their phase sensitive combination. This method is based on the observation that the plasmon-terminal coupling is cut off in saturation, resulting in only one-sided sensitivity. A polarimetric example is presented with intensity and polarization angle reconstruction using a single three-terminal antenna-coupled Si-metal-oxide semiconductor FET (MOSFET). The technique is applicable to various detection schemes and technologies (high electron mobility transistors and GaAs-, GaN-, and Si-MOSFETs), and other application possibilities are discussed. PMID:23903147

  7. High-efficiency zero current soft switching mode high-frequency inverter using normally off bipolar mode SIT for induction-heating

    Microsoft Academic Search

    H. Ogiwara; Syed Mobin Ulhaq; M. Nakaoka

    1996-01-01

    This paper is mainly concerned with a half-bridge voltage-clamped high frequency induction heating inverter circuit using a high-power bipolar-mode normally-off type static induction transistor, which efficiently operates in a zero current soft-switching (ZCS) mode. This proposed ZCS inverter is found to work safely with sufficiently high conversion efficiency. A new conceptional induction heating power supply is mentioned from a practical

  8. 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…

  9. The phenotypic spectra of bipolar disorder

    Microsoft Academic Search

    Martin Alda

    2004-01-01

    Many findings that seem to be inconsistent in bipolar disorder research could be explained by heterogeneity of the illness and by imprecise diagnostic boundaries. This review of published data finds support for the existence of three main subtypes of bipolar disorder: (1) classical, (2) psychosis spectrum and (3) ‘characterological’. These differ with respect to clinical presentation and course of illness,

  10. Childhood Onset Bipolar Disorder: Pharmacological Treatment Overview

    Microsoft Academic Search

    Gianni L. Faedda

    2004-01-01

    The diagnosis of Bipolar Disorder is still quite controversial in child psychiatry: its boundaries remain uncertain while treatment is based as much on research as on clinical wisdom. Several questions on the treatment of Bipolar Disorder in children await an answer: 1)Does age affect treatments effectiveness and side effects? 2) Can mania be induced by Antidepressant or Stimulant treatment, and

  11. Suicide attempts amongst elderly bipolar patients

    Microsoft Academic Search

    Dov Aizenberg; Ahikam Olmer; Yoram Barak

    2006-01-01

    BackgroundBipolar disorder is associated with high risk of suicide. In the elderly suicide rates are the highest of all age groups. There is a paucity of data regarding suicide amongst elderly bipolar patients. Mood stabilizers and particularly lithium are established as “antisuicide” compounds.

  12. Interstitial thermotherapy with bipolar electrosurgical devices

    Microsoft Academic Search

    Kai Desinger; T. Stein; A. Boehme; Martin G. Mack; Gerhard J. Mueller

    1998-01-01

    In addition to the laser, microwave or other energy sources, interstitial thermotherapy with radio-frequency current (RFITT) in bipolar technique has already been shown in vitro to be a safe and economical alternative energy source with a comparable operating performance. The bipolar technique is, from the technical point of view, completely without risk whereas with monopolar devices, where a neutral electrode

  13. Social influences on bipolar affective disorders

    Microsoft Academic Search

    R. Ramana; P. Bebbington

    1995-01-01

    The impact of psychosocial adversity on the onset and course of bipolar disorder has been assessed in studies that have relied on methods of eliciting life event histories and evaluating family atmosphere. The results of life event studies have been inconsistent, perhaps because the relationship between bipolar disorder and major stress is only pronounced in first or early episodes. If

  14. arXiv:1105.5342v1[cond-mat.mes-hall]26May2011 Multiscale Modeling of Nanowire-based Schottky-Barrier Field-Effect Transistors for

    E-print Network

    Cuniberti, Gianaurelio

    -Barrier Field-Effect Transistors for Sensor Applications Daijiro Nozaki1 , Jens Kunstmann1 , Felix Z¨orgiebel1NW devices such as ultrasensitive sensors,5,6 photodetectors,7 and bipolar field effect tran- sistors (FETs)8arXiv:1105.5342v1[cond-mat.mes-hall]26May2011 Multiscale Modeling of Nanowire-based Schottky

  15. A bipolar analog front-end integrated circuit for the SDC silicon tracker

    SciTech Connect

    Kipnis, I.; Spieler, H.; Collins, T.

    1993-11-01

    A low-noise, low-power, high-bandwidth, radiation hard, silicon bipolar-transistor full-custom integrated circuit (IC) containing 64 channels of analog signal processing has been developed for the SDC silicon tracker. The IC was designed and tested at LBL and was fabricated using AT&T`s CBIC-U2, 4 GHz f{sub T} complementary bipolar technology. Each channel contains the following functions: low-noise preamplification, pulse shaping and threshold discrimination. This is the first iteration of the production analog IC for the SDC silicon tracker. The IC is laid out to directly match the 50 {mu}m pitch double-sided silicon strip detector. The chip measures 6.8 mm {times} 3.1 mm and contains 3,600 transistors. Three stages of amplification provide 180 mV/fC of gain with a 35 nsec peaking time at the comparator input. For a 14 pF detector capacitance, the equivalent noise charge is 1300 el. rms at a power consumption of 1 mW/channel from a single 3.5 V supply. With the discriminator threshold set to 4 times the noise level, a 16 nsec time-walk for 1.25 to 10fC signals is achieved using a time-walk compensation network. Irradiation tests at TRIUMF to a {Phi}=10{sup 14} protons/cm{sup 2} have been performed on the IC, demonstrating the radiation hardness of the complementary bipolar process.

  16. Neurocognitive function in bipolar disorder: a comparison between bipolar I and II disorder and matched controls

    PubMed Central

    2013-01-01

    Background Cognitive deficits have been documented in patients with bipolar disorder. Further, it has been suggested that the degree and type of cognitive impairment differ between bipolar I and bipolar II disorder, but data is conflicting and remains inconclusive. This study aimed to clarify the suggested differences in cognitive impairment between patients with bipolar I and II disorder in a relatively large, clinically stable sample while controlling for potential confounders. Methods 67 patients with bipolar I disorder, 43 with bipolar II disorder, and 86 randomly selected population-based healthy controls were compared. A number of neuropsychological tests were administered, assessing verbal and visual memory and executive functions. Patients were in a stable phase during testing. Results Patients with bipolar type I and type II were cognitively impaired compared to healthy controls, but there were no statistically significant differences between the two subtypes. The strongest predictor of cognitive impairment within the patient group was current antipsychotic treatment. Conclusions The present study suggests that the type and degree of cognitive dysfunction is similar in bipolar I and II patients. Notably, treatment with antipsychotics - but not a history of psychosis - was associated with more severe cognitive impairment. Given that patients with bipolar I disorder are more likely to be on antipsychotic drugs, this might explain why some previous studies have found that patients with type I bipolar disorder are more cognitively impaired than those with type II. PMID:23758923

  17. Elastic and piezoelectric fields in substrates GaAs ,,001... and GaAs ,,111... due to a buried quantum dot

    E-print Network

    Pan, Ernie

    for predicting elastic and piezoelectric fields in the semiconductor GaAs. 2 The magnitude of the QDElastic and piezoelectric fields in substrates GaAs ,,001... and GaAs ,,111... due to a buried present a rigorous study on the elastic and piezoelectric fields in substrates GaAs 001 and GaAs 111 due

  18. Adiabatic Quantum Transistors

    E-print Network

    Dave Bacon; Steven T. Flammia; Gregory M. Crosswhite

    2013-06-18

    We describe a many-body quantum system which can be made to quantum compute by the adiabatic application of a large applied field to the system. Prior to the application of the field quantum information is localized on one boundary of the device, and after the application of the field this information has propagated to the other side of the device with a quantum circuit applied to the information. The applied circuit depends on the many-body Hamiltonian of the material, and the computation takes place in a degenerate ground space with symmetry-protected topological order. Such adiabatic quantum transistors are universal adiabatic quantum computing devices which have the added benefit of being modular. Here we describe this model, provide arguments for why it is an efficient model of quantum computing, and examine these many-body systems in the presence of a noisy environment.

  19. Stable gallium arsenide MIS capacitors and MIS field effect transistors by (NH4)2Sx treatment and hydrogenation using plasma deposited silicon nitride gate insulator

    Microsoft Academic Search

    Kariyadan Remashan; K. N. Bhat

    2002-01-01

    The beneficial effects of sulfur passivation of gallium arsenide (GaAs) surface by (NH4)2Sx chemical treatment and by hydrogenation of the insulator-GaAs interface using the plasma-enhanced chemical vapor-deposited (PECVD) silicon nitride gate dielectric film as the source of hydrogen are illustrated by fabricating Al\\/PECVD silicon nitride\\/n-GaAs MIS capacitors and metal insulator semiconductor field effect transistors (MISFET). Post metallization annealing (PMA) at

  20. The fabrication of a back-gated high electron mobility transistor-a novel approach using MBE regrowth on an in situ ion beam patterned epilayer

    Microsoft Academic Search

    E. H. Linfield; G. A. C. Jones; D. A. Ritchie; J. H. Thompson

    1993-01-01

    A new technique for the fabrication of GaAs\\/AlGaAs back-gated high electron mobility transistors (HEMTs) is described. First the authors demonstrate that a dose of >2*1013 cm-2 Ga ions at an energy of 10 keV can be used to damage a 67 nm n+ GaAs layer, rendering the implanted regions non-conducting. After implantation the epilayer has a 4 K sheet resistivity

  1. Transistor sizing in CMOS circuits

    Microsoft Academic Search

    Mehmet A. Cirit

    1987-01-01

    The problem of optimally sizing transistors in a VLSI CMOS circuit is considered. Models and algorithms for performing optimization on a single path using RC-tree approximation are presented. The results of an automatic optimization procedure are discussed.

  2. Major Depressive Disorder with Anger: A Bipolar Spectrum Disorder?

    Microsoft Academic Search

    Franco Benazzi

    2003-01-01

    Background: Depression with anger may be more common in bipolar disorders. The aim of the study was to assess whether major depressive disorder (MDD) with anger could be included in the bipolar spectrum, by comparing it to MDD without anger and to bipolar II disorder. Methods: Consecutive outpatients (281 bipolar II disorder and 202 MDD) presenting for major depressive episode

  3. Bipolar II Disorder: Personality and Outcome in two Clinical Samples

    Microsoft Academic Search

    Peter R. Joyce; Suzanne E. Luty; Janice M. McKenzie; Roger T. Mulder; Virginia V. McIntosh; Frances A. Carter; Cynthia M. Bulik; Patrick F. Sullivan

    2004-01-01

    Objective: To compare the personality traits and disorders of patients with bipolar II disorder and major depression and to examine the impact on treatment outcome of a bipolar II diagnosis.Method: Patients from two clinical trials, a depressive sample (n = 195, 10% bipolar II) and a bulimic sample (n = 135, 16% bipolar II), were assessed for personality traits using

  4. Design optimization of GaAs betavoltaic batteries

    Microsoft Academic Search

    Haiyanag Chen; Lan Jiang; Xuyuan Chen

    2011-01-01

    GaAs junctions are designed and fabricated for betavoltaic batteries. The design is optimized according to the characteristics of GaAs interface states and the diffusion length in the depletion region of GaAs carriers. Under an illumination of 10 mCi cm-2 63Ni, the open circuit voltage of the optimized batteries is about ~0.3 V. It is found that the GaAs interface states

  5. Excited states of the Mg acceptor in GaAs

    Microsoft Academic Search

    J. R. Cavins; Y. K. Yeo; R. L. Hengehold

    1988-01-01

    The acceptor impurities in undoped vapor-phase epitaxial (VPE) grown GaAs and Mg-implanted VPE GaAs were identified by measuring the excited states of shallow acceptors in these GaAs samples by means of photoluminescence and selective pair luminescence (SPL). It was found that the SPL technique successfully identified acceptor impurities in GaAs. In addition to confirming the known values of excited states

  6. 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, E-mail: kimura.hideo@nims.go.jp [National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Zhao, Hongyang [Shanghai Institute of Ceramics, Chinese Academy of Sciences, Dingxi Road 1295, Shanghai 200050 (China); Yao, Qiwen; Cheng, Zhenxiang [Institute for Superconducting and Electronic Materials, University of Wollongong, Squires Way, North Wollongong, NSW 2500 (Australia); Cheng, Xinghong; Yu, Yuehui [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Micro-system and Information Technology, Chinese Academy of Sciences, Changning Road 865, Shanghai 200050 (China)

    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)

  7. 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.

  8. 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.

  9. 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…

  10. Content The classic outranking concept Outranking with bipolar veto Conclusion On a bipolar foundation of the outranking

    E-print Network

    Bisdorff, Raymond

    Content The classic outranking concept Outranking with bipolar veto Conclusion On a bipolar April 2010 1 / 17 Content The classic outranking concept Outranking with bipolar veto Conclusion Outranking with bipolar veto Conclusion Notations · A = {x, y, z, ...} is a finite set of decision

  11. Harnessing denatured protein for controllable bipolar doping of a monolayer graphene.

    PubMed

    Jang, Sung Kyu; Jang, Ji-Ryang; Choe, Woo-Seok; Lee, Sungjoo

    2015-01-21

    In this work, we demonstrated tunable p- and/or n-type doping of chemical vapor deposition-grown graphene with the use of protein bovine serum albumin (BSA) as a dopant. BSA undergoes protonation or deprotonation reaction subject to solution pH, thereby acting as either an electron donor or an electron acceptor on the graphene surface layered with denatured BSA through ?-stacking interaction. This direct annealing of graphene with denatured BSA of amphoteric nature rendered facilitated fabrication of a p- and/or n-type graphene transistor by modulating pH-dependent net charges of the single dopant. Following AFM confirmation of the BSA/graphene interface assembly, the carrier transport properties of BSA-doped graphene transistors were assessed by I-V measurement and Raman spectra to show effective charge modulation of the graphene enabled by BSA doping at various pH conditions. The protein-mediated bipolar doping of graphene demonstrated in our work is simple, scalable, and straightforward; the proposed scheme is therefore expected to provide a useful alternative for fabricating graphene transistors of novel properties and promote their implementation in practice. PMID:25546483

  12. GaAs as a backscattering crystal

    NASA Astrophysics Data System (ADS)

    Alefeld, B.; Dohmen, L.; Heidemann, A.

    2000-06-01

    The first neutron backscattering instrument was developed about 30 years ago, and since this time, mainly silicon wafers were used as monochromator- and analyser-crystals. GaAs is another candidate for backscattering. The internal strains of GaAs wafers with a diameter of 10 cm were studied at five points of the diameter and reached a value ? a/ a?2.5×10 -5. These strains could be removed by cutting the wafer in pieces of 8 mm×8 mm, giving a homogenous lattice constant within an experimental accuracy of ? a/ a=±10 -6. The experimental value of the integrated reflectivity of the (200)-reflex was determined to be R=0.2 cm/s, which is in excellent agreement with the width of the plateau of the Ewald reflection curve. The energy resolution of GaAs is expected to be ten times better than that of silicon.

  13. 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.

  14. Influence of the local environment on Mn acceptors in GaAs.

    PubMed

    Lee, Donghun; Gohlke, David; Benjamin, Anne; Gupta, Jay A

    2015-04-22

    As transistors continue to shrink toward nanoscale dimensions, their characteristics are increasingly dependent on the statistical variations of impurities in the semiconductor material. The scanning tunneling microscope (STM) can be used to not only study prototype devices with atomically precise placement of impurity atoms, but can also probe how the properties of these impurities depend on the local environment. Tunneling spectroscopy of Mn acceptors in GaAs indicates that surface-layer Mn act as a deep acceptor, with a hole binding energy that can be tuned by positioning charged defects nearby. Band bending induced by the tip or by these defects can also tune the ionization state of the acceptor complex, evident as a ring-like contrast in STM images. The interplay of these effects is explored over a wide range of defect distances, and understood using iterative simulations of tip-induced band bending. PMID:25782688

  15. Influence of the local environment on Mn acceptors in GaAs

    NASA Astrophysics Data System (ADS)

    Lee, Donghun; Gohlke, David; Benjamin, Anne; Gupta, Jay A.

    2015-04-01

    As transistors continue to shrink toward nanoscale dimensions, their characteristics are increasingly dependent on the statistical variations of impurities in the semiconductor material. The scanning tunneling microscope (STM) can be used to not only study prototype devices with atomically precise placement of impurity atoms, but can also probe how the properties of these impurities depend on the local environment. Tunneling spectroscopy of Mn acceptors in GaAs indicates that surface-layer Mn act as a deep acceptor, with a hole binding energy that can be tuned by positioning charged defects nearby. Band bending induced by the tip or by these defects can also tune the ionization state of the acceptor complex, evident as a ring-like contrast in STM images. The interplay of these effects is explored over a wide range of defect distances, and understood using iterative simulations of tip-induced band bending.

  16. Composite substrate for bipolar electrodes

    DOEpatents

    Tekkanat, Bora (Milwaukee, WI); Bolstad, James J. (Shorewood, WI)

    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.

  17. 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.

  18. 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

  19. Progression along the bipolar spectrum: a longitudinal study of predictors of conversion from bipolar spectrum conditions to bipolar I and II disorders.

    PubMed

    Alloy, Lauren B; Uroševi?, Snežana; Abramson, Lyn Y; Jager-Hyman, Shari; Nusslock, Robin; Whitehouse, Wayne G; Hogan, Michael

    2012-02-01

    Little longitudinal research has examined progression to more severe bipolar disorders in individuals with "soft" bipolar spectrum conditions. We examine rates and predictors of progression to bipolar I and II diagnoses in a nonpatient sample of college-age participants (n = 201) with high General Behavior Inventory scores and childhood or adolescent onset of "soft" bipolar spectrum disorders followed longitudinally for 4.5 years from the Longitudinal Investigation of Bipolar Spectrum (LIBS) project. Of 57 individuals with initial cyclothymia or bipolar disorder not otherwise specified (BiNOS) diagnoses, 42.1% progressed to a bipolar II diagnosis and 10.5% progressed to a bipolar I diagnosis. Of 144 individuals with initial bipolar II diagnoses, 17.4% progressed to a bipolar I diagnosis. Consistent with hypotheses derived from the clinical literature and the Behavioral Approach System (BAS) model of bipolar disorder, and controlling for relevant variables (length of follow-up, initial depressive and hypomanic symptoms, treatment-seeking, and family history), high BAS sensitivity (especially BAS Fun Seeking) predicted a greater likelihood of progression to bipolar II disorder, whereas early age of onset and high impulsivity predicted a greater likelihood of progression to bipolar I (high BAS sensitivity and Fun-Seeking also predicted progression to bipolar I when family history was not controlled). The interaction of high BAS and high Behavioral Inhibition System (BIS) sensitivities also predicted greater likelihood of progression to bipolar I. We discuss implications of the findings for the bipolar spectrum concept, the BAS model of bipolar disorder, and early intervention efforts. PMID:21668080

  20. GaAs photoconductive semiconductor switch

    DOEpatents

    Loubriel, Guillermo M. (Sandia Park, NM); Baca, Albert G. (Albuquerque, NM); Zutavern, Fred J. (Albuquerque, NM)

    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.

  1. 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.

  2. Empirical typology of bipolar I mood episodes*

    PubMed Central

    Solomon, David A.; Leon, Andrew C.; Endicott, Jean; Coryell, William H.; Li, Chunshan; Fiedorowicz, Jess G.; Keller, Martin B.

    2009-01-01

    Background Much remains unknown about the phenomenology of bipolar I disorder. Aims To determine the type of bipolar I mood episodes that occur over time, and their relative frequency. Method A total of 219 individuals with Research Diagnostic Criteria bipolar I disorder were prospectively followed for up to 25 years (median 20 years). Psychopathology was assessed with the Longitudinal Interval Follow-up Evaluation. Results Overall, 1208 mood episodes were prospectively observed. The episodes were empirically classified as follows: major depression, 30.9% (n = 373); minor depression, 13.0% (n = 157); mania, 20.4% (n = 246); hypomania, 10.4% (n = 126); cycling, 17.3% (n = 210); cycling plus mixed state, 7.8% (n = 94); and mixed, 0.2% (n = 2). Conclusions Cycling episodes constituted 25% of all episodes. Work groups revising ICD–10 and DSM–IV should add a category for bipolar I cycling episode. PMID:19949203

  3. Restoring functioning in bipolar disorder: functional remediation.

    PubMed

    Bonnin, Caterina M; Torrent, Carla; Vieta, Eduard; Martínez-Arán, Anabel

    2014-01-01

    Over the past several years, many evidence-based interventions have proven to be effective as adjunctive therapies in the treatment of bipolar disorder. Only a few, however, have addressed the issue of functional recovery in bipolar euthymic patients, which is difficult to achieve after an affective episode. The functional remediation program has been designed at the Hospital Clinic of Barcelona with the main aim of treating functional impairment in bipolar disorder. The program consists of 21 weekly group sessions and is based on a neuro-cognitive-behavioral approach. Throughout the sessions, euthymic patients are trained in the use of neurocognitive skills to be applied during their daily routines. Modeling techniques, role playing, self-instructions, verbal instructions, positive reinforcement, and metacognitive cues are some of the techniques that are used in the program. The present report aims at explaining this new intervention to improve functional outcomes in euthymic bipolar patients. PMID:25377603

  4. A Si bipolar monolithic RF bandpass amplifier

    Microsoft Academic Search

    N. M. Nguyen; R. G. Meyer

    1992-01-01

    The application of monolithic inductors to the realization of Si bipolar monolithic RF amplifiers is investigated. As a test vehicle, a bipolar monolithic bandpass amplifier was fabricated and characterized. A 4-nH silicon integrated inductor was used to achieve a peak S 21 gain of 8 dB, a simulated noise figure of 6.4 dB, and a matched input impedance of 50

  5. Sensing with electrochemical transistors

    NASA Astrophysics Data System (ADS)

    Cicoira, Fabio; Malliaras, George G.

    2010-03-01

    Organic electrochemical transistors are particularly promising for applications in chemical and biological sensing and are expected to play a primary role in the emerging field of organic bioelectronics [1]. These devices can be operated in aqueous electrolytes as ion-to-electron converters, thus providing an interface between the worlds of biology and electronics. OECTs sensors are currently able to detect micromolar analyte concentrations. Besides their application in sensing, OECT can help understanding the distribution of ions at the interface between conducting polymers and electrolytes.Of particular interest is the ratio between ions that accumulate at the surface vs. ions that enter in the polymer film, as this ratio ultimately determines the ease with which a conducting polymer can be de-doped (hence, it controls the maximum detectable analyte concentration). We addressed this issue by using energy dispersive X-ray spectroscopy to study the change in chemical composition of the conducting polymers PEDOT:PSS upon application of a gate bias in presence of several electrolytes. [1] F. Cicoira, M. Sessolo, O. Yaghmazadeh, J. A. DeFranco, S. Y. Yang, G. G. Malliaras, Adv. Mater. 2009, 21 (in press).

  6. Paper field effect transistor

    NASA Astrophysics Data System (ADS)

    Fortunato, E.; Correia, Nuno; Barquinha, Pedro; Costa, Cláudia; Pereira, Luís; Gonçalves, Gonçalo; Martins, Rodrigo

    2009-02-01

    In this paper we report the use of a sheet of cellulose fiber-based paper as the dielectric layer used in oxide based semiconductor thin film field-effect transistors (FETs). In this new approach we are using the cellulose fiber-based paper in an "interstrate" structure since the device is build on both sides of the cellulose sheet. Such hybrid FETs present excellent operating characteristics such as high channel saturation mobility (>30 cm2/Vs), drain-source current on/off modulation ratio of approximately 104, near-zero threshold voltage, enhancement n-type operation and sub-threshold gate voltage swing of 0.8 V/decade. The cellulose fiber-based paper FETs characteristics have been measured in air ambient conditions and present good stability. The obtained results outpace those of amorphous Si TFTs and rival with the same oxide based TFTs produced on either glass or crystalline silicon substrates. The compatibility of these devices with large-scale/large-area deposition techniques and low cost substrates as well as their very low operating bias delineates this as a promising approach to attain high-performance disposable electronics like paper displays, smart labels, smart packaging, RFID and point-of-care systems for self analysis in bio-applications, among others.

  7. Ballistic superconductivity in high mobility two dimensional electron gas in GaAs heterostructures

    NASA Astrophysics Data System (ADS)

    Wan, Zhong; Kazakov, Aleksandr; Manfra, Michael; Pfeiffer, Loren; West, Ken; Rokhinson, Leonid

    2015-03-01

    Introduction of a Josephson field effect transistor (JoFET) concept sparked active research on proximity effects in semiconductors. Induced superconductivity and electrostatic control of critical current has been demonstrated in two-dimensional gases in InAs, graphene and topological insulators, and in one-dimensional systems including quantum spin Hall edges. Recently, interest in superconductor-semiconductor interfaces was renewed by the search for non-Abelian states when fractional quantum Hall edge states interface with superconductivity. However, the highest mobility 2D gases in GaAs, where variety of strongly correlated states including fractional quantum Hall effect can be observed, are notoriously absent from the list of materials where superconductivity have been induced. We report formation of transparent superconducting contacts to the high mobility 2DEG in GaAs and demonstrate induced superconductivity across several microns. Ballistic supercurrent has been observed across 0.6 ?m of 2DEG, a regime essential to the formation of well separated non-Abelian states. High critical fields (> 16 Tesla) in NbN contacts enables investigation of a regime of an interplay between superconductivity and strongly correlated states in a 2DEG at high magnetic fields.

  8. Quantum Point Contact Transistor and Ballistic Field-Effect Transistors

    NASA Astrophysics Data System (ADS)

    Grémion, E.; Niepce, D.; Cavanna, A.; Gennser, U.; Jin, Y.

    2012-12-01

    We report the experimental results and theoretical understanding of the Quantum Point Contact Transistor - a fully ballistic one-dimensional (1D) Field-Effect Transistor (FET). Experimentally obtained voltage gain greater than 1 in our Quantum-Point-Contact transistors at 4.2 K can be explained with the help of an analytical modeling based on the Landauer-Büttiker approach in mesosopic physics: the lowest 1D subband and the band gap play the key role in increasing its transconductance, especially by reducing its output conductance, and thus achieving a voltage gain higher than 1. This work provides a general basis for devising future ballistic FETs and the quantum limits found in this work may be used to estimate normalized transconductance and channel resistance in future two-dimensional (2D) ballistic FETs.

  9. Common-Emitter Transistor Video Amplifiers

    Microsoft Academic Search

    Georg Bruun

    1956-01-01

    A design procedure and theory are given for the common-emitter transistor video amplifier with and without a feedback resistor in the emitter lead. In the analysis a junction transistor of the alloy type is represented by the Johnson-Giacoletto hybrid-pi equivalent circuit for the common-emitter transistor. The design theory accounts for the most significant part of the bilateralness of the transistor

  10. Kondo Effect in a Single Electron Transistor

    Microsoft Academic Search

    David Goldhaber-Gordon

    1998-01-01

    When a field-effect transistor is made very small, and electrons in the channel are separated from those in the leads by tunnel junctions, the transistor turns on and off every time an extra electron is added to the channel. The droplet of electrons confined in the channel of such a single-electron transistor (SET) interacts with electrons in the leads. This

  11. Update: Researchers pencil in graphene transistors

    Microsoft Academic Search

    Neil Savage

    2008-01-01

    Graphene, found in pencil marks, is a candidate material for making future transistors. It's extracted from graphite crystals using sticky tape. Graphene's weird electrical properties allow for smallest transistor yet. Silicon's remarkable run as ruler of the chip world may be nearing an end as engineers eventually lose the ability to make faster silicon transistors by making them smaller. In

  12. High Performance Silicon Nanowire Field Effect Transistors

    Microsoft Academic Search

    Yi Cui; Zhaohui Zhong; Deli Wang; Wayne U. Wang; Charles M. Lieber

    2003-01-01

    Silicon nanowires can be prepared with single-crystal structures, diameters as small as several nanometers and controllable hole and electron doping, and thus represent powerful building blocks for nanoelectronics devices such as field effect transistors. To explore the potential limits of silicon nanowire transistors, we have examined the influence of source-drain contact thermal annealing and surface passivation on key transistor properties.

  13. 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.

  14. Image transfer in photorefractive GaAs

    NASA Technical Reports Server (NTRS)

    Cheng, Li-Jen; Gheen, Gregory; Rau, Mann-Fu; Wang, Faa-Ching

    1987-01-01

    Image transfer from one beam to the other using counterpropagation beam coupling in GaAs was demonstrated. Good image quality was achieved. The results also reveal that local birefringence due to the residual stress/strain field in the crystal can degrade the image quality.

  15. GaAs MMIC technology radiation effects

    NASA Astrophysics Data System (ADS)

    Anderson, W. T.; Christou, A.; Simons, M.; Beall, J.

    1985-12-01

    A comprehensive study was made of radiation effects in the component devices that comprise a particular technology developed by Texas Instruments for GaAs MMICs. Total dose, transient, and neutron radiation effects were measured in FETs. Transient effects were measured in capacitors, resistors, Schottky barrier diodes and the MMICs. Results are compared with predictions of radiation effects models.

  16. 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.

  17. 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,…

  18. Bipolar Bozuklukta Koruyucu Tedavi Long-term Treatment in Bipolar Disorder

    Microsoft Academic Search

    Meliha Zengin

    2010-01-01

    Although the importance of long-term prophylactic treatment is certain in bipolar disorder, there is stil debate on how to which patients and evaluate the treatment response. Efficacious long-term treatment can reduce morbidity and mortality significantly and improve quality of life of bipolar patients. The concept of ideal response should also be defined very clearly in order to discuss the difficulties

  19. Treatment Guidelines for Children and Adolescents With Bipolar Disorder: Child Psychiatric Workgroup on Bipolar Disorder

    Microsoft Academic Search

    ROBERT A. KOWATCH; MARY FRISTAD; BORIS BIRMAHER; KAREN DINEEN WAGNER; ROBERT L. FINDLING; MARTHA HELLANDER

    Clinicians who treat children and adolescents with bipolar disorder desperately need current treatment guidelines. These guidelines were developed by expert consensus and a review of the extant literature about the diagnosis and treatment of pediatric bipolar disorders. The four sections of these guidelines include diagnosis, comorbidity, acute treatment, and main- tenance treatment. These guidelines are not intended to serve as

  20. Thresholds for Cenozoic bipolar glaciation.

    PubMed

    Deconto, Robert M; Pollard, David; Wilson, Paul A; Pälike, Heiko; Lear, Caroline H; Pagani, Mark

    2008-10-01

    The long-standing view of Earth's Cenozoic glacial history calls for the first continental-scale glaciation of Antarctica in the earliest Oligocene epoch ( approximately 33.6 million years ago), followed by the onset of northern-hemispheric glacial cycles in the late Pliocene epoch, about 31 million years later. The pivotal early Oligocene event is characterized by a rapid shift of 1.5 parts per thousand in deep-sea benthic oxygen-isotope values (Oi-1) within a few hundred thousand years, reflecting a combination of terrestrial ice growth and deep-sea cooling. The apparent absence of contemporaneous cooling in deep-sea Mg/Ca records, however, has been argued to reflect the growth of more ice than can be accommodated on Antarctica; this, combined with new evidence of continental cooling and ice-rafted debris in the Northern Hemisphere during this period, raises the possibility that Oi-1 represents a precursory bipolar glaciation. Here we test this hypothesis using an isotope-capable global climate/ice-sheet model that accommodates both the long-term decline of Cenozoic atmospheric CO(2) levels and the effects of orbital forcing. We show that the CO(2) threshold below which glaciation occurs in the Northern Hemisphere ( approximately 280 p.p.m.v.) is much lower than that for Antarctica ( approximately 750 p.p.m.v.). Therefore, the growth of ice sheets in the Northern Hemisphere immediately following Antarctic glaciation would have required rapid CO(2) drawdown within the Oi-1 timeframe, to levels lower than those estimated by geochemical proxies and carbon-cycle models. Instead of bipolar glaciation, we find that Oi-1 is best explained by Antarctic glaciation alone, combined with deep-sea cooling of up to 4 degrees C and Antarctic ice that is less isotopically depleted (-30 to -35 per thousand) than previously suggested. Proxy CO(2) estimates remain above our model's northern-hemispheric glaciation threshold of approximately 280 p.p.m.v. until approximately 25 Myr ago, but have been near or below that level ever since. This implies that episodic northern-hemispheric ice sheets have been possible some 20 million years earlier than currently assumed (although still much later than Oi-1) and could explain some of the variability in Miocene sea-level records. PMID:18833277

  1. 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.

  2. InGaAs metal-semiconductor field-effect transistor with Langmuir-Blodgett deposited gate structure

    Microsoft Academic Search

    W. K. Chan; Gee-Kung Chang; Rajaram Bhat; N. E. Schlotter

    1988-01-01

    A high-transconductance n-channel, depletion-mode InGaAs metal-semiconductor field-effect transistor (MESFET) with a Langmuir-Blodgett deposited gate fabricated on organometallic chemical vapor deposition (OMCVD)-grown InGaAs lattice matched to InP is reported. The fabrication process is similar to epitaxial GaAs FET technology and is suitable for making optoelectronic integrated circuits (OEICs) for long-wavelength fiber-optic communicatons systems. Devices with 1-micron gate and 6 x 1016

  3. [Non pharmacological treatment for bipolar disorder].

    PubMed

    Mirabel-Sarron, Christine; Giachetti, Raphaël

    2012-12-01

    Bipolar disorder is a chronic and recurring disorder associated with significant psychosocial impairment. A number of psychosocial interventions have been developed to address impairment. The consensus makes mood stabilizer the treatment of bipolar disorder. However, numerous patients are not in complete remission despite a controlled observance. Every patient can follow a psycho educational program. What this paper adds. The review identifies that a range of interventions have demonstrated efficacy in extended periods of euthymia, improved social and occupational functioning and alleviation of subsyndromal symptoms. Adjunctive, short-term psychotherapies have been shown to offer fairly consistent benefits to bipolar disorder patients. Cognitive-behavioural therapy, family-focused therapy, and psychoeducation offer the most robust efficacy in regard to relapse prevention. The most complex situations including comorbidities can be helped by behavioral and cognitive therapy for bipolar disorder. Evaluations emphasize positive impact. The psychosocial interventions reviewed provide mental health nurses with evidence-based approaches to improving mental health care for patients with bipolar disorder. There is a need for mental health nurses to conduct high quality trials of the clinical effectiveness of these interventions. PMID:23395231

  4. Overview of antidepressant treatment of bipolar depression.

    PubMed

    Vázquez, Gustavo H; Tondo, Leonardo; Undurraga, Juan; Baldessarini, Ross J

    2013-08-01

    Bipolar depression remains a major unresolved challenge for psychiatric therapeutics. It is associated with significant disability and mortality and represents the major proportion of the approximately half of follow-up time spent in morbid states despite use of available treatments. Evidence regarding effectiveness of standard treatments, particularly with antidepressants, remains limited and inconsistent. We reviewed available clinical and research literature concerning treatment with antidepressants in bipolar depression and its comparison with unipolar depression. Research evidence concerning efficacy and safety of commonly used antidepressant treatments for acute bipolar depression is very limited. Nevertheless, an updated meta-analysis indicated that overall efficacy was significantly greater with antidepressants than with placebo-treatment and not less than was found in trials for unipolar major depression. Moreover, risks of non-spontaneous mood-switching specifically associated with antidepressant treatment are less than appears to be widely believed. The findings encourage additional efforts to test antidepressants adequately in bipolar depression, and to consider options for depression in types I vs. II bipolar disorder, depression with subsyndromal hypomania and optimal treatment of mixed agitated-dysphoric states--both short- and long-term. Many therapeutic trials considered were small, varied in design, often involved co-treatments, or lacked adequate controls. PMID:23428003

  5. Toward stratified treatments for bipolar disorders.

    PubMed

    Hasler, Gregor; Wolf, Andreas

    2015-03-01

    In bipolar disorders, there are unclear diagnostic boundaries with unipolar depression and schizophrenia, inconsistency of treatment guidelines, relatively long trial-and-error phases of treatment optimization, and increasing use of complex combination therapies lacking empirical evidence. These suggest that the current definition of bipolar disorders based on clinical symptoms reflects a clinically and etiologically heterogeneous entity. Stratification of treatments for bipolar disorders based on biomarkers and improved clinical markers are greatly needed to increase the efficacy of currently available treatments and improve the chances of developing novel therapeutic approaches. This review provides a theoretical framework to identify biomarkers and summarizes the most promising markers for stratification regarding beneficial and adverse treatment effects. State and stage specifiers, neuropsychological tests, neuroimaging, and genetic and epigenetic biomarkers will be discussed with respect to their ability to predict the response to specific pharmacological and psychosocial psychotherapies for bipolar disorders. To date, the most reliable markers are derived from psychopathology and history-taking, while no biomarker has been found that reliably predicts individual treatment responses. This review underlines both the importance of clinical diagnostic skills and the need for biological research to identify markers that will allow the targeting of treatment specifically to sub-populations of bipolar patients who are more likely to benefit from a specific treatment and less likely to develop adverse reactions. PMID:25595029

  6. GaAs HEMT low-noise cryogenic amplifiers from C-band to X-band with 0.7-K\\/GHz noise temperature

    Microsoft Academic Search

    Christophe Risacher; Victor Belitsky

    2003-01-01

    Cryogenic low-noise two-stage amplifiers were developed for frequency bands of 3.4-4.6 GHz, 4-8 GHz, and 8-9 GHz using commercial GaAs high electron mobility transistor. The performances are in very good agreement with simulations, and at a cryogenic temperature of 12 K, input noise temperatures get as low as 0.6 K\\/GHz (2.8 K for the 3.4-4.6 GHz LNA and 5 K

  7. 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.

  8. Tunable Graphene Single Electron Transistor

    Microsoft Academic Search

    C. Stampfer; E. Schurtenberger; F. Molitor; J. Güttinger; T. Ihn; K. Ensslin

    2008-01-01

    We report electronic transport experiments on a graphene single electron transistor. The device consists of a graphene island connected to source and drain electrodes via two narrow graphene constrictions. It is electrostatically tunable by three lateral graphene gates and an additional back gate. The tunneling coupling is a strongly nonmonotonic function of gate voltage indicating the presence of localized states

  9. Matching properties of MOS transistors

    Microsoft Academic Search

    MARCEL J. M. PELGROM; AAD C. J. DUINMAIJER; P. G. WELBERS

    1989-01-01

    The matching properties of the threshold voltage, substrate factor, aud current factor of MOS transistors have been analyzed and measrrred. Improvements to the existing theory are giveu, as well as extensions for Iong-dktance matching and rotation of devices. Matching parameters of several processes are compared. The matching results have been verified by measurements and calculations on several basic circuits.

  10. 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.

  11. 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.

  12. Electrodeionization Using Microseparated Bipolar Membranes

    NASA Technical Reports Server (NTRS)

    Lyons, Donald; Jackson, George; Andrews, Craig C.; Tennakoon, Charles L, K.; Singh, Waheguru; Hitchens, G. Duncan; Jabs, Harry; Chepin, James F.; Archer, Shivaun; Gonzalez-Martinez, Anukia; Cisar, Alan J.

    2004-01-01

    An electrochemical technique for deionizing water, now under development, is intended to overcome a major limitation of prior electrically-based water-purification techniques. The limitation in question is caused by the desired decrease in the concentration of ions during purification: As the concentration of ions decreases, the electrical resistivity of the water increases, posing an electrical barrier to the removal of the remaining ions. In the present technique, this limitation is overcome by use of electrodes, a flowfield structure, and solid electrolytes configured to provide conductive paths for the removal of ions from the water to be deionized, even when the water has already been purified to a high degree. The technique involves the use of a bipolar membrane unit (BMU), which includes a cation-exchange membrane and an anion-exchange membrane separated by a nonconductive mesh that has been coated by an ionically conductive material (see figure). The mesh ensures the desired microseparation between the ion-exchange membranes: The interstices bounded by the inner surfaces of the membranes and the outer surfaces of the coated mesh constitute a flow-field structure that allows the water that one seeks to deionize (hereafter called "process water" for short) to flow through the BMU with a low pressure drop. The flow-field structure is such that the distance between any point in the flow field and an ionically conductive material is small; thus, the flow-field structure facilitates the diffusion of molecules and ions to and from the ion-exchange membranes. The BMU is placed between an anode and a cathode, but not in direct contact with these electrodes. Instead, the space between the anion-exchange membrane and the anode is denoted the anode compartment and is filled with an ionic solution. Similarly, the space between the cation-exchange membrane and the cathode is denoted the cathode compartment and is filled with a different ionic solution. The electrodes are made of titanium coated with platinum.

  13. Peeled film GaAs solar cell development

    Microsoft Academic Search

    D. M. Wilt; R. D. Thomas; S. G. Bailey; D. J. Brinker; F. L. DeAngelo; N. S. Fatemi; G. A. Landis

    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 (>106) of the etching rate of aluminum arsenide (AlAs) over GaAs in dilute hydrofluoric acid (HF). The feasibility of

  14. Peeled film GaAs solar cell development

    Microsoft Academic Search

    D. M. Wilt; R. D. Thomas; S. G. Bailey; D. J. Brinker; F. L. Deangelo

    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

  15. Biomimetic subwavelength antireflective gratings on GaAs

    Microsoft Academic Search

    Chih-Hung Sun; Brian J. Ho; Bin Jiang; Peng Jiang

    2008-01-01

    We have developed a simple and scalable bottom-up approach for fabricating moth-eye antireflective coat- ings on GaAs substrates. Monolayer, non-close-packed silica colloidal crystals are created on crystalline GaAs wafers by a spin-coating-based single-layer reduction technique. These colloidal monolayers can be used as etching masks during a BCl3 dry-etch process to generate subwavelength-structured antireflective gratings directly on GaAs substrates. The gratings

  16. The Friedreich ataxia GAA triplet repeat: premutation and normal alleles

    Microsoft Academic Search

    Laura Montermini; Eva Andermann; Margaret Labuda; Andrea Richter; Massimo Pandolfo; Luigi Pianese; Luisa Iodice; Gerardina Farina; Antonella Monticelli; Mimmo Turano; Alessandro Filla; Sergio Cocozza; Québec Montréal

    1997-01-01

    The most common mutation causing Friedreich ataxia (FRDA), an autosomal recessive neurodegenerative disease, is the hyperexpansion of a polymorphic GAA triplet repeat localized within an Alu sequence (GAA-Alu) in the first intron of the frataxin (X25) gene. GAA-Alu belongs to the AluSx subfamily and contains several polymorphisms in strong linkage disequili- brium either with a subgroup of normal alleles, or

  17. Energy Storage in an Asymmetric Bipolar Corona

    NASA Astrophysics Data System (ADS)

    Wolfson, Richard; Kennedy, M.

    2010-05-01

    We consider magnetic energy storage in a force-free model corona with bipolar boundary conditions at the coronal base. Unlike the usual dipole, our boundary conditions are asymmetric, with the bipolar structure centered in one hemisphere. We explore the role of latitudinal position and extent of the bipolar structure on the amount of energy that can be stored by longitudinal shearing of the magnetic footpoints. As found earlier for dipolar and quadrupolar boundary conditions, our solutions develop detached flux ropes, whose energy can exceed that of the corresponding open field. We compare this energy with that of previously-examined configurations, and with the energy needed to drive coronal mass ejections. This work is funded by NSF grant AGS0940503 to Middlebury College.

  18. Bipolar illness, lithium prophylaxis, and pregnancy.

    PubMed

    van Gent, E M; Verhoeven, W M

    1992-07-01

    In advising bipolar patients wishing to become pregnant, Weinstein's guidelines were extended to seven stages: contraceptive measures; genetic counseling; discontinuing lithium in the first trimester or prescribing alternatives; ultrasound scanning for congenital anomalies, low lithium levels during pregnancy; discontinuing lithium at the end of pregnancy; starting immediately after birth, no breast feeding, observation of the neonate in the neonatal ward; and close observation of the patient in the follow-up year. Of the 15 bipolar patients, 11 gave birth to healthy children (five of them twice). Most patients knew nothing about the inheritance of bipolar illness. Four made no further attempt to become pregnant: two in view of a serious possibility of inheritance, the other two after a severe relapse. Three patients chose an alternative to lithium medication (carbamazepine and haloperidol). Postpartum, 27% of the patients who used medication relapsed and 60% of the patients who used none relapsed. PMID:1528958

  19. Family Functioning and the Course of Adolescent Bipolar Disorder

    ERIC Educational Resources Information Center

    Sullivan, Aimee E.; Judd, Charles M.; Axelson, David A.; Miklowitz, David J.

    2012-01-01

    The symptoms of bipolar disorder affect and are affected by the functioning of family environments. Little is known, however, about the stability of family functioning among youth with bipolar disorder as they cycle in and out of mood episodes. This study examined family functioning and its relationship to symptoms of adolescent bipolar disorder,…

  20. Bipolar II versus unipolar chronic depression: A 312-case study

    Microsoft Academic Search

    Franco Benazzi

    1999-01-01

    Differences between bipolar II depression and unipolar depression have been reported, such as a lower age at onset and more atypical features in bipolar II depression. The aim of the present study was to compare chronic\\/nonchronic bipolar II depression with chronic\\/nonchronic unipolar depression to determine whether the reported differences are present when chronicity is taken into account. Three hundred twelve

  1. Pharmacotherapy of depression and mixed states in bipolar disorder

    Microsoft Academic Search

    Stuart A Montgomery; Alan F Schatzberg; J. D Guelfi; Siegfried Kasper; Charles Nemeroff; Alan Swann; John Zajecka

    2000-01-01

    The treatment of bipolar depression requires the resolution of depression and the establishment of mood stability. A basic problem is that the treatments used in treating bipolar depression were developed and proven effective for other disease states: antidepressants for unipolar depression, and mood stabilizers for mania. The panel addressed four unresolved questions regarding depression in relation to bipolar disorder: (1)

  2. Perturbed reward processing in pediatric bipolar disorder: an antisaccade study

    Microsoft Academic Search

    Sven C Mueller; Pamela Ng; Veronica Temple; Michael G Hardin; Daniel S Pine; Ellen Leibenluft; Monique Ernst

    2010-01-01

    Pediatric bipolar disorder is a severe and impairing illness. Characterizing the impact of pediatric bipolar disorder on cognitive function might aid in understanding the phenomenology of the disorder. While previous studies of pediatric bipolar disorder have reported deficits in cognitive control and reward behavior, little is understood about how affective processes influence behavioral control. Relative to prior studies using manual-response

  3. Bipolar SQLf: a Flexible Querying Language for Relational Databases

    E-print Network

    Paris-Sud XI, Université de

    Bipolar SQLf: a Flexible Querying Language for Relational Databases Nouredine Tamani1 , Ludovic Li allows expressing complex preferences in user queries. Such preferences can be modeled by fuzzy bipolar to satisfy w".We define in this article the main elements of the Bipolar SQLf language, which is an SQL

  4. Uncertainty in Bipolar Preference Problems Stefano Bistarelli1,2

    E-print Network

    Rossi, Francesca

    Uncertainty in Bipolar Preference Problems Stefano Bistarelli1,2 , Maria Silvia Pini3 , Francesca on bipolar preferences and on uncertainty modelled via uncontrollable variables. However, some information of preference and robustness. 1 Introduction Bipolar preferences and uncertainty are present in many application

  5. Increasing the High Speed Torque of Bipolar Stepper

    E-print Network

    Peters, Dennis

    Increasing the High Speed Torque of Bipolar Stepper Motors Introduction To successfully follow at the desired rates, and drive the load torque at the desired speeds. While the size of a bipolar stepper motor rates of the winding currents in a bipolar stepper motor pushes the motor to deliver more torque at high

  6. InP Bipolar ICs: Scaling Roadmaps, Frequency Limits,

    E-print Network

    Rodwell, Mark J. W.

    INVITED P A P E R InP Bipolar ICs: Scaling Roadmaps, Frequency Limits, Manufacturable Technologies Doubling the bandwidth of phosphide heterojunction bipolar integrated circuits, used for imaging, radio, and Berinder Brar, Member IEEE ABSTRACT | Indium phosphide heterojunction bipolar tran- sistors (HBTs) find

  7. Fuzzy Bipolar Conditions of Type "or else" Ludovic Lietard

    E-print Network

    Paris-Sud XI, Université de

    Fuzzy Bipolar Conditions of Type "or else" Ludovic Li´etard IRISA/IUT/Univ. Rennes 1, Rue Edouard Email: rocacher@enssat.fr Abstract--Previously studied fuzzy bipolar conditions of type "and if possible of a conjunctive nature. We define in this paper, a new kind of fuzzy bipolar conditions of the form "or else

  8. Bipolar and bivariate models in multi-criteria decision analysis

    E-print Network

    Paris-Sud XI, Université de

    Bipolar and bivariate models in multi-criteria decision analysis: descriptive and constructive the alternatives with respect to a viewpoint are bipolar and univariate or unipolar and bivariate. In the former, Decision analysis, Preference, Bipolar models, Choquet integral. The authors are indebted to Denis

  9. The Bipolar Man Framework for Human-Centred Intelligent Systems

    E-print Network

    Amigoni, Francesco

    The Bipolar Man Framework for Human-Centred Intelligent Systems F. AMIGONI, V. SCHIAFFONATI, M by the concept of the bipolar man, which has an impact on both the analysis and the design of human based on the peculiar concept of bipolar man to which potentially every kind of human

  10. Bipolar preference problems: framework, properties and solving techniques

    E-print Network

    Rossi, Francesca

    Bipolar preference problems: framework, properties and solving techniques Stefano Bistarelli1 preferences, that we call bipolar prefer- ence problems. Although seemingly specular notions, these two kinds the notion of arc consis- tency to bipolar problems, and we show how branch and bound (with or without

  11. hal00271217, The Quest for Rings on Bipolar Scales

    E-print Network

    Paris-Sud XI, Université de

    hal­00271217, version 1 ­ 8 Apr 2008 The Quest for Rings on Bipolar Scales Michel GRABISCH 1 on bipolar scales #15; unipolar scales (not necessarily bounded): typically R + , suitable e.g. for pri- ority degrees (one can always imagine something of higher priority); #15; bipolar scales (bounded

  12. On a bipolar foundation of the outranking concept Raymond BISDORFF

    E-print Network

    Bisdorff, Raymond

    URPDM2010 On a bipolar foundation of the outranking concept Raymond BISDORFF University of Luxembourg, FSTC/ILIAS raymond.bisdorff@uni.lu ABSTRACT In this paper we introduce a bipolarly extended veto that the identity between the asymmetric part and bipolar codual of the latter outranking relation is given

  13. hal00282571, BAXTER PERMUTATIONS AND PLANE BIPOLAR ORIENTATIONS

    E-print Network

    hal­00282571, version 1 ­ 27 May 2008 BAXTER PERMUTATIONS AND PLANE BIPOLAR ORIENTATIONS NICOLAS Baxter permutations of size n and plane bipolar orientations with n edges. This bijection translates-to-right minima...) into natural parameters of plane bipolar orientations (number of vertices, degree of the sink

  14. Modelling and solving bipolar preference problems Stefano Bistarelli1

    E-print Network

    Rossi, Francesca

    Modelling and solving bipolar preference problems Stefano Bistarelli1 , Maria Silvia Pini2 with both positive and negative preferences, that we call bipolar problems. Although seemingly specular with bipolar problems. 1 Introduction Many real-life problems contain statements which can be expressed

  15. Multilayer GaAs injection laser

    Microsoft Academic Search

    W. Kosonocky; R. Cornely; I. Hegyi

    1968-01-01

    Experimental data are presented for multijunction GaAs lasers made by vapor-phase epitaxial growth in the form ofp-n-p-n-p-nstructures. The overall thickness of the four inside layers was 5 microns for the multilayer material for which experimental data are given. The diodes made from this material exhibited current-controlled negative-resistance characteristics. The emitted output beams of the multilayer lasers were extremely narrow, with

  16. 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.

  17. Reliability testing of GaAs MMICs

    Microsoft Academic Search

    W. T. Anderson; J. A. Roussos; K. A. Christianson

    1995-01-01

    GaAs MMICs were reliability life tested under accelerated high temperature conditions while operating under normal bias conditions under RF drive. These circuits (EG6010 power amplifiers) were standard evaluation circuit (SEC) deliverables on the US Department of Defense ARPA MIMIC Program. The median life, t50, was found to be 1×107 hours at a channel temperature of 140°C, with an activation energy

  18. Electrical Properties OF GaAs Doped with Iron

    NASA Astrophysics Data System (ADS)

    Khludkov, S. S.; Prudaev, I. A.; Novikov, V. A.; Budnitskii, D. L.; Lopatetskaya, K. S.

    2014-04-01

    Electrical characteristics of GaAs doped with Fe in the diffusion process are studied. It is shown that as in the case of the single-crystal GaAs doped with Fe during growth, in GaAs doped in the diffusion process, the impurity Fe creates an acceptor level 0.53 eV above the top of the GaAs valence band. The position of the energy level of Fe and the electrical characteristics of GaAs:Fe are independent of the regime of the samples annealing at a temperature below the doping temperature.

  19. Electron irradiation effects in AlGaAs\\/GaAs single heterojunction bipolar transistors

    Microsoft Academic Search

    Aveek Sarkar; S. Subramanian; S. M. Goodnick

    2000-01-01

    The effects of high-energy electron irradiation on the dc characteristics of polyimide passivated AlGaAs\\/GaAs HBTs of different base thicknesses and different emitter sizes are investigated. The devices show gain degradation for doses greater than 1015 e\\/cm2. The gain degradation of the passivated devices decreases (1) with increase in the base thickness, (2) with increase in the perimeter to area ratio

  20. Design of Integrated Fiber-Optic Receivers Using Heterojunction Bipolar Transistors.

    NASA Astrophysics Data System (ADS)

    Buchwald, Aaron Wayne

    Recent demands for increased information transfer through communication networks are stretching channel capacities to the limit. Telecommunication trunking, local-area data networks, video on demand, integrated multi-media applications, etc. require ever increasing bandwidths. Optical fibers are the best known medium for point-to-point communication because of their high bandwidth (1400 GHz-km) and low losses (0.15 dB/km). Electronic circuits are not fast enough to fully exploit the broadhand fiber-optic channel, and cause a bottleneck in the throughput of optical communication systems. This dissertation focuses on the theory and practice of the design of integrated circuits for multi-gigabit -per-second fiber-optic receivers. Realizing a 10 Gb/s system consistent with the SONET hierarchy is the ultimate goal of the research, and test circuits were developed to this end. Difficulty in implementing clock recovery circuits at rates greater than 3 Gb/s have limited the capacity of integrated receivers. Therefore, considerable attention is paid to clock extraction techniques. Architectures applicable to high-speed systems and insensitive to parasitic effects are presented. Among the test circuits developed was a 12 GHz InP-based HBT preamplifier. The circuit contains a PIN photodetector and can achieve an rms input noise of approximately 1.25muA at a data rate of 10 Gb/s. Two VCOs were designed in an AIGaAs/GaAs HBT process. A ring oscillator and emitter-coupled multivibrator, both operating at 2.75 GHz were fabricated. A patented 7 GHz ring VCO with frequency doubling was also designed. The new VCO was used to implement a 6 GHz phase-lock loop. The test circuits demonstrate functionality of key building blocks of a high-speed clock recovery circuit. Simulations based on models extracted from the test circuit predict that the architectures presented are applicable for clock recovery at a data rate of 10 Gb/s. Further research is needed to implement a complete integrated receiver.

  1. THZ INDIUM PHOSPHIDE BIPOLAR TRANSISTOR TECHNOLOGY M. J. W. Rodwell1

    E-print Network

    Rodwell, Mark J. W.

    -density-operation, and in the removal of heat. With present InP HBTs showing 1.1 THz maxf at the 128 nm node, there are no obviously. There is intense competition among technologies for these applications, with InP HBTs [1, 2] and HEMTs [3], Si voltages of InP HBTs remain 2:1 to 3:1 larger, allowing larger operating frequencies and greater output

  2. Minority carrier transport properties of GaInNAs heterojunction bipolar transistors with 2% nitrogen

    E-print Network

    Asbeck, Peter M.

    % nitrogen Rebecca J. Welty,a) Huoping Xin, Charles W. Tu, and Peter M. Asbeck University of California) of 0.98 eV; this is achieved with a nitrogen composition of 2%. These devices have a turn-on voltage HFE is 8. The current gain of nitrogen containing HBTs is degraded due to the complex change

  3. Extending the bandwidth performance of heterojunction bipolar transistor-based distributed amplifiers

    Microsoft Academic Search

    Kevin W. Kobayashi; Liem T. Tran; John C. Cowles; T. R. Block; A. K. Oki; D. C. Streit

    1996-01-01

    An InAlAs-InGaAs-InP HBT CPW distributed amplifier (DA) with a 2-30 GHz 1-dB bandwidth has been demonstrated which benchmarks the widest bandwidth reported for an HBT DA. The DA combines a 100 GHz fmax and 60 GHz fT HBT technology with a cascode coplanar waveguide DA topology to achieve this record bandwidth. The cascode gain cell offers 5-7 dB more available

  4. Field Dependent Dopant Deactivation in Bipolar Devices at Elevated irradiation Temperatures

    SciTech Connect

    WITCZAK,STEVEN C.; LACOE,RONALD C.; SHANEYFELT,MARTY R.; MAYER,DONALD C.; SCHWANK,JAMES R.; WINOKUR,PETER S.

    2000-08-15

    Metal-oxide-silicon capacitors fabricated in a bi-polar process were examined for densities of oxide trapped charge, interface traps and deactivated substrate acceptors following high-dose-rate irradiation at 100 C. Acceptor neutralization near the Si surface occurs most efficiently for small irradiation biases in depletion. The bias dependence is consistent with compensation and passivation mechanisms involving the drift of H{sup +} ions in the oxide and Si layers and the availability of holes in the Si depletion region. Capacitor data from unbiased irradiations were used to simulate the impact of acceptor neutralization on the current gain of an npn bipolar transistor. Neutralized acceptors near the base surface enhance current gain degradation associated with radiation-induced oxide trapped charge and interface traps by increasing base recombination. The additional recombination results from the convergence of carrier concentrations in the base and increased sensitivity of the base to oxide trapped charge. The enhanced gain degradation is moderated by increased electron injection from the emitter. These results suggest that acceptor neutralization may enhance radiation-induced degradation of linear circuits at elevated temperatures.

  5. Simulating Hybrid Circuits of Single-Electron Transistors and Field-Effect Transistors

    Microsoft Academic Search

    Günther Lientschnig; Irek Weymann; Peter Hadley

    2003-01-01

    An exact model for a single-electron transistor was developed within the circuit simulation package SPICE. This model uses the orthodox theory of single-electron tunneling and determines the average current through the transistor as a function of the bias voltage, the gate voltage, and the temperature. Circuits including single-electron transistors, field-effect transistors (FETs), and operational amplifiers were then simulated. In these

  6. On the wide-range bias dependence of transistor d.c. and small-signal current gain factors.

    NASA Technical Reports Server (NTRS)

    Schmidt, P.; Das, M. B.

    1972-01-01

    Critical reappraisal of the bias dependence of the dc and small-signal ac current gain factors of planar bipolar transistors over a wide range of currents. This is based on a straightforward consideration of the three basic components of the dc base current arising due to emitter-to-base injected minority carrier transport, base-to-emitter carrier injection, and emitter-base surface depletion layer recombination effects. Experimental results on representative n-p-n and p-n-p silicon devices are given which support most of the analytical findings.

  7. 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 8.4 GHz, as shown. Record performance was also demonstrated at 12.6 and 18 GHz. Developers have combined these state-of-the-art transistors with transmission lines and micromachined passive circuit components, such as inductors and capacitors, to build multistage amplifiers. Currently, a 1-W, 8.4-GHz power amplifier is being built for NASA deep space communication architectures.

  8. PNPN latchup in bipolar LSI devices. Final report, 1 January 1980-1 October 1981

    SciTech Connect

    Pease, R.L.; Alexander, D.R.

    1982-01-01

    PNPN latchup was studied both analytically and experimentally in several bipolar LSI technologies including integrated injection logic (I to the second power L), integrated Schottky logic (ISL), Schottky Transistor logic (STL) and emitter coupled logic (ECL). The latchup analysis procedure was expanded and applied to LSI microcircuits representing each of the technologies. This procedure consists of a) the identification of parasitic PNPN paths, b) the electrical characterization of the paths, c) detailed circuit analysis, and d) determination of worst case bias conditions for radiation testing. The identification was performed from chip photomicrographs and composite mask drawings. The characterization was performed experimentally by measuring parasitic transistor gains and SCR parameters on decoupled paths and analytically by using a semiconductor device physics code (PN code) in conjunction with doping profiles. The detailed circuit analysis was performed either by hand or with the circuit analysis code SPICE. Radiation testing was performed at the White Sands Missile Range LINAC facility. The results of the study were, a) latchup cannot occur in non-isolated I to the second power L, b) latchup cannot occur in the internal logic of ISL or STL without causing a problem with electrical performance, c) no latchable paths were found by analysis in the 93471 ECL 4kK RAM, the I/0 buffers on a ISL/STL gate array or the I to the second power L peripherals of the 9408 I to the 3rd power L microprogram sequencer.

  9. Thermal properties of high-power transistors

    Microsoft Academic Search

    R. H. Winkler

    1967-01-01

    The temperature of a transistor can be determined from the emitter-base voltage versus collector-current characteristic. This characteristic was used for studying the stability of parallel pairs of high-frequency high-power transistors. The thermal effect may cause the incremental emitter-base resistance to assume a negative value. This, in turn, will cause the current flow in a pair of transistors to be asymmetrical.

  10. A Study of Transistor Circuits for Television

    Microsoft Academic Search

    G. C. Sziklai; R. D. Lohman; G. B. Herzog

    1953-01-01

    This paper describes a general study of transistors in television receivers. For this purpose the development of a completely transistorized television receiver was undertaken. An experimental model using 37 developmental transistors and a five-inch kinescope housed in a cabinet 13??12??7 inches was constructed. This portable receiver operates on a single channel using a self-contained loop, and has a total battery-power

  11. 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.

  12. Coaxial inverted geometry transistor having buried emitter

    NASA Technical Reports Server (NTRS)

    Hruby, R. J.; Cress, S. B.; Dunn, W. R. (inventors)

    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.

  13. Large-Signal Behavior of Junction Transistors

    Microsoft Academic Search

    J. J. Ebers; J. L. Moll

    1954-01-01

    In the consideration of the junction transistor as a switch there are three characteristics of primary interest, the open impedance, the closed impedance, and the switching-time. A generalized two-terminal-pair theory of junction transistors is presented which is applicable, on a dc basis, in all regions of operation. Using this theory, the open and closed impedances of the transistor switch are

  14. Cognitive style in bipolar disorder sub-types.

    PubMed

    Fletcher, Kathryn; Parker, Gordon; Manicavasagar, Vijaya

    2013-04-30

    Clearer understanding of psychological processes and mechanisms such as cognitive style inform more targeted psychological treatments for mood disorders. Studies to date have focused on bipolar I disorder or combined bipolar sub-types, precluding identification of any distinctive cognitive style profiles. We examined cognitive style separately in the bipolar sub-types, contrasted with unipolar and non-clinical controls. A total of 417 participants (94 bipolar I, 114 bipolar II, 109 unipolar, 100 healthy controls) completed cognitive style measures including the Rosenberg Self-Esteem Scale, Dysfunctional Attitudes Scale, Inferential Styles Questionnaire, Stress Appraisal Measure and the Behavioural Inhibition System/Behavioural Activation System Scale. Overall, cognitive styles were similar in unipolar and bipolar participants, but with styles relevant to the Behavioral Activation System differentiating bipolar I disorder in particular. State anxiety influenced negative inferential style in unipolar participants and appraisal of stress in bipolar II participants. Analyses restricted to bipolar I vs. II comparisons revealed subtle differences in terms of dispositional stress appraisal, with higher scores on two stress appraisal sub-scales in the bipolar I group. Further exploration of cognitive style in bipolar sub-types is indicated in order to determine whether there are specific psychological vulnerabilities that would benefit from more targeted psychological interventions. PMID:23273610

  15. Electrode assembly for bipolar battery. [Patent application

    Microsoft Academic Search

    Fritts

    1975-01-01

    A bipolar electrode having, between active materials, a heat sink fabricated from a porous electrical and heat conductive material, such as sintered silver, is described. The porous material is impregnated with a phase-change heat-absorbent material having a high heat of fusion, such as beeswax. The electrode has a very large thermal capacity for a high-discharge-current-density battery.

  16. Neuropsychology of bipolar disorder: a review

    Microsoft Academic Search

    Seema Quraishi; Sophia Frangou

    2002-01-01

    Background: Bipolar disorder (BD) may be associated with significant and persistent cognitive impairment. The aim of this study was to describe the profile of cognitive deficits in BD at different phases of the illness and determine whether it is different from that of schizophrenia and unipolar (UP) depression. Methods: A systematic review of the computerised literature of neuropsychological studies of

  17. Modeling of dynamic bipolar plasma sheaths

    NASA Astrophysics Data System (ADS)

    Grossmann, J. M.; Swanekamp, S. B.; Ottinger, P. F.

    1992-01-01

    The behavior of a one-dimensional plasma sheath is described in regimes where the sheath is not in equilibrium because it carries current densities that are either time dependent, or larger than the bipolar Child-Langmuir level determined from the injected ion flux. Earlier models of dynamic bipolar sheaths assumed that ions and electrons evolve in a series of quasiequilibria. In addition, sheath growth was described by the equation Zen0?s=? ji?-Zen0u0, where ?s is the velocity of the sheath edge, ji is the ion current density, n0u0 is the injected ion flux density, and Ze is the ion charge. In this paper, a generalization of the bipolar electron-to-ion current density ratio formula is derived to study regimes where ions are not in equilibrium. A generalization of the above sheath growth equation is also developed, which is consistent with the ion continuity equation and which reveals new physics of sheath behavior associated with the emitted electrons and their evolution. Based on these findings, two new models of dynamic bipolar sheaths are developed. Larger sheath sizes and potentials than those of earlier models are found. In certain regimes, explosive sheath growth is predicted.

  18. CONSIDERAÇÕES ACERCA DO TRANSTORNO AFETIVO BIPOLAR

    Microsoft Academic Search

    Sérgio de Campos

    A característica mais notável da melancolia, e aquela mais precisa de explicação, é sua tendência a se transformar em mania. Freud (1917)2. Ao iniciarmos uma reflexão sobre o transtorno afetivo bipolar, é preciso considerar que a psicanálise sempre esteve acanhada para lidar com esse mote. Os trabalhos sobre o tema são raros, para não dizer inexistentes. Se há alguma dúvida,

  19. Titanium Carbide Bipolar Plate for Electrochemical Devices

    SciTech Connect

    LaConti, Anthony B.; Griffith, Arthur E.; Cropley, Cecelia C.; Kosek, John A.

    1998-05-08

    Titanium carbide comprises a corrosion resistant, electrically conductive, non-porous bipolar plate for use in an electrochemical device. The process involves blending titanium carbide powder with a suitable binder material, and molding the mixture, at an elevated temperature and pressure.

  20. Organic field-effect transistors

    Microsoft Academic Search

    M. J. Ma?achowski; J. ?mija

    2010-01-01

    The paper reviews the recent year publications concerning organic field-effect transistors (OFETs). A lot of works have been\\u000a performed to help understanding the structural and electrical properties of materials used to construct OFETs. It has been\\u000a established that in partially ordered systems, the charge transport mechanism is thermally activated and field-assisted hopping\\u000a transport and the hopping transport between disorder-induced localized