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  • 1
    Electronic Resource
    Electronic Resource
    In0.52Al0.48As/In0.53Ga0.47As heterojunction bipolar transistor on GaAs by molecular beam epitaxy (1988)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 53 (1988), S. 2311-2313 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report on the first In0.52Al0.48As/In0.53Ga0.47As heterojunction bipolar transistors grown on a GaAs substrate. In order to suppress the propagation of threading dislocations to the surface, a ten-period AlAs/In0.52Al0.48As (20 A(ring)/20 A(ring)) strained-layer superlattice was repeated twice with intervening undoped In0.52Al0.48As layers. The typical common emitter current gain in 50×50 μm2 emitter area devices was 50, with a maximum of 63, at a collector current density of 2×103 A/cm2.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.100263
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  • 2
    Electronic Resource
    Electronic Resource
    High-speed performance of InP/In0.53Ga0.47As/InP double-heterojunction bipolar transistors (1988)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 52 (1988), S. 552-554 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A theoretical comparison of In0.53Ga0.47As/InP and Al0.3Ga0.7As/GaAs heterojunction bipolar transistors has been undertaken in an effort to determine the relative merits of these material systems. The analysis uses a compact transistor model and considers devices with self-aligned geometries including both extrinsic and intrinsic parameters. The high electron mobility in the In0.53Ga0.47As base layer and high peak velocity of electrons in the collector depletion layer result in a current gain cutoff frequency in excess of 150 GHz for an InP/In0.53Ga0.47As transistor with base thickness of 0.1 μm. Calculations revealed, however, that maximum oscillation frequency is strongly dependent on the contact resistance of the p-type base layer, even for a self-aligned base transistor. A maximum oscillation frequency of 138 GHz is theoretically predicted for an InP/In0.53Ga0.47As transistor with base thickness of 0.06 μm, base doping of 1×1020 cm−3, a p-type contact resistance of 1.0×10−7 Ω cm2, a current density of 5×104 A/cm2, and a VCB of 5 V.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.99414
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  • 3
    Electronic Resource
    Electronic Resource
    GaAs-Si heterojunction bipolar transistor (1988)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 52 (1988), S. 822-824 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A GaAs/Si heterojunction bipolar transistor (HBT) structure is proposed having application for high-frequency operation. The structure combines the high-frequency capability of the GaAs/AlGaAs system with the advanced processing technology of Si. The proposed device consists of an n-AlGaAs/p-GaAs emitter and base layers on an n-Si collector with improved junction characteristics at the GaAs/Si heterointerface afforded by thermal annealing. This novel device structure combines the advantages associated with a wide band-gap AlGaAs emitter, the high electron mobility of GaAs, and the substantial reduction in device parasitics accorded the self-aligned structure. Additionally, the proposed device offers the possibility of planar GaAs processing. With the use of a compact transistor model, calculations of the high-speed capability of this transistor are presented. For an emitter-base junction area of 1 μm×5 μm, optimized fmax=108 GHz and fmax=ft=89 GHz were computed for the GaAs/Si HBT, compared to 76 and 62 GHz, respectively, for equivalent GaAs/AlGaAs HBT's.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.99295
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  • 4
    Electronic Resource
    Electronic Resource
    Comment on "Interface charge polarity of a polar on nonpolar semiconductor GaAs/Si with Ga and As prelayers'' [Appl. Phys. Lett. 49, 1257 (1986)] (1987)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 51 (1987), S. 1756-1756 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: In this comment we report new experimental results for the capacitance voltage measurement of p−GaAs/n−Si heterojunction diodes and point out the inappropiate assumption used in our previous letter that the boundaries of the depletion layer do not change much despite the presence of the prelayer. (AIP)
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.98514
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  • 5
    Electronic Resource
    Electronic Resource
    Characteristics of p-GaAs/n-Si heterojunctions grown by molecular-beam epitaxy (1987)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 62 (1987), S. 3860-3865 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have studied the electrical characteristics of p-GaAs/n-Si heterojunction diodes grown by molecular-beam epitaxy in an effort to investigate the quality of the heterointerface. Both Ga and As prelayers were used to initiate the growth of GaAs epilayers on Si substrates. Current-voltage and capacitance-voltage measurements were made between 300 and 83 K. Ideality factors for heterojunction diodes were as good as n=2.0, despite the 4.1% lattice mismatch between Si and GaAs. At high temperatures the I-V characteristics were dominated by generation-recombination mechanisms that lead to a temperature-independent logarithmic slope with applied bias. By removing a thin layer from the Si surface, the surface leakage current was reduced by more than an order of magnitude. The measured intercept voltages, as determined by capacitance-voltage measurements, have no strong dependence on the type of prelayer used to initiate the growth of the GaAs epilayer on Si substrates. The maximum spread in measured intercept voltages was about 1 V, the absolute value of which depends upon the condition of the interface.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.339230
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  • 6
    Electronic Resource
    Electronic Resource
    Characteristics of annealed p/n junctions between GaAs and Si (100) (1987)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 51 (1987), S. 1995-1997 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Electrical characteristics of GaAs( p)/Si(n) interface were determined from capacitance-voltage (C-V), current-voltage (I-V), and secondary ion mass spectroscopy (SIMS) measurements and compared to those on GaAs( p) epitaxial layes on GaAs(n) substrates. The comparison was made between the junctions as grown and after an anneal at 850 °C for 20 min in 10% forming gas under an As overpressure. For the GaAs/Si junction the ideality factor changed from 2 or larger to 1.5 and the apparent intercept voltage changed from 2.5 to 1.3 V after annealing. For the GaAs homojunction, the intercept voltage increased from 1.1 to 1.3 V. In addition, the excess current in the forward and reverse bias conditions dropped drastically in the heterojunction. No movement of the metallurgical junction was discernible to within the resolution capability of SIMS. The junction properties obtained by annealing suggest an atomic restructuring of the Si(100) interface during growth or annealing. These new results raise the possibility that the GaAs/Si interface can be made into an electrically viable junction and incorporated into active devices.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.98322
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  • 7
    Electronic Resource
    Electronic Resource
    AlGaAs/GaAs single heterojunction bipolar transistors grown on InP by molecular beam epitaxy (1989)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 54 (1989), S. 1151-1153 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: AlGaAs/GaAs single heterojunction bipolar transistors grown on InP substrates by molecular beam epitaxy have been fabricated and tested. An eight-period 25 A(ring)/25 A(ring) In0.53Ga0.47As/GaAs strained-layer superlattice is incorporated in the buffer structure to reduce dislocation propagation to the active region. Small-signal common emitter current gains of about 20 and 30 at a collector current density of 2×103 A/cm2 have been obtained for devices on InP as compared to about 60 and 150 for those on GaAs in structures with base thickness of 0.12 μm doped with Be to 1×1019 and 1×1018 cm−3, respectively. Current densities as high as 1×104 A/cm2 have been achieved in these devices with emitter area of 50×50 μm2 without degradation, demonstrating the excellent stability of this material. From the collector current dependence of the current gain, ideality factors of 1.3 and 1.2 for the emitter junctions have been obtained for devices on InP and GaAs, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.100745
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  • 8
    Electronic Resource
    Electronic Resource
    A new submicron MOSFET technology with Gate Overlap on Twin Oxide (GOTO) LDD structure
    Amsterdam : Elsevier
    Microelectronic Engineering 15 (1991), S. 253-256 
    Details
    ISSN: 0167-9317
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Electrical Engineering, Measurement and Control Technology
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0167-9317(91)90223-Z
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  • 9
    Electronic Resource
    Electronic Resource
    The C-S lyases of higher plants. Purification and characterization of homogeneous alliin lyase of leek (Allium porrum) (1989)
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 77 (1989), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The characteristic odors of freshly macerated tissue of Allium species such as garlic and onion are due to the action of the enzyme alliin lyase (EC 4.4.1.4) on endogenous S-alkyl-I-cysteine sulfoxides which are present as secondary amino acids yielding volatile sulfur-containing products. Purification and characterization of the alliin lyase of leek (Allium porrum L.) has been carried out for comparison with the analogous enzymes previously characterized from garlic and onion. The purification involved homogenization, followed by ammonium sulfate fractionation, elution from an hydroxylapatite column, concentration of the active fractions and passage through a concanavalin A-Sepharose 4B affinity column. The purified enzyme was found to be a glycoprotein with a pH optimum for activity of 8.0. Sodium dodecylsulfate-urea polyacrylamide gel electrophoresis gels of the homogeneous leek enzyme showed it consisted of 1 subunit with a molecular weight of 48000. By gel filtration, 2 stable forms of the native enzyme with molecular weights of 386000 and 580000 were found.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1399-3054.1989.tb05982.x
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  • 10
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    Ideology: "Its Meaning and Measurement" (1972)
    Beverley Hills, Calif. : Periodicals Archive Online (PAO)
    Comparative Political Studies. 5:2 (1972:July) 151 
    Details
    ISSN: 0010-4140
    Topics: Political Science
    URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pao:&rft_dat=xri:pao:article:c420-1972-005-02-000002
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