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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 27 for “"current gain"”.
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Experimental Investigation of Current Gain in Bipolar Transistors Operating Above Cutoff
Made available in DSpace on 2014-12-10T19:06:47Z (GMT). No. of bitstreams: 1 7207031.pdf: 2818799 bytes, checksum: 8e1c68d0c94676e9d1f4d614549e3221 (MD5) Previous issue date: 1971
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Development of Asymmetric Fabry -Perot Modulators and Power HBT Circuits for High-Speed Applications
… the limiting issues related to the low CE current gain of a GaN HBT. We have measured a CE current gain of 31.0 at 175 K and 11.3 at 295 K. The increase in collector current and CE current gain at lower temperature can be attributed to the reduced base recombination current, which is due to …
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DC and AC modeling of heterostructure bipolar transistors (HBTS)
… extended to the abrupt double HBT. The collector current as a function of collector-emitter voltage, the collector and base currents as a function of base-emitter voltage, the dc current gain as a function of collector current, the h parameters as a function of collector current, the ac current …
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GaAsP/InGaP heterojunction bipolar transistors for III-V on Si microelectronics
… density (in the active device layers) on current gain were developed. A GaAsP/InGaP HBT grown on Si was demonstrated with a current gain as high as 158. Changes in GaAsxP₁-x composition from 0.825 < x < 1 did not have a significant effect on current gain. Collector current was determined …
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InP/InGaAs Heterojunction Bipolar Transistors and Field-Effect Transistors Grown by Gas -Source Molecular Beam Epitaxy
… The degradation of the junction properties and current gain-base sheet resistance ratio can be attributed to the formation of C precipitates. These findings are important for improving the reliability of C-doped InP/InGaAs HBTs. (Abstract shortened by UMI.).
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A study of the turn-on mechanisms in thyristors
… plasma spreading velocity to the small signal current gain value of the n-p-n transistor section of the thyristor. The extent to which the thyristor turns on initially largely affects the speed of turning-on the device. A model is proposed to calculate the initial turned-on area of thyristors.
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Modeling and Characterization of Heterojunction Bipolar Transistors
… bandgaps. These advantages include high current gain, large cut-off frequency and short gate delay in digital logic circuits. This thesis selects a few important and critical issues connected with the operation of HBTs with a view to provide a clear and comprehensive understanding thereof.
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Antimonide-based field-effect transistors and heterojunction bipolar transistors grown by molecular beam epitaxy
… eliminate the carrier blocking and enhance the current gain. InAlP was used to replace the InP emitter and form a type-I emitter-base junction. Results for large devices show that this modification could improve DC current gain from 80 to 120. The results indicate that type-I/II InAlP/GaAsSb …
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Minority Electron Base Transport in Heterojunction Bipolar Transistors Determined by Magneto-Transport Measurements
… mobility in the base of the HBT and the dc current gain of the device. The minority electron lifetime can be determined using these two measurements. Therefore, this technique is very valuable for its ability to characterize the quality of the base material in terms of the minority …
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Fabrication of graphene-on-GaN vertical transistors
… first device prototype exhibits very promising current density(~mA/cm 2 ) and current gain ([alpha] ~ 50 %). Simulations further support that with proper optimization of the materials and device structure, the proposed transistor can be a promising candidate for future high frequency …
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Compact modeling of neutron damage effects in a bipolar junction transistor
… the increase in recombination rate degrades the current gain. Two approaches were taken in the development of a compact BJT model that include the effects of static neutron damage. One approach is based on the Gummel-Poon term for recombination current. The other approach is based on the …
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Three -Port Modulation of Indium Gallium Phosphide/gallium Arsenide Transistor Lasers
… is manifest as a distinct change in the HBT current-voltage characteristics, specifically a decrease in the common-emitter current gain (betadc = IC/IB) and the occurrence of even a more striking peak in the small signal (ac) gain betaac = DeltaIC/DeltaIB. Using a larger QW width to enhance …
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An HBT magnetic sensor with integrated 3-dimensional magnetic structures
… surface quality and increased surface leakage currents for enhanced sensor performance. In order to improve the sensitivity of an HBT to magnetic field 3–dimensional magnetic structures were designed to be incorporated onto the surface of the extrinsic base. This design process was informed by …
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High-speed Type-II GaAsSb/InP DHBTs for mixed-signal IC applications
… the emitter peripheral surface recombination current becomes a significant portion of the total base current, leading to reduced current gain. Chapter 6 discusses the development of an emitter ledge process for the doping-graded Type-II GaAsSb/InP DHBT. Compared with devices without an emitter …
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Design, fabrication, and characterization of indium phosphide-based heterostructure field-effect transistors for high-power microwave applications
… (MODFETs) have exhibited world-record unity current gain frequencies ($f\sb{t}$s) as well as extremely high power cutoff frequencies ($f\sb{\rm max}$s) and have, therefore, become the optimum devices for small-signal applications at high frequencies, particularly in low-noise applications. …
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Deeply-scaled GaN high electron mobility transistors for RF applications
… challenges is the lower-than-expected maximum current gain cutoff frequency (fT) of deeply-scaled GaN HEMTs. The fT of the short channel devices is well below both projections from maximum frequency in the long channel devices and theoretical expectations based on material properties. Another …
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Device Characterization and Compact Modeling of the SiGe HBT in Extreme Temperature Environments
… exceptionally at low temperatures. The device DC current gain and AC small-signal gain significantly increase in the cryogenic temperature range. Applications at low temperatures with expansive temperature range specifications need an HBT compact model to accurately represent the device's …
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Hybrid plasma-semiconductor devices
… field yields a transistor with photosensitivity, gain, and a light-emitting collector whose radiative output can be modulated or switched using voltages that are less than 1 V. It has been found that the current gain of the transistor increases as a function of the increasing gas pressure and Vcc …
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Design, Fabrication and Characterization of a GaAs/InxGa1-xAs/GaAs Heterojunction Bipolar Transistor
… the linearly graded case has the lowest leakage current and the highest current gain. IV curves for all four possible classes of InAs/GaAs heterojunction (nN, nP, pN, pP) are calculated. A pN heterojunction is fabricated and characterized. In spite of the 7% lattice mismatch between InAs and …
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Development of electrical and optical devices for next generation high-speed optical interconnects
… showing a 160-nm ledge can more than double DC current gain β by suppressing surface recombination, but with trade-offs in ideality factor, yield, base resistance, and fT/fmax. Together, these results provide the process capability and device understanding needed to co-optimize Cryo-VCSEL …
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