High-frequency output characteristics of AlGaAs/GaAs heterojunction bipolar transistors for large-signal applications

Chen, J.; Gao, Guangjun; Ünlü, M. Selim; Morkoç̌, H.

doi:10.1016/0038-1101(91)90067-9

Cited by 3 publications

(2 citation statements)

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“…fr (1/27r)(OIc/OQn)vcE (8) where Q, is electron charges in the device and VCE is the collector-emitter voltage. VCE is set to 1.5 V in this study.…”

Section: Simulated Fr-ic Characteristicsmentioning

confidence: 99%

“…Usually, the cutoff frequency of A1GaAs/GaAs HBTs increases with the collector current density Ic and begins to decrease at a certain Ic, showing a single peak in the experimental fT'-Ic characteristics. However, according to the simulation using a drift-diffusion model, the fT-Ic characteristics show a steep second peak in some cases [5,8]. This is attributed to the fact that in the drift-diffusion approximation, electron mobility is given as a function of local electric field and the electron velocity versus electric field curve of GaAs shows a peak behavior.…”

Section: Introductionmentioning

confidence: 97%

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Study on Possible Double Peaks in CutoffFrequency Characteristics of AlGaAs/GaAsHBTs by Energy Transport Simulation

Horio

1998

VLSI Design

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By using an energy transport model, we simulate cutoff frequency fT versus collector current density IC characteristics of npn−n AlGaAs/GaAs heterojunction bipolar transistors (HBTs) with various n−-collector thickness and n−-doping densities. It is found that the calculated fT characteristics show double peak behavior when the n−- layer is thick enough and the n−-doping is high enough to allow existence of neutral n−- region. The mechanism of the double peak behavior is discussed by studying energy band diagrams, electron-energy profiles and electron-velocity profiles. Particularly, we discuss the origin of the second peak (at higher IC) which is not usually reported experimentally.

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“…fr (1/27r)(OIc/OQn)vcE (8) where Q, is electron charges in the device and VCE is the collector-emitter voltage. VCE is set to 1.5 V in this study.…”

Section: Simulated Fr-ic Characteristicsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%