Two-dimensional analysis of high injection effects in AlGaAs/GaAs HBTs with semi-insulating external collectors

Kazushige Horio, Akira Oguchi, Hisayoshi Yanais

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Two-dimensional simulations of AlGaAs/GaAs HBTs with various collector structures were performed. The introduction of a semi-insulating external collector improves cutoff frequency fT in the low current region because the base-collector capacitance decreases. However, it leads to an earlier fall of fT in the high current region, because a high injection effect is enhanced. This high injection effect has two features: (1) expansion of the collector depletion layer is remarkable near the interface between the intrinsic collector and the semi-insulating external collector, resulting in a longer transit time in this region; and (2) the effective channel in the intrinsic collector becomes narrow by introducing the semi-insulating external collector and so the effective current density there becomes high, leading to an earlier appearance of the high injection situation. It is shown that to minimize these unfavourable high injection effects, the semi-insulating layer should be slightly away from the intrinsic collector region so that it may not affect electron transport in the intrinsic collector region.

Original languageEnglish
Pages (from-to)1393-1400
Number of pages8
JournalSolid State Electronics
Volume34
Issue number12
DOIs
Publication statusPublished - 1991

Fingerprint

dimensional analysis
Heterojunction bipolar transistors
Cutoff frequency
accumulators
aluminum gallium arsenides
Capacitance
Current density
injection
Electron Transport
gallium arsenide
transit time
low currents
high current
depletion
cut-off
capacitance
current density
expansion

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Cite this

Two-dimensional analysis of high injection effects in AlGaAs/GaAs HBTs with semi-insulating external collectors. / Horio, Kazushige; Oguchi, Akira; Yanais, Hisayoshi.

In: Solid State Electronics, Vol. 34, No. 12, 1991, p. 1393-1400.

Research output: Contribution to journalArticle

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