Analysis of Carrier-Blocking Effect in AlGaAs/GaAs HBT's with Insulating External Collector and Design Criteria for Collector-Up HBT's

Kazushige Horio, Akio Nakatani

Research output: Contribution to journalArticle

4 Citations (Scopus)


Two-dimensional simulations of cutoff frequencies for AlGaAs/GaAs HBT's with perfectly insulating external collector are made, and the results are compared with those for a case with semi-insulating external collector and for a case with normal n~ external collector. It is found that in the case with perfectly insulating external collector, minority carriers injected into the base from the emitter are partially blocked by the insulating layer and accumulate in the external base region. These carriers increase the effective base delay time, resulting in remarkable degradation of the cutoff frequency. In relation to this effect, a collector-up HBT is also simulated, and the design criteria for it are discussed. It is concluded that the effective emitter width should be made narrower than the collector width.

Original languageEnglish
Pages (from-to)1897-1902
Number of pages6
JournalIEEE Transactions on Electron Devices
Issue number11
Publication statusPublished - 1995 Nov


ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering

Cite this