Analytical modeling of current gain-Earth voltage products in Si/Si1-xGex/Si heterojunction bipolar transistors

Erwin J. Prinz, James Christopher Sturm

Research output: Chapter in Book/Report/Conference proceedingConference contribution

21 Scopus citations

Abstract

The tradeoff between common emitter current gain beta and Early voltage VA in heterojunction bipolar transistors (HBTs), where both bandgap and doping can vary in the base, has been studied. The Early voltage depends exponentially on the difference between the bandgap at the collector side of the base and the largest bandgap in the base, allowing very high Early voltages with only very thin narrow bandgap regions. Using Si/Si1-xGex/Si narrow gap base HBTs with a two layer stepped base, beta VA products of over 100000 V have been achieved for devices with a base width of only 400 AA. However, the presence of parasitic potential barriers for minority carriers at the base-collector junction of a HBT degrades VA because changing the base-collector voltage affects not only the width but also the height of these barriers. They can be caused, e.g., by base dopant outdiffusion into the collector due to high-temperature processing. An analytical model of the effect of such barriers on the Early voltage is presented.

Original languageEnglish (US)
Title of host publicationInternational Electron Devices Meeting 1991, IEDM 1991
PublisherInstitute of Electrical and Electronics Engineers Inc.
Pages853-856
Number of pages4
Volume1991-January
ISBN (Electronic)0780302435
DOIs
StatePublished - Jan 1 1991
EventInternational Electron Devices Meeting, IEDM 1991 - Washington, United States
Duration: Dec 8 1991Dec 11 1991

Other

OtherInternational Electron Devices Meeting, IEDM 1991
CountryUnited States
CityWashington
Period12/8/9112/11/91

All Science Journal Classification (ASJC) codes

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

Fingerprint Dive into the research topics of 'Analytical modeling of current gain-Earth voltage products in Si/Si<sub>1-x</sub>Ge<sub>x</sub>/Si heterojunction bipolar transistors'. Together they form a unique fingerprint.

  • Cite this

    Prinz, E. J., & Sturm, J. C. (1991). Analytical modeling of current gain-Earth voltage products in Si/Si1-xGex/Si heterojunction bipolar transistors. In International Electron Devices Meeting 1991, IEDM 1991 (Vol. 1991-January, pp. 853-856). [235291] Institute of Electrical and Electronics Engineers Inc.. https://doi.org/10.1109/IEDM.1991.235291