@inproceedings{50a1abe0cd104edb91752f0ba3285b5d,
title = "Analytical modeling of current gain-Earth voltage products in Si/Si1-xGex/Si heterojunction bipolar transistors",
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.",
keywords = "Analytical models, Bipolar transistors, Capacitance, Degradation, Digital circuits, Doping profiles, Heterojunction bipolar transistors, Photonic band gap, Temperature, Voltage",
author = "Prinz, {Erwin J.} and Sturm, {James C.}",
note = "Publisher Copyright: {\textcopyright} 1991 IEEE.; International Electron Devices Meeting, IEDM 1991 ; Conference date: 08-12-1991 Through 11-12-1991",
year = "1991",
doi = "10.1109/IEDM.1991.235291",
language = "English (US)",
series = "Technical Digest - International Electron Devices Meeting, IEDM",
publisher = "Institute of Electrical and Electronics Engineers Inc.",
pages = "853--856",
booktitle = "International Electron Devices Meeting 1991, IEDM 1991",
address = "United States",
}