Purpose – The main purpose of this paper is to ﬁnd a simple method to improve the breakdown voltage of BJTs fabricated on SOI.
Design/methodology/approach – We have used two-dimensional device simulation to examine the effect of a collector tub on the collector
breakdown of the SOI based BJTs. This method involves creating a collector tub by etching the buried oxide followed by an n-type implantation on the collector n/n þ junction side.
Findings – First, our method reduces the peak electric ﬁeld at the silicon ﬁlm-BOX interface and secondly, the collector-tub facilitates the collector
potential to be absorbed by both collector drift and substrate regions improving the collector breakdown signiﬁcantly.
Practical implications – An improved breakdown voltage improves the reliability of BJTs on SOI.
Originality/value – Our results show that the BVCEO of the bipolar transistors with a collector-tub is enhanced by 2.7 times when compared with a conventional lateral bipolar transistor (LBT) with identical drift region doping. This improvement has an important practical value in the fabrication of SOI-based LBTs.
Keywords Bipolar transistors, Breakdown voltage, Simulation
This paper can be downloaded from http://web.iitd.ac.in/~mamidala/id11.htm