High performance GaAsSb∕InP double heterojunction bipolar transistors grown by gas-source molecular beam epitaxy

Abstract

High quality GaAsSb∕InP double heterojunction bipolar transistor (DHBT) structures were grown using gas-source molecular beam epitaxy. The substrate temperature and V/III flux ratio were optimized to grow single phase GaAsSb base layers lattice matched to InP. The dc gain as high as 40 was obtained in 60×60μm2 GaAsSb∕InP DHBTs with a 500Å carbon doped (7×1019cm−3) GaAsSb base layer. High performance DHBT with a 250Å base layer shows a current gain cutoff frequency fT of 346GHz and maximum oscillation frequency fmax of 145GHz.