300 GHz InP/GaAs(1-x)Sb(x)/InP DHBTs

Abstract

We report the implementation of 300 GHz f T and f MAX InP/GaAsSb/InP double heterojunction bipolar transistors (DHBTs) with BV CEO = 6 V in structures using a 200 Å carbon-doped base layer and a 2000 Å InP collector. The epitaxial layers are grown by MOCVD, and do not necessitate any form of compositional grading either at the E/B or the B/C heterojunction because of the non-blocking nature of the staggered band lineup at InP/GaAsSb interfaces. The absence of compositional grading between the base and the wider gap InP emitter and collector layers greatly simplifies epitaxial growth as well as device fabrication because selective wet etching can be used to expose each layer separately and reliability. The resulting structure is therefore eminently manufacturable. The measured transistor performance suggests these devices should be suitable for 80-100 Gbit/s operation.