Hot electron injection effect on the microwave performance of type-I/II AlInP/GaAsSb/InP double-heterojunction bipolar transistors

Abstract

A type-I/II double heterojunction bipolar transistor (DHBT) with a layer structure of AlInP(emitter)/GaAsSb(composition graded base)/InP(collector) was designed and grown by molecular beam epitaxy technique. The band alignment of the type-I AlInP/GaAsSb emitter-base interface provides hot electron injection into the base to enhance the effective base velocity to 2.54×107 cm/s, resulting in an improved device gain and high frequency performance. We have fabricated a submicron emitter (AE=0.35×4 μm2) type-I/II DHBT with a demonstrated current gain of β=50 and a breakdown voltage of BVCEO=4.2 V, with a cutoff frequency of fT=455 GHz and fMAX=400 GHz at a collector current density, JC=10 mA/μm2.