480-GHz f\max in InP/GaAsSb/InP DHBT With New Base Isolation \mu-Airbridge Design.

Self-aligned \0.55\times \3.5\ \mu \m^2 emitter InP/GaAsSb/InP double heterojunction bipolar transistors demonstrating an ft of 310 GHz and an f \max of 480 GHz are reported. Common–emitter current gain of 24, together with a breakdown voltage of 4.6 V, is measured. The devices were fabricated with a triple-mesa process and easily fabricated with a new base isolation \mu-airbridge design which, moreover, significantly reduced the base–collector capacitance CBC. [ABSTRACT FROM AUTHOR]