High-speed AlGaAs/GaAs HBTs with reduced base-collector capacitance

Abstract

A new layout for high-speed AlGaAs/GaAs heterojunction bipolar transistors (HBTs) is presented. The layout is horseshoe shaped and designed to simultaneously reduce base resistance (R-B) and base-collector capacitance (C-BC). A horseshoe-shaped HBT and a conventional single-finger HBT with the same emitter, width of 2 mum were fabricated and tested. The reduction of R-B and C-BC using the horseshoe-shaped HBT resulted in a 25% improvement of the maximum oscillation frequency (f(max) = 130 GHz).