InP/GaAsSb/InP DHBTs with high f_T and f_MAXfor wireless communication applications

摘要

We study the DC and microwave performance of MOCVD-growncarbon-doped InP/GaAsSb/InP double heterojunction transistors (DHBTs)with high cut-off frequencies. A maximum cutoff frequency of 106 GHz isobtained while maintaining a relatively high breakdown voltage(BV_CEO=8 V) in devices with a 2000 Å InP collector. Inthese devices, the maximum frequency of oscillation is limited by theGaAsSb base sheet resistance (which is high in comparison to GaAs orGaInAs conventional bases), and high f_MAX values can only beachieved by scaling the devices to simultaneously reduce the total baseresistance R_B and the base-collector capacitance C_BC. A new self-aligned process was developed which results inf_T=80 GHz and C_BC=90 GHz for devices with a 3000Å collector and a 1 μm emitter stripe fabricated by contactlithography and all-wet etching