InP/GaAsSb/InP double HBTs: a new alternative for InP-based DHBTs

We report on the physical operation and performance of MOCVD-grown abrupt heterojunction InP/GaAs_0.51Sb_0.49/InP double heterojunction bipolar transistors (DHBTs). In particular, the effect of the InP collector thickness on the breakdown voltage and on the current gain cutoff frequency is assessed and a f_T of 106 GHz is reported for a DHBT with a 400 Å base and a 2000 Å InP collector with a BV_CEO of 8 V. We show that InP/GaAsSb/InP DHBTs are characterized by a weak variation of f_T as a function of temperature. Finally, we also demonstrate that high maximum oscillation frequencies f_MAX>f_T can be achieved in scaled high-speed InP/GaAsSb/InP DHBTs, and provide estimates of the maximum cutoff frequencies achievable for this emergent but promising material system. Recent results on improved structures validate our performance predictions with cutoff frequencies well beyond 200 GHz