Ultrahigh fT and fmax new self-alignmentInP/InGaAs HBT's with a highly Be-doped base layer grown by ALE/MOCVD

We report on a new self-alignment (SA) process and microwave performance of ALE/MOCVD grown InP/InGaAs heterojunction bipolar transistors (HBT's) with a base doping concentration of 1×10² 0 cm^-3. We obtained f_T of 161 GHz and f_max of 167 GHz with a 2×10 μm emitter. These high values indicate the best performance of InP/InGaAs HBT's ever reported, in so far as we know. These values were attained by reducing the base resistance using ALE/MOCVD and base-collector capacitance using a new SA process. These results indicate the great potential of these devices for ultrahigh-speed application