200 GHz InP/GaAs/sub x/Sb/sub 1-x//InP double heterojunction bipolar transistors

We report the fabrication and characterization of abrupt junction InP/GaAsSb/InP DHBTs with a current gain cutoff frequency f/sub T/ and a maximum oscillation frequency f/sub MAX/ above 200 GHz with a breakdown voltage BV/sub CEO/>6 V. This level of performance was reached by thinning the base layer to 200 /spl Aring/ and increasing the C-doping level to /spl sim/10/sup 20//cm/sup 3/ while using a 2000 /spl Aring/ thick InP collector layer.