InP/GaAsSb/InP double heterojunction bipolar transistors with high cut-off frequencies and breakdown voltages

In this work, we report on the DC and microwave performance of MOCVD-grown carbon-doped InP/GaAsSb/InP double heterojunction transistors (DHBTs) with various collector thicknesses. The cut-off frequencies (and breakdown voltages) are 106 GHz (8 V), 82 GHz (10 V) and 40 GHz (15 V) for the 2000 /spl Aring/, 3000 /spl Aring/ and 5000 /spl Aring/, lightly doped collectors. The 106 GHz, which is the best f/sub T/ ever reported in this material system, is obtained while maintaining a relatively high breakdown voltage (BV/sub CEO/=8 V). The lower cut-off frequencies obtained for the 3000 /spl Aring/ and 5000 /spl Aring/, collectors are attributed to the longer transit time in the collector and also to the Kirk like limitation brought about by high current densities in the thicker collectors.