GaInP/GaAs double heterojunction bipolar transistor with high f/sub T/, f/sub max/, and breakdown voltage

We report on the dc and microwave performance of an MOCVD-grown carbon-doped GaInP/GaAs double heterojunction bipolar transistor (DHBT) with a thin highly doped n-type GaInP layer in the collector. The DHBT showed improved current-voltage characteristics at low collector-emitter bias compared with those of a DHBT without the heavily doped GaInP layer, while maintaining a high breakdown voltage (BV/sub CEO//spl sim/20 V). Small area, self-aligned emitter transistors with two 2/spl times/5 /spl mu/m/sup 2/ emitter fingers were fabricated and exhibited f/sub T/ and f/sub max/ of 53 GHz and 75 GHz, respectively. These results indicate the promise of carbon-doped base GaInP/GaAs DHBT's for high-power microwave applications. >