Collector-up InGaP/GaAs-double heterojunction bipolar transistors with high fmax

The first fabrication and RF characterisation of an InGaP/GaAs double heterojunction bipolar transistor in collector-up configuration is reported. Boron implantation is used to avoid electron injection into the extrinsic base regions. The InGaP collector offers f/sub max/=115 GHz and a high breakdown voltage (BV/sub ceo/=27V).