Monolithic HEMT-HBT integration by selective MBE

We have achieved successful monolithic integration of high electron mobility transistors and heterojunction bipolar transistors in the same microwave circuit. We have used selective molecular beam epitaxy and a novel merged processing technology to fabricate monolithic microwave integrated circuits that incorporate both 0.2 /spl mu/m gate-length pseudomorphic InGaAs-GaAs HEMTs and 2 /spl mu/m emitter-width GaAs-AlGaAs HBTs. The HEMT and HBT devices produced by selective MBE and fabricated using our merged HEMT-HBT process exhibited performance equivalent to devices fabricated using normal MBE and our baseline single-technology processes. The selective MBE process yielded 0.2 /spl mu/m HEMT devices with g/sub m/=600 mS/mm and f/sub T/=70 GHz, while 2/spl times/10 /spl mu/m/sup 2/ HBT devices achieved /spl beta/>50 and f/sub T/=21.4 GHz at J/sub c/=2/spl times/10/sup 4/ A/cm/sup 2/. The performance of both a 5-10 GHz HEMT LNA with active on-chip HBT regulation and a 20 GHz Darlington HBT amplifier are shown to be equivalent whether fabricated using normal or selective MBE.<
>