MONOLITHIC HEMT-HBT INTEGRATION BY SELECTIVE MBE

We have achieved successful monolithic integration of high electron mo bility 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 mu m gate-length pseudom orphic InGaAs-GaAs HEMTs and 2 mu m emitter-width GaAs-AlGaAs HBTs. Th e HEMT and HBT devices produced by selective MBE and fabricated using our merged HEMT-HBT process exhibited performance equivalent to device s fabricated using normal MBE and our baseline single-technology proce sses. The selective MBE process yielded 0.2 mu m HEMT devices with g(m ) = 600 mS/mm and f(T) = 70 GHz, while 2 x 10 mu m(2) HBT devices achi eved beta, 50 and f(T) = 21.4 GHz at J(C) = 2 x 10(4) A/cm(2). The per formance of both a 5-10 GHz HEMT LNA with active on-chip HBT regulatio n and a 20 GHz Darlington HBT amplifier are shown to be equivalent whe ther fabricated using normal or selective MBE.