INALAS/INGAAS HETEROSTRUCTURE FETS PROCESSED WITH SELECTIVE REACTIVE-ION-ETCHING GATE-RECESS TECHNOLOGY

A newly developed highly selective reactive-ion-etching process based on HBr plasma has been applied as a gate-recess technique in the fabrication of InAlAs/InGaAs heterostructure FET's. A typical 0.75-mum gate-length transistor exhibited a threshold voltage of -1.0 V, a maximum extrinsic transconductance of 600 mS/mm, an extrinsic current-gain cutoff frequency of 37 GHz, and a maximum frequency of oscillation of 90 GHz. These dc and RF device parameters compare favorably with that of a corresponding device gate-recessed with a selective wet-etching technique.