GaAs MOSFET with oxide gate dielectric grown by atomic layer deposition

Abstract

For the first time, a III-V compound semiconductor MOSFET with the gate dielectric grown by atomic layer deposition (ALD) is demonstrated. The novel application of the ALD process on III-V compound semiconductors affords tremendous functionality and opportunity by enabling the formation of high-quality gate oxides and passivation layers on III-V compound semiconductor devices. A 0.65-μm gate-length depletion-mode n-channel GaAs MOSFET with an Al2O3 gate oxide thickness of 160 Å shows a gate leakage current density less than 10-4 A/cm2 and a maximum transconductance of 130 mS/mm, with negligible drain current drift and hysteresis. A short-circuit current-gain cut-off frequency fT of 14.0 GHz and a maximum oscillation frequency fmax of 25.2 GHz have been achieved from a 0.65-μm gate-length device.