GaAs-based metal-oxide semiconductor field-effect transistors with Al2O3 gate dielectrics grown by atomic layer deposition

Abstract

We demonstrate GaAs-based, metal-oxide-semiconductor field-effect transistors (MOSFETs) with excellent performance using an Al2O3 gate dielectric, deposited by atomic layer deposition (ALD). This achievement is very significant because Al2O3 possesses highly desirable physical and electrical properties as a gate dielectric. These MOSFET devices exhibit extremely low gate-leakage current, high transconductance, and high dielectric breakdown strength. A short-circuit, current-gain, cutoff frequency (fT) of 14 GHz and a maximum oscillation frequency (fmax) of 25.2 GHz have been achieved from a 0.65-µm gate-length device. The interface trap density (Dit) of Al2O3/GaAs is evaluated by the hysteresis of drain-source current, Ids, versus gate-source bias, Vgs, and the frequency dispersion of transconductance, gm.