Demonstration of submicron depletion-mode GaAs MOSFETs with negligible drain current drift and hysteresis

We successfully fabricated submicron depletion-mode GaAs MOSFETs with negligible hysteresis and drift in drain current using Ga₂O₃(Gd₂O₃) as the gate oxide. The 0.8-μm gate-length device shows a maximum drain current density of 450 mA/mm and a peak extrinsic transconductance of 130 mS/mm. A short-circuit current gain cutoff frequency (f_T) of 17 GHz and a maximum oscillation frequency (f_max) of 60 GHz were obtained from the 0.8 μm×60 μm device. The absence of drain current drift and hysteresis along with excellent characteristics in the submicron devices is a significant advance toward the manufacture of commercially useful GaAs MOSFETs.