GaAs Enhancement-Mode NMOSFETs Enabled by Atomic Layer Epitaxial La1.8Y0.2O3 as Dielectric

Abstract

We demonstrate high-performance enhancement-mode (E-mode) GaAs NMOSFETs with an epitaxial gate dielectric layer of La1.8Y0.2O3 grown by atomic layer epitaxy (ALE) on GaAs(111) A substrates. A 0.5-mu m-gate-length device has a record-high maximum drain current of 336 mA/mm for surface-channel E-mode GaAs NMOSFETs, a peak intrinsic transconductance of 210 mS/mm, a subthreshold swing of 97 mV/dec, and an I-ON/I-OFF ratio larger than 10(7). The thermal stability of the single-crystalline La1.8Y0.2O3-single-crystalline GaAs interface is investigated by capacitance-voltage (C-V) and conductance-voltage (G-V) analysis. High-temperature annealing is found to be effective to reduce D-it