GaAs Enhancement-Mode NMOSFETs Enabled by Atomic Layer Epitaxial \(La_{1.8}Y_{0.2}O_3\) as Dielectric

Abstract

We demonstrate high performance enhancement-mode (E-mode) GaAs NMOSFETs with an epitaxial gate dielectric layer of \(La_{1.8}Y_{0.2}O_3\) 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 \(10^7\). Thermal stability of the single crystalline \(La_{1.8}Y_{0.2}O_3\)-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 the \(D_{it}\).