Investigation of InAlP Native Oxides for GaAs Metal-Oxide-Semiconductor Device Applications

The wet thermal oxides of InAlP have been carefully studied to explore the potential of such films for use as a gate dielectric in GaAs metal-oxide-semiconductor (MOS) device applications. The kinetics of wet thermal oxidation of InAlP epitaxial layers lattice-matched to GaAs and the electrical properties of the resulting InAlP wet thermal oxides when scaled to reduced thicknesses have been investigated. Also presented are results of investigations of the dry thermal oxidation of InAlP epilayers and the electrical properties of the resulting dry oxide films. GaAs-based metaloxide- semiconductor field-effect transistor (MOSFET) devices with InAlP wet oxides as the gate insulator have been fabricated and characterized on two heterostructures. MOSFETs having a 1 å_ÌÎm gate length exhibit excellent microwave performance with a current gain cutoff frequency of 17.0 GHz and a maximum frequency of oscillation of 74.8 GHz on a device heterostructure with a 7.5 nm thick gate oxide layer.