Thermal Oxidation of III-V Materials and Heterostructures

Thermal oxide films formed on n-GaAs(100) and Al x Ga 1-x As (x = 0.25-0.80) from 450-500°C have been characterized by Auger electron spectroscopy and electron microscopy, and the relative oxidation rates of AlGaAs in GaAs-based heterostructures and InAlAs in InP-based heterostructures have been determined. The kinetics and mechanism of oxidation depend on the particular oxidant. Selective oxidation of Al-containing layers in device structures depends on the layer thickness but is independent of the dopant level, and is optimized by oxidation in moist nitrogen (95°C). Electrical measurements have been performed on oxidized InAlAs/InGaA, heterostructure diodes.