X-ray photoelectron spectroscopic study of oxidation of InP. II: Thermal oxides grown at high temperatures

A previous X-ray photoelectron spectroscopic (XPS) study on oxidation of InP was extended to thermal oxides grown at higher temperatures (400°C and 700°C). The chemical compositions and depth distributions of these thermal oxides are essentially the same as those reported earlier for native and chemical oxides. Hence, the oxidation model we have proposed is also applicable to the oxides grown at higher temperatures (>400°C). XPS analysis was performed for native oxide grown on the substrate which was not subjected to heat treatment such as ohmic contact annealing, and whoes surface stoichiometry was considered to be maintained. The results showed the dominance of In2O3 near the oxide-InP interface, indicating that the depletion of P from the InP surface was not the reason for the formation of In2O3 in the first stage of oxidation. Indium is thus considered to be more readily oxidized than phosphorus.