Growth and XPS depth profiling of thermal oxides on polycrystalline GaAs thin films

Oxide layers on polycrystalline GaAs thin films were grown by thermal oxidation at 10 torr. In depath profiles of the oxide layers were obtained by in situ Ar+ ion etching in X-ray photoelectron studies at different stages of sputter etching. These studies reveal a pile up of elemental As at the interface between the GaAs film and the oxide layer. The observ-ed compositional variation in the oxide layer at different depths is related to the selective sputtering of As 0 to As. Some of these results are presented.