Ne[sup +] ion sputtering effect on amorphous Ga-In-Zn-O thin-film surface investigated by high-resolution XPS

The effect of Ne+ ion sputtering on amorphous Ga‐In‐Zn‐O (a‐GIZO) thin films was investigated by using surface‐sensitive, synchrotron‐radiation‐based, high‐resolution X‐ray photoelectron spectroscopy (XPS). a‐GIZO thin films having different compositions (Ga2O3:In2O3:ZnO = 1:1:1, 2:2:1, 3:2:1, 4:2:1) were investigated. It was found out that the amounts of the In and Zn contents relative to that of Ga decreased noticeably after sufficient sputtering, and that there occurred a subgap state above the valence band maximum and metallic states at the In 3d and 4d core levels as well as at the Fermi edge.