Optical and X-Ray Studies of Indium Oxide Films on Sapphire Substrates

Abstract

The results of ellipsometric, X-ray, and spectral studies of In₂O₃ films deposited by dc-magnetron sputtering on Al₂O₃ (012) substrates are presented. The experimental data are interpreted in terms of the three-layer model of the film. As a result, it is assumed that large particles of the material are formed on the substrate surface at the beginning of the deposition process, and then the size of the crystallites decreases and they fill the gaps between the larger particles. After that, the film formation goes into the stationary mode. The presence of a transition layer with a band-gap of 1.39 eV, refractive index of about 3, and thickness of 25 nm is shown at the interface between film and substrate. The properties of this layer do not depend on the deposition time.