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

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 a three-layer model of the fi lm. It is assumed that large particles of the material are formed on the surface of the substrate at the beginning of the deposition process. The size of the crystallites then decreases, and they fill the gaps between the larger particles, after which the film formation goes into the stationary mode. It was shown that there is a transition layer with a band gap of 1.39 eV, a refractive index of ~3, and thickness of 25 nm at the interface between the film and the substrate. The properties of this layer do not depend on the deposition time.