Microstructure and optical properties of TiO2 thin films prepared by low pressure hot target reactive magnetron sputtering

Thin films of TiO2 were deposited onto (1 0 0) oriented silicon and glass substrates using modified magnetron sputtering method. The method, among the others, consisted in employing low pressure of reactive gas (< 10− 1 Pa), hot target (additional heating of the target) and low deposition rate (about 0.1 nm/s). X-ray diffraction, X-ray photoelectron spectroscopy and optical transmission measurements have been applied to study the influence of film thickness, substrate type and post annealing process on the microstructure, composition, and optical properties of prepared thin films. It was found that the lattice spacings were a bit smaller than those of bulk material what indicated the contraction of the thin film. Optical examinations have shown that the fundamental absorption edge was shifted toward longer wavelength region (from 330 to 351 nm) as the thickness of the film increased. It was stated that thin films of TiO2 were almost stoichiometric after additional annealing.