Structural and optical properties of TiO2 films prepared using reactive RF magnetron sputtering

Preparation of TiO2 films having superior optical and structural characteristics was attempted using a conventional rf magnetron sputtering by modifying deposition variables, such as the substrate temperature and the gas composition in the sputtering ambient. TiO2 films grown without O-2 addition showed considerable optical loss due to the optical absorption by an oxygen deficiency in the film and the scattering by large surface roughness. However, TiO2 films grown with O-2 addition had a stoichiometric composition and a smooth surface morphology without optical loss. Substrate heating during deposition enhanced the packing density and crystallinity of the film, and as a result, TiO2 films with higher refractive index and better homogeneity could be obtained with substrate heating between 200 degreesC and 400 degreesC.