A multi-technique investigation of TiO2 films prepared by magnetron sputtering

We have investigated seven samples of radio frequency magnetron-sputtered TiO2 thin films by using near-edge X-ray absorption fine structure (NEXAFS) spectroscopy, X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). A detailed analysis of the Ti 2p and O 1s NEXAFS edges allows determining the degree of order and the polymorphs of the investigated samples. We have found that thin films grown by using a Ti target and lower deposition rates have a rutile character, while, by using a TiO2 target and higher deposition rates, amorphous/mixed thin films are obtained. We have also found that this correlation between phase and preparation conditions is perfectly reproducible leading to films with equal characteristics for the same preparation conditions. The NEXAFS results are supported by complementary XRD results.