Rutherford backscattering and channeling studies of a TiO2(100) substrate, epitaxially grown pure and Nb-doped TiO2 films

We have investigated the crystalline quality of a TiO2(100) substrate, homoepitaxially grown TiO2 film and Nb-doped TiO2 films using Rutherford backscattering (RBS) and channeling experiments. The minimum yields obtained from the aligned and random spectra are 2.4 +/- 0.2% for the TiO2(100) substrate, and 4.0 +/- 0.2% for a homoepitaxial TiO2 film. The minimum yields for Ti and Nb are 1.6 +/- 0.2% and 7.0 +/- 1.0%, respectively, for a Nb-doped TiO2 film. Also, about 95% of the Nb atoms occupy cation sites in the Nb-doped TiO2 film. The angular yield curves for Ti and Nb from the Nb-doped film confirm the good crystalline quality of the film in which most Nb atoms occupy the cation sites. The calculated surface peak areas for Ti and Nb using a model which incorporates Nb surface segregation from the bulk, agree very well with the corresponding surface peak areas for Ti and Nb extracted from the experiment. (C) 1997 Pacific Northwest Laboratories, Battelle. Published by Elsevier Science B.V.