ABSTRACT: Nb-doped SrTiO3 (STNO) films were grown on (001)-oriented LaAlO3 substrates by a reactive ion beam sputter deposition at various mixing ratios (OMRs) with a substrate temperature of 800oC. The STNO films exhibited good crystallinity with an epitaxial orientation as characterized by high-resolution X-ray diffraction, grazing-incidence X-ray diffraction, and in-plane pole figure analysis. A decrease of out-of-plane and in-plane lattice constants was observed with an increase of OMR. The surface morphology of the STNO films showed a very dense fine-grain structure. The root-mean-square roughness was found to be increased as the OMR increased. Moreover, the elemental compositions of the STNO films were examined by X-ray photoelectron spectroscopy.