The diffusivity of oxygen in thin, sputter-deposited TiO2 films, as can be used in RRAMs, is measured using electron and ion backscattering techniques. The as-grown sample consisted of two layers (Ti O-16(2) and Ti O-18(2)) and was annealed between 500 degrees C and 900 degrees C. The depth profiles of O-18, as measured with both techniques, were similar. The extent of diffusion was much larger than expected from the literature data for O diffusion in single-crystal rutile, suggesting that defects in the sputter-deposited film play an essential role in the diffusion process. (C) 2017 Elsevier B.V. All rights reserved.