Tantalum oxide films deposited by DC magnetron sputtering in the transition mode and ion-beam oxidation (1130) at room temperature showed that the deposition rate of the IBO film was four times higher than that obtained by conventional reactive magnetron sputtering, and was correlated with the oxygen ratio, X-O2=O-2/(O-2+Ar), in the ion beam. The results of Rutherford backscattering and X-ray photoelectron spectroscopy indicated that the films deposited by IBO with various ion energy had the same composition and chemical bonding; the refractive index changed with the ion energy. The Fourier transform infrared absorption spectra indicated that the films deposited by IBO had excellent moisture-resistant characteristics. (c) 2005 Elsevier B.V. All rights reserved.