BiFeO3 (BFO) films were grown on LaNiO3-coated Si substrate by a RF magnetron sputtering system at temperatures in the range of 300-700 degrees C. X-ray reflectivity and high-resolution diffraction measurements were employed to characterize the microstructure of these films. For a substrate temperature below 300 degrees C and at 700 degrees C only partially crystalline films and completely randomly polycrystalline films were grown, whereas highly (001)-orientated BFO film was obtained for a substrate temperature in the range of 400-600 degrees C. The crystalline quality of BFO thin films increase as the deposition temperature increase except for the film deposited at 700 degrees C. The fitted result from X-ray reflectivity curves show that the densities of the BFO films are slightly less than their bulk values. For the BFO films deposited at 300-600 degrees C, the higher the deposition temperature, the larger the remnant polarization and surface roughness of the films present. (C) 2010 Elsevier B.V. All rights reserved.