X-ray reflectivity and high-resolution X-ray diffraction measurements were employed to characterize the microstructure and morphology of buried layers and the interfacial structure of Ru films on Si substrates prepared by radio frequency magnetron sputtering technique. Extremely highly c-axis orientated Ru films were obtained at substrate temperatures ranging from 400 to 700 degreesC. The presence of oscillation fringe in the diffuse scattering indicates that the conformal relationship exists between the Ru surface and the film/substrate interface in high temperature deposition. The films deposited at temperatures greater than or equal to600degreesC exhibited clear interference fringes on the high-resolution X-ray diffraction measurements around the (0 0 2) diffraction peak. The pronounced interference fringes show not only a highly c-axis orientation of the layers but also a rather smooth surface and interface. The as-deposited films have extremely good texture with very smooth surface when deposited at high temperature. The full-width at half-maximum (FWHM) of similar to1degrees was obtained for the films deposited at high temperature. High temperature deposited Ru films have a lowest electrical resistivity of similar to11 muOmega cm. (C) 2003 Elsevier B.V. All rights reserved.