In this study, we examined the microstructure of Ag films grown on Si(001) substrates by radio frequency (rf) magnetron sputtering in a synchrotron x-ray scattering experiment. At a low rf power of0.22 W/cm2,the film was initially nucleated in the form of fine-grained epitaxial film with the crystalline axes parallel to the substrate crystalline axes. As the growth proceeded further, it changed to nonepitaxial three dimensional island growth. The Ag islands were not epitaxial, but grew preferentially along the ⟨111⟩ direction. At a higher rf power of0.44 W/cm2,the Ag film developed a nonepitaxial island growth from the early stage. Annealing the films at 500 °C increased the island size and enhanced the crystalline quality. The thin epitaxial film grown at the low rf power was recrystallized into islands during the annealing. This study suggests that it is feasible to grow heteroepitaxial Ag films on silicon substrates even by a sputtering process when the energy of the sputtered particles is minimized. ©1997 American Institute of Physics.