The influence of the oxygen concentration and the rf power variation on the zinc oxide films structural properties were studied. ZnO films were deposited on silicon substrate by rf magnetron sputtering in reactive plasma using a zinc oxide target. Crystalline structures and roughness characteristics of the films were investigated by X-ray diffraction (XRD) and atomic force microscopy (AFM) measurements, respectively. Deposition conditions were optimized to obtain films of good quality suitable for the fabrication of surface acoustic wave (SAW) devices. The optimal parameters to obtain a good piezoelectric material have been: rf power 50 W and reactive plasma. © 2004 Elsevier B.V. All rights reserved.