Preparation of Nano-Crystalline ZnO Thin Films

摘要

Zinc oxide (ZnO) thin films were identified as very suitable piezoelectric material for SAW on the basis of its relatively high electromechanical coupling coefficient, as well as high resistivity for low insertion loss and little distortion in the frequency. In this paper ZnO thin films were deposited on Si(100) substrate covered with SiO_2 using a reactive DC magnetic sputtering system from a zinc target. The effects of various deposition parameters on structural and performances have been investigated through experiments. Theoretical and experimental results are also discussed in this paper. XRD showed that the prepared ZnO films had strongly c-axis preferred-orientation. The composition of the film was also determined through high-resolution photoelectron spectroscopy (XPS). AFM showed that the films had smooth surface and that the crystallite sizes of deposited films were in the range 30 nm～50 nm. The above results showed that the films deposited by magnetic sputtering met the demands for surface acoustic wave (SAW) devices.