Materials with high phase velocity are required to achieve high frequency surface acoustic wave devices. Diamond can be considered as the utmost material when it is coupled with piezoelectric materials such as ZnO. ZnO/diamond/Si structures have exhibited a phase velocity as large as 10 km/s

which enables one to develop a high frequency SAW device without requiring high resolution lithography technologies.In this paper

the piezoelectric characteristic of ZnO multi layer and the potential application for SAW device with ZnO/diamond/Si film are studied. Firstly

ZnO films have been deposited on diamond/Si substrate by plasma-assisted metal-organic chemical vapour deposition (MOCVD). The characteristic of the films is optimized through two-step growth method. X-ray diffraction (XRD) spectra show that the as-prepared ZnO films are strongly c-axis oriented. Photoluminescence (PL) spectra exhibit an intensive ultraviolet emission peak for our samples

while the emission band for deep energy level transition disappears. Scanning probe microscopy (SPM) measurement is also used to analyze the surface roughness of the grown ZnO/diamond/Si films

the sample with lower roughness will reduce the surface influence on SAW device application. To investigate the SAW properties of the ZnO multi-layer structure approximatively

the theoretic frequency dispersion curves of SAW for ZnO material on different substrates are studied. The thickness of ZnO film has obvious effect on the working frequency of SAW devices

i.e

.

the thinner the ZnO film

the higher the phase velocity of the SAW for our material. And the center frequency of ZnO SAW devices on diamond/Si substrate is about two times of that of ZnO materials on other substrates. So the ZnO/diamond/Si multi-layer is promising to fabricate high frequency SAW filter.