Research on property ZnO films on diamond substrates grown by RF magnetron sputtering for saw device applications

ZnO is a wide band gap piezoelectric semiconductor material with large electromechanical coupling, which has great potential for photoelectronics devices, acoustooptic devices and SAW devices. In this paper, ZnO films were deposited on diamond substrates by RF magnetron sputtering, while the depositing and annealing parameters of ZnO film were optimized. High-purity (99.999%) ZnO target, O2 and Ar were used in deposition process. Base pressure was 3×10^-5 mTorr and sputtering pressure was 3.6 mTorr. ZnO films were investigated by X-ray diffraction (XRD). Deposition parameters of ZnO film with preferred c-axis orientation: O2 and Ar partial pressure ratio, 1:2; substrate temperature, 400°C; sputtering power, 200W; deposition time, 2 hours. ZnO diffraction peak was found: (002). The FWHM of ZnO (002) was 0.589. We achieve a fine IDT pattern form ZnO films with the line width as 1.59¿m. The filter´s frequency measured by vector network analyzer was 1.07GHz.