The Investigation of Preferred Orientation Growth of ZnO Films on the Ceramic Substrates

Poly-crystal ZnO films with c-axis (002) orientation have been successfully grown on the lead-based ceramic substrates by r.f. magnetron sputtering technique. The deposited films were characterized as a function of deposition time and argon-oxygen gas flow ratio. Crystalline structures of the films were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). Highly oriented films with c-axis normal to the substrates can be obtained by depositing under a total pressure of 10mTorr containing 50% argon and 50% oxygen and r.f. power of 70W for 3 hours. The phase velocity, electromechanical coupling coefficient and temperature coefficient of frequency of SAW device with ZnO/IDT/PT-ceramic structure were investigated. It shows that the preferred oriented ZnO film is beneficial for improving the electromechanical coupling coefficient of SAW device.