Fabrication of high frequency SAW devices with ZnO thin film on Al2O3/glass substrates by RF sputtering

• Main Authors: Yan-Kai Peng, 彭彥凱
• Other Authors: Wen-Ching Shih
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/50620200062988798197

碩士 === 大同大學 === 光電工程研究所 === 98 === Abstract Now communication elements are developing towards high frequency. SAW (Surface acoustic wave, SAW) devices must have high velocity, high electromechanical coupling coefficient and low insertion loss. SAW devices composed of the piezoelectric thin film and different substrate materials or buffer layers can improve the operating frequency of SAW devices and the electromechanical coupling coefficient. Consequently, SAW devices have been widely applied in mobile communication due to their small size and light weight. This study employs Al2O3 thim film as the experimental buffer layer on glass(Corning 7059) substrate and ZnO as the piezoelectric material to contrast the frequency responses of SAW devices. We use Al2O3 buffer layers with different thicknesses and compare with the glass and sapphire substrates. Successfully, the phase velocity of IDT/ZnO/Al2O3/Glass with Al2O3 thin film has been improved to increase from 2710.0 to 3227.6 m/s . e-beam evaporated Al2O3 buffer layers with high velocity of wave has been proved to lower the cost and shorten the time of production. The method is sure of producing high frequency SAW devices,with lower cost.