Optimization of zinc oxide thin film for surface acoustic wave filters by radio frequency sputtering

摘要

Electrical characteristics of zinc oxide (ZnO)/glass surface acoustic wave (SAW) filters, the structure of which is ZnO thin film on a glass substrate with aluminum inter digital transducers, are greatly influenced by deposition parameters of a radio frequency sputtering for making ZnO thin films. The deposition conditions for making the ZnO thin film are also considered to obtain good piezoelectricity for SAW devices. Oxygen concentration in the radio frequency sputtering greatly affects the properties of ZnO thin films. The interface microstructure of ZnO thin films is investigated by cross-section transmission electron spectroscopy. The growth figures of ZnO on glass and ZnO on Al are similar. The average crystal size of ZnO on glass is larger than that of ZnO on Al.