Processing of ZnO thin films for SAW devices

Summary form only given. The aim of the present study was to evaluate the potential of thin film SAW devices as strain sensors. ZnO (zinc oxide) was identified as the most suitable piezoelectric thin film material, on the basis of its relatively high SAW coupling factor and low acoustic losses. Other factors, including the processing techniques and temperatures required for film growth, were also considered in making this decision. ZnO thin films were deposited by RF magnetron sputtering onto (100) oriented Si wafers. The use of intermediate layers of SiO₂ and Al were also investigated for temperature compensation and for enhancement of the coupling factor K_SAW respectively. The influence of the substrate type and processing parameters on the film structure, microstructure and electrical resistivity will be reported. The design and performance of prototype 1-port SAW resonators based on the ZnO thin films will also be described