ZnO based SAW delay line sensor: fabrication and characteristics

ZnO, a well-known piezoelectric material, is used to develop micro-scale surface acoustic wave (SAW) delay line sensor. In this work, SAW delay line sensors are fabricated employing ZnO films that are deposited by RF sputtering technique. Films are characterized prior to device fabrication by X-ray diffraction (XRD) for film crystalline quality, UV-visible transmission spectroscopy for optical characteristics, and atomic force microscopy (AFM) for surface morphology. Interdigital electrodes producing surface acoustic waves in the hundreds of MHz are developed by photolithography and metallization techniques. SAW delay line sensor device testing, measurement and characteristics on RF sputtered ZnO films are presented and compared.