SAW Properties of SiO2/128° Y-X LiNb03Structure Fabricated by Magnetron Sputtering Technique

The propagation characteristics of the layered structure consistingof anSiO2 film on 128"rotated Y-cut X-propagating LiNb03 structure are investigated for surface acoustic waves (SAWS). The SiOz fiis are fabricated by radio-frequency (RF) magnetron sputtering techniques. Rayleigh-type waves are excited and detected by conven- tional inter digital transducers (IDT's) fabricated on the LiNbO3 crystal plates. Excellent results have been obtained not only for the tempera- ture characteristics with a temperature coefficient of delay (TCD, of about 0 ppm/"C but also for the frequency characteristics with a very small spurious response. Also, the attenuation constant is found to be very small and the layered structure exhibits a high value of electro- mechanical coupling coefficient (K') of about 0.08. The spurious re- sponse characteristics of the layered structure have been investigated theoretically by analyzing the generation of acoustic waves using IDT's and the spurious response is found to be small.