Design and Fabrication of SAW Resonators on Silicon Substrate Employing Transverse BAW in Patterned ZnO

Abstract

The paper presents the design and fabrication of surface acoustic wave (SAW) resonators on silicon (Si) substrate employing transverse bulk acoustic wave (BAW) in periodically patterned ZnO thin film. Two types of resonators are fabricated and tested: Patterned-ZnO/Si and patterned-ZnO/SiO2/Si. Transverse BAW excited in the ZnO pattern couples acoustically and transforms into surface wave in silicon substrate with a unique characteristic of high phase velocity and high coupling coefficient compared to conventional thin film SAW devices on silicon. The performance parameters of the proposed device are estimated through finite element simulations and SAW resonators are designed using equivalent circuit model, fabricated and tested. The measured S21 results show the excitation of surface mode at 285.12 MHz with an insertion loss of -29.72 dB and effective coupling coefficient of 15.16%.