Finite element simulation of Rayleigh surface acoustic wave in (100) AlN/(100) ZnO/diamond layered structure

Abstract

With the rapid development of the fifth-generation (5G) wireless system, the explosive growth of transmitted data raises higher requirements for high-performance surface acoustic wave (SAW) devices as filters and duplexers. (100) AlN/(100) ZnO/diamond layered structures are theoretically simulated by finite element method (FEM) to investigate the Rayleigh SAW propagation properties, including phase velocity, electromechanical coupling coefficient K², and temperature coefficient of frequency (TCF). Three types of layered structures with different interdigital transducers (IDTs) arrangements, which are IDTs/(100) AlN/(100) ZnO/diamond, (100) AlN/IDTs/(100) ZnO/diamond, and (100) AlN/(100) ZnO/IDTs/diamond structures, are considered in the simulations. The results show that the Sezawa mode exhibits larger K² than the other modes. We found that the (100) AlN/IDTs/(100) ZnO/diamond structure exhibited better SAW properties, including high K² and appropriate phase velocity.