Investigation of SH-SAW Resonators Based on a Single-Pair Bragg Reflector With 42°YX-LiTaO 3 Single-Crystalline Film

This work investigates shear horizontal surface acoustic wave (SH-SAW) resonators based on a Bragg reflector. The performances of the SH-SAW resonators are systematically analyzed by finite element method (FEM) simulation. The influences of the high acoustic-impedance (HAI) and low-acoustic-impedance (LAI) layers on the performances of the resonators are investigated, and the effect of the substrate material is also discussed. By using a Ta2O5/SiO2single-pair Bragg reflector, the SH-SAW resonator shows good performances due to the confinement of acoustic energy within the LiTaO3(LT) thin film. A series of SH-SAW resonators with different wavelengths was prepared. The prepared resonators exhibit a maximum Bode$\textit{Q}$factor (Q${}_{\text{max} }\text {)}$of 2513 and an effective electromechanical coupling coefficient (K${}^{\text{2}}_{\text {eff}}\text {)}$of 8.38%. The influences of the lattice damage and residual stress on Qmaxin the LT film are also discussed. Notably, the proposed SH-SAW based on a Bragg reflector demonstrates intrinsic advantages, including the elimination of the parasitic surface conduction (PSC) effect and reduced substrate dependency, which provides an alternative way of developing high-performance SH-SAW resonators.