Theorectical Optimazation Of Surface Acoustic Waves Resonator Based On 30 Degrees Y-Cut Linbo3/Sio2/Si Multilayered Structure

Surface acoustic wave devices based on LiNbO3/interlayer/substrate layered structure have attracted great attention due to the high electromechanical coupling coefficient (K-2) of LiNbO3 and the energy confinement effect of the layered structure. In this study, 30 degrees YX-LiNbO3(LN)/SiO2/Si multilayered structure, which can excited shear-horizontal surface acoustic wave (SH-SAW) with high K-2, was proposed. The optimized orientation of LiNbO3 was verified by the effective permittivity method based on the stiffness matrix. The phase velocity, K-2 value, and temperature coefficient of frequency (TCF) of the SH-SAW were calculated as a function of the LiNbO3 thickness at different thicknesses of the SiO2 in 30 degrees YX-LiNbO3/SiO2/Si multilayer structure by finite element method (FEM). The results show that the optimized LiNbO3 thickness is 0.1 lambda and the optimized SiO2 thickness is 0.2 lambda. The optimized Al electrode thickness and metallization ratio are 0.072 and 0.4, respectively. The K-2 of the SH-SAW is 29.89%, the corresponding phase velocity is 3624.00 m/s and TCF is about 10 ppm/degrees C with the optimized IDT/30 degrees YX-LiNbO3/SiO2/Si layered structure.