FEM simulation of Rayleigh waves for CMOS compatible SAW devices based on AlN/SiO₂/Si(100).

A simulation study of Rayleigh wave devices based on a stacked AlN/SiO₂/Si(100) device was carried out. Dispersion curves with respect to acoustic phase velocity, reflectivity and electromechanical coupling efficiency for tungsten W and aluminium Al electrodes and different layer thicknesses were quantified by 2D FEM COMSOL simulations. Simulated acoustic mode shapes are presented. The impact of these parameters on the observed Rayleigh wave modes was discussed. High coupling factors of 2% and high velocities up to 5000 m/s were obtained by optimizing the AlN/SiO₂ thickness ratio.