Study on characteristics of surface acoustic wave based on (110)ScAlN/R-sapphire structrue

The propagation characteristics of surface acoustic wave (SAW) in IDT/(110)ScAlN/R-sapphire, including the Rayleigh wave propagating along [001] direction and Love wave propagating along [100] direction, are investigated by 3 dimension-finite element method (3D-FEM). The phase velocity (v
_p
), electromechanical coupling coefficient (k
²
) and mass sensitivity (S
_m
) of first two orders of Rayleigh wave and Love wave are calculated. The simulated results show that the mode 0 of SAWs has better performances than that of mode 1. The mode 0 of Rayleigh wave shows the maximum k
²
of 3.57% as h/λ=1 associated with v
_p
of 3676 m/s and S
_m
of 23.6 m
²
/kg; and the mode 0 of Love wave exhibits the maximum k
²
of 6.39% as h/λ=0.33 associated with v
_p
of 4644 m/s and S
_m
of 38.3 m
²
/kg. The results indicate that (110)ScAlN/R-sapphire structure can be used for the fabrication of SAW devices with high frequency and good sensitivity.