Characteristics of surface acoustic waves based on (110)ZNO/(110)ALN/R-sapphire structure

The propagation characteristics of Love waves in (110)ZnO/(110)AlN/R-sapphire structure are theoretically investigated by 3-dimensional finite element method (3D FEM). The phase velocity v
_P
, coupling coefficient k
²
and temperature coefficient of frequency (TCF) of the first two orders of Love wave are calculated, in which the thicknesses of (110) ZnO and (110) AlN are varied. The results show that the 0th Love wave has the largest coupling coefficient, and at H
_ALN
/λ=0.37 and h
_zno
=3.4 μm, the maximum k
²
of 4.27% associated with Vp of 3773 m/s and TCF of -22.1 ppm/°C can be obtained. Simulation results indicate that the (110)ZnO/(110)AlN/R-sapphire structure exhibits high phase velocity, large coupling coefficient and small TCF, which can be used for designing the high-frequency and temperature-compensated SAW devices.