PZT Based Multilayer Surface Acoustic Wave Device for High Frequency Applications

This paper presents a study on the integration of PZT thin film on SiO
₂
/Si substrate, which offers a great deal of potential in high frequency applications. A finite element method (FEM) simulation analysis of the proposed PZT/SiO
₂
/Si multilayer surface acoustic wave device is performed, and two propagation modes are studied i.e. the Rayleigh and Sezawa wave mode. The proposed structure is optimized by PZT (t
_PZT
) and SiO
₂
(t
_SiO2
) layers thicknesses. The Rayleigh mode is optimized with k
²
=6.27% at t
_PZT
/λ=0.4 and t
_SiO2
/λ=0.025 and the Sezawa mode with k
²
=13.13% at t
_PZT
/λ =0.2 and t
_SiO2
/λ=0.025. The temperature coefficient of frequency of the Sezawa mode is 2.7 times lower than that of the Rayleigh mode. Which makes it a more suitable choice for temperature stable high frequency and high k
²
SAW devices.