Effects of Silicon Dioxide Cladding Layer on Langasite Based Resonators

Deposition of SiO
2
cladding layer is adopted as an option to promote the high temperature performance of LGS based applications. Besides improving the stability of the electrode, the cladding layer also protects the substrate and provides an indirect bonding possibility. By means of a weak form nonlinear FEM simulation, we get thorough understanding of the influences the SiO
2
layer brings. With a SiO
2
cladding layer, the electromechanical coupling factor (K2) decreases and wave velocity increases. The layer also suppresses spurious mode on (0°, 22°, 31°) cut. Additionally, the temperature-frequency relation of the resonator can be manipulated by varying the thickness of the layer due to the positive temperature coefficiency of frequency (TCF) of SiO
2
. The simulation results provide options and references for a more stable high temperature LGS based application design.