Temperature characteristics of langasite surface acoustic wave resonators coated with SiO2 films

Abstract In this paper, the SiO 2 temperature compensation layers were deposited on LGS SAW resonators. The temperature characteristics of SAW resonators with different thicknesses of SiO 2 coating layers were investigated from room temperature to 450 °C. The results show that the SAW velocity, the turnover temperature, the first and second order temperature coefficients of frequency (TCF 1 and |TCF 2 |) increase as the SiO 2 films thickness increasing. The Q factor of the SAW resonator decreases greatly due to the poor quality of the SiO 2 film. Zero TCF 1 is achieved when the SiO 2 coating layer is about 0.25 μm. The results show that the LGS SAW resonators can be temperature compensated by SiO 2 coating layer.