The Suppression of Transverse Modes in POI SAW Resonators with Selective Thinning of Silicon Substrate

This work introduces a novel method for the suppression of transverse modes in POI SAW resonators by selective thinning of silicon substrate and the impact of design parameters of thinned substrate on transverse modes was analyzed by 3D FEM. Based on the modulation of SAW velocity at different regions along the aperture direction through selective thinning of the silicon substrate, the lateral energy can be confined to the aperture region and an almost spurious-free response can be obtained without deterioration of Q factor.