Higher-order wine glass mode piezoelectric square resonator with improved quality factor in water

This paper reports on the design and experimental characterization of a higher-order wine glass (third order: WG3) mode MEMS square plate resonator to reduce the effect of fluidic damping and thereby enhancing the quality (Q) factor in water for biosensing applications. We show that the lateral strain profile of the WG3 mode is well suited for fully-differential piezoelectric transduction (which helps to reduce parasitic feedthrough) and offers reasonable electromechanical coupling. We experimentally demonstrate that exciting the WG3 mode in water results in a higher Q factor (Q of 410 at 36.36 MHz) compared to the fundamental wine glass (WG1) mode (Q of 340 at 10.53 MHz).