Elimination of Spurious Modes in SH0 Lithium Niobate Laterally Vibrating Resonators.

This letter reports on a spurious mode suppression technique for the shear horizontal (SH0) mode lithium niobate laterally vibrating resonators. The concept utilizes triangular and arched edge shapes on the transversal sides of a resonant cavity to effectively distribute and scatter the acoustic waves in the inactive regions, yielding the suppression of transverse spurious modes. 2D models and 3D finite-element analyses were employed to theoretically verify the technique. For devices with the arched-shape edges, complete removal of higher order transverse modes has been experimentally demonstrated with $2\times $ enhancement for quality factor ( Q$ ). The Q$ enhancement arises from the improved concentration of mechanical energy under the inter-digitated transducers. The fabricated device exhibits a Q ) of 17.8%, and a figure of merit of 164. [ABSTRACT FROM PUBLISHER]