Elimination of Spurious Modes in SH0 Lithium Niobate Laterally Vibrating Resonators

摘要

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 enhancement for quality factor (). The enhancement arises from the improved concentration of mechanical energy under the inter-digitated transducers. The fabricated device exhibits a of 920, a large electromechanical coupling () of 17.8%, and a figure of merit of 164.