Opportunities for shear energy scaling in bulk acoustic wave resonators

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    Abstract

    An important energy loss contribution in bulk acoustic wave resonators is formed by so-called shear waves, which are transversal waves that propagate vertically through the devices with a horizontal motion. In this work, we report for the first time scaling of the shear-confined spots, i.e., spots containing a high concentration of shear wave displacement, controlled by the frame region width at the edge of the resonator. We also demonstrate a novel methodology to arrive at an optimum frame region width for spurious mode suppression and shear wave confinement. This methodology makes use of dispersion curves obtained from finite-element method (FEM) eigenfrequency simulations for arriving at an optimum frame region width. The frame region optimization is demonstrated for solidly mounted resonators employing several shear wave optimized reflector stacks. Finally, the FEM simulation results are compared with measurements for resonators with Ta2O5/SiO2 stacks showing suppression of the spurious modes.
    Original languageUndefined
    Pages (from-to)1720-1728
    Number of pages9
    JournalIEEE transactions on ultrasonics, ferroelectrics and frequency control
    Volume61
    Issue number10
    DOIs
    Publication statusPublished - 1 Oct 2014

    Keywords

    • EWI-25134
    • IR-92210
    • METIS-306057

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