Abstract: A micromechanical resonator operable in a bulk acoustic mode includes a resonator apparatus suspended over a substrate by a plurality of pairs of anchors. The resonator apparatus includes a conductive metal layer, a piezoelectric layer on the conductive metal layer and a plurality of interdigitated electrodes on the piezoelectric layer. The interdigitated electrodes are configured so that a total number of electrode fingers in the plurality of interdigitated electrodes is greater than a total number of the plurality of pairs of anchors.

Abstract: Disclosed are micromechanical resonator apparatus having features that permit multiple resonators on the same substrate to operate at different operating frequencies. Exemplary micromechanical resonator apparatus includes a support substrate and suspended micromechanical resonator apparatus having a resonance frequency. In one embodiment, the suspended micromechanical resonator apparatus comprises a device substrate that is suspended from and attached to the support substrate, a piezoelectric layer formed on the suspended device substrate, and a plurality of interdigitated upper electrodes formed on the piezoelectric layer. In another embodiment, the suspended micromechanical resonator apparatus comprises a device substrate that is suspended from and attached to the support substrate, a lower electrode formed on the suspended device substrate, a piezoelectric layer formed on the lower electrode, and a plurality of interdigitated upper electrodes formed on the piezoelectric layer.