A resonator is provided having a first electrode and a second electrode; and a piezoelectric film that is disposed between the first and second electrodes, has an upper surface opposing the first electrode, and that vibrates in a predetermined vibration mode when a voltage is applied between the first and second electrodes. Moreover, the resonator includes a protective film made of an insulator and disposed opposing the upper surface of the piezoelectric film with the first electrode interposed therebetween. Furthermore, a conductive film made of a conductor is provided that is disposed opposing the upper surface of the piezoelectric film with the protective film interposed therebetween, where the conductive film is electrically connected to any one of the first and second electrodes.

Embodiments of the disclosure are directed to a Bulk Acoustic Wave (BAW) filter structure with internal electrostatic shielding. In exemplary aspects disclosed herein, a shielded BAW filter structure includes a substrate, a plurality of transducers over the substrate, and a planar electrostatic shield between the substrate and a top electrode of the plurality of transducers. Each of the plurality of transducers forms a portion of a BAW resonator and resides in a filter including a parasitic capacitance. The planar electrostatic shield is coupled to a ground node and interrupts an electrical field associated with the parasitic capacitance of the filter to reduce the parasitic capacitance. Accordingly, the shielded BAW filter structure reduces the influence of parasitic capacitance providing improved filtering performance compared to an unshielded BAW filter structure.

Embodiments of the disclosure are directed to a Bulk Acoustic Wave (BAW) filter structure with internal electrostatic shielding. In exemplary aspects disclosed herein, a shielded BAW filter structure includes a substrate, a plurality of transducers over the substrate, and a planar electrostatic shield between the substrate and a top electrode of the plurality of transducers. Each of the plurality of transducers forms a portion of a BAW resonator and resides in a filter including a parasitic capacitance. The planar electrostatic shield is coupled to a ground node and interrupts an electrical field associated with the parasitic capacitance of the filter to reduce the parasitic capacitance. Accordingly, the shielded BAW filter structure reduces the influence of parasitic capacitance providing improved filtering performance compared to an unshielded BAW filter structure.

A resonator is provided having a first electrode and a second electrode; and a piezoelectric film that is disposed between the first and second electrodes, has an upper surface opposing the first electrode, and that vibrates in a predetermined vibration mode when a voltage is applied between the first and second electrodes. Moreover, the resonator includes a protective film made of an insulator and disposed opposing the upper surface of the piezoelectric film with the first electrode interposed therebetween. Furthermore, a conductive film made of a conductor is provided that is disposed opposing the upper surface of the piezoelectric film with the protective film interposed therebetween, where the conductive film is electrically connected to any one of the first and second electrodes.

An acoustic wave device includes an insulating layer including a recess, a piezoelectric layer on the insulating layer and over the recess to define a cavity, a first excitation electrode on a first surface of the piezoelectric layer opposite to the cavity, a second excitation electrode on a second surface of the piezoelectric layer and within the cavity, a dielectric layer on the first excitation electrode, and a first frame on the second excitation electrode and within the cavity.

An acoustic wave device includes an insulating layer and a piezoelectric layer defining a cavity, a first excitation electrode on a first surface of the piezoelectric layer opposite to the cavity, a second excitation electrode on a second surface of piezoelectric layer and within the cavity, a wiring electrode on the piezoelectric layer and connected to the first excitation electrode, a lid, a conductive wall extending between a first portion of the wiring electrode and the lid, and a sealing frame extending between a second portion of the wiring electrode and the lid. A first width of a first portion of the sealing frame is larger than a second width of a second portion of the sealing frame. A third width of the second portion of the wiring electrode is smaller than the first width and is larger than the second width.