An acoustic resonator device includes a piezoelectric plate attached to a substrate. A portion of the piezoelectric plate forms a diaphragm suspended over a cavity in the substrate. A first conductor level includes first and second interdigital transducer (IDT) first-level busbars disposed along opposing sides of the diaphragm, and first and second sets of IDT fingers extending from the first and second busbars, respectively, wherein the first and second sets of IDT fingers are interleaved and disposed on the diaphragm. A second conductor level includes first and second second-level busbars that overlap at least a portion of the first and second busbars, respectively.

Acoustic resonator devices and methods are disclosed. An acoustic resonator device includes a piezoelectric plate having opposed front and back surfaces. A first electrode and a second electrode are formed on the front surface of the piezoelectric plate, the first and second electrodes and the piezoelectric plate configured such that a radio frequency signal applied between the first and second electrodes excites a shear primary acoustic mode in the piezoelectric plate. The first electrode and the second electrode have trapezoidal cross-sectional shapes. A sidewall angle of at least one side surface of the first electrode and a sidewall angle of at least one side surface of the second electrode are greater than or equal to 70 degrees and less than or equal to 110 degrees.

An acoustic wave device includes an acoustic wave substrate including a first main surface and a second main surface, IDT electrodes provided on the first main surface, and sealing resin covering at least the second main surface of the acoustic wave substrate. A hollow is provided in a region where the IDT electrodes on the first main surface of the acoustic wave substrate is located. The sealing resin has through-holes each extending from a top surface 13B of the sealing resin to the second main surface of the acoustic wave substrate. The acoustic wave substrate is made of silicon or includes a layer made of silicon.

A bulk acoustic wave filter, a manufacturing method thereof, and a communication device are disclosed. The bulk acoustic wave filter includes a first filter substrate and a second filter substrate; the first filter substrate includes a first base substrate and a first resonator, a first electrode pad and a first auxiliary pad arranged on the first base substrate; the second filter substrate includes a second base substrate and a second resonator, a second electrode pad and a second auxiliary pad arranged on the second base substrate, the first filter substrate is arranged opposite to the second filter substrate, the first electrode pad and the second auxiliary pad are in contact with each other, and the second electrode pad and the first auxiliary pad are in contact with each other.

A single crystal piezoelectric layer includes a first recess in a first opposing surface opposing a first main surface of a base. The single crystal piezoelectric layer is bonded to the first main surface of the base at a portion of the first opposing surface other than the first recess. A lower electrode layer defining at least a portion of a pair of electrode layers and extending over a surface of the single crystal piezoelectric layer opposing the base is at least partially located in the first recess. A second opposing surface of the lower electrode layer opposing the first main surface of the base has surface roughness greater than the surface roughness of the first opposing surface of the single crystal piezoelectric layer.

A bulk acoustic resonator architecture is fabricated by epitaxially forming a piezoelectric film on a top surface of post formed from an underlying substrate. In some cases, the acoustic resonator is fabricated to filter multiple frequencies. In some such cases, the resonator device includes two different resonator structures on a single substrate, each resonator structure configured to filter a desired frequency. Including two different acoustic resonators in a single RF acoustic resonator device enables that single device to filter two different frequencies in a relatively small footprint.

A bulk-acoustic wave resonator includes: a first electrode; a piezoelectric layer at least partially disposed on an upper portion of the first electrode; and a second electrode disposed to cover at least a portion of the piezoelectric layer. The second electrode includes a frame disposed at an edge of an active region of the bulk-acoustic wave resonator, and the first electrode, the piezoelectric layer and the second electrode are disposed to overlap one another at the edge of the active region. The frame includes a wall disposed at the edge of the active region and a trench formed on an internal side of the wall. An internal boundary line of the trench has a concave-convex shape in a plane parallel to an upper surface of the frame.

A bulk-acoustic wave resonator includes: a substrate; a membrane layer forming a cavity with the substrate; a lower electrode disposed on the membrane layer; an insertion layer disposed to cover at least a portion of the lower electrode; a piezoelectric layer disposed on the lower electrode to cover the insertion layer; and an upper electrode at least partially disposed on the piezoelectric layer, wherein the upper electrode includes a reflection groove disposed on the insertion layer.

A method of manufacture for an acoustic resonator or filter device. In an example, the present method can include forming metal electrodes with different geometric areas and profile shapes coupled to a piezoelectric layer overlying a substrate. These metal electrodes can also be formed within cavities of the piezoelectric layer or the substrate with varying geometric areas. Combined with specific dimensional ratios and ion implantations, such techniques can increase device performance metrics. In an example, the present method can include forming various types of perimeter structures surrounding the metal electrodes, which can be on top or bottom of the piezoelectric layer. These perimeter structures can use various combinations of modifications to shape, material, and continuity. These perimeter structures can also be combined with sandbar structures, piezoelectric layer cavities, the geometric variations previously discussed to improve device performance metrics.

A laterally excited bulk acoustic wave device is disclosed. The laterally excited bulk acoustic wave device can include a first solid acoustic mirror, a second solid acoustic mirror, a piezoelectric layer that is positioned between the first solid acoustic mirror and the second solid acoustic mirror, an interdigital transducer electrode on the piezoelectric layer, and a support substrate arranged to dissipate heat associated with the bulk acoustic wave. The interdigital transducer electrode is arranged to laterally excite a bulk acoustic wave. The first solid acoustic mirror and the second solid acoustic mirror are arranged to confine acoustic energy of the bulk acoustic wave. The first solid acoustic mirror is positioned on the support substrate.