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 radio-frequency module includes a mounting substrate, a first filter, a second filter, a shield layer, and a conductor. The mounting substrate has a first main surface and a second main surface on opposite sides. The shield layer is disposed on an outer surface of a resin layer with which the first filter and the second filter are covered. The radio-frequency module is capable of performing simultaneous transmission by using both the first filter and the second filter. The conductor is disposed on the first main surface of the mounting substrate and is in contact with the transmitting filter and the mounting substrate. The conductor is in contact with the shield layer on a side other than a side closer to the second filter than to the first filter.

An acoustic wave device includes a piezoelectric substrate, a first interdigital transducer electrode on the piezoelectric substrate, and a first reflector and a second reflector. The first interdigital transducer electrode, the first reflector, and the second reflector each include a plurality of electrode fingers. At least one of the first interdigital transducer electrode, the first reflector, and the second reflector has a nonuniform duty ratio area where three successive electrode fingers in an acoustic wave propagation direction all have different duty ratios.

The present disclosure provides a single crystal film bulk acoustic resonator, a manufacturing method for a single crystal film bulk acoustic resonator, and a filter, and relates to the technical field of filters. The method includes: sequentially forming a buffer layer, a piezoelectric layer, and a first electrode that are stacked on a temporary base substrate; forming a first bonding layer on the first electrode; providing a substrate; etching the substrate to form a plurality of first bumps on a surface of the substrate; forming a second bonding layer covering top surfaces of the plurality of first bumps on the surface of the substrate; and bonding the second bonding layer located at the top surfaces of the plurality of first bumps to the first bonding layer. During bonding, the area of the top surfaces of the first bumps can be controlled by etched grooves, so the area of the second bonding layer located at the top surfaces of the first bumps can be controlled, thereby realizing the control of a bonding area. By controlling the bonding area, the balance between the bonding requirement and the bonding reliability is realized.

The present disclosure relates to a Bulk Acoustic Wave (BAW) resonator with tunable electromechanical coupling. The disclosed BAW resonator includes a bottom electrode, a top electrode, and a multilayer transduction structure sandwiched therebetween. Herein, the multilayer transduction structure is composed of multiple transduction layers, and at least one of the transduction layers is formed of a ferroelectric material, whose polarization will vary with an electric field across the ferroelectric material. Upon adjusting direct current (DC) bias voltage across the bottom electrode and the top electrode, an overall polarization of the multilayer transduction structure and an overall electromechanical coupling coefficient of the multilayer transduction structure are capable of being changed. Once the change of the overall electromechanical coupling coefficient of the multilayer transduction structure is completed, the overall electromechanical coupling coefficient of the multilayer transduction structure will remain unchanged after removing the DC bias voltage.

Dispersive delay lines are disclosed. The dispersive delay line can include a piezoelectric substrate having a first interdigital transducer electrode on a first region of the piezoelectric substrate and a second interdigital transducer electrode on a second region of the piezoelectric substrate. The dispersive delay line is arranged such that an acoustic wave is configured to propagate from the first interdigital transducer electrode to the second interdigital transducer electrode though a third region of the piezoelectric substrate. An additional material positioned on the third region of the piezoelectric substrate can impact acoustic wave propagation velocity. Related radio frequency modules, wireless communications devices, and methods are disclosed.

A bulk-acoustic wave (BAVV) resonator is provided. The BAW includes a substrate, a first electrode disposed on the substrate, a piezoelectric layer disposed to cover at least a portion of the first electrode, and a second electrode disposed to cover at least a portion of the piezoelectric layer, wherein the piezoelectric layer includes an intermediate layer, a first layer disposed above the intermediate layer and a second layer disposed below the intermediate layer, the first layer and the second layer are symmetrical in relation to a plane through which a central line of the intermediate layer passes in a thickness direction, and a thickness of the intermediate layer is greater than a thickness of each of the first and second layers.

An elastic wave device includes a piezoelectric film made of lithium niobate or lithium tantalate, and a first electrode finger and a second electrode finger opposing each other in a direction intersecting a thickness direction of the piezoelectric film. When an average thickness of the piezoelectric film is d and a distance between centers of the first electrode finger and the second electrode finger is p, d/p is about 0.5 or less. The first electrode finger and the second electrode finger are connected to the first and second bus bars, respectively. The first and second bus bars include corner portions. At least one of corner portions of the first and second bus bars is outside a cavity portion when viewed in plan view.

An acoustic resonator device includes a substrate having a surface and a single-crystal piezoelectric plate bonded to the substrate surface. A portion of the piezoelectric plate forms a diaphragm that spans a cavity. A conductor pattern including an interdigital transducer (IDT) formed on a surface of the single-crystal piezoelectric plate such that interleaved fingers of the IDT are disposed on the diaphragm. A dielectric cover is disposed over the IDT and the plate, and the dielectric cover forms an air gap above the IDT and the plate.

A filter device includes a filter circuit including series-arm resonators and series-arm-resonator connecting wires, and an additional circuit including a resonator including first and second interdigital transducer electrodes, first and second capacitors connected between the first and second interdigital transducer electrodes and the filter circuit, and first and second I-C connecting wires connected to the first and second interdigital transducer electrodes and the first and second capacitors, the additional circuit being connected in parallel with a portion of the series-arm resonators in the filter circuit. The first and second interdigital transducer electrodes are output-side interdigital transducer electrodes. A capacitance of the first capacitor is smaller than the capacitance of the second capacitor. A shortest distance among distances between the first I-C connecting wire and the series-arm-resonator connecting wires is shortest among shortest distances between the I-C connecting wires and the series-arm-resonator connecting wires.