An acoustic wave device includes an electrode finger on a principal surface of a piezoelectric substrate and extending in a Y-axis direction. In the acoustic wave device, an acoustic wave velocity is distributed in an order of an intermediate velocity, a low velocity, and a high velocity from a center of the electrode finger toward outer side portions in the Y-axis direction. The acoustic wave device further includes a dielectric between the piezoelectric substrate and a tip-end portion of the electrode finger. An end surface of the dielectric in the Y-axis direction includes first and second side surfaces. A tilt angle of the first side surface is smaller than a tilt angle of the second side surface.

The invention relates to a method for manufacturing an electroacoustic resonator comprising the steps of: Providing a first substrate having a first side and an opposite second side; depositing a diamond layer having a first side and an opposite second side on said first substrate, wherein the second side of the diamond layer is in contact with said first side of the first substrate; removing the first substrate; forming a piezoelectric layer on the second side of the diamond layer; applying a second substrate to the first side of the diamond layer.

The invention relates to a method for manufacturing an electroacoustic resonator comprising the steps of: Providing a first substrate having a first side and an opposite second side; depositing a diamond layer having a first side and an opposite second side on said first substrate, wherein the second side of the diamond layer is in contact with said first side of the first substrate; removing the first substrate; forming a piezoelectric layer on the second side of the diamond layer; applying a second substrate to the first side of the diamond layer.

An acoustic resonator includes a substrate and a resonant portion. The resonant portion has a central portion in which a first electrode, a first piezoelectric layer, a second piezoelectric layer, and a second electrode are stacked in order on the substrate, and an extension portion extending outwardly from the central portion and including an insertion layer. A ratio of an average thickness of the first piezoelectric layer to an average thickness of the second piezoelectric layer is 18.4% to 40%.

An acoustic resonator includes a substrate and a resonant portion. The resonant portion has a central portion in which a first electrode, a first piezoelectric layer, a second piezoelectric layer, and a second electrode are stacked in order on the substrate, and an extension portion extending outwardly from the central portion and including an insertion layer. A ratio of an average thickness of the first piezoelectric layer to an average thickness of the second piezoelectric layer is 18.4% to 40%.

An acoustic wave device can have a plurality of coupling portions configured to electrically couple electrodes of the device to the substrate of the device to provide a bypass current pathway through the substrate for heat management. The substrate can be a semiconductor material, which can become more conductive as the temperature increases so that the bypass current pathway diverts more power through the substrate as the temperature increases. The acoustic wave device can be a surface acoustic wave device, which can have an interdigital transducer electrode that has the coupling portions on each of the bus bars and extending through the piezoelectric layer to contact the substrate. The acoustic wave device can be a bulk acoustic wave device in some implementations.

Bulk acoustic wave (BAW) resonators and particularly top electrodes with step arrangements for BAW resonators are disclosed. Top electrodes on piezoelectric layers are disclosed that include a border (BO) region with a dual-step arrangement where an inner step and an outer step are formed with increasing heights toward peripheral edges of the top electrode. Dielectric spacer layers may be provided between the outer steps and the piezoelectric layer. Passivation layers are disclosed that extend over the top electrode either to peripheral edges of the piezoelectric layer or that are inset from peripheral edges of the piezoelectric layer. Piezoelectric layers may be arranged with reduced thickness portions in areas that are uncovered by top electrodes. BAW resonators as disclosed herein are provided with high quality factors and suppression of spurious modes while also providing weakened BO modes that are shifted farther away from passbands of such BAW resonators.

The present disclosure relates to a method for fabricating a laterally excited shear mode acoustic resonator. The method includes: providing a piezoelectric layer including monocrystalline lithium niobate and/or monocrystalline lithium tantalate; forming an acoustic mirror on a first surface of the piezoelectric layer; the acoustic mirror including at least one first acoustic reflection layer and at least one second acoustic reflection layer, the first acoustic reflection layers and the second acoustic reflection layers being alternately superimposed, and acoustic impedance of each of the first acoustic reflection layers being less than that of each of the second acoustic reflection layers; bonding a bearing wafer on a first surface of the acoustic mirror; and forming an electrode unit and a lateral reflector on a second surface of the piezoelectric layer.

Disclosed are a resonator and a manufacturing method thereof, a filter, and an electronic device. The resonator includes a substrate, a Bragg reflection layer, and a piezoelectric layer that are sequentially stacked. A first electrode is disposed on a surface that is of the piezoelectric layer and that faces the Bragg reflection layer, a second electrode is disposed on a surface that is of the piezoelectric layer and that is away from the Bragg reflection layer, a border ring is disposed on a surface that is of the second electrode and that is away from the piezoelectric layer, and the resonator has a first resonance region and a second resonance region corresponding to the border ring.

Disclosed are a resonator and a manufacturing method thereof, a filter, and an electronic device. The resonator includes a substrate, a Bragg reflection layer, and a piezoelectric layer that are sequentially stacked. A first electrode is disposed on a surface that is of the piezoelectric layer and that faces the Bragg reflection layer, a second electrode is disposed on a surface that is of the piezoelectric layer and that is away from the Bragg reflection layer, a border ring is disposed on a surface that is of the second electrode and that is away from the piezoelectric layer, and the resonator has a first resonance region and a second resonance region corresponding to the border ring.