An acoustic resonator includes: a resonating unit including a resonating unit including a piezoelectric layer and first and second electrodes disposed on a lower side and an upper side of the piezoelectric layer, respectively; a substrate disposed on a lower side of the resonating unit; a support unit providing a cavity between the substrate and the resonating unit; and an intermediate metal layer separated from the second electrode and disposed in the resonating unit such that at least a portion thereof is surrounded by the piezoelectric layer and the second electrode.

The present disclosure provides a film piezoelectric acoustic resonator. The resonator includes an upper electrode, a piezoelectric layer and a lower electrode which are stacked sequentially from a top to a bottom. A projection of the effective resonance region along a direction of the piezoelectric layer is a hexagon. The hexagon has a first side with a longest length, a second side opposite to the first side, a third side with a shortest length, and a fourth side opposite to the third side. A portion of the upper electrode extending out of the effective resonance region through a first boundary of the effective resonance region is defined as an upper electrode led-out portion; a portion of the lower electrode extending out of the effective resonance region through a second boundary of the effective resonance region is defined as a lower electrode led-out portion.

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.

A resonator includes a piezoelectric layer comprising a piezoelectric material, the piezoelectric layer having a first surface and a second surface; an inner electrode disposed on the first surface of the piezoelectric layer, the inner electrode connected to a circuit; and an outer electrode surrounding the inner electrode on the first surface of the piezoelectric layer, the outer electrode left floating or connected to ground. The inner electrode and the outer electrode are separated by at least one gap smaller than an acoustic wavelength. One single piece electrode or multiple piece electrodes may be disposed on the second surface of the piezoelectric layer. The outer electrodes are configured for optimal modal confinement of an acoustic resonance while the inner electrodes are configured to produce a higher motional resistance than the interconnect resistance for maintaining high Q.

An acoustic filter device includes first and second series resonators and at least one shunt resonator, each shunt resonator electrically coupled to the first series resonator or the second series resonator. Each of the first and second series resonators includes respective first and second sub-resonators electrically connected in series, The first sub-resonators of the first and second series resonators are acoustically coupled along a first shared acoustic track. The second sub-resonators of the first and second series resonators are acoustically coupled along a second shared acoustic track.

A piezoelectric structure is disclosed which includes a single crystal having piezoelectric coefficients d.sub.31 and d.sub.32 of opposite magnitude, such that when an alternating electric field is applied in the Z direction, the piezoelectric structure expands in one of the X and Y directions and contracts in the other of the X and Y direction, a first electrode coupled to the single crystal, and a second electrode coupled to the single crystal, wherein the alternating electric field is input to the single crystal through the first and second electrodes.

An acoustic wave device includes a support substrate, a piezoelectric layer, and a functional electrode. As seen in a first direction of the support substrate, the piezoelectric layer overlaps the support substrate. The functional electrode extends over a first major surface of the piezoelectric layer. A space is opposite to the first major surface of the piezoelectric layer and at or adjacent to a second major surface of the piezoelectric layer. In the first direction, the functional electrode extends over an overlap region that overlaps the space, and a non-overlap region that does not overlap the space. In the non-overlap region, at least one of an insulating film and a void is located between the functional electrode and the piezoelectric layer.

An acoustic resonator with a reinforcing structure is provided according to the present disclosure. The acoustic resonator includes a substrate and a cavity formed on the substrate, a piezoelectric layer is arranged above the substrate and an opening passing through the piezoelectric layer is formed in a peripheral region of the piezoelectric layer. The reinforcing structure includes a reinforcing layer, part of the reinforcing layer is formed at the edge of the opening with being fitted to the edge, to reinforce a resonant functional layer near the edge of the opening, which can reduce a change in stress of the piezoelectric layer and the lower electrode near the edge of the opening after the cavity is released, so that the piezoelectric layer and the lower electrode do not easily collapse due to stress, thereby ensuring the performance of a device. A method for manufacturing the same is further provided.

An acoustic resonator package is provided. The acoustic resonator package includes a substrate, a cap, a plurality of acoustic resonators disposed between the substrate and the cap and configured to be electrically connected to each other, a grounding member disposed between the substrate and the cap, and a breakdown voltage shortener configured to provide an air gap to shorten a breakdown voltage between one of the plurality of acoustic resonators and the grounding member.

An acoustic wave device is provided comprising a substrate and at least one resonator structure of a first type and at least one resonator structure of a second type mounted on the substrate. The resonator structures of the first type are configured to operate as capacitors and have a first thickness, causing the resonator structures to have a first passband frequency range. The resonator structures of the second type have a second thickness that is different from the first thickness, causing the resonator structures to have a second passband frequency range. A method for forming such an acoustic wave device is also provided. A die comprising such an acoustic wave device, a filter comprising such an acoustic wave device, a radio-frequency module comprising such an acoustic wave device, and a wireless mobile device comprising such an acoustic wave device are also provided.