A bulk acoustic wave (BAW) resonator includes a substrate defining a cavity, a bottom electrode disposed over the substrate and the cavity, a piezoelectric layer disposed on the bottom electrode, and a top electrode disposed on the piezoelectric layer. The piezoelectric layer includes polycrystalline lithium niobate (LN) material or polycrystalline lithium tantalite (LT) material. The BAW resonator may further include an encapsulant layer formed on side and top surfaces of the piezoelectric layer. The encapsulant layer is configured to protect the LN material or the LT material of the piezoelectric layer from a release solvent previously applied to sacrificial material within the cavity in the substrate.

A bulk acoustic wave filter includes: a first bulk acoustic wave resonator including, in an order from bottom to top, a first cavity, a first bottom electrode, a first segment of a piezoelectric layer, and a first top electrode; a second bulk acoustic wave resonator disposed adjacent to the first bulk acoustic wave resonator, and including, in the order from bottom to top, a second cavity, a second bottom electrode, a second segment of the piezoelectric layer, and a second top electrode; a boundary structure surrounding the first cavity and the second cavity, the boundary structure including a boundary portion extending between and separating the first cavity and the second cavity, and the boundary portion being disconnected at a disconnection region; and a first release hole formed in the piezoelectric layer, and overlapping the disconnection region.

A suspended device structure comprises a substrate, a cavity disposed in a surface of the substrate, and a device suspended entirely over a bottom of the cavity. The device is a piezoelectric device and is suspended at least by a tether that physically connects the device to the substrate. The tether has a non-linear centerline. A wafer can comprise a plurality of suspended device structures.

The disclosure provides a film bulk acoustic resonator and a manufacturing method therefor, and a film bulk acoustic wave filter, and relates to the technical field of resonators. The film bulk acoustic resonator includes a substrate, where the substrate is provided with two opposite protective walls protruding out of a surface of the substrate, a cavity is formed between the two protective walls, and an insulating layer is further arranged on one side, away from the cavity, of each protective wall on the substrate; and the film bulk acoustic resonator further includes a transducer stacking structure, where the transducer stacking structure covers the insulating layer, the cavity and the protective walls, and two sides, along a stacking direction, of the transducer stacking structure are in communication with the cavity and the outside respectively. With the cavity formed through the protective walls, the cavity being in communication with the outside, and the cavity formed by releasing corrosive substances to the cavity area from the outside, accurate control over cavity release machining is achieved, a process is simpler, cost is controlled, and a process period is shortened; an area proportion of the protective walls is small, and a chemical mechanical polishing (CMP) requirement is low, so as to advantageously improve a yield; and a structure of the film bulk acoustic resonator is built on the insulating layer, so as to advantageously reduce parasitic capacitance and resistance and improve comprehensive device performance.

A resonator, a filter and a duplexer, which relate to the technical field of resonators. The resonator includes: a substrate, and a lower electrode layer, a piezoelectric layer and an upper electrode layer, which are sequentially formed on the substrate, wherein an acoustic reflection structure is formed on a surface of the substrate that is close to the lower electrode layer, and an overlapping region of the acoustic reflection structure, the lower electrode layer, the piezoelectric layer and the upper electrode layer along a stacking direction forms a resonant region; and in the resonant region, the surface, which is away from the substrate, of at least one of the lower electrode layer, the piezoelectric layer and the upper electrode layer is etched to form an etched region, the depth of the etched region is less than the thickness of an etched layer, and the area of the etched region is less than the area of the resonant region. By means of controlling an etching area ratio of the resonant region to the etched region, the resonator can obtain a plurality of different resonant frequencies on the same wafer without increasing processes.

Provided are a bulk acoustic resonator and a filter. The bulk acoustic resonator includes a substrate having a cavity, and a bottom electrode, a piezoelectric layer and a top electrode that are sequentially arranged on the substrate, where an overlapping area of orthographic projections of the bottom electrode, the piezoelectric layer and the top electrode on the substrate forms a resonance area; and in the resonance area, an outline shape of the orthographic projection of each of the bottom electrode and the top electrode on the substrate is a closed figure formed by connecting M arcs end to end, and the closed figure is an axisymmetric figure, where M is an integer greater than or equal to 2, and the arcs include a concave arc that is concave toward a center of the resonance area and a convex arc that is convex away from the center of the resonance area.

A bulk acoustic wave resonator is provided. The bulk acoustic wave resonator incudes a carrier substrate, having a main surface extending along a first direction; a piezoelectric layer, located on a side of the carrier substrate in a second direction perpendicular to the main surface of the carrier substrate; a first electrode and a second electrode; a cavity boundary structure, having a body part extending along the first direction and a protruding part protruding from the body part toward the piezoelectric layer; a resonant cavity, defined by the cavity boundary structure and the piezoelectric layer; and a periphery dielectric layer, located on a side of the protruding part of the cavity boundary structure away from the resonant cavity, a material of the periphery dielectric layer is different from a material of at least a portion of the protruding part adjacent to the periphery dielectric layer.

An acoustic resonator that has a first electrode with a first planar portion. A second electrode having a second planar portion is disposed parallel to the first planar portion. This second electrode has a bifurcated end that defines a gap. A piezoelectric layer is disposed between and contacts both the first planar portion and the second planar portion. Also contacting the piezoelectric layer is the bifurcated end of the second electrode. The gap is formed in the periphery of each resonator within a filter. It is formed in the top electrode, that is typically formed of molybdenum, but could be formed from other metals as well. Unlike a gap between a top electrode and piezoelectric material, the gap recited herein is entirely within the second electrode. This structure is compatible with an inner passivation layer that enables a single crystal piezoelectric layer and a larger bottom electrode.

A bulk acoustic resonator includes: a substrate; a protective layer; and a resonant portion including a piezoelectric layer, a first electrode disposed between the piezoelectric layer and the substrate, and a second electrode disposed between the piezoelectric layer and the protective layer. The protective layer covers a central portion of the resonant portion and a reflective portion surrounding the central portion and formed in a region in which an upper surface of the second electrode rises relative to the central portion. An upper surface of a portion of the protective layer covering the reflective portion is more gently inclined than the upper surface of a portion of the second electrode in the reflective portion.

An RF circuit device using modified lattice, lattice, and ladder circuit topologies. The devices can include four resonator devices and four shunt resonator devices. In the ladder topology, the resonator devices are connected in series from an input port to an output port while shunt resonator devices are coupled the nodes between the resonator devices. In the lattice topology, a top and a bottom serial configurations each includes a pair of resonator devices that are coupled to differential input and output ports. A pair of shunt resonators is cross-coupled between each pair of a top serial configuration resonator and a bottom serial configuration resonator. The modified lattice topology adds baluns or inductor devices between top and bottom nodes of the top and bottom serial configurations of the lattice configuration. These topologies may be applied using single crystal or polycrystalline bulk acoustic wave (BAW) resonators.