A resonance structure of bulk acoustic wave resonator comprises a bottom electrode, a dielectric layer and a top electrode, wherein the dielectric layer is formed on the bottom electrode; the top electrode is formed on the dielectric layer. A resonance area is defined by the overlapping area of the projection of the bottom electrode, the dielectric layer and the top electrode. The resonance area has a contour. The contour includes at least three curved edges and is formed by connecting the at least three curved edges. Each curved edge is concave to a geometric center of the contour.

The present invention relates to a wave control apparatus using change of elastic modulus of thermoresponsive material, comprising: a wave modulation member having thermoresponsive material whose elastic modulus changes according to temperature variation, a wave source propagating wave through the wave modulation member, and a heating unit forming a wave modulation region by heating the wave modulation member, wherein the wave propagating through the wave modulation member from the wave source is configured to change wave characteristics when the wave passes through the wave modulation region heated by the heating unit.

A bulk acoustic wave resonator device of the present invention comprises: a cavity; a first electrode layer, at least one end of the first electrode layer being located above or inside the cavity; a piezoelectric layer, the cavity and the first electrode layer being located on a first side of the piezoelectric layer; a second electrode layer located on a second side, a region where the first electrode layer, the second electrode layer and the piezoelectric layer overlap being a resonance region; a first passive structure located on the first side and having a first overlapping portion with at least one edge of the first electrode layer; and a second passive structure located on the second side and having a second overlapping portion with at least one edge of the second electrode layer. The first passive structure comprises: a first raised portion located inside the resonance region; and a first extension portion located outside the resonance region, wherein the first raised portion protrudes with respect to the first extension portion. The second passive structure comprises: a second raised portion located inside the resonance region; and a second extension portion located outside the resonance region, wherein the second raised portion protrudes with respect to the second extension portion. The present invention suppresses parasitic edge mode, and improves Z.sub.P and corresponding Q value.

In one example, a method of forming a bulk acoustic wave (BAW) resonator comprises: forming an electrode on at least one of a semiconductor substrate, a sacrificial layer, or an acoustic reflector; and forming a piezoelectric layer on the electrode, the piezoelectric layer having a convex surface.

An acoustic wave device includes a piezoelectric layer, a first electrode, a second electrode, a first divided resonator, a second divided resonator, and a support substrate. The support substrate includes first and second energy confinement layers. The first energy confinement layer at least partially overlaps with a first region of the piezoelectric layer. The second energy confinement layer at least partially overlaps with a second region of the piezoelectric layer. The first and second energy confinement layers are integrally provided in the support substrate.

A laterally excited bulk acoustic wave device is disclosed. The laterally excited bulk acoustic wave device can include a support substrate, a solid acoustic mirror on the support substrate, a piezoelectric layer on the solid acoustic mirror, and an interdigital transducer electrode on the piezoelectric layer. The interdigital transducer electrode is arranged to laterally excite a bulk acoustic wave.

Aspects of this disclosure relate to a bulk acoustic wave structure that includes a bulk acoustic wave resonator and a circuit element electrically connected to the bulk acoustic wave resonator. The circuit element can include conductive material buried in a dielectric layer. The dielectric layer can extend under an acoustic reflector of the bulk acoustic wave resonator. In certain embodiments, the circuit element can be an inductor, a tuning stub, or a fuse element. Related filters, multiplexers, radio frequency modules, radio frequency systems, wireless communication devices, and methods are disclosed.

Aspects of this disclosure relate to a bulk acoustic wave structure that includes a bulk acoustic wave resonator and a metal-insulator-metal capacitor. The bulk acoustic wave resonator can include an acoustic reflector, a top electrode, a bottom electrode, and a piezoelectric layer including at least a portion over the acoustic reflector and between the top electrode and the bottom electrode. The metal-insulator-metal capacitor can be electrically connected to the bulk acoustic wave resonator. The metal-insulator-metal capacitor can include material of a dielectric layer under the acoustic reflector and an electrode buried in the dielectric layer. Related filters, multiplexers, radio frequency modules, radio frequency systems, wireless communication devices, and methods are disclosed.

Aspects of this disclosure relate to a bulk acoustic wave component that includes a bulk acoustic wave resonator, a capacitor, and a circuit element electrically connected to the bulk acoustic wave resonator. The capacitor includes an electrode buried in dielectric material. The circuit element includes conductive material in the dielectric layer. Related filters, multiplexers, radio frequency modules, radio frequency systems, wireless communication devices, and methods are disclosed.

Aspects of this disclosure relate to a filter that includes a bulk acoustic wave resonator and a capacitor in parallel with the bulk acoustic wave resonator. The bulk acoustic wave resonator can include a first electrode, a second electrode, a piezoelectric layer positioned between the first electrode and the second electrode, and an acoustic reflector positioned between the first electrode and a substrate. The capacitor can include an electrode buried in a dielectric layer that is over the substrate. Related multiplexers, radio frequency modules, radio frequency systems, wireless communication devices, and methods are disclosed.