Techniques for improving Bulk Acoustic Wave (BAW) resonator structures are disclosed, including fluidic systems, oscillators and systems that may include such devices. A bulk acoustic wave (BAW) resonator may comprise a substrate and a first layer of piezoelectric material. The bulk acoustic wave (BAW) resonator may comprise a top electrode. A sensing region may be acoustically coupled with the top electrode of the bulk acoustic wave (BAW) resonator.

A ladder filter comprises a plurality of series arm bulk acoustic wave resonators electrically connected in series between an input port and an output port of the ladder filter and a plurality of shunt bulk acoustic wave resonators electrically connected in parallel between adjacent ones of the plurality of series arm bulk acoustic wave resonators and ground, at least one of the plurality of shunt bulk acoustic wave resonators including raised frame regions having a first width, at least one of the plurality of series arm bulk acoustic wave resonators having one of raised frame regions having a second width less than the first width or lacking raised frame regions.

An acoustic wave device includes a piezoelectric substrate in which a reverse-velocity surface is convex and an IDT electrode on the piezoelectric substrate. When an acoustic wave propagation direction is a first direction and a direction perpendicular or substantially perpendicular to the first direction is a second direction, the portion of the IDT electrode where first and second electrode fingers overlap in the first direction is a crossing region. The crossing region includes a center region centrally located in the second direction and a first and second edge regions located on two sides of the center region. Recesses 17 and 18 are respectively provided in portions of the piezoelectric substrate located in the first and second edge regions between the portions where the first and second electrode fingers are provided.

Aspects of this disclosure relate to a bulk acoustic wave device with a floating raised frame structure. The bulk acoustic wave device includes a first electrode, a second electrode, a piezoelectric layer positioned between the first electrode and the second electrode, and a floating raised frame structure positioned on a same side of the piezoelectric layer as the first electrode and spaced apart from the first electrode. The floating raised frame structure is at a floating potential. The bulk acoustic wave device can suppress a raised frame mode. Related methods, filters, multiplexers, radio frequency front ends, radio frequency modules, and wireless communication devices are disclosed.

A resonance apparatus that processes an electrical loss using a conductive material and a method of manufacturing the resonance apparatus are provided. The resonance apparatus includes a lower electrode formed at a predetermined distance from a substrate, and a piezoelectric layer formed on the lower electrode. The resonance apparatus further includes an upper electrode formed on the piezoelectric layer, and a conductive layer formed on the upper electrode or the lower electrode.

Acoustic resonator devices, filter devices, and methods of fabrication are disclosed. A resonator device includes a substrate having a surface and a single-crystal piezoelectric plate including one of rotated Y-cut lithium niobate and rotated Y-cut lithium tantalate. The single-crystal piezoelectric plate has a front surface and a back surface opposite the front surface, wherein the back surface is coupled to the surface. A floating back-side conductor pattern is formed on a portion of the back surface. A front-side conductor pattern consisting of two electrodes is formed on a portion of the front surface opposite the back-side conductor, wherein a radio frequency applied between the two electrodes excites a primary acoustic mode in the single-crystal piezoelectric plate.

In bulk acoustic wave (BAW) resonators having convex surfaces, an example BAW resonator includes a first electrode, a piezoelectric layer formed on the first electrode, the piezoelectric layer having a convex surface, and a second electrode formed on the convex surface. An example integrated circuit (IC) package includes a BAW resonator in the IC package, the BAW resonator including a piezoelectric layer having a convex surface.

A film bulk acoustic wave resonator (FBAR) comprises a recessed frame region including an undulating perimeter.

A high Q acoustic BAW resonator with high coupling and improved spurious mode suppression is given. The BAW resonator comprises an active resonator region (AR) formed by an overlap of the three layers bottom electrode (BE), piezoelectric layer (PL) and top electrode layer (TE). An inner-flap (IF) is formed by a dielectric 3D structure sitting on a marginal region (MR) of the active resonator region (AR) or adjacent thereto, extending inwardly towards the center thereof and having a section that runs in parallel and distant to the top surface of the resonator keeping an inner gap (IG) thereto or an angle .

An encapsulated integrated circuit is provided that includes an integrated circuit (IC) die. A phonon device is fabricated on the IC die that is configured to emit or to receive phonons that have a range of ultrasonic frequencies. An encapsulation material encapsulates the IC die. A phononic bandgap structure is included within the encapsulation material that is configured to have a phononic bandgap with a frequency range that includes at least a portion of the range of ultrasonic frequencies. A phononic channel is located in the phononic bandgap structure between the phonon device and a surface of the encapsulated IC.