A method of fabricating an FBAR filter device including an array of resonators, each resonator comprising a single crystal piezoelectric film sandwiched between a first metal electrode and a second metal electrode, wherein the first electrode is supported by a support membrane over an air cavity, the air cavity embedded in a silicon dioxide layer over a silicon handle, with through-silicon via holes through the silicon handle and into the air cavity, the side walls of said air cavity in the silicon dioxide layer being defined by perimeter trenches that are resistant to a silicon oxide etchant.

An acoustic resonator includes a substrate, and a resonant portion comprising a center portion in which a first electrode, a piezoelectric layer and a second electrode are sequentially laminated on the substrate, and an extending portion disposed along a periphery of the center portion, wherein the resonant portion is configured to have an asymmetrical polygonal plane, an insertion layer is disposed below the piezoelectric layer in the extending portion, and the piezoelectric layer is configured to have a top surface which is raised to conform to a shape of the insertion layer, and the insertion layer is configured to have an asymmetrical polygonal shape corresponding to a shape of the extending portion.

A bulk-acoustic resonator module includes: a module substrate; a bulk-acoustic resonator connected to the module substrate by a connection terminal and disposed spaced apart from the module substrate; and a sealing portion sealing the bulk-acoustic resonator. The bulk-acoustic resonator includes a resonating portion disposed opposite to an upper surface of the module substrate. A space is disposed between the resonating portion and the upper surface of the module substrate.

An FBAR filter device comprising an array of resonators, each resonator comprising a single crystal piezoelectric layer sandwiched between a first and a second metal electrode, wherein the first electrode is supported by a support membrane over an air cavity, the air cavity being embedded in a silicon dioxide layer over a silicon handle, with through-silicon via holes through the silicon handle and into the air cavity, the side walls of said air cavity in the silicon dioxide layer being defined by barriers of a material that is resistant to silicon oxide etchants, and wherein the interface between the support membrane and the first electrode is smooth and flat.

An acoustic wave device includes an acoustic wave filter configured to filter a radio frequency signal and a loop circuit coupled to the acoustic wave filter. The loop circuit is configured to generate an anti-phase signal to a target signal at a particular frequency. The loop circuit includes a Lamb wave resonator having a piezoelectric layer and an interdigital transducer electrode disposed on the piezoelectric layer. The piezoelectric layer includes free edges. An edge of the piezoelectric layer is configured to one of suppress or scatter reflections of acoustic waves generated by the interdigital transducer electrode from the edge of the piezoelectric layer.

An acoustic resonator includes a substrate, and a resonant portion comprising a center portion in which a first electrode, a piezoelectric layer and a second electrode are sequentially laminated on the substrate, and an extending portion disposed along a periphery of the center portion, wherein the resonant portion is configured to have an asymmetrical polygonal plane, an insertion layer is disposed below the piezoelectric layer in the extending portion, and the piezoelectric layer is configured to have a top surface which is raised to conform to a shape of the insertion layer, and the insertion layer is configured to have an asymmetrical polygonal shape corresponding to a shape of the extending portion.

Band N77 bandpass filters include a first plurality of transversely-excited film bulk acoustic resonators (XBARs) on a first chip comprising a first rotated YX-cut lithium niobate piezoelectric plate having a thickness less than or equal to 535 nm, and a second plurality of XBARs on a second chip comprising a second rotated YX-cut lithium niobate piezoelectric plate having a thickness greater than or equal to 556 nm. A circuit card is coupled to the first chip and the second chip. The circuit card includes conductors for making electrical connections between the first chip and the second chip.

An acoustic resonator is fabricated by bonding a first piezoelectric plate to a substrate and spans locations for a first and second cavity in the substrate. A top surface of the first piezoelectric plate is planarized to a first thickness. A bonding layer is formed on the first piezoelectric plate and spans the first and second cavity locations. A second piezoelectric plate is bonded to the bonding layer and spans the first and second cavity locations. A portion of the second piezoelectric plate spanning the second cavity location is etched away to form a first membrane over the first cavity location and a second membrane over the second cavity location. Interdigital transducers are formed on the first and second membranes over the first and second cavity location to form a first and second resonator on the same die.

A thin film bulk acoustic resonator and a method for manufacturing the same. The thin film bulk acoustic resonator comprises a bottom electrode layer, a piezoelectric layer, and a top electrode layer, which are disposed on a substrate in which an acoustic reflection structure is located, where a portion which is of the piezoelectric layer and corresponds to a boundary of the acoustic reflection structure is depolarized to form a depolarized portion. The method comprises providing a bottom electrode layer on a substrate to cover an acoustic reflection structure which is formed or to be formed on the substrate; providing a piezoelectric layer on the bottom electrode layer; depolarizing a portion, which is of the piezoelectric layer and corresponds to a boundary of the acoustic reflection structure, to form a depolarized portion; and providing a top electrode layer on the piezoelectric layer.

A germanium-containing aluminum nitride piezoelectric film and a method for manufacturing an aluminum nitride piezoelectric film in which a germanium-containing aluminum nitride piezoelectric film is grown on a substrate by sputtering.