An acoustic resonator includes: a substrate; a resonance part including a lower electrode, a piezoelectric layer, and an upper electrode sequentially stacked on the substrate, and a frame formed on the upper electrode along an edge of the upper electrode; and a trench part formed in at least one side of the resonance part and making a thickness of the resonance part asymmetrical.

A method and structure for a transfer process for an acoustic resonator device. In an example, a bulk acoustic wave resonator (BAWR) with an air reflection cavity is formed. A piezoelectric thin film is grown on a crystalline substrate. A first patterned electrode is deposited on the surface of the piezoelectric film. An etched sacrificial layer is deposited over the first electrode and a planarized support layer is deposited over the sacrificial layer, which is then bonded to a substrate wafer. The crystalline substrate is removed and a second patterned electrode is deposited over a second surface of the film. The sacrificial layer is etched to release the air reflection cavity. Also, a cavity can instead be etched into the support layer prior to bonding with the substrate wafer. Alternatively, a reflector structure can be deposited on the first electrode, replacing the cavity.

A bulk acoustic resonator architecture is fabricated by epitaxially forming a piezoelectric film on a top surface of post formed from an underlying substrate. In some cases, the acoustic resonator is fabricated to filter multiple frequencies. In some such cases, the resonator device includes two different resonator structures on a single substrate, each resonator structure configured to filter a desired frequency. Including two different acoustic resonators in a single RF acoustic resonator device enables that single device to filter two different frequencies in a relatively small footprint.

Techniques are disclosed for forming integrated circuit single-flipped resonator devices that include an electrode formed of a two-dimensional electron gas (2 DEG). The disclosed resonator devices may be implemented with various group III-nitride (III-N) materials, and in some cases, the 2 DEG may be formed at a heterojunction of two epitaxial layers each formed of III-N materials, such as a gallium nitride (GaN) layer and an aluminum nitride (AlN) layer. The 2 DEG electrode may be able to achieve similar or increased carrier transport as compared to a resonator device having an electrode formed of metal. Additionally, in some embodiments where AlN is used as the piezoelectric material for the resonator device, the AlN may be epitaxially grown which may provide increased performance as compared to piezoelectric material that is deposited by traditional sputtering techniques.

Techniques are disclosed for forming high frequency film bulk acoustic resonator (FBAR) devices that include a bottom electrode formed of a two-dimensional electron gas (2DEG). The disclosed FBAR devices may be implemented with various group III-nitride (III-N) materials, and in some cases, the 2DEG may be formed at a heterojunction of two epitaxial layers each formed of III-N materials, such as a gallium nitride (GaN) layer and an aluminum nitride (AlN) layer. The 2DEG bottom electrode may be able to achieve similar or increased carrier transport as compared to an FBAR device having a bottom electrode formed of metal. Additionally, in some embodiments where AlN is used as the piezoelectric material for the FBAR device, the AlN may be epitaxially grown which may provide increased performance as compared to piezoelectric material that is deposited by traditional sputtering techniques.

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.

A communication system using a single crystal acoustic resonator device. The device includes a piezoelectric substrate with a piezoelectric layer formed overlying a transfer substrate. A topside metal electrode is formed overlying the substrate. A topside micro-trench is formed within the piezoelectric layer. A topside metal with a topside metal plug is formed within the topside micro-trench. First and second backside cavities are formed within the transfer substrate under the topside metal electrode. A backside metal electrode is formed under the transfer substrate, within the first backside cavity, and under the topside metal electrode. A backside metal plug is formed under the transfer substrate, within the second backside cavity, and under the topside micro-trench. The backside metal plug is connected to the topside metal plug and the backside metal electrode. The topside micro-trench, the topside metal plug, the second backside cavity, and the backside metal plug form a micro-via.

A bulk acoustic wave resonator and method for manufacturing the same, the bulk acoustic wave resonator includes: a piezoelectric layer; a first electrode layer, a carrier structure, and first and second conductive connectors disposed on a first side of the piezoelectric layer, and a second electrode layer, an interconnection pad and a cover structure disposed on a second side of the piezoelectric layer, wherein the first electrode layer includes a first electrode and an additional electrode electrically isolated from each other; the second electrode layer includes a second electrode; the interconnection pad is electrically connected to the second electrode and the additional electrode; a first cavity is disposed between the carrier structure and the piezoelectric layer; the first conductive connector is electrically connected to the first electrode, the second conductive connector is electrically connected to the second electrode through the additional electrode and the interconnection pad.

A method for making a bandpass filter including a first and second bulk acoustic wave resonators, the resonant frequency of the second resonator being offset from that of the first resonator by a predetermined offset, the method including providing a piezoelectric on insulator substrate, forming a lower electrode of the first resonator and a lower electrode of the second resonator, assembling by bonding the donor substrate to a receiver substrate, removing the donor substrate with a barrier on the piezoelectric layer, forming an upper electrode of the first resonator and an upper electrode, forming the lower electrodes being preceded by forming a mass overload pattern at the second zone, and/or forming the upper electrodes being preceded by forming a mass overload pattern at the second zone, the total thickness of the mass overload pattern or patterns being chosen to offset the resonant frequency of the second resonator by the offset.

A method of forming a MEMS/integrated circuit structure can include forming a piezoelectric layer on a surface of a growth substrate, forming a first electrode on the piezoelectric layer, forming a support layer on the piezoelectric layer and the first electrode, bonding an upper surface of the support layer to an upper surface of an integrated circuit wafer to form a bonded interface therebetween, wherein the integrated circuit wafer includes a substrate, a plurality of first layers on the substrate, the plurality of first layers forming a front-end of line portion of the integrated circuit wafer having electronic semiconductor switching devices therein, and a plurality of second layers forming a back-end of line portion of the integrated circuit wafer including ohmic conductors ohmically coupling regions of the electronic semiconductor switching devices to an outer one of the second layers of the integrated circuit wafer positioned opposite the electronic semiconductor switching devices.