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. One or more patterned electrodes are deposited on the surface of the piezoelectric film. An etched sacrificial layer is deposited over the one or more electrodes and a planarized support layer is deposited over the sacrificial layer. The support layer is etched to form one or more cavities overlying the electrodes to expose the sacrificial layer. The sacrificial layer is etched to release the cavities around the electrodes. Then, a cap layer is fusion bonded to the support layer to enclose the electrodes in the support layer cavities.

A film bulk acoustic resonator (FBAR) structure includes a top electrode, a piezoelectric layer disposed below the top electrode, a bottom electrode disposed below the piezoelectric layer, a dielectric layer disposed below the bottom electrode, a bonding substrate disposed below the dielectric layer, a bottom cap wafer disposed below the bonding substrate, and a cavity disposed below the bottom electrode and formed by the dielectric layer, the bonding substrate, and the bottom cap wafer.

A method and structure for single crystal acoustic electronic device. The device includes a substrate having an enhancement layer formed overlying its surface region, a support layer formed overlying the enhancement layer, and an air cavity formed through a portion of the support layer. Single crystal piezoelectric material is formed overlying the air cavity and a portion of the enhancement layer. Also, a first electrode material coupled to the backside surface region of the crystal piezoelectric material and spatially configured within the cavity. A second electrode material is formed overlying the topside of the piezoelectric material, and a dielectric layer formed overlying the second electrode material. Further, one or more shunt layers can be formed around the perimeter of a resonator region of the device to connect the piezoelectric material to the enhancement layer.

An acoustic resonator includes a membrane layer disposed on an insulating layer; a cavity formed by the insulating layer and the membrane layer and having a hydrophobic layer disposed on at least one of a portion of an upper surface of the cavity and a portion of a lower surface of the cavity; and a resonating portion disposed on the cavity and having a second electrode on a piezoelectric layer on a first electrode.

A method for manufacturing a micromechanical layer structure, including: providing a first protective layer patterned to have at least one opening which is filled with sacrificial layer material; depositing a functional-layer layer structure; producing a first opening in the functional-layer layer structure to at least one opening of the first protective layer, so that in at least one of the layers of the functional-layer layer structure; depositing a second protective layer so that the first opening is filled with material of the second protective layer; patterning the second protective layer and the filled first opening to have a second opening to the first protective layer, the second opening having the same or a lesser width than the first opening; removing sacrificial layer material at least in the opening of the first protective layer; and removing protective layer material at least in the second opening.

A method of forming a piezoelectric thin film includes sputtering a first surface of a substrate to provide a piezoelectric thin film comprising AlN, AlScN, AlCrN, HfMgAlN, or ZrMgAlN thereon, processing a second surface of the substrate that is opposite the first surface of the substrate to provide an exposed surface of the piezoelectric thin film from beneath the second surface of the substrate, wherein the exposed surface of the piezoelectric thin film includes a first crystalline quality portion, removing a portion of the exposed surface of the piezoelectric thin film to access a second crystalline quality portion that is covered by the first crystalline quality portion, wherein the second crystalline quality portion has a higher quality than the first crystalline quality portion and processing the second crystalline quality portion to provide an acoustic resonator device on the second crystalline quality portion.

Certain aspects provide an integrated circuit (IC) including a resonator. One example IC generally includes a substrate, a first oxide region disposed above the substrate, and a resonator. The resonator may include a piezoelectric layer, a second oxide region disposed below the piezoelectric layer and bonded to the first oxide region, and a cavity in the second oxide region, wherein at least a portion of the second oxide region is below the cavity.

A front-end module (FEM) for a 6.1 GHz Wi-Fi acoustic wave resonator RF filter circuit. The device can include a power amplifier (PA), a 6.1 GHz resonator, and a diversity switch. The device can further include a low noise amplifier (LNA). The PA is electrically coupled to an input node and can be configured to a DC power detector or an RF power detector. The resonator can be configured between the PA and the diversity switch, or between the diversity switch and an antenna. The LNA may be configured to the diversity switch or be electrically isolated from the switch. Another 6.1 GHZ resonator may be configured between the diversity switch and the LNA. In a specific example, this device integrates a 6.1 GHz PA, a 6.1 GHZ bulk acoustic wave (BAW) RF filter, a single pole two throw (SP2T) switch, and a bypassable LNA into a single device.

A Lamb wave resonator includes a piezoelectric material layer, a first finger electrode, a second finger electrode, at least two floating electrodes, and at least two gaps. The first finger electrode is disposed on one side of the piezoelectric material layer and includes a first main portion and first fingers. The second finger electrode is disposed on the side of the piezoelectric material layer and includes a second main portion and second fingers. The first fingers are parallel to and alternately arranged with the second fingers. The floating electrodes are disposed between each first finger and each second finger, and the gaps are disposed at two ends of each floating electrode, respectively.

An acoustic resonator has a piezoelectric plate attached to the surface of the substrate except for a portion of the piezoelectric plate forming a diaphragm spanning a cavity in the substrate. An interdigital transducer (IDT) formed on the plate has interleaved fingers on the diaphragm with first parallel fingers extending from a first busbar and second parallel fingers extending from a second busbar of the IDT. A distance between the interleaved fingers defines an IDT pitch. The IDT has a gap distance between the ends of the first plurality of parallel fingers and the second busbar, and between the ends of the second plurality of parallel fingers and the first busbar; and the gap distance is less than ⅔ times the IDT pitch.