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. Patterned electrodes are deposited on the surface of the piezoelectric film. An etched sacrificial layer is deposited over the electrodes and a planarized support layer is deposited over the sacrificial layer. The device can include temperature compensation layers (TCL) that improve the device TCF. These layers can be thin layers of oxide type materials and can be configured between the top electrode and the piezoelectric layer, between the bottom electrode and the piezoelectric layer, between two or more piezoelectric layers, and any combination thereof. In an example, the TCLs can be configured from thick passivation layers overlying the top electrode and/or underlying the bottom electrode.

A process for fabricating a component includes an operation of transferring at least one layer of one or more piezoelectric or pyroelectric or ferroelectric materials forming part of a donor substrate to a final substrate, the process comprising a prior step of joining the layer to a temporary substrate via production of a fragile separating region between the donor substrate of single-crystal piezoelectric or pyroelectric or ferroelectric material and the temporary substrate, the region comprising at least two layers of different materials in order to ensure two compounds apt to generate an interdiffusion of one or more constituent elements of at least one of the two compounds make contact, the fragile region allowing the temporary substrate to be separated.

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.

Resonator devices, filter devices, and methods of fabrication are disclosed. A resonator device includes a substrate and a single-crystal piezoelectric plate having front and back surfaces. An acoustic Bragg reflector is sandwiched between a surface of the substrate and the back surface of the piezoelectric plate. An interdigital transducer (IDT) is formed on the front surface of the piezoelectric plate. The IDT and the piezoelectric plate are configured such that a radio frequency signal applied to the IDT excites a primary acoustic mode within the piezoelectric plate. The acoustic Bragg reflector comprises alternating SiO.sub.2 and diamond layers and is configured to reflect the primary acoustic mode.

Disclosed is a method for manufacturing a piezoelectric Al.sub.xGa.sub.1-xN (0.5≤x≤1) thin film, comprising: forming a stress control layer comprised of a Group III nitride on a silicon substrate by chemical vapor deposition (CVD); and depositing a piezoelectric Al.sub.xGa.sub.1-xN (0.5≤x≤1) thin film on the stress control layer, the thin film being deposited by PVD at 0.3 Tm (Tm is melting temperature of a piezoelectric thin film material) or higher. Further, a method for manufacturing a device in conjunction with piezoelectric Al.sub.xGa.sub.1-xN (0.5≤x≤1) thin films is provided.

A front end module (FEM) for a 5.6/6.6 GHz Wi-Fi acoustic wave resonator RF filter circuit. The device can include a power amplifier (PA), a 5.6/6.6 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 5.6/6.6 GHZ resonator may be configured between the diversity switch and the LNA. In a specific example, this device integrates a 5.6/6.6 GHz PA, a 5.6/6.6 GHZ bulk acoustic wave (BAW) RF filter, a single pole two throw (SP2T) switch, and a bypassable LNA into a single device.

A deposition system is disclosed that allows for growth of inclined c-axis piezoelectric material structures. The system integrates various sputtering modules to yield high quality films and is designed to optimize throughput lending it to a high-volume in manufacturing environment. The system includes two or more process modules including an off-axis module constructed to deposit material at an inclined c-axis and a longitudinal module constructed to deposit material at normal incidence; a central wafer transfer unit including a load lock, a vacuum chamber, and a robot disposed within the vacuum chamber and constructed to transfer a wafer substrate between the central wafer transfer unit and the two or more process modules; and a control unit operatively connected to the robot.

A piezoelectric thin film includes a piezoelectric element and a substrate supporting the piezoelectric element. The piezoelectric element includes a piezoelectric thin film and first and second electrodes opposing each other with the piezoelectric thin film interposed therebetween. The piezoelectric thin film has a first-electrode-side content of each of aluminum and scandium higher than a second-electrode-side content thereof and a first-electrode-side content of nitrogen lower than a second-electrode-side content thereof.

In certain aspects, a chip includes an acoustic resonator, and a mirror under the acoustic resonator. The mirror includes a first plurality of porous silicon layers, and a second plurality of porous silicon layers, wherein the mirror alternates between the first plurality of porous silicon layers and the second plurality of porous silicon layers, and each of the first plurality of porous silicon layers has a higher porosity than each of the second plurality of porous silicon layers.

A bulk acoustic wave (BAW) resonator includes a solidly mounted reflector, for example, a Bragg-type reflector, a piezoelectric layer, and first and second electrodes on first and second surfaces, respectively, of the piezoelectric layer. A filter device or filter system includes at least one BAW resonator. Related methods of fabrication include forming the BAW resonator.