Acoustic resonator devices, filters, and methods are disclosed. An acoustic resonator includes a substrate, a lithium niobate plate having front and back surfaces, wherein Euler angles of the lithium niobate plate are [0°, β, 0° ], where β is greater than or equal to 0° and less than or equal to 60°, and an acoustic Bragg reflector between the surface of the substrate and the back surface of the lithium niobate plate. An interdigital transducer (IDT) is formed on the front surface of the piezoelectric plate. At least one finger of the IDT is disposed in a groove in the lithium niobate plate.

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.

A method of fabricating a configurable single crystal acoustic resonator (SCAR) device integrated circuit. The method includes providing a bulk substrate structure having first and second recessed regions with a support member disposed in between. A thickness of single crystal piezo material is formed overlying the bulk substrate with an exposed backside region configured with the first recessed region and a contact region configured with the second recessed region. A first electrode with a first terminal is formed overlying an upper portion of the piezo material, while a second electrode with a second terminal is formed overlying a lower portion of the piezo material. An acoustic reflector structure and a dielectric layer are formed overlying the resulting bulk structure. The resulting device includes a plurality of single crystal acoustic resonator devices, numbered from (R1) to (RN), where N is an integer greater than 1.

A method of manufacturing an integrated circuit. This method includes forming an epitaxial material comprising single crystal piezo material overlying a surface region of a substrate to a desired thickness and forming a trench region to form an exposed portion of the surface region through a pattern provided in the epitaxial material. Also, the method includes forming a topside landing pad metal and a first electrode member overlying a portion of the epitaxial material and a second electrode member overlying the topside landing pad metal. Furthermore, the method can include processing the backside of the substrate to form a backside trench region exposing a backside of the epitaxial material and the landing pad metal and forming a backside resonator metal material overlying the backside of the epitaxial material to couple to the second electrode member overlying the topside landing pad metal.

A digitally tunable acoustic wave resonator includes, in part, a first electrode positioned above a substrate, a composite stack positioned above the first electrode, and a second electrode positioned above the composite stack. The composite stack may include one or more alternate layers of a ferroelectric layer and a transition-metal nitride layer. The transition-metal nitride layer can be positioned above the ferroelectric layer, except the ferroelectric layer at the top of the composite stack. The ferroelectric layer comprises an aluminum scandium nitride layer Al.sub.1-xSc.sub.xN, where 0<x<1.

A single-crystal bulk acoustic wave resonators with better performance and better manufacturability and a process for fabricating the same are described. A low-acoustic-loss layer of one or more single-crystal and/or poly-crystal piezoelectric materials is epitaxially grown and/or physically deposited on a surrogate substrate, followed with the formation of a bottom electrode and then a support structure on a first side of the piezoelectric layer. The surrogate substrate is subsequently removed to expose a second side of the piezoelectric layer that is opposite to the first side. A top electrode is then formed on the second side of the piezoelectric layer, followed by further processes to complete the BAW resonator and filter fabrication using standard wafer processing steps. In some embodiments, the support structure has a cavity or an acoustic mirror adjacent the first electrode layer to minimize leakage of acoustic wave energy.

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.

A method of forming a piezoelectric thin film can include depositing a material on a first surface of a Si substrate to provide a stress neutral template layer. A piezoelectric thin film including a Group III element and nitrogen can be sputtered onto the stress neutral template layer and a second surface of the Si substrate that is opposite the first surface can be processed to remove that Si substrate and the stress neutral template layer to provide a remaining portion of the piezoelectric thin film. A piezoelectric resonator can be formed on the remaining portion of the piezoelectric thin film.

An acoustic wave device assembly is disclosed. The acoustic wave device assembly can include a first acoustic wave device that includes a first substrate, a first piezoelectric layer, a first solid acoustic mirror that is disposed between the first substrate and the first piezoelectric layer, and a first interdigital transducer electrode that is in contact with the first piezoelectric layer. The acoustic wave device assembly can include a second acoustic wave device that includes a second substrate, a second piezoelectric layer, a second solid acoustic mirror that is disposed between the second substrate and the second piezoelectric layer, a second interdigital transducer electrode that is in contact with the second piezoelectric layer, and a third solid acoustic mirror over the second interdigital transducer electrode. The first acoustic wave device and the second acoustic wave device being stacked on one another. The acoustic wave device assembly can include a spacer assembly that is disposed over the first piezoelectric layer.

An acoustic wave device assembly is disclosed. The acoustic wave device assembly can include a first acoustic wave device that includes a first substrate, a first piezoelectric layer, a first solid acoustic mirror that is disposed between the first substrate and the first piezoelectric layer, and a first interdigital transducer electrode that is embedded in the piezoelectric layer. The acoustic wave device assembly can include a second acoustic wave device that includes a second substrate, a second piezoelectric layer, a second solid acoustic mirror that is disposed between the second substrate and the second piezoelectric layer, and a second interdigital transducer electrode that is in contact with the second piezoelectric layer. The second acoustic wave device is stacked over the first acoustic wave device. The first acoustic wave device and the second acoustic wave device are spaced by a spacer assembly such that a cavity is formed between the first acoustic wave device and the second acoustic wave device.