An acoustic resonator is provided that includes a substrate; an acoustic Bragg reflector supported by the substrate; a piezoelectric layer above the acoustic Bragg reflector and opposite the substrate, the piezoelectric plate having at least one groove extending into a surface thereof; and an interdigital transducer (IDT) having a plurality of interleaved fingers with at least one finger is disposed in the at least one groove of the piezoelectric plate, respectively.

Acoustic resonator devices, filter devices, and methods of fabrication are disclosed. An acoustic resonator includes a substrate having a surface and a single-crystal piezoelectric plate having front and back surfaces. The back surface is attached to the surface of the substrate except for a portion of the piezoelectric plate forming a diaphragm that spans a cavity in the substrate. An interdigital transducer (IDT) is formed on the front surface of the single-crystal piezoelectric plate such that interleaved fingers of the IDT are disposed on the diaphragm. The IDT is configured to excite a primary acoustic mode in the diaphragm in response to a radio frequency signal applied to the IDT. The interleaved fingers extend at an oblique angle to an Z crystalline axis of the piezoelectric plate.

An RF filter system includes a plurality of bulk acoustic wave resonators arranged in a circuit having serial and parallel shunt configurations of resonators. Each resonator having a reflector, a support member including a surface, a first electrode including tungsten, overlying the reflector, a piezoelectric film including crystalline aluminum scandium nitride overlapping the first electrode, a second electrode including tungsten overlapping the piezoelectric film and the first electrode, and a passivation layer including silicon nitride overlying the second electrode. Portions of the support member surface of at least one resonator define a cavity region having a portion of the first electrode of the at least one resonator is located within the cavity region. The pass band circuit response has a bandwidth corresponding to a thickness of at least one of the first electrode, piezoelectric film, second electrode, and passivation layer. The system can include single crystal or polycrystalline BAW resonators.

A lower electrode and an adhesive layer made of an insulator are formed on a back surface on the ion implantation layer side of a piezoelectric single crystal substrate. A supporting substrate in which sacrificial layers made of a conductive material have been formed is bonded to the surface of the adhesive layer. By heating the composite body including the piezoelectric single crystal substrate, the lower electrode, the adhesive layer, and the supporting substrate, a layer of the piezoelectric single crystal substrate is detached to form a piezoelectric thin film. A liquid polarizing upper electrode is formed on a detaching interface of the piezoelectric thin film. A pulsed electric field is applied using the polarizing upper electrode and the sacrificial layers as counter electrodes. Consequently, the piezoelectric thin film is polarized.

A piezoelectric device that prevents defects due to pyroelectric charge without limiting how the piezoelectric device can be used includes a first metal layer located on a bonding surface of a piezoelectric single crystal substrate. A second metal layer is located on a bonding surface of a support substrate. The first and second metal layers are overlaid on each other to define a metal bonded layer. Subsequently, by oxidizing the metal bonded layer, a semi-conducting layer is formed.

There are disclosed acoustic resonators and method of fabricating acoustic resonators. An acoustic resonator includes a single-crystal piezoelectric plate having front and back surfaces, the back surface attached to a surface of a substrate except for portions of the piezoelectric plate forming a diaphragm spanning a cavity in the substrate. A conductor pattern on the front surface includes an interdigital transducer (IDT) with interleaved fingers of the IDT disposed on the diaphragm. A periodic array of holes is provided in the diaphragm.

A bulk acoustic resonator comprises a membrane including a piezoelectric film having multiple layers of piezoelectric material. At least one of the multiple layers of piezoelectric material has a different dopant concentration than another of the multiple layers of piezoelectric material.

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 method for fabricating a bulk acoustic wave (BAW) resonator includes sequentially forming a second electrode layer, a piezoelectric layer and a first electrode layer, performing a patterning process on the first electrode layer to form a first electrode and an additional electrode spaced apart from each other and electrically isolated from each other, forming a carrier structure on a first side of the piezoelectric layer, performing a patterning process on the second electrode layer to form a second electrode, forming one or more conductive pads on a second side of the piezoelectric layer, and bonding a cover structure to the second side of the piezoelectric layer.