Abstract: Resonator devices and filter devices are disclosed. A radio frequency filter includes substrate; a piezoelectric layer; a conductor pattern comprising a plurality of interdigital transducers (IDTs) on the piezoelectric layer; and an acoustic Bragg reflector between the substrate and the piezoelectric layer. The plurality of IDTs comprises a first IDT of first acoustic resonator and a second IDT of a second acoustic resonator. Moreover, a first thickness of the piezoelectric layer under the first IDT is greater than a second thickness of piezoelectric layer under the second IDT.

Abstract: Acoustic resonator devices and filters are disclosed. An acoustic resonator includes a substrate having a surface. A back surface of a single-crystal piezoelectric plate is 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) is formed on a front surface of the piezoelectric plate with interleaved IDT fingers of the IDT disposed on the diaphragm. Back-side fingers are formed the back surface of the diaphragm.

Abstract: A filter device is provided that includes a substrate; a piezoelectric layer; an acoustic Bragg reflector between the substrate and the piezoelectric layer; and a conductor pattern on a surface of the piezoelectric layer. The conductor pattern includes interdigital transducers (IDTs) of a plurality of resonators, and a plurality of conductors that connect the plurality of resonators in a ladder filter circuit, the plurality of conductors comprising adjacent first and second conductors. Moreover, the piezoelectric layer has an opening between the first and second conductors. A width dp of the opening of the piezoelectric layer is less than a distance dm between the first and second conductors.

Abstract: 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°, ?, 0°], where ? is greater than or equal to 0° and less than or equal to 60°. An interdigital transducer (IDT) is formed on the piezoelectric plate.

Abstract: Acoustic filters are disclosed. A filter device includes a plurality of resonators connected in a ladder filter circuit, each resonator of the plurality of resonators comprising an interdigital transducer (IDT) with interleaved fingers disposed on a respective piezoelectric diaphragm. A first frequency setting dielectric layer having a first thickness is disposed over the interleaved fingers of one or more IDTs of a first subset of the plurality of resonators. A second frequency setting dielectric layer having a second thickness greater than the first thickness is disposed over the interleaved fingers of one or more IDTs of a second subset of the plurality of resonators, wherein the first subset and the second subset are not identical.

Abstract: Resonator and filter devices and methods of fabrication. A resonator chip includes a substrate, a piezoelectric plate, and an acoustic Bragg reflector between the substrate and a back surface of the piezoelectric plate. A conductor pattern on a surface of the piezoelectric plate includes a first plurality of contact pads and an interdigital transducer (IDT). The acoustic Bragg reflector is configured to reflect the shear primary acoustic mode. An interposer has a second plurality of contact pads on a back surface. A seal connects a perimeter of the piezoelectric plate to a perimeter of the interposer. Each contact pad of the first plurality of contact pads is directly connected to a respective contact pad of the second plurality of contact pads.

Abstract: A filter includes first and second shunt resonators, at least one series resonator connected to the first and second shunt resonators in a ladder filter circuit, and a first ground contact pad. The first shunt resonator has two or more first sub-resonators and the second shunt resonator has two or more second sub-resonators. At least one first sub-resonator and at least one, but less than all, of the two or more second sub-resonators are connected to the first ground contact pad.

Abstract: Filters and methods of making filters are disclosed. A filter device includes a substrate, a piezoelectric plate, and an acoustic Bragg reflector between a surface of the substrate and a back surface of the piezoelectric plate. A conductor pattern on a front surface of the piezoelectric plate includes interdigital transducers (IDTs) of a plurality of resonators and a plurality of conductors to connect the plurality of resonators in a ladder filter circuit, the plurality of conductors including adjacent first and second conductors. A portion of the piezoelectric plate between the first and second conductors is removed.

Abstract: Acoustic filters, resonators and methods are disclosed. An acoustic filter device includes a substrate; a piezoelectric layer attached to the substrate, wherein at least a portion of the piezoelectric layer is disposed over a cavity of the acoustic resonator device; and an interdigital transducer (IDT) on a surface of the piezoelectric layer, the IDT including interleaved fingers extending at least over the portion of the piezoelectric layer disposed over the cavity. The cavity has at least one rounded corner, and a portion of interleaved fingers extend from at least one busbar. Moreover, at least a portion of the rounded corner of the cavity is under the at least one busbar in a plan view of the piezoelectric layer.

Abstract: An acoustic resonator is fabricated with a substrate having a substrate top surface and a piezoelectric plate having plate front and plate back surfaces. An acoustic Bragg reflector is sandwiched between the substrate top surface and the plate back surface. The reflector has a cavity with a top surface perimeter, and the acoustic Bragg reflector is configured to reflect shear acoustic waves at a resonance frequency of the acoustic resonator. The back surface is mounted on the cavity top surface perimeter except for a portion of the plate forming a diaphragm that spans the cavity. An interdigital transducer (IDT) is formed on the plate front surface such that interleaved fingers of the IDT are disposed on the diaphragm. Two or more layers of the acoustic Bragg reflector form pedestals that support the back surface of the plate opposite some or all interleaved fingers of the IDT.

Abstract: An acoustic resonator device, filter devices, and methods of making the same. An acoustic resonator device includes a substrate having a surface and a single-crystal piezoelectric plate having front and back surfaces, where 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. The device further includes an interdigital transducer formed on the front surface of the piezoelectric plate, where interleaved fingers of the IDT disposed on the diaphragm are configured such that a radio frequency signal applied to the IDT excites a primary shear acoustic mode in the diaphragm. The interleaved fingers include a first layer adjacent the diaphragm and a second layer over the first layer, the second layer having a narrower width than the first layer.

Abstract: 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.

Abstract: A filter device is provided that includes a substrate; a piezoelectric layer coupled to the substrate either directly or via one or more intermediate layers; a first interdigital transducer (IDT) of a first bulk acoustic resonator device on the piezoelectric layer and having interleaved fingers over a first cavity the first bulk acoustic resonator device; a second IDT of a second bulk acoustic resonator device on the piezoelectric layer and having interleaved fingers over a second cavity of the second bulk acoustic resonator device; a first dielectric layer having a first thickness disposed between the interleaved fingers of the first IDT; and a second dielectric layer having a second thickness disposed between the interleaved fingers of the second IDT. The first thickness is greater than the second thickness.

Abstract: An acoustic resonator is fabricated with a substrate having a substrate top surface and a piezoelectric plate having plate front and plate back surfaces. An acoustic Bragg reflector is sandwiched between the substrate top surface and the plate back surface. The reflector has a cavity with a top surface perimeter, and the acoustic Bragg reflector is configured to reflect shear acoustic waves at a resonance frequency of the acoustic resonator. The back surface is mounted on the cavity top surface perimeter except for a portion of the plate forming a diaphragm that spans the cavity. An interdigital transducer (IDT) is formed on the plate front surface such that interleaved fingers of the IDT are disposed on the diaphragm. Two or more layers of the acoustic Bragg reflector form pedestals that support the back surface of the plate opposite some or all interleaved fingers of the IDT.

Abstract: Acoustic resonator devices and acoustic filter devices. An acoustic resonator includes a piezoelectric plate having front and back surfaces, a portion of the piezoelectric plate forming a diaphragm, and a conductor pattern on the front surface, the conductor pattern comprising an interdigital transducer (IDT), interleaved fingers of the IDT on the diaphragm. A ratio of a mark of the interleaved fingers to a pitch of the interleaved fingers is greater than or equal to 0.12 and less than or equal to 0.3. A thickness of the interleaved fingers is greater than or equal to 0.85 times a thickness of the piezoelectric plate and less than or equal to 2.5 times the thickness of the piezoelectric plate.

Abstract: Filters and methods of making filters are disclosed. A filter device includes a substrate, a piezoelectric plate, and an acoustic Bragg reflector between a surface of the substrate and a back surface of the piezoelectric plate. A first portion of the piezoelectric plate has a first thickness, and a second portion of the piezoelectric plate has a second thickness less than the first thickness. A conductor pattern on front surfaces of the first and second portions of the piezoelectric plate includes a first interdigital transducer (IDT) with interleaved fingers on the first portion, and a second IDT with interleaved fingers on the second portion.

Abstract: A radio frequency filter includes bulk acoustic resonator chips that each include a substrate; a piezoelectric plate that includes multiple separate plates; and a conductor pattern on the piezoelectric layer and including an interdigitated transducer (IDT) with interleaved fingers on the piezoelectric layer opposite the substrate. The filter further includes an interposer having a surface facing the piezoelectric layer of each of the plurality of bulk acoustic resonator chips; a conductor pattern on the surface of the interposer; a conductive metal bump between the piezoelectric layer and the interposer that electrically connects the plurality of bulk acoustic resonator chips to the interposer; and a cover bonded to the substrates of the plurality of bulk acoustic resonator chips and to the interposer, wherein the cover seals an interior of the plurality bulk acoustic resonator chips.

Abstract: Resonator devices and filter devices are disclosed. An acoustic resonator includes a substrate and a piezoelectric plate having front and back surfaces separated by a piezoelectric plate thickness greater than or equal to 50 nm and less than or equal to 200 nm. An acoustic Bragg reflector is between the substrate and the back surface of the piezoelectric plate. A conductor pattern including an interdigital transducer (IDT) is on the front surface of the piezoelectric plate.

Abstract: An acoustic resonator device is provided that includes a substrate; a piezoelectric plate having front and back surfaces, the back surface attached to the substrate; a decoupling dielectric layer on the front surface of the piezoelectric plate; and an interdigital transducer (IDT) on the decoupling dielectric layer such that interleaved fingers of the IDT are over a portion of the piezoelectric plate that is over a cavity. Moreover, a thickness of the interleaved fingers is greater than or equal to 0.6 times a thickness of the piezoelectric plate and less than or equal to 1.7 times the thickness of the piezoelectric plate.

Abstract: Acoustic resonator devices and filters are disclosed. An acoustic resonator includes a substrate having a surface and a single-crystal lithium niobate (LN) plate having front and back surfaces, the back surface attached to the surface of the substrate except for a portion of the LN plate forming a diaphragm that spans a cavity in the substrate. An interdigital transducer (IDT) is formed on the front surface of the LN plate such that interleaved fingers of the IDT are disposed on the diaphragm. A half-lambda dielectric layer is formed on one of the front surface and back surface of the diaphragm. Euler angles of the LN plate are [0°, ?, 0°], where 20°???25°.