Abstract: Filter devices are disclosed. A filter device includes a piezoelectric plate comprising a supported portion, a first diaphragm, and a second diaphragm. The supported portion is attached to a substrate and the first and second diaphragms spans respective cavities in the substrate. A first interdigital transducer (IDT) has interleaved fingers on the first diaphragm. A second interdigital transducer (IDT) has interleaved fingers on the second diaphragm. A first dielectric layer is between the interleaved fingers of the first IDT, and a second dielectric layer is between the interleaved fingers of the second IDT. A thickness of the first dielectric layer is greater than a thickness of the second dielectric layer. The piezoelectric plate and the first and second IDTs are configured such that radio frequency signals applied to first and second IDTs excite primary shear acoustic modes in the respective diaphragms.

Abstract: Acoustic resonators and 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 including an interdigital transducer (IDT), fingers of the IDT on the diaphragm. 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. The IDT comprises a first portion having a first pitch and a first mark and a second portion having a second pitch and a second mark not equal to the first pitch and first mark.

Abstract: An acoustic wave device is provided that includes a support substrate, a piezoelectric layer on the support substrate, a first electrode and a second electrode on the piezoelectric layer in a lamination direction of the support substrate and the piezoelectric layer, the first and the second electrodes are opposed in a first direction that intersects with the lamination direction; and a space that defines either a cavity in a portion of the support substrate or an air gap between the support substrate and the piezoelectric layer. A portion of each of the first and the second electrodes overlaps the space in a plan view in the lamination direction. A first roughness of a major surface of the support substrate, opposite from the piezoelectric layer, is greater than a second roughness of a major surface of the piezoelectric layer on which the first and second electrodes are located.

Abstract: Methods of making acoustic resonators and filter devices. A method includes attaching a piezoelectric plate to a substrate, and forming a conductor pattern including an interdigital transducer (IDT) on a portion of the piezoelectric plate that forms a diaphragm spanning a cavity such that interleaved fingers of the IDT are on the diaphragm. The substrate and the piezoelectric plate are the same material.

Abstract: An acoustic wave device is provided that includes a support substrate, a piezoelectric layer on the support substrate, and an interdigital transducer electrode. A ratio d/p is less than or equal to approximately 0.5, where d is a thickness of the piezoelectric layer and p is a distance between centers of adjacent electrode fingers of the multiple electrode fingers. The interdigital transducer electrode includes an intersection region in which the adjacent electrode fingers overlap when viewed in a direction in which multiple electrode fingers face each other. Moreover, two gap regions are located between the intersection region and a corresponding one of the two busbars and includes an I-B gap that is a dimension in a direction in which the multiple electrode fingers extend. The I-B gap of at least one of the two gap regions is less than or equal to about 1.1p.

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°, 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.

Abstract: An acoustic wave device is provided that includes a cavity in a substrate, an overlapping region in which portions of adjacent first and second interdigitated electrodes oppose each other, a first gap region between a first busbar and the overlapping region and that includes the first interdigitated electrodes but not the second interdigitated electrodes, and a second gap region between a second busbar and the overlapping region and that includes the second interdigitated electrodes but not the first interdigitated electrodes. A ratio d/p is about 0.5 or less, where d is a thickness of the piezoelectric layer and p is a distance between centers of adjacent first and second interdigitated electrodes. A first wall of the cavity is located under the first busbar or the first gap region, and a second wall of the cavity is located under the second busbar or the second gap region.

Abstract: A bulk acoustic resonator that includes a substrate, a piezoelectric plate, and an interdigital transducer (IDT) formed on the front surface of the piezoelectric plate. The IDT is configured to excite a primary shear acoustic mode within the piezoelectric plate. Also included is a half-lambda dielectric layer on at least one of the front surface or the back surface of the piezoelectric plate, where a thickness of the half-lambda dielectric layer is related to a wavelength of a fundamental shear bulk acoustic wave resonance in the half-lambda dielectric layer. The device further includes an acoustic Bragg reflector sandwiched between the surface of the substrate and the back surface of the piezoelectric plate, the acoustic Bragg reflector configured to reflect the primary acoustic mode. A top layer of the alternating layers of the acoustic Bragg reflector contacts the piezoelectric plate or the half-lambda dielectric layer.

Abstract: A filter device is provided that includes a substrate having a surface and a piezoelectric plate supported by the substrate. A plurality of interdigital transducers (IDTs) for multiple resonators are provided that each have interleaved fingers at respective diaphragms of the piezoelectric plate disposed over one or more cavities. Moreover, a first resonator includes a first plurality of interleaved fingers having a first pitch and a second resonator includes a second plurality of interleaved fingers having a second pitch that is different than the first pitch. This configuration adjusts the resonance frequencies of each resonator. Moreover, a dielectric layer may be uniformly disposed over at least one surface of the respective diaphragms of the piezoelectric plate.

Abstract: An acoustic wave device is provided that includes a support substrate including top and bottom surfaces and a cavity or air gap, a piezoelectric layer supported by the support substrate and including top and bottom surfaces, and an electrode on a surface of the piezoelectric layer and including top and bottom surfaces. At least a portion of the electrode is over the cavity or the air gap, and an equation 0.002 Tg?0.5(Lb?Ls)<Te is satisfied, where Ls is a maximum length of the top surface of the electrode, Lb is a maximum length of the bottom surface of the electrode, Tg is a distance between the top surface of the piezoelectric layer and the top surface of the support substrate, and Te is a thickness of the electrode.

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°, 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.

Abstract: A filter device is provided that includes a substrate, a piezoelectric plate attached to the substrate; interdigital transducers (IDTs) of a plurality of resonators, respectively, that each have interleaved fingers at respective diaphragms of the one piezoelectric plate disposed over one or more cavities; and a dielectric layer over at least one surface of the respective diaphragms. For at least two resonators, the dielectric layer has a thickness distribution that includes a first thickness layer and a second thickness layer over the first thickness layer, and the second thickness layer of a first resonator of the at least two resonators has a coverage distribution over the first thickness layer that is different than a coverage distribution of a second resonator of the at least two resonators.

Abstract: Acoustic filters and methods of fabricating acoustic filters are disclosed. A filter includes a single-crystal piezoelectric plate having a front surface and a back surface attached to a substrate, and a plurality of acoustic resonators including a first shunt resonator, a second shunt resonator, and one or more series resonators. Each of the plurality of acoustic resonators includes an interdigital transducer (IDT) formed on the front surface of the piezoelectric plate, interleaved fingers of the IDT disposed on a respective diaphragm formed by a portion of the piezoelectric plate that spans a cavity in the substrate. A frequency setting dielectric layer is formed over the first and second shunt resonators but not over the one or more series resonators. The frequency setting dielectric layer has a thickness t1 on the first shunt resonator and a thickness t2 on the second shunt resonator, where t1 is not equal to t2.

Abstract: An acoustic resonator has a piezoelectric plate having first and second surfaces, the second surface facing a substrate, and a diaphragm of the piezoelectric plate spanning a cavity. A conductor pattern is formed on at least one of the first and second surfaces and has an interdigital transducer (IDT) having interleaved fingers on the diaphragm portion of the piezoelectric plate. At least one of a pitch of the interleaved IDT fingers or a mark of the interleaved IDT fingers varies over an area of the IDT to compensate for process-induced distortion of the diaphragm portion of the piezoelectric plate.

Abstract: An acoustic resonator device includes a substrate having a surface and a piezoelectric plate having front and back surfaces, with the back surface 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 piezoelectric plate such that interleaved fingers of the IDT are disposed on the diaphragm. Stripes of a dielectric material formed over the plate in gaps between ends of the interleaved fingers and opposing busbars of the IDT.

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°, 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.

Abstract: Acoustic filters and methods of fabricating acoustic filters are disclosed. A filter includes a single-crystal piezoelectric plate having a front surface and a back surface attached to a substrate, and a plurality of acoustic resonators including a first shunt resonator, a second shunt resonator, and one or more series resonators. Each of the plurality of acoustic resonators includes an interdigital transducer (IDT) formed on the front surface of the piezoelectric plate, interleaved fingers of the IDT disposed on a respective diaphragm formed by a portion of the piezoelectric plate that spans a cavity in the substrate. A frequency setting dielectric layer is formed over the first and second shunt resonators but not over the one or more series resonators. The frequency setting dielectric layer has a thickness t1 on the first shunt resonator and a thickness t2 on the second shunt resonator, where t1 is not equal to t2.

Abstract: There are disclosed matrix filters having an input port and sub-filters connected between the input port and respective output ports. Each of the sub-filters includes a ladder circuit with n transversely-excited film bulk acoustic resonator (XBAR) series elements and n?1 capacitor shunt elements, where n, the order of the sub-filter, is an integer greater than 2. The sub-filters having noncontiguous passbands.

Abstract: An acoustic resonator has a piezoelectric plate, a portion of the piezoelectric plate spanning a cavity in an intermediate layer of a substrate. The resonator also has an interdigital transducer on a surface of the piezoelectric plate, interleaved fingers of the IDT on the portion of the piezoelectric plate that spans the cavity The resonator has a dielectric layer over the interleaved fingers and the surface of the portion of the piezoelectric plate that spans the cavity. A thickness of the dielectric layer optimizes electromechanical coupling of the acoustic resonator.

Abstract: Acoustic resonator devices are disclosed. An acoustic resonator device includes a plurality of cells electrically connected in parallel. Each cell includes an interdigital transducer (IDT) on a piezoelectric plate, the IDT having at least 15 and not more than 35 interleaved fingers.