An acoustic wave resonator is disclosed. The acoustic wave resonator can include a piezoelectric layer, an interdigital transducer electrode positioned over the piezoelectric layer, a temperature compensation layer positioned over the interdigital transducer electrode, and a velocity reduction cover that extends over at least a portion of a central region of the interdigital transducer electrode and over at least a portion of the temperature compensation layer. The velocity reduction cover is arranged to cause a velocity of an acoustic wave generated by the acoustic wave resonator to be reduced.

An acoustic wave resonator includes: an IDT located on a piezoelectric substrate, including comb-shaped electrodes facing each other and including electrode fingers and a bus bar connecting the electrode fingers; a first silicon oxide film located on the electrode fingers in an overlap region where the electrode fingers overlap and having a film thickness in a part of edge regions, which correspond to both ends of the overlap region, equal to or less than that in a center region sandwiched between the edge regions; and a second silicon oxide film located on the electrode fingers, containing an element slowing an acoustic velocity in a silicon oxide film when being added to the silicon oxide film, having a concentration of the element greater than that in the first silicon oxide film, and having a film thickness in a part of the edge regions greater than that in the center region.

An acoustic wave device comprises a substrate including a piezoelectric material, and interdigital transducer (IDT) electrodes disposed on a surface of the substrate. The IDT electrodes have gap regions, edge regions, and center regions. A maximum width of the IDT electrodes in the gap regions is greater than the maximum width of the IDT electrodes in the edge regions, thereby achieving a velocity of an acoustic wave in the gap regions being greater than the velocity of the acoustic wave in the center regions, and the velocity of the acoustic wave in the center regions being greater than the velocity of the acoustic wave in the edge regions.

An acoustic wave device comprises a substrate including a piezoelectric material, interdigital transducer (IDT) electrodes disposed on a surface of the substrate, the IDT electrodes having gap regions, edge regions, and center regions, a first dielectric film having a lower surface disposed on the IDT electrodes and the surface of the substrate, and a material having a density greater than a density of the first dielectric film disposed above the gap regions of the IDT electrodes.

An acoustic wave device comprises a substrate including a piezoelectric material, interdigital transducer (IDT) electrodes disposed on an upper surface of the substrate. The IDT electrodes having gap regions, edge regions, and center regions. A duty factor of the IDT electrodes in the edge regions is greater than the duty factor of the IDT electrodes in the center regions. A first dielectric film is disposed above the IDT electrodes and an upper surface of the substrate. The first dielectric film has a greater thickness in portions of the center regions than in portions proximate the gap regions.

A surface acoustic wave resonator comprises at least one set of interdigital transducer (IDT) electrodes disposed on an upper surface of a piezoelectric substrate between first and second reflector gratings, a layer of silicon nitride disposed over the at least one set of IDT electrodes and the first and second reflector gratings, and a continuous trench formed in the layer of silicon nitride over portions of bus bar electrodes and tips of electrode fingers of the at least one set of IDT electrodes and over portions of bus bar electrodes and electrode fingers of the first and second reflector gratings to reduce acoustic leakage at electrode fingers of the first and second reflector gratings proximate the at least one set of IDT electrodes.

A longitudinally coupled resonator acoustic wave filter includes first, second, and third IDT electrodes disposed on a piezoelectric substrate. The first, second, and third IDT electrodes include first electrode fingers and second electrode fingers. The first, second, and third IDT electrodes include narrow-pitch electrode finger portions in which the pitch between electrode fingers is narrower than in the remaining electrode finger portions. In the first, second, and third IDT electrodes, an overlap area includes a central area and first and second edge areas at opposite ends of the central area in the direction in which the first and second electrode fingers extend. In the remaining electrode finger portions the first electrode fingers and the second electrode fingers include wide portions in the first or second edge area.

Surface acoustic wave (SAW) resonator, SAW filters, and methods of fabricating SAW filters. A first plurality of parallel conductors extending from a first bus bar are formed on a surface of a 128-degree Y-cut lithium niobate substrate. A second plurality of parallel conductors extending from a second bus bar are formed on the surface of the substrate, the second plurality of parallel conductors interleaved with the first plurality of parallel conductors. An SiO2 layer overlays the first and second pluralities of parallel conductors. The first and second pluralities of parallel conductors are substantially copper and have a thickness D.sub.CU defined by 0.12PD.sub.CU0.24P, where P is a center-to-center spacing of adjacent parallel conductors. The SiO2 layer has a thickness D.sub.OX defined by 3.1D.sub.CUD.sub.OX4.5D.sub.CU.

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.

An acoustic wave resonator includes: a piezoelectric substrate that is a lithium tantalate substrate or a lithium niobate substrate and has a thickness of 20 m or less; a support substrate that has an upper surface bonded with a lower surface of the piezoelectric substrate And is a glass substrate mainly composed of silicon oxide; a plurality of electrode fingers that are located on an upper surface of the piezoelectric substrate, excite an acoustic wave, and include a metal film mainly composed of at least one of Cr, Mo, and W.