A surface acoustic wave (SAW) device includes a substrate; an interdigital transducer (IDT) having lead-out portions and arrays of interdigital electrodes formed on the substrate, wherein the interdigital electrodes includes central portions, end portions, and intermediate portions between the end portions and the lead-out portions, and a thickness of the interdigital electrodes at the end portions is greater than a thickness of the interdigital electrodes at the central portions and the intermediate portions, thereby forming protruding structures at the end portions of the interdigital electrodes; a protective layer formed on the protruding structures at the end portions of the interdigital electrodes; a first temperature compensation layer formed on the protective layer; a second temperature compensation layer formed on the first temperature compensation layer and on the central portions and the intermediate portions of the interdigital electrodes; and a passivation layer formed on the second temperature compensation layer.

A surface acoustic wave (SAW) device includes: a substrate; a finger portion of an interdigital transducer (IDT) electrode disposed on the substrate; a pad portion of the interdigital transducer electrode electrically connected to the finger portion; and a wiring electrode disposed on the pad portion. The wiring electrode includes a contact metal layer and an aluminum-based layer. The contact metal layer is disposed between the pad portion and the aluminum-based layer. The contact metal layer includes platinum, palladium, or gold.

An acoustic wave device is disclosed. The acoustic wave device can include a piezoelectric layer, and an interdigital transducer electrode formed with the piezoelectric layer. The interdigital transducer electrode includes a finger extending from a bus bar. The finger has a first region and a second region between the first region and the bus bar. The finger has a lower side and an upper side opposite the lower side. The lower side is closer to the piezoelectric layer than the upper side. Widths of the lower side in the first and second regions are generally the same, and a width of the upper side in the first region is greater than a width of the upper side in the second region.

An acoustic wave filter device includes series arm resonators and parallel arm resonators. A parallel arm resonator that has the highest resonant frequency has a reflector wavelength that is the same or substantially the same as an IDT wavelength and has an IDT-reflector gap that is about 0.5 times the reflector wavelength. The remaining parallel arm resonators each have a reflector wavelength longer than the IDT wavelength and have an IDT-reflector gap shorter than about 0.5 times the reflector wavelength.

A surface acoustic wave device comprising a base substrate, a piezoelectric layer and an electrode layer in between the piezoelectric layer and the base substrate, a comb electrode formed on the piezoelectric layer comprising a plurality of electrode means with a pitch p, defined asp=A, with A being the wavelength of the standing acoustic wave generated by applying opposite potentials to the electrode layer and comb electrode, wherein the piezoelectric layer comprises at least one region located in between the electrode means, in which at least one physical parameter is different compared to the region underneath the electrode means or fingers. A method of fabrication for such surface acoustic wave device is also disclosed. The physical parameter may be thickness, elasticity, doping concentration of Ti or number of protons obtained by proton exchange.

A filter device includes a piezoelectric substrate, a dielectric layer on the piezoelectric substrate, a first IDT electrode on the dielectric layer, a second IDT electrode positioned on the piezoelectric substrate in an area where the dielectric layer is not provided such that the first and second IDT electrodes are side by side in an acoustic wave propagation direction extending along a principal surface of the piezoelectric substrate, a first reflector on the dielectric layer and adjacent to the first IDT electrode on a side of the second IDT electrode, and a second reflector on the piezoelectric substrate and adjacent to the second IDT electrode on a side of the first IDT electrode. The dielectric layer includes an edge portion between the first and second reflectors in planar view seen from a stacking direction of the piezoelectric substrate and the dielectric layer.

An acoustic wave device includes a piezoelectric substrate and an IDT electrode including an adhesive layer on the piezoelectric substrate, and an electrode layer on the adhesive layer. The electrode layer and the adhesive layer each include a metal element as a main material, and an additive. The additive in the electrode layer and the additive in the adhesive layer are of the same element.

A surface acoustic wave (SAW) filter having improved performance. In one example the SAW filter includes a piezoelectric substrate on which a plurality of interdigital transducer (IDT) electrodes are disposed, the piezoelectric substrate having at least two different thicknesses corresponding to regions where the plurality of IDT electrodes are disposed, and a support substrate supporting the piezoelectric substrate. In one example the piezoelectric substrate has different thicknesses selected based on respective pitches of the IDT electrodes. The piezoelectric substrate may have a flat bottom surface and top surfaces, different heights being defined between the flat bottom surface and each of the top surfaces based on the thicknesses of the piezoelectric substrate.

An acoustic wave device comprises a substrate including a piezoelectric material, interdigital transducer (IDT) electrodes disposed on a surface of the substrate, a first dielectric film having a lower surface disposed on the IDT electrodes and the surface of the substrate, first strips formed of a first material having a density greater than a density of the first dielectric film disposed within the first dielectric film over tips of the interdigitated electrode fingers in the edge regions of the IDT electrodes, and second strips formed of a second material having a density greater than the density of the first dielectric film disposed within the first dielectric film in the gap regions of the IDT electrodes, laterally spaced from the first strips in a direction perpendicular to a direction of propagation of a main acoustic wave through the acoustic wave device, and extending only partially over the gap regions.

A surface acoustic wave device comprising a base substrate, a piezoelectric layer and an electrode layer in between the piezoelectric layer and the base substrate, a comb electrode formed on the piezoelectric layer comprising a plurality of electrode means with a pitch p, defined asp=A, with A being the wavelength of the standing acoustic wave generated by applying opposite potentials to the electrode layer and comb electrode, wherein the piezoelectric layer comprises at least one region located in between the electrode means, in which at least one physical parameter is different compared to the region underneath the electrode means or fingers. A method of fabrication for such surface acoustic wave device is also disclosed. The physical parameter may be thickness, elasticity, doping concentration of Ti or number of protons obtained by proton exchange.