A surface acoustic wave device according to the present disclosure includes a support substrate; an intermediate layer laminated on the support substrate; a piezoelectric layer laminated on the intermediate layer; and an IDT electrode formed on the piezoelectric layer, an Euler angle of the support substrate is (−45°±10°, −54°±10°, 180°±30°) and an Euler angle of the piezoelectric layer is (0°±5°, 112.5°±22.5°, 0°±5°) or (0°±5°, −67.5°±22.5°, 0°±5°).

A bonded body has a supporting substrate composed of silicon, piezoelectric material substrate, and a bonding layer provided on a bonding surface of the supporting substrate and composed of a metal oxide. An amount of aluminum atoms on the bonding surface of the supporting substrate is 1.0×10.sup.11 to 1.0×10.sup.15 atoms/cm.sup.2.

An acoustic wave device includes a functional electrode provided on a first main surface of an element substrate, extended wiring lines that are electrically connected to the functional electrode and that are adjacent to each other on a second main surface facing away from the first main surface, external terminals that are connected to the extended wiring lines, respectively, and that are provided on the second main surface, a first resin portion that seals the acoustic wave device, and a second resin portion that is provided at a position which is between the element substrate and the first resin portion and which is on the second main surface.

An elastic wave device includes a supporting substrate, a high-acoustic-velocity film stacked on the supporting substrate and in which an acoustic velocity of a bulk wave propagating therein is higher than an acoustic velocity of an elastic wave propagating in a piezoelectric film, a low-acoustic-velocity film stacked on the high-acoustic-velocity film and in which an acoustic velocity of a bulk wave propagating therein is lower than an acoustic velocity of a bulk wave propagating in the piezoelectric film, the piezoelectric film is stacked on the low-acoustic-velocity film, and an IDT electrode stacked on a surface of the piezoelectric film.

The invention relates to a SAW resonator (100) comprising at least: a substrate (102); a layer (108) of piezoelectric material arranged on the substrate; a first attenuation layer (112) arranged between the substrate and the layer of piezoelectric material, and/or, when the substrate comprises at least two different layers (104, 106), a second attenuation layer (114) arranged between the two layers of the substrate; and in which the at least one attenuation layer is/are heterogeneous.

In a composite component, a semiconductor device is stacked on an elastic wave device. Side electrodes extend from at least one side surface of a piezoelectric substrate of the elastic wave device to at least a side surface of a semiconductor substrate of the semiconductor device and are connected to an IDT electrode and functional electrodes. The side electrodes extend onto at least one of a second main surface of the piezoelectric substrate and a second main surface of the semiconductor substrate.

An acoustic wave resonator includes: a support substrate; a piezoelectric substrate located on the support substrate; a first amorphous layer that is in contact with the support substrate and is mainly composed of one or more constituent elements of the support substrate; a second amorphous layer that is in contact with the piezoelectric substrate and the first amorphous layer, is mainly composed of one or more constituent elements of the piezoelectric substrate, and is thinner than the first amorphous layer; and a pair of comb-shaped electrodes that is located on an opposite surface of the piezoelectric substrate from the support substrate, each of the pair of comb-shaped electrodes including electrode fingers.

An acoustic wave device includes a piezoelectric layer, an IDT electrode, a high-acoustic-velocity support substrate, and a low-acoustic-velocity film. The high-acoustic-velocity support substrate is located on an opposite side of the piezoelectric layer from the IDT electrode in the thickness direction of the piezoelectric layer. The low-acoustic-velocity film is disposed between the high-acoustic-velocity support substrate and the piezoelectric layer in the thickness direction. The high-acoustic-velocity support substrate includes a base region and a surface region disposed nearer to the low-acoustic-velocity film than the base region in the thickness direction and whose crystal quality is worse than that of the base region. The surface region includes first and second layers disposed nearer to the base region than the first layer in the thickness direction and whose crystal quality is better than that of the first layer.

A multilayer piezoelectric substrate for a surface acoustic wave resonator comprises a carrier substrate having an upper surface, a high acoustic velocity dielectric layer having a lower surface disposed on the upper surface of the carrier substrate and an upper surface to reflect acoustic energy generated by the surface acoustic wave resonator away from the carrier substrate, a low acoustic velocity dielectric layer having a lower surface disposed on the upper surface of the high acoustic velocity dielectric layer and an upper surface, the low acoustic velocity dielectric layer exhibiting a lower acoustic velocity than an acoustic velocity of the high acoustic velocity dielectric layer, and a layer of piezoelectric material having a lower surface disposed on the upper surface of the low acoustic velocity dielectric layer.

An acoustic wave device includes a support substrate, a piezoelectric layer, and an IDT electrode. The piezoelectric layer is over the support substrate. The IDT electrode is on the piezoelectric layer, and includes a plurality of electrode fingers. An intersecting width of the plurality of electrode fingers is equal to or smaller than about 5λ.