Abstract: An acoustic wave device includes a piezoelectric layer, and at least one pair of comb-shaped electrodes provided on the piezoelectric layer, each of the comb-shaped electrodes including electrode fingers each having a first layer and a second layer provided on the first layer, the first layer being a titanium nitride layer with a thickness greater than 50 nm, the second layer being a metal layer.

Abstract: An acoustic wave resonator includes a support substrate, a piezoelectric layer that is disposed on the support substrate and is a rotated Y-cut X-propagation lithium tantalate of which a cut angle is within a range of greater than 50° and less than 150°, and a pair of comb-shaped electrodes disposed on the piezoelectric layer, each of the comb-shaped electrodes including a plurality of electrode fingers, an average pitch of the electrode fingers of one of the comb-shaped electrodes being equal to or greater than ½ of a thickness of the piezoelectric layer.

Abstract: An acoustic wave device includes a piezoelectric layer, a pair of comb-shaped electrodes disposed on a first surface of the piezoelectric layer, each of the pair of comb-shaped electrodes including electrode fingers that excite an acoustic wave, a support substrate disposed at a second surface side of the piezoelectric layer, and having protruding portions and/or recessed portions on a first surface, which is closer to the piezoelectric layer, of the support substrate, each of the protruding portions and/or the recessed portions having a shape in which each of left and right side surfaces has linear slopes inclined at different angles with respect to the first surface of the piezoelectric layer in a cross-sectional view, and a second insulating layer located between the piezoelectric layer and the support substrate and disposed on the third surface, on which the protruding portions and/or the recessed portions are formed, of the support substrate.

Abstract: An acoustic wave device includes: a piezoelectric substrate: a pair of comb-shaped electrodes located on the piezoelectric substrate, each of the comb-shaped electrodes including a plurality of electrode fingers; a support substrate having protruding portions and/or recessed portions in a region overlapping with the pair of comb-shaped electrodes in plan view, the protruding portions and/or recessed portions being regularly arranged; and an insulating layer directly or indirectly bonded between the piezoelectric substrate and the support substrate, a boundary face between the insulating layer and the support substrate being provided along the protruding portions and/or the recessed portions.

Abstract: An acoustic wave resonator includes a support substrate, a piezoelectric layer that is disposed on the support substrate and is a rotated Y-cut X-propagation lithium tantalate of which a cut angle is within a range of greater than 50° and less than 150°, and a pair of comb-shaped electrodes disposed on the piezoelectric layer, each of the comb-shaped electrodes including a plurality of electrode fingers, an average pitch of the electrode fingers of one of the comb-shaped electrodes being equal to or greater than ½ of a thickness of the piezoelectric layer.

Abstract: An acoustic wave resonator includes: a piezoelectric substrate; a pair of comb-shaped electrodes that is located on the piezoelectric substrate and excites an acoustic wave, each of the pair of comb-shaped electrodes including a plurality of electrode fingers; and a polycrystalline substrate that is located at an opposite side of the piezoelectric substrate from a surface on which the pair of comb-shaped electrodes is located, an average particle size of the polycrystalline substrate being equal to or less than 66 times an average pitch of the plurality of electrode fingers.

Abstract: An acoustic wave device includes: a piezoelectric substrate: a pair of comb-shaped electrodes located on the piezoelectric substrate, each of the comb-shaped electrodes including a plurality of electrode fingers; a support substrate having protruding portions and/or recessed portions in a region overlapping with the pair of comb-shaped electrodes in plan view, the protruding portions and/or recessed portions being regularly arranged; and an insulating layer directly or indirectly bonded between the piezoelectric substrate and the support substrate, a boundary face between the insulating layer and the support substrate being provided along the protruding portions and/or the recessed portions.

Abstract: An acoustic wave resonator includes: a piezoelectric substrate; a pair of comb-shaped electrodes that is located on the piezoelectric substrate and excites an acoustic wave, each of the pair of comb-shaped electrodes including a plurality of electrode fingers; and a polycrystalline substrate that is located at an opposite side of the piezoelectric substrate from a surface on which the pair of comb-shaped electrodes is located, an average particle size of the polycrystalline substrate being equal to or less than 66 times an average pitch of the plurality of electrode fingers.