Abstract: An acoustic wave device includes a supporting substrate, a piezoelectric layer, and an IDT electrode. The piezoelectric layer is on the supporting substrate. The IDT electrode is on the piezoelectric layer. The supporting substrate is a silicon carbide substrate, which has a hexagonal crystal structure. The acoustic wave device uses an SH wave as a main mode.

Abstract: An acoustic wave device includes a support substrate, a piezoelectric layer on the support substrate, and an IDT electrode on the piezoelectric layer and including a plurality of electrode fingers. The support substrate is a silicon carbide substrate including a 3C-SiC cubic crystal structure. The piezoelectric layer is a lithium tantalate layer or a lithium niobate layer. An SH wave is used as a main mode.

Abstract: An acoustic wave device includes a piezoelectric layer and first and second electrodes facing each other in a direction intersecting a thickness direction of the piezoelectric layer. The acoustic wave device utilizes a bulk wave in a thickness-shear primary mode. A material of the piezoelectric layer is lithium niobate or lithium tantalate. At least a portion of each of the first and second electrodes is embedded in the piezoelectric layer.

Abstract: An acoustic wave device includes a piezoelectric layer and first and second electrodes. The first and second electrodes face each other in a direction intersecting with a thickness direction of the piezoelectric layer. The acoustic wave device uses a bulk wave of a thickness-shear primary mode. A material of the piezoelectric layer is lithium niobate or lithium tantalate. The piezoelectric layer is on a first main surface of the silicon substrate. The acoustic wave device further includes a trap region on a side of a second main surface of the piezoelectric layer.

Abstract: An elastic wave device includes a SiNx layer stacked directly or indirectly on a supporting substrate made of a semiconductor material, a piezoelectric film stacked on directly or indirectly the SiNx layer, and an interdigital transducer electrode stacked directly or indirectly on at least one main surface of the piezoelectric film. In the SiNx layer, x is about 1.34 or more and about 1.66 or less.

Abstract: An acoustic wave device includes a support substrate, a piezoelectric layer, and an IDT electrode. The support substrate is made of quartz. The piezoelectric layer is provided on the support substrate and is made of LiTaO3. The IDT electrode is on the piezoelectric layer and includes electrode fingers. The IDT electrode is on a negative surface side of the piezoelectric layer. The cut angle of the piezoelectric layer is equal to or more than about 39° Y and equal to or less than about 48° Y.

Abstract: An acoustic wave device includes a support substrate, a piezoelectric layer, and an IDT electrode. The support substrate is made of quartz. The piezoelectric layer is on the support substrate and is made of LiTaO3. The IDT electrode is on the piezoelectric layer and includes electrode fingers. The IDT electrode is on a positive surface side of the piezoelectric layer. The cut angle of the piezoelectric layer is equal to or less than about 49° Y.

Abstract: A multiplexer includes N acoustic wave filters each including one end connected in common and having a different pass band, in which when the N acoustic wave filters are in order from a side of a lower frequency of the pass band, at least one n-th acoustic wave filter among the N acoustic wave filters excluding an acoustic wave filter having the highest frequency of the pass band includes one or more acoustic wave resonators including a support substrate, a silicon nitride film laminated on the support substrate, a silicon oxide film laminated on the silicon nitride film, a piezoelectric body laminated on the silicon oxide film, and an IDT electrode provided on the piezoelectric body. All acoustic wave filters having a pass band in a higher frequency than a frequency of a pass band of the n-th acoustic wave filter satisfy fh1_t(n)>fu(m) or fh1_t(n)<fl(m).

Abstract: An acoustic wave device includes a support substrate including silicon, a piezoelectric layer in which a rotated Y-cut X-propagation lithium tantalate is included, and an IDT electrode. A film thickness of the piezoelectric layer is less than or equal to about 1?. When ?111 is an angle between a directional vector k111, and a direction of silicon and n is an arbitrary integer, the angle ?111 is in a range of about 0°+120°×n??111?45°+120°×n or in a range of about 75°+120°×n??111?120°+120°×n when the IDT electrode is on a positive surface of the piezoelectric layer and the angle ?111 is in a range of about 15°+120°×n??111?105°+120°×n when the IDT electrode is on the negative surface of the piezoelectric layer.

Abstract: An elastic wave device includes a piezoelectric layer, an IDT electrode on the piezoelectric layer, a high-acoustic-velocity member, a low-acoustic-velocity film between the high-acoustic-velocity member and the piezoelectric layer. The piezoelectric layer is made of lithium tantalate, the IDT electrode includes metal layers including an Al metal layer and a metal layer having a higher density than Al. Expression 1 is satisfied: 301.74667?10.83029×TLT?3.52155×TELE+0.10788×TLT2+0.01003×TELE2+0.03989×TLT×TELE?0 expression 1, where ? represents a wavelength defined by an electrode finger pitch of the IDT electrode, TLT (%) represents a normalized film thickness of the piezoelectric layer to the wavelength ?, and TELE (%) represents a normalized film thickness of the IDT electrode in terms of Al to the wavelength ?.

Abstract: An acoustic wave device includes a support substrate, a piezoelectric film, a functional electrode, and a support. The support substrate includes a cavity. The piezoelectric film is provided on the support substrate to cover the cavity. The functional electrode is provided on the piezoelectric film to overlap the cavity when viewed in a plan view. The support is in the cavity of the support substrate to support the piezoelectric film. The functional electrode includes electrodes arranged in a direction crossing the thickness direction of the piezoelectric film. The electrodes include a first electrode and a second electrode. The first electrode and the second electrode oppose each other in a direction crossing the thickness direction of the piezoelectric film and are connected to different potentials. Adjacent ones of the electrodes overlap each other in a direction orthogonal to a longitudinal direction of the first electrode.

Abstract: An acoustic wave device includes a semiconductor substrate having a first main surface and a second main surface, a piezoelectric thin film provided directly on or indirectly above the first main surface of the semiconductor substrate, and an IDT electrode provided on the piezoelectric thin film. A semiconductor defining the semiconductor substrate is a high acoustic velocity material in which an acoustic velocity of a bulk wave propagating therethrough is higher than an acoustic velocity of an acoustic wave propagating through the piezoelectric thin film. The semiconductor substrate includes a first region including the first main surface and a second region which is a region other than the first region and includes the second main surface. An electric resistance of the first region is lower than an electric resistance of the second region.

Abstract: An acoustic wave device includes a (111)-oriented silicon substrate, a silicon nitride layer, a silicon oxide layer, a lithium tantalate layer, and an IDT electrode on the lithium tantalate layer. When the wavelength determined by the electrode finger pitch of the IDT electrode is ?, the thickness of the silicon nitride layer, SiN [?], the thickness of the silicon oxide layer, SiO2 [?], the thickness of the lithium tantalate layer, LT [?], and one of the Euler angles of the lithium tantalate layer, LT? [deg.], are thicknesses and an angle in ranges in which the phase of a first higher-order mode is about ?20° or less.

Abstract: In an acoustic wave device, an antenna end resonator electrically closest to a first terminal is a first acoustic wave resonator. In each of the first acoustic wave resonator and a second acoustic wave resonator, a thickness of a piezoelectric layer is equal to or less than about 3.5?. A cut angle of the piezoelectric layer of the first acoustic wave resonator is within a range of ?B±4°. The cut angle of the piezoelectric layer of the second acoustic wave resonator has a larger difference from ?B (°) than the cut angle of the piezoelectric layer of the first acoustic wave resonator.

Abstract: An acoustic wave device includes a piezoelectric body including first and second main surfaces facing each other, an IDT electrode provided on the first main surface of the piezoelectric body and including electrode fingers, a high acoustic velocity member on the second main surface side of the piezoelectric body, in which an acoustic velocity of a propagating bulk wave is higher than an acoustic velocity of an acoustic wave propagating through the piezoelectric body, and a first dielectric film provided on an upper surface of the electrode fingers, in which a portion where a dielectric is not present is provided between the electrode fingers of the IDT electrode.

Abstract: An acoustic wave device includes a silicon oxide film, a lithium tantalate film, an IDT electrode, and a protection film that are laminated on a support substrate made of silicon. A wavelength normalized film thickness of a lithium tantalate film is denoted by TLT, an Euler angle is ?LT, a wavelength normalized film thickness of the silicon oxide film is TS, a wavelength normalized film thickness of the IDT electrode in terms of aluminum thickness is TE, a wavelength normalized film thickness of a protection film is TP, a propagation direction in the support substrate is ?Si, and a wavelength normalized film thickness of the support substrate is TSi. Values of TLT, ?LT, TS, TE, TP, and ?Si are set such that Ih corresponding to an intensity of a response of a spurious response represented by Formula (1) is greater than about ?2.4 in a spurious response.

Abstract: An acoustic wave device includes N band pass filters with first ends connected to define a common connection and having different pass bands. At least one of the band pass filters includes acoustic wave resonators including a lithium tantalate film having Euler angles (?LT=0°±5°, ?LT, ?LT=0°±15°), a silicon support substrate, a silicon oxide film between the lithium tantalate film and the silicon support substrate, an IDT electrode, and a protective film. In at least one acoustic wave resonator, a frequency fh1_t(n) satisfies Formula (3) or Formula (4) for all m where m>n: fh1_t(n)>fu(m)??Formula (3); and fh1_t(n)<fl(m)??Formula (4). In Formulas (3) and (4), fu(m) and fl(m) represent the frequencies of the high-frequency end and the low-frequency end of the pass band in the m band pass filters.

Abstract: An elastic wave device includes a piezoelectric substrate and an interdigital transducer electrode on the piezoelectric substrate, the piezoelectric substrate including a piezoelectric layer and a high-acoustic-velocity member layer, the piezoelectric layer being stacked on the high-acoustic-velocity member layer. The piezoelectric layer is made of lithium tantalate. Denoting an elastic wave propagation direction as a first direction, and a direction perpendicular or substantially perpendicular to the first direction as a second direction, a central region, low-acoustic-velocity regions, and high-acoustic-velocity regions are provided in the interdigital transducer electrode in the second direction. The low-acoustic-velocity regions include mass-adding films on electrode fingers.

Abstract: An acoustic wave device includes a high-acoustic-velocity support substrate, a low-acoustic-velocity film provided on the high-acoustic-velocity support substrate, a piezoelectric layer provided on the low-acoustic-velocity film, and an IDT electrode provided on the piezoelectric layer. An acoustic velocity of a bulk wave propagating through the high-acoustic-velocity support substrate is higher than an acoustic velocity of an acoustic wave propagating through the piezoelectric layer. An acoustic velocity of a bulk wave propagating through the low-acoustic-velocity film is lower than an acoustic velocity of a bulk wave propagating through the piezoelectric layer. The low-acoustic-velocity film has a first portion and a second portion that is located closer to the high-acoustic-velocity support substrate than the first portion. The first and second portions include the same or similar materials.

Abstract: In an acoustic wave device, an antenna end resonator electrically closest to a first terminal is a first acoustic wave resonator. In each of the first acoustic wave resonator and a second acoustic wave resonator, a thickness of a piezoelectric layer is equal to or less than about 3.5?. A cut angle of the piezoelectric layer of the first acoustic wave resonator is within a range of ?B±4°. The cut angle of the piezoelectric layer of the second acoustic wave resonator has a larger difference from ?B (°) than the cut angle of the piezoelectric layer of the first acoustic wave resonator.