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.

An acoustic wave device includes a support substrate made of silicon, a piezoelectric body provided directly or indirectly on the support substrate, the piezoelectric body including a pair of main surfaces facing each other, and an interdigital transducer electrode provided directly or indirectly on at least one of the main surfaces of the piezoelectric body, a wave length that is determined by an electrode finger pitch of the interdigital transducer electrode being λ. An acoustic velocity V.sub.Si=(V.sub.1).sup.1/2 of bulk waves that propagate in the support substrate, which is determined by V.sub.1 out of solutions V.sub.1, V.sub.2, V.sub.3 of x derived from the expression, Ax.sup.3+Bx.sup.2+Cx+D=0, is higher than or equal to about 5500 m/s.

An acoustic wave device includes a laminated film on a support substrate and inside a portion of an outer edge of the support substrate in plan view and including a piezoelectric thin film, an IDT electrode on the laminated film, an insulating layer on the support substrate and the laminated film and extending from a region above the support substrate to a region above the laminated film, a connecting electrode on the insulating layer and electrically connected to the IDT electrode, and an external connection terminal electrically connected to the connecting electrode and disposed directly on or above the connecting electrode and outside a region where the laminated film is on the support substrate. A principal surface of the support substrate on the laminated film side includes a recess at an outer edge of the laminated film, and the recess is covered with the insulating layer.

A TF-SAW resonator with improved quality factor is provided. The resonator has its piezoelectric material in the form of a thin film and an electrode structure arranged on the piezoelectric layer. Pitch (P) and metallization ratio (n) are chosen to maximize the quality factor (Q).

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.

A ladder-type filter includes a support substrate, a piezoelectric layer provided on the support substrate, a parallel resonator including first electrode fingers provided on the piezoelectric layer and having a first average pitch and a first average duty ratio, a largest first average pitch being equal to or greater than two times a thickness of the piezoelectric layer, a first end of the parallel resonator being coupled to a path between input and output terminals, a second end of the parallel resonator being coupled to a ground, and a series resonator connected in series between the input and output terminals, the series resonator including second electrode fingers provided on the piezoelectric layer and having a second average pitch and a second average duty ratio, a second average duty ratio in at least one series resonator being less than a smallest first average duty ratio.

An electronic device comprises a first substrate having a first surface bonded to a first surface of a second substrate, one or more acoustic wave devices disposed on the first surface of each of the first substrate and the second substrate, and a thermally conductive layer disposed on a second surface of the first substrate opposite the first surface of the first substrate. The thermally conductive layer has a higher thermal conductivity than a material of which the first substrate is formed to reduce an operating temperature of the first substrate.

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.

An acoustic wave device is disclosed. The acoustic waved device can be a shear horizontal mode surface acoustic wave device. The acoustic wave device can include a piezoelectric layer, an interdigital transducer electrode over the piezoelectric layer, and a temperature compensation layer over the interdigital transducer electrode. The piezoelectric layer can be a lithium niobate layer with a cut angle in a range of −20° YX to 25° YX. The interdigital transducer electrode includes a first layer having a first thickness and a second layer having a second thickness. The first layer affects acoustic properties of the acoustic wave device and the second layer affects electrical properties of the acoustic wave device. The first layer is positioned between the piezoelectric layer and the second layer. The first thickness is configured such that a frequency response of the acoustic wave device includes a Rayleigh mode response at a frequency higher than a shear horizontal mode response resonance. The first thickness can be greater than the second thickness.

Aspects of this disclosure relate to acoustic wave devices on stacked die. A first die can include first acoustic wave device configured to generate a boundary acoustic wave. A second die can include a second acoustic wave device configured to generate a second boundary acoustic wave, in which the second die is stacked with the first die. The first acoustic wave resonator can include a piezoelectric layer, an interdigital transducer electrode on the piezoelectric layer, and high acoustic velocity layers on opposing sides of the piezoelectric layer. The high acoustic velocity layers can each have an acoustic velocity that is greater than a velocity of the boundary acoustic wave.