A surface acoustic wave package has a piezoelectric layer over a substrate and a thermally conductive structure attached to the substrate. The outer boundary of the piezoelectric layer is removed (e.g., etched) so that a resulting outer edge of the piezoelectric layer is spaced inward of an inner edge of the thermally conductive structure. The piezoelectric layer does not contact the thermally conductive structure to inhibit damage to the piezoelectric layer due to a stress differential between the substrate and the thermally conductive structure during a packaging process.

A method of making an acoustic wave device includes forming or providing a substrate, forming or providing a functional layer over at least a portion of the substrate, forming or providing a piezoelectric layer over at least a portion of the functional layer, and forming or providing an interdigital transducer electrode over the piezoelectric layer. Forming or providing the piezoelectric layer includes removing a portion of the piezoelectric layer so that the piezoelectric layer has an outer edge spaced inward of an outer edge of the substrate, and so that the outer edge of the piezoelectric layer is tapered at an angle relative to a surface of the substrate to thereby reduce an acoustic reflection magnitude at said outer edge of the piezoelectric layer.

A surface acoustic wave device using a longitudinally polarized guided wave comprises a composite substrate comprising a piezoelectric layer formed over a base substrate, wherein the crystalline orientation of the piezoelectric layer with respect to the base substrate is such that, the phase velocity of the longitudinally polarized wave is below the critical phase velocity of the base substrate at which wave guiding within the piezoelectric layer vanishes. A method of fabrication of such surface acoustic wave device is also disclosed.

A SAW device having a stacked design of functional layers is proposed that is build up on a carrier substrate (SUB) that is chosen to provide a high acoustic velocity. The stack further comprises a thin TCF compensation layer (TCL), a thin film piezoelectric layer (PEL) and a set of interdigital electrodes (IDE) on top of the piezoelectric layer. Energy of the desired mode mainly in the high acoustic velocity material. Despite the high possible operating frequencies the SAW device can reliably be manufactured with present lithographic techniques.

Disclosed are a resonant device and an acoustic filter. The resonant device includes a wafer substrate, a piezoelectric layer and an interdigital electrode layer. The piezoelectric layer is located on a side of the wafer substrate and includes a piezoelectric monocrystal material, and the piezoelectric monocrystal material includes a first crystal axis, a second crystal axis and a third crystal axis perpendicular to each other. A direction of an electric field generated by the interdigital electrode layer in the piezoelectric layer is a device direction.

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.

A hybrid structure for a surface acoustic wave device comprises a useful layer of piezoelectric material having a free first surface and a second surface disposed on a support substrate that has a lower coefficient of thermal expansion than that of the useful layer. The hybrid structure further comprises a trapping layer disposed between the useful layer and the support substrate, and at least one functional interface of predetermined roughness between the useful layer and the trapping layer.

A layered structure (100) for transmission of an acoustic wave, the layered structure (100) comprising: a substrate layer (102); and a second layer (104) over the substrate layer (102), wherein the second layer (104) comprises a plurality of discrete portions (105) adjacent to each other, each discrete portion (105) of the plurality of discrete portions (105) comprising a first subregion (104A) and a second subregion (104B). Also an epitaxial layer (108), grown over the second layer (104), for transmission of the acoustic wave in a major plane of the epitaxial layer (108), wherein a periodicity (λ) of a wavelength of the acoustic wave to be transmitted through the epitaxial layer (108) is approximately equal to a sum of a width (d.sub.A) of the first subregion (104A) and a width (d.sub.B) of the second subregion (104B).

An elastic wave device includes a support substrate made of silicon, a piezoelectric film disposed directly or indirectly on the support substrate, and an interdigital transducer electrode disposed on one surface of the piezoelectric film. A higher-order mode acoustic velocity of propagation through the piezoelectric film is equal or substantially equal to an acoustic velocity V.sub.si=(V.sub.1).sup.1/2 of propagation through silicon or higher than the acoustic velocity V.sub.si, where V.sub.si is specified by V.sub.1 among solutions V.sub.1, V.sub.2, and V.sub.3 with respect to x derived from Ax.sup.3+Bx.sup.2+Cx+D=0.

A SAW device having a stacked design of functional layers is proposed that is build up on a carrier substrate (SUB) that is chosen to provide a high acoustic velocity. The stack further comprises a thin TCF compensation layer (TCL), a thin film piezoelectric layer (PEL) and a set of interdigital electrodes (IDE) on top of the piezoelectric layer. Energy of the desired mode mainly in the high acoustic velocity material. Despite the high possible operating frequencies the SAW device can reliably be manufactured with present lithographic techniques.