A method of manufacturing a surface acoustic wave resonator includes forming or providing a support substrate layer, forming or providing piezoelectric layer of lithium niobate over the support substrate layer, and forming or providing an interdigital transducer electrode including a plurality of fingers over the piezoelectric layer. The piezoelectric layer formed or provided having a cut angle (e.g., the piezoelectric angle is cut so as to have a crystal orientation) that allows the surface acoustic wave device to operate as a longitudinally leaky surface acoustic wave device that confines the acoustic wave energy within the piezoelectric substrate and that has less propagation attenuation and a higher electromechanical coupling coefficient k.sup.2.

A surface acoustic wave device includes a quartz layer, a piezoelectric layer, and an Inter Digital Transducer. A rotation in a right-screw direction is assumed as a +-rotation. A three-dimensional coordinate system formed by an x1-axis, a y1-axis, and a z1-axis respectively matching an X-axis, a Y-axis, and a Z-axis as crystallographic axes of a quartz-crystal is rotated from +125.25° in a range of ±3° with the x1-axis as a rotation axis. Subsequently, the three-dimensional coordinate system is rotated from +45° in a range of ±2° with the z1-axis as the rotation axis. Subsequently, the three-dimensional coordinate system is rotated from −45° in a range of ±2° with the x1-axis as the rotation axis. The quartz layer is cut along a surface as a sectional plane perpendicular to the z1-axis. The quartz layer has a propagation direction of the surface acoustic wave in a direction parallel to the x1-axis.

An acoustic wave device includes a piezoelectric layer made of lithium niobate or lithium tantalate, and first and second electrodes opposed to each other in a direction that intersects with a thickness direction of the piezoelectric layer. The first and second electrodes are adjacent electrodes, and, when a thickness of the piezoelectric layer is d and a distance between centers of the first and second electrodes is p, d/p is less than or equal to about 0.5.

An acoustic wave device includes a piezoelectric layer, at least one pair of electrodes adjacent to each other, and an additional film. The piezoelectric layer is made of lithium niobate or lithium tantalate, and includes first and second opposing principal surfaces. The at least one pair of electrodes is located on the first principal surface of the piezoelectric layer. The additional film is located on the piezoelectric layer or either one or both of the electrodes so as to overlap, in plan view, either one or both of areas in which the electrodes are located and an area between the electrodes. When d represents a thickness of the piezoelectric layer and p represents a center-to-center distance between the electrodes, d/p is equal to or less than about 0.5.

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.

A surface acoustic wave (SAW) device and methods of making the same are disclosed. The surface acoustic wave device includes a piezoelectric layer coupled to a high acoustic velocity layer at a first surface of the piezoelectric layer. At least one transducer is provided over a second surface of the piezoelectric layer. The at least one transducer comprises a plurality of IDT electrodes that are formed from a substantially two-dimensional (2D) conductive material and configured to propagate a surface acoustic wave having an operating wavelength along the piezoelectric layer.

An elastic wave device includes a substrate, a multilayer film located on the substrate, an LT layer located on the multilayer film and made of a single crystal of LiTaO.sub.3, and an IDT electrode located on the LT layer. The LT layer has a thickness of 0.3λ or less, where λ is twice a pitch of electrode fingers of the IDT electrode. The LT layer has Euler angles of (0°±10°, −25° or more and 15° or less, 0° or more and 360° or less).

An acoustic wave device includes a piezoelectric substrate and an IDT electrode on the piezoelectric substrate. The IDT electrode includes a first comb-shaped electrode including first electrode fingers and a second comb-shaped electrode including second electrode fingers. The IDT electrode includes a first portion in which a main electrode layer includes a first metal and a second portion in which a main electrode layer includes a second metal. The first electrode fingers and the second comb-shaped electrode include first facing portions facing each other with a gap in between, and the second electrode fingers and the first comb-shaped electrode include second facing portions facing each other with a gap in between. At least one of the first facing portions and second facing portions is the second portion, and a portion of the IDT electrode other than the second portion is the first portion.

Sputter depositing a metallic layer on a substrate in the fabrication of a resonator device includes providing a magnetron sputtering apparatus comprising a chamber, a substrate support disposed within the chamber, a target made from a metallic material, and a plasma generating device, wherein the substrate support and the target are separated by a distance of 10 cm or less; supporting the substrate on the substrate support; performing a DC magnetron sputtering step that comprises sputtering the metallic material from the target onto the substrate so as to form a metallic layer on the substrate, wherein during the DC magnetron sputtering step the chamber has a pressure of at least 6 mTorr of a noble gas, the target is supplied with a power having a power density of at least 6 W/cm.sup.2, and the substrate has a temperature in the range of 200-600° C.

An acoustic wave resonator includes a piezoelectric substrate and an IDT electrode on the top surface of the piezoelectric substrate. Between a resonance frequency and anti-resonance frequency due to a surface acoustic wave, one to four of at least one of resonance frequencies or anti-resonance frequencies due to bulk waves are located.