A vibration element includes: a quartz crystal substrate having a first vibration part and a second vibration part; a pair of first excitation electrodes formed at two main surfaces of the quartz crystal substrate, at the first vibration part; and a pair of second excitation electrodes formed in such a way as to sandwich the second vibration part in a direction of thickness of the quartz crystal substrate, at the second vibration part. At least one second excitation electrode of the pair of second excitation electrodes is formed at an inclined surface inclined to at least one of the two main surfaces.

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.

A substrate for a surface acoustic wave device or bulk acoustic wave device, comprising a support substrate and an piezoelectric layer on the support substrate, wherein the support substrate comprises a semiconductor layer on a stiffening substrate having a coefficient of thermal expansion that is closer to the coefficient of thermal expansion of the material of the piezoelectric layer than that of silicon, the semiconductor layer being arranged between the piezoelectric layer and the stiffening substrate.

To provide a vibrator made of a piezoelectric crystal having a larger electromechanical coupling coefficient and a more satisfactory frequency-temperature characteristic than those of quartz, a vibrating piece (101) is made of a Ca.sub.3Ta(Ga.sub.1-xAl.sub.x).sub.3Si.sub.2O.sub.14 single crystal (0<x≤1). In the single crystal, letting θ be a rotation angle from an X-Z plane about an X-axis serving as a rotation axis, 18x+17.5≤θ≤24x+24.5 is set. In addition, the vibrating piece (101) is made of a Ca.sub.3Nb(Ga.sub.1-xAl.sub.x).sub.3Si.sub.2O.sub.14 single crystal (0<x≤1). In the single crystal of this arrangement, letting θ be a rotation angle from an X-Z plane about an X-axis serving as a rotation axis, 25x+23.083≤θ≤32x+26.167 is set.

A vibration element includes: a quartz crystal substrate having a first vibration part and a second vibration part; a pair of first excitation electrodes formed at two main surfaces of the quartz crystal substrate, at the first vibration part; and a pair of second excitation electrodes formed in such a way as to sandwich the second vibration part in a direction of thickness of the quartz crystal substrate, at the second vibration part. At least one second excitation electrode of the pair of second excitation electrodes is formed at an inclined surface inclined to at least one of the two main surfaces.

A substrate for a surface acoustic wave device or bulk acoustic wave device, comprising a support substrate and an piezoelectric layer on the support substrate, wherein the support substrate comprises a semiconductor layer on a stiffening substrate having a coefficient of thermal expansion that is closer to the coefficient of thermal expansion of the material of the piezoelectric layer than that of silicon, the semiconductor layer being arranged between the piezoelectric layer and the stiffening substrate.

A piezoelectric film that includes crystalline AlN; at least one first element partially replacing Al in the crystalline AlN; and a second element doping the crystalline AlN and which has an ionic radius smaller than that of the first element and larger than that of Al.

Provided are a piezoelectric resonator and a manufacturing method of the piezoelectric resonator. The piezoelectric resonator includes a substrate, a recess is formed on an upper surface of the substrate; a first piezoelectricity layer covering the upper surface of the substrate and an opening of the recess to enable the recess and the first piezoelectricity layer to form a cavity; a first electrode and a temperature compensation layer, which are both disposed on a side of the first piezoelectricity layer facing away from the substrate, in a direction perpendicular to the substrate, a projection of the first electrode on the substrate is located at an area in which the recess is located.

A method for forming an aluminum nitride layer (310, 320) comprises the provision of a substrate (100) and the forming of a patterned metal nitride layer (110). A bottom electrode metal layer (210) is formed on the exposed portions (101) of the substrate. An aluminum nitride layer portion (320) grown above the exposed portion (101) of the substrate (100) exhibits piezoelectric properties. An aluminum nitride layer portion (310) grown above the patterned metal nitride layer (110) exhibits no piezoelectric properties (310). Both aluminum nitride layer portions (320, 310) are grown simultaneously.

Surface acoustic wave (SAW) resonator, SAW filters, and methods of fabricating SAW filters. A first plurality of parallel conductors extending from a first bus bar are formed on a surface of a 128-degree Y-cut lithium niobate substrate. A second plurality of parallel conductors extending from a second bus bar are formed on the surface of the substrate, the second plurality of parallel conductors interleaved with the first plurality of parallel conductors. An SiO2 layer overlays the first and second pluralities of parallel conductors. The first and second pluralities of parallel conductors are substantially copper and have a thickness D.sub.CU defined by 0.12PD.sub.CU0.24P, where P is a center-to-center spacing of adjacent parallel conductors. The SiO2 layer has a thickness D.sub.OX defined by 3.1D.sub.CUD.sub.OX4.5D.sub.CU.