There are disclosed acoustic resonators, filter devices, and methods of fabricating acoustic resonators and filter devices. An acoustic resonator includes a piezoelectric plate having front and back surfaces, the back surface attached to a surface of a substrate except for portions of the piezoelectric plate forming a diaphragm spanning a cavity in the substrate. A conductor pattern on the front surface includes an interdigital transducer (IDT) with interleaved fingers of the IDT disposed on the diaphragm. A plurality of holes is in the diaphragm, wherein each of the plurality of holes is configured to scatter spurious modes in the diaphragm.

Acoustic resonator devices and methods are disclosed. An acoustic resonator device includes a substrate having a surface and a single-crystal piezoelectric plate having front and back surfaces. An etch-stop layer is sandwiched between the surface of the substrate and the back surface of the piezoelectric plate, a portion of the piezoelectric plate and the etch-stop layer forming a diaphragm spanning a cavity in the substrate. An interdigital transducer (IDT) is formed on the front surface of the single-crystal piezoelectric plate with interleaved fingers of the IDT disposed on the diaphragm. The etch-stop layer is impervious to an etch process used to form the cavity. The etch-stop layer is a high thermal conductivity material selected from aluminum nitride, boron nitride, and diamond.

In an acoustic wave device, a first IDT electrode is provided on a first main surface of a piezoelectric film, and a second IDT electrode is provided on a second main surface of the piezoelectric film. A crystal c-axis of the piezoelectric film is tilted with respect to a direction normal to the first and second main surfaces. A direction of an electric field generated between a busbar of a comb-shaped electrode and end portions of electrode fingers facing the busbar in the first IDT electrode and a direction of an electric field generated between a busbar and end portions of electrode fingers facing the busbar in the second IDT electrode are opposite directions.

A sensor that includes a substrate with a first side having a cavity extending into the first side. A resonator is connected to the substrate and extends over the cavity with the resonator including first and second electrodes overlapping on opposing sides of the piezoelectric crystal. The substrate is connected to the resonator such that one or more physical parameters exerted on the substrate are transferred to the resonator.

An acoustic wave element which can be reduced in size and produced relatively easily, practically used without using harmful substances, and can suppress a surface acoustic wave propagation loss, which has an excellent temperature coefficient of frequency and a velocity dispersion characteristic, and with which an increase in the reflection coefficient of interdigital transducers can be suppressed, and a method for manufacturing the acoustic wave element are provided. The acoustic wave element includes a pair of electrodes provided on both surfaces of a piezoelectric substrate, and a dielectric film provided on a first surface of the piezoelectric substrate so as to cover the electrode. The acoustic wave element alternatively includes interdigital transducers provided on a first surface of the piezoelectric substrate, and a dielectric film provided on the interdigital transducers, a gap between the interdigital transducers, and/or a second surface of the piezoelectric substrate.

Oscillators that use resonator elements formed from langasite or one of its isomorphs are described herein. The resonator elements include crystal orientations that are stress and/or temperature compensated. The resonators vibrate at an oscillating frequency in a thickness-shear mode of vibration. The oscillating frequency can be used to derive temperature, derive pressure, and/or for frequency control applications.

There are disclosed acoustic resonators and method of fabricating acoustic resonators. An acoustic resonator includes a single-crystal piezoelectric plate having front and back surfaces, the back surface attached to a surface of a substrate except for portions of the piezoelectric plate forming a diaphragm spanning a cavity in the substrate. A conductor pattern on the front surface includes an interdigital transducer (IDT) with interleaved fingers of the IDT disposed on the diaphragm. A periodic array of holes is provided in the diaphragm.

Acoustic resonator devices, filter devices, and methods of fabrication are disclosed. An acoustic resonator includes a substrate having a surface and a single-crystal piezoelectric plate having front and back surfaces. The back surface is attached to the surface of the substrate except for a portion of the piezoelectric plate forming a diaphragm that spans a cavity in the substrate. An interdigital transducer (IDT) is formed on the front surface of the single-crystal piezoelectric plate such that interleaved fingers of the IDT are disposed on the diaphragm. The IDT is configured to excite a primary acoustic mode in the diaphragm in response to a radio frequency signal applied to the IDT. At least a portion of an edge of the diaphragm is at an oblique angle to the fingers.

A sensor that includes a substrate with a first side having a cavity extending into the first side. A resonator is connected to the substrate and extends over the cavity with the resonator including first and second electrodes overlapping on opposing sides of the piezoelectric crystal. The substrate is connected to the resonator such that one or more physical parameters exerted on the substrate are transferred to the resonator.

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<x1). In the single crystal, letting be a rotation angle from an X-Z plane about an X-axis serving as a rotation axis, 18x+17.524x+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<x1). In the single crystal of this arrangement, letting be a rotation angle from an X-Z plane about an X-axis serving as a rotation axis, 25x+23.08332x+26.167 is set.