An acoustic resonator device includes a piezoelectric plate attached to a substrate. A portion of the piezoelectric plate forms a diaphragm suspended over a cavity in the substrate. A first conductor level includes first and second interdigital transducer (IDT) first-level busbars disposed along opposing sides of the diaphragm, and first and second sets of IDT fingers extending from the first and second busbars, respectively, wherein the first and second sets of IDT fingers are interleaved and disposed on the diaphragm. A second conductor level includes first and second second-level busbars that overlap at least a portion of the first and second busbars, respectively.

An acoustic wave device includes a piezoelectric layer and first and second electrodes. The piezoelectric layer is made of lithium niobate or lithium tantalate. The first electrode and the second electrode oppose each other in a direction intersecting with a thickness direction of the piezoelectric layer. The first electrode and the second electrode are electrodes adjacent to each other. d/p is about 0.5 or smaller, where d is a thickness of the piezoelectric layer and p is a center-to-center distance between the first electrode and the second electrode. An intersecting width is about 4.6p or greater. The intersecting width is a dimension of a region where the first electrode and the second electrode oppose each other. The direction of the dimension is an extending direction of the first electrode and the second electrode.

Acoustic resonator devices and methods are disclosed. An acoustic resonator device includes a piezoelectric plate having opposed front and back surfaces. A first electrode and a second electrode are formed on the front surface of the piezoelectric plate, the first and second electrodes and the piezoelectric plate configured such that a radio frequency signal applied between the first and second electrodes excites a shear primary acoustic mode in the piezoelectric plate. The first electrode and the second electrode have trapezoidal cross-sectional shapes. A sidewall angle of at least one side surface of the first electrode and a sidewall angle of at least one side surface of the second electrode are greater than or equal to 70 degrees and less than or equal to 110 degrees.

Nonlinear acoustic media and related methods are described herein. The nonlinear acoustic media are configured to generate higher harmonic output signals from a single-frequency input signal. The higher harmonic output signals can be generated through the coupling of an acoustic dielectric medium to a nonlinear piezoelectric medium having four ports.

A fabrication method of a surface acoustic wave (SAW) filter includes obtaining a piezoelectric substrate, forming a back electrode on a first portion of the piezoelectric substrate, forming a first dielectric layer on the first portion of the piezoelectric substrate, forming a trench in the first dielectric layer, forming a second dielectric layer on the first dielectric layer formed with the trench, forming a third dielectric layer on the second dielectric layer, removing a second portion of the piezoelectric substrate to obtain a piezoelectric layer, forming an interdigital transducer (IDT) on the piezoelectric layer, and etching and releasing a portion of the first dielectric layer surrounded by the trench to form a cavity below the back electrode.

A laterally excited bulk acoustic wave device is disclosed. The laterally excited bulk acoustic wave device can include a first solid acoustic mirror, a second solid acoustic mirror, a piezoelectric layer that is positioned between the first solid acoustic mirror and the second solid acoustic mirror, an interdigital transducer electrode on the piezoelectric layer, and a support substrate arranged to dissipate heat associated with the bulk acoustic wave. The interdigital transducer electrode is arranged to laterally excite a bulk acoustic wave. The first solid acoustic mirror and the second solid acoustic mirror are arranged to confine acoustic energy of the bulk acoustic wave. The first solid acoustic mirror is positioned on the support substrate.

A device includes a stack of at least two piezoelectric layers configured to propagate a Lamb wave in a mode having an order corresponding to a number of piezoelectric layers of the stack. The stack includes a first piezoelectric layer and a second piezoelectric layer disposed on the first piezoelectric layer. The first piezoelectric layer has a first cut plane orientation, and the second piezoelectric layer has a second cut plane orientation complementary to the first cut plane orientation. The device further includes an interdigitated transducer (IDT) disposed on at least a top surface of the stack or a bottom surface of the stack. In some embodiments, the device is an acoustic resonator. In some embodiments, the device is an acoustic delay line.

Acoustic resonators 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 spanning a cavity in the substrate. An interdigital transducer (IDT) is formed on the front surface of the piezoelectric plate. The IDT includes: a first busbar and a second busbar disposed on respective portions of the piezoelectric plate other than the diaphragm; a first set of elongate fingers extending from the first bus bar onto the diaphragm; and a second set of elongate fingers extending from the second bus bar onto the diaphragm, the second set of elongate fingers interleaved with the first set of elongate fingers.

Acoustic resonators and filter devices. 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 spanning a cavity in the substrate. A conductor pattern formed is formed on the front surface of the piezoelectric plate, including an interdigital transducer (IDT) with interleaved fingers of the IDT on the diaphragm. The substrate and the piezoelectric plate are the same material.

A radio frequency filter includes at least a first sub-filter and a second sub-filter connected in parallel between a first port and a second port. Each of the sub-filters has a piezoelectric plate having front and back surfaces, the back surface attached to a substrate, and portions of the piezoelectric plate forming diaphragms spanning respective cavities in the substrate. A conductor pattern is formed on the front surface of the plate, the conductor pattern includes interdigital transducers (IDTs) of a respective plurality of resonators, with interleaved fingers of each IDT disposed on a respective diaphragm of the plurality of diaphragms. A thickness of the portions of the piezoelectric plate of the first sub-filter is different from a thickness of the portions of the piezoelectric plate of the second sub-filter.