There are disclosed acoustic resonators and radio frequency filter devices. A back surface of a single-crystal piezoelectric plate is attached to a surface of a substrate except for portions of the piezoelectric plate forming a plurality of diaphragms, each of which spans a respective cavity in the substrate. A conductor pattern is formed on the front surface, the conductor pattern including interdigital transducers (IDTs) of one or more pairs of sub-resonators, each pair consisting of two sub-resonators. The IDT of each sub-resonator includes interleaved fingers disposed on a respective diaphragm. The piezoelectric plate and the IDTs are configured such that respective radio frequency signals applied to each IDT excite respective shear primary acoustic modes in the respective diaphragms. The two sub-resonators of each pair of sub-resonators are positioned symmetrically about a central axis.

A laterally excited bulk acoustic wave device is disclosed. The laterally excited bulk acoustic wave device can include a support substrate, a solid acoustic mirror on the support substrate, a piezoelectric layer on the solid acoustic mirror, and an interdigital transducer electrode on the piezoelectric layer. The interdigital transducer electrode is arranged to laterally excite a bulk acoustic wave.

An acoustic wave device is disclosed. The acoustic wave deice can include a membrane structure and a support substrate. The membrane structure includes a piezoelectric layer, an interdigital transducer electrode arranged on the piezoelectric layer, and a thermally conductive layer arranged at least partially in contact with the piezoelectric layer. The support substrate is connected to the membrane structure and configured such that a cavity is provided next to the membrane structure. The acoustic wave device can laterally excite a bulk acoustic wave.

An elastic wave device includes a piezoelectric body including a main surface, an IDT electrode provided on the main surface of the piezoelectric body, and a wiring electrode provided on the main surface of the piezoelectric body and electrically connected to the IDT electrode, in which the wiring electrode includes a portion that extends to an edge of the main surface of the piezoelectric body, and a width of the wiring electrode on the edge is narrower than a width of the wiring electrode in a portion not on the edge.

Acoustic resonator devices are disclosed. An acoustic resonator device includes a plurality of cells electrically connected in parallel. Each cell includes an interdigital transducer (IDT) on a piezoelectric plate, the IDT having at least 15 and not more than 35 interleaved fingers.

MEMS based sensors, particularly capacitive sensors, potentially can address critical considerations for users including accuracy, repeatability, long-term stability, ease of calibration, resistance to chemical and physical contaminants, size, packaging, and cost effectiveness. Accordingly, it would be beneficial to exploit MEMS processes that allow for manufacturability and integration of resonator elements into cavities within the MEMS sensor that are at low pressure allowing high quality factor resonators and absolute pressure sensors to be implemented. Embodiments of the invention provide capacitive sensors and MEMS elements that can be implemented directly above silicon CMOS electronics.

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.

An acoustic wave device includes a piezoelectric layer made of lithium niobate or lithium tantalate and including a first main surface, and an IDT electrode and a first dielectric film on the first main surface. A ratio d/p is equal to or less than about 0.5, when a thickness of the piezoelectric layer is d and a center-to-center distance between adjacent electrodes is p. The first dielectric film includes first and second surfaces facing each other. The second surface is a surface on a side of the piezoelectric layer. The IDT electrode includes third and fourth surfaces facing each other. The fourth surfaces are on the side of the piezoelectric layer. The first surface of the first dielectric film is at a same height as or higher than the third surfaces of the IDT electrode. A second dielectric film is on the first surface of the first dielectric film.

In an acoustic wave device, a piezoelectric body is directly or indirectly provided on a high acoustic velocity material layer, an interdigital transducer electrode is directly or indirectly provided on the piezoelectric body, the interdigital transducer electrode includes a first busbar, a second busbar spaced away from the first busbar, a plurality of first electrode fingers, and a plurality of second electrode fingers, and a weighting is applied to the interdigital transducer electrode by providing a floating electrode finger not electrically connected to the first busbar or the second busbar or applied by providing an electrode finger formed by metallizing a gap between the first electrode fingers or a gap between the second electrode fingers to integrate the first electrode fingers or the second electrode fingers.

An interdigital transducer increased propagation frequency and a method for making the same is described. The transducer comprises a substrate for propagation of acoustic waves comprising a first surface having alternating high and low surface portions extending laterally across the substrate, a set of elongate first electrodes, each first electrode disposed on a respective high surface portion and a set of elongate second electrodes, each second electrode disposed on a respective low surface portion such that the first and second electrodes are alternately adjacent to one another, the high and low surface portions being substantially equal in width to each electrode of the first and second sets of electrodes.