Provided is an acoustic resonator in a transverse excitation shear mode. The acoustic resonator comprises: an acoustic mirror (120), which comprises at least one first acoustic reflecting layer (121, 123, 125) and at least one second acoustic reflecting layer (122, 124), wherein the acoustic impedance of each first acoustic reflecting layer is less than that of each second acoustic reflecting layer; a piezoelectric layer (130), which is arranged on the acoustic mirror, and which comprises lithium niobate of a single crystal material and/or lithium tantalate of a single crystal material; electrode units (142, 143, 144), which are arranged on the piezoelectric layer (130) and are used for forming an electric field; and transverse reflectors (152, 154), which are arranged on the piezoelectric layer, are used for transversely reflecting acoustic waves, and can have a high electromechanical coupling coefficient and a high Q value at a frequency greater than 3 GHz.

Dispersive delay lines are disclosed. The dispersive delay line can include a piezoelectric substrate having a first interdigital transducer electrode on a first region of the piezoelectric substrate and a second interdigital transducer electrode on a second region of the piezoelectric substrate. The dispersive delay line is arranged such that an acoustic wave is configured to propagate from the first interdigital transducer electrode to the second interdigital transducer electrode though a third region of the piezoelectric substrate. An additional material positioned on the third region of the piezoelectric substrate can impact acoustic wave propagation velocity. Related radio frequency modules, wireless communications devices, and methods are disclosed.

An acoustic resonator device with low thermal impedance has a substrate and a single-crystal piezoelectric plate having a back surface attached to a top surface of the substrate via a bonding oxide (BOX) layer. An interdigital transducer (IDT) formed on the front surface of the plate has interleaved fingers disposed on the diaphragm, the overlapping distance of the interleaved fingers defining an aperture of the resonator device. Contact pads are formed at selected locations over the surface of the substrate to provide electrical connections between the IDT and contact bumps to be attached to the contact pads. The piezoelectric plate is removed from at least a portion of the surface area of the device beneath each of the contact pads to provide lower thermal resistance between the contact bumps and the substrate.

The present disclosure provides a bulk acoustic wave resonance device, a bulk acoustic wave filter device and a radio frequency front end device. The bulk acoustic wave resonance device includes a first layer including a cavity disposed at a first side of the first layer; a first electrode layer disposed in the cavity; a second layer disposed at the first side and disposed on the first electrode layer, and the second layer is a flat layer and covers the first cavity; and a second electrode layer disposed at the first side and disposed on the second layer, and the first electrode layer includes at least two first electrode bars or the second electrode layer includes at least two second electrode bars. The present disclosure can increase the difference between acoustic impedance of a resonance region and a non-resonance region, thereby increasing Q value of the resonance device.

An elastic wave device includes a supporting substrate including an upper surface including a recessed portion, a piezoelectric thin film on the supporting substrate to cover the recessed portion of the supporting substrate, an IDT electrode on a main surface of the piezoelectric thin film, the main surface being adjacent to the supporting substrate, and an intermediate layer on a main surface of the piezoelectric thin film, the main surface being remote from the supporting substrate. A space is defined by the supporting substrate and the piezoelectric thin film. The IDT electrode faces the space. Through holes are provided in the piezoelectric thin film and the intermediate layer to extend from a main surface of the intermediate layer to the space, the main surface being remote from the piezoelectric thin film. The elastic wave device further includes a cover member on the intermediate layer and covering opening ends of the through holes.

An acoustic wave device includes a substrate, a multilayer film on the substrate, an LT layer configured by a single crystal of LiTaO.sub.3 on the multilayer film, and an IDT electrode on the LT layer. The thickness of the LT layer is 0.3λ or less where λ is two times a pitch p of electrode fingers in the IDT electrode. Euler angles of the LT layer are (0°±20°, −5° to 65°, 0°±10°), (−120°±20°, −5° to 65°, 0°±10°), or (120°±20°, −5° to 65°, 0°±10°). The multilayer film configured by alternately stacking at least one first layer and at least one second layer. The first layer is comprised of SiO.sub.2. The second layer is comprised of any one of Ta.sub.2O.sub.5, HfO.sub.2, ZrO.sub.2, TiO.sub.2, and MgO.

An acoustic wave device including: a POI structure including: a material layer where a high acoustic velocity layer and a low acoustic velocity layer are alternate, a substrate is a lowermost high acoustic velocity layer; a first piezoelectric layer located above the material layer, wherein a layer adjacent to the first piezoelectric layer is referred to as a surface low acoustic velocity layer; wherein an acoustic velocity of a bulk wave propagated in the high acoustic velocity layer and the low high acoustic velocity layer is higher than and lower than an acoustic velocity of a bulk wave of the first piezoelectric layer, respectively. The POI structure includes at least two regions, a first device having a resonance of a first vibration mode is manufactured in the first region, and a second device having a resonance of a second vibration mode is manufactured in a second region.

An acoustic wave device includes a support substrate, first and second piezoelectric layers, and an IDT electrode. The first and second piezoelectric layers are on the support substrate. The IDT electrode is on the first piezoelectric layer and includes electrode fingers. The second piezoelectric layer is between the first piezoelectric layer and the support substrate. The first and second piezoelectric layers are made of lithium tantalate or lithium niobate. Euler angles of the second piezoelectric layer are different from Euler angles of the first piezoelectric layer.

A acoustic wave resonator comprises a piezoelectric substrate and a plurality of interdigital transducer (IDT) electrodes disposed on the piezoelectric substrate, the plurality of IDT electrodes formed of a mixture of tungsten and chromium to provide for reduction in size and increase in quality factor of the acoustic wave resonator.

An acoustic wave filter device with two-stage acoustic wave filters is provided. Each of the two stages includes a respective acoustic wave filter element. A first acoustic wave filter element (100a) includes a first input electrode (150a), a first output electrode (174a), and a first counter electrode (120a). The first input electrode and the first output electrode are located on a top surface of piezoelectric layer (650), and the first counter electrode is located on a bottom surface of the piezoelectric layer. A second acoustic wave filter element (100b) includes a second input electrode (154b), a second output electrode (174b), and a second counter electrode (120b). The second input electrode and the second output electrode are located on the top surface of the piezoelectric layer, and the second counter electrode is located on a bottom surface of the piezoelectric layer. The two acoustic wave filter elements are connected in series through a common floating electrode (602).