Abstract: Aspects of this disclosure relate to a bulk acoustic wave device with a plurality of piezoelectric layers having at least one polarization inversion. The bulk acoustic wave device can include a first piezoelectric layer and a second piezoelectric layer over the first piezoelectric layer. The second piezoelectric layer can be formed by atomic layer deposition. The second piezoelectric layer can have an opposite polarization relative to the first piezoelectric layer. Related filters, multiplexers, packaged radio frequency modules, radio frequency front ends, wireless communication devices, and methods are disclosed.

Abstract: Acoustic wave devices, including bulk and surface acoustic wave devices, include a temperature compensation layer in thermal communication with a piezoelectric layer. The temperature compensation layer includes a metal having a positive temperature coefficient of elasticity.

Abstract: Aspects of this disclosure relate to a bulk acoustic wave having a higher order mode as a main mode. The bulk acoustic wave device includes a frame structure in a frame region and a piezoelectric layer that has an engineered region in at least part of the frame region. Related acoustic wave filters, multiplexers, radio frequency modules, radio frequency systems, wireless communication devices, methods of manufacture, and methods of filtering are disclosed.

Abstract: Aspects of this disclosure relate to a bulk acoustic wave that includes a piezoelectric layer with an engineered region. The engineered region can vertically overlap with a frame structure of the bulk acoustic wave device. The engineered region and/or the frame structure can have non-unform width to suppress a lateral spurious mode. Related bulk acoustic wave dies, acoustic wave filters, multiplexers, radio frequency modules, radio frequency systems, wireless communication devices, and methods are disclosed.

Abstract: Aspects of this disclosure relate to a bulk acoustic wave that includes a piezoelectric layer with an island region laterally surrounded by an active region. The piezoelectric layer is less piezoelectric in the island region than in the active region. Related bulk acoustic wave dies, acoustic wave filters, multiplexers, radio frequency modules, radio frequency systems, wireless communication devices, and methods are disclosed.

Abstract: An acoustic wave device structure has first and second electrode layers and a piezoelectric layer extending across series and shunt resonator sections. A piezoelectric layer is positioned between the first and second electrode layers. A first mass loading layer extends across the shunt resonator sections and is positioned between the first electrode layer and the piezoelectric layer. A second mass loading layer extends across the shunt resonator sections and at least one of the series resonator sections. The second electrode layer is positioned between the piezoelectric layer and the second mass loading layer.

Abstract: Aspects of this disclosure relate to a Lamb wave resonator with a piezoelectric layer that is less piezoelectric in a border region than in an active region. End portions of interdigital transducer electrode fingers of the Lamb wave resonator are in the border region. Related filters, multiplexers, radio frequency modules, radio frequency systems, wireless communication devices, and methods are also disclosed.

Abstract: Aspects and embodiments disclosed herein include a bulk acoustic wave (BAW) device comprising a first electrode and a second electrode, at least one of the first electrode and the second electrode including at least one of a binary intermetallic compound, a metal nitride, a metal carbide, a metal carbonitride, a metal boride, a MXene, a MAX phase, or a MAB phase, and a piezoelectric material layer positioned between the first electrode and the second electrode.

Abstract: Aspects of this disclosure relate to bulk acoustic wave devices that include a first electrode, a second electrode, and a piezoelectric layer that includes a first region and a second region. The first region laterally surrounds the second region. The first region has a first effective piezoelectric coefficient having a greater magnitude than a second effective piezoelectric coefficient of the second region. Related acoustic wave filters, multiplexers, radio frequency modules, radio frequency systems, wireless communication devices, methods of manufacture, and methods of filtering are disclosed.

Abstract: Aspects of this disclosure relate to a bulk acoustic wave that includes a piezoelectric layer positioned between electrodes. The piezoelectric layer includes a first region and a plurality of second regions. The plurality of second regions each have an effective piezoelectric coefficient with a lower magnitude than an effective piezoelectric coefficient of the first region. Related acoustic wave filters, multiplexers, radio frequency modules, radio frequency systems, wireless communication devices, methods of manufacture, and methods of filtering are disclosed.

Abstract: Aspects of this disclosure relate to an acoustic wave device with a piezoelectric layer that includes a wurtzite structure. The wurtzite structure can include a group 2 element and have a high acoustic velocity. For example, the wurtzite structure can include a carbide and the group 2 element can be carbon of the carbide. The high acoustic velocity can be over 10,000 meters per second. Related piezoelectric layers, acoustic wave filters, radio frequency modules, wireless communication devices, and methods are disclosed.

Abstract: Aspects of this disclosure relate to a bulk acoustic wave resonator and an integrated capacitor. In certain embodiments, the integrated capacitor can be a metal-insulator-metal capacitor in parallel with the bulk acoustic wave resonator. The metal-insulator-metal capacitor can include a portion of a first electrode and a portion of a second electrode of the bulk acoustic wave resonator. At least part of the metal-insulator-metal capacitor is positioned laterally relative to an acoustic reflector of the bulk acoustic wave resonator. Other embodiments of capacitors integrated with a bulk acoustic wave resonator are disclosed. Related filters, multiplexers, radio frequency modules, radio frequency systems, wireless communication devices, and methods are disclosed.

Abstract: Aspects of this disclosure relate to an acoustic wave device with a piezoelectric layer that includes a wurtzite structure. The wurtzite structure can include aluminum nitride and silicon carbide. Related piezoelectric layers, acoustic wave filters, radio frequency modules, wireless communication devices, and methods are disclosed.

Abstract: Aspects and embodiments disclosed herein include a radio frequency filter comprising a plurality of series bulk acoustic wave resonators and a plurality of shunt bulk acoustic wave resonators, at least one of the plurality of shunt bulk acoustic wave resonators exhibiting a different electromechanical coupling coefficient than at least one of the plurality of series bulk acoustic wave resonators, at least one of the bulk acoustic wave resonators exhibiting a higher electromechanical coupling coefficient than another one of the bulk acoustic wave resonators having a thicker piezoelectric material layer stack than the another one of the bulk acoustic wave resonators.

Abstract: An acoustic wave device is disclosed. The acoustic wave device can include a substrate, a lid, a resonator, and an inductor. The lid has a first side facing the substrate and a second side opposite the first side. The lid is coupled to the substrate. The resonator is positioned between the substrate and the lid. The inductor is formed with the lid. The inductor is at least partially positioned over a portion of the resonator.

Abstract: An acoustic wave device is disclosed. The acoustic wave device can include a substrate, a resonator and an inductor. The substrate has a first side and a second side opposite the first side. The resonator is positioned over the first side of the substrate. The inductor is formed with the substrate. At least a portion of the inductor is disposed on the second side of the substrate.

Abstract: Aspects and embodiments disclosed herein include a bulk acoustic wave resonator comprising a layer of piezoelectric material and one of a top electrode disposed on top of the layer of piezoelectric material or a bottom electrode disposed on a bottom of the layer of piezoelectric material, the one of the top electrode or the bottom electrode including a Bragg pair having alternating layers of a first metal and a second metal.

Abstract: Disclosed is a bulk acoustic wave resonator including a piezoelectric material layer comprising alternating layers of AlxSc1?xN and one of AlyGa1?yN or AlyIn1?yN, 0<x<1, 0<y<1 and methods of forming same.

Abstract: The disclosed technology relates to an acoustic wave device including a piezoelectric layer with localized regions having atoms implanted therein, and an electrode over the piezoelectric layer, where the acoustic wave device is configured to generate an acoustic wave.

Abstract: The disclosed technology relates to a method of fabricating an acoustic wave device including providing a piezoelectric layer for forming the acoustic wave device, selectively implanting ions into localized regions of the piezoelectric layer, and further processing to configure the acoustic wave device to generate an acoustic wave.