An acoustic wave device includes a piezoelectric material substrate, an intermediate layer on the piezoelectric material substrate and composed of one or more materials selected from the group consisting of silicon oxide, aluminum nitride and sialon. A bonding layer is on the intermediate layer and is composed of one or more materials selected from the group consisting of tantalum pentoxide, niobium pentoxide, titanium oxide, mullite, alumina, and a high resistance silicon and hafnium oxide. A supporting body is composed of a polycrystalline ceramic and is bonded to the bonding layer by direct bonding, and an electrode is on the piezoelectric material substrate.

A method for forming a MEMS device is provided. The method includes forming a stack of layers on a base piezoelectric layer. The stack of layers includes a base metal film over the base piezoelectric layer; a first piezoelectric film over the base metal film; and a first metal film having an opening therein over the first piezoelectric film. The method also includes forming a trench in the stack of layers, wherein the trench passes through the opening in the first metal film but does not expose the base metal film; after forming the trench, forming a spacer structure under the first metal film but spaced apart from the base metal film; after forming the spacer structure, deepening the trench to expose the base metal film; and forming a contact in the trench.

To manufacture an oscillating structure, a wafer is processed by: forming torsional elastic elements; forming a mobile element connected to the torsional elastic elements; processing the first side of the wafer to form a mechanical reinforcement structure; and processing the second side of said wafer by steps of chemical etching, deposition of metal material, and/or deposition of piezoelectric material. Processing of the first side of the wafer is carried out prior to processing of the second side of the wafer so as not to damage possible sensitive structures formed on the first side of the wafer.

The present invention relates to a piezoelectric fiber having excellent flexibility, the piezoelectric fiber employs a conductive fiber member as an inner electrode, on which a piezoelectric polymer layer, an outer electrode and a coating layer are sequentially formed, thereby having excellent flexibility and sufficient elasticity to be sewed, woven, knotted or braided. Therefore, the piezoelectric fiber can be applied in power supplies for a variety of sizes and types of wearable electronic devices, portable devices, clothing, etc. In addition, since the piezoelectric fiber has excellent piezoelectricity and durability because of the above-described structure, it can effectively convert deformation or vibration caused by external physical force into electric energy, and thus can replace existing ceramic-based and polymer piezoelectric bodies, etc. Furthermore, an economical and simple method of manufacturing a piezoelectric fiber having excellent piezoelectricity is provided.

A polymeric piezoelectric film including an optically active helical chiral polymer (A) having a weight average molecular weight of from 50,000 to 1,000,000, wherein: a crystallinity obtained by a DSC method is from 20% to 80%; a standardized molecular orientation MORc measured by a microwave transmission-type molecular orientation meter based on a reference thickness of 50 μm is from 3.5 to 15.0; and in a waveform measured with an inline film thickness meter and representing a relationship between a position in a width direction on the film and a thickness of the film, a number of peaks A is 20 or less per 1,000 mm of a film width, wherein the peaks A have a peak height of 1.5 μm or more and a peak slope of 0.000035 or more.

The present disclosure relates to a precursor solution for the preparation of a ceramic of the BZT-αBXT type, where X is selected from Ca, Sn, Mn, and Nb, and α is a molar fraction selected in the range between 0.10 and 0.90, said solution comprising: 1) at least one barium precursor compound; 2) a precursor compound selected from the group consisting of at least one calcium compound, at least one tin compound, at least one manganese compound, and at least one niobium compound; 3) at least one anhydrous precursor compound of zirconium; 4) at least one anhydrous precursor compound of titanium; 5) a solvent selected from the group consisting of a polyol and mixtures of a polyol and a secondary solvent selected from the group consisting of alcohols, carboxylic acids, ketones, and mixtures thereof; and 6) a chelating agent, as well as method of using the same.

A method of making a solvent cast polymer composite film comprising (a) contacting barium titanate, a titanate coupling agent (TCA) and a mixing solvent to form a barium titanate and TCA solution; (b) dispersing at least a portion of the barium titanate and TCA solution to form TCA treated barium titanate; (c) contacting at least a portion of the TCA treated barium titanate with a polyetherimide and a casting solvent to form a polymer composite casting solution; (d) casting at least a portion of the polymer composite casting solution onto a casting substrate to form a solvent cast polymer composite solution; and (e) curing at least a portion of the solvent cast polymer composite solution to form the solvent cast polymer composite film.

Devices and processes for preparing devices are described for a bulk acoustic wave resonator. A stack includes a first electrode that is coupled to a first side of a piezoelectric layer and a second electrode that is coupled to a second side of the piezoelectric layer. The stack is configured to resonate in response to an electrical signal applied between the first electrode and the second electrode. A cavity frame is coupled to the first electrode and to the substrate. The cavity frame forms a perimeter around a cavity. Optionally, a heat dissipating frame is formed and coupled to the second electrode. The cavity frame and/or the heat dissipating frame improve the thermal stability of the bulk acoustic resonator.

Devices and processes for preparing devices are described for a bulk acoustic wave resonator. A stack includes a first electrode that is coupled to a first side of a piezoelectric layer and a second electrode that is coupled to a second side of the piezoelectric layer. The stack is configured to resonate in response to an electrical signal applied between the first electrode and the second electrode. A cavity frame is coupled to the first electrode and to the substrate. The cavity frame forms a perimeter around a cavity. Optionally, a heat dissipating frame is formed and coupled to the second electrode. The cavity frame and/or the heat dissipating frame improve the thermal stability of the bulk acoustic resonator.

A bulk-acoustic wave resonator includes: a substrate; and a resonator portion in which a first electrode, a piezoelectric layer, and a second electrode are sequentially stacked on the substrate. The piezoelectric layer is formed of aluminum nitride (AlN) containing scandium (Sc). The bulk-acoustic wave resonator satisfies the following expression: leakage current density×scandium (Sc) content<20. The leakage current density is a leakage current density of the piezoelectric layer in μA/cm2, and the scandium (Sc) content is a weight percentage (wt %) of scandium (Sc) in the piezoelectric layer.