A resonator includes a substrate, an acoustic Bragg mirror disposed above the substrate, and a bottom metal layer disposed above the acoustic Bragg mirror. The resonator also includes a piezoelectric plate disposed above the bottom metal layer. The resonator further includes a top metal layer disposed above the piezoelectric plate. The top metal layer comprises multiple fingers within a single plane and the width of each of the fingers is between 75%-125% of a thickness of the piezoelectric plate.

A method of fabricating a piezoelectric layer includes depositing a piezoelectric material onto a substrate in a first crystallographic phase by physical vapor deposition while the substrate remains at a temperature below 400° C., and thermally annealing the substrate at a temperature above 500° C. to convert the piezoelectric material to a second crystallographic phase. The physical vapor deposition includes sputtering from a target in a plasma deposition chamber.

A method of forming an Al.sub.1-xSc.sub.xN film can include heating a substrate, in a reactor chamber, to a temperature range, providing a precursor comprising Sc to the reactor chamber, providing a dopant comprising Mg, C, and/or Fe to the reactor chamber, and forming an epitaxial Al.sub.1-xSc.sub.xN film on the substrate in the temperature range, the epitaxial Al.sub.1-xSc.sub.xN film including the dopant in a concentration in a range between about 1×10.sup.17/cm.sup.3 and about 2×10.sup.20/cm.sup.3 on the substrate.

A method for making a piezoelectric microelectromechanical systems (MEMS) microphone is provided, comprising depositing a piezoelectric film layer onto a substrate; selectively etching the piezoelectric film layer to define lines; removing the substrate to define a cavity; and breaking the piezoelectric film layer along the lines, such that the microphone has at least two cantilevered beams. The piezoelectric microelectromechanical systems (MEMS) microphone is also provided.

A piezoelectric device including a substrate, a metal-insulator-metal element, a hydrogen blocking layer, a passivation layer, a first contact terminal and a second contact terminal is provided. The metal-insulator-metal element is disposed on the substrate. The hydrogen blocking layer is disposed on the metal-insulator-metal element. The passivation layer covers the hydrogen blocking layer and the metal-insulator-metal element. The first contact terminal is electrically connected to the metal-insulator-metal element. The second contact terminal is electrically connected to the metal-insulator-metal element.

Provided is an aluminum nitride film in which, aluminum nitride crystal grains containing a metal element differing from aluminum and substituting for aluminum are main crystal grains of a polycrystalline film formed of crystal grains, and a concentration of the metal element in a grain boundary between the aluminum nitride crystal grains in at least one region of first and second regions corresponding to both end portions of the polycrystalline film in a film thickness direction of the polycrystalline film is higher than a concentration of the metal element in a center region of the aluminum nitride crystal grain in the at least one region, and is higher than a concentration of the metal element in a grain boundary between the aluminum nitride crystal grains in a third region located between the first region and the second region in the film thickness direction of the polycrystalline film.

A piezoelectric film laminated body includes a metal film, an amorphous film, and a scandium aluminum nitride film. The amorphous film has an insulation property and is disposed on the metal film. The scandium aluminum nitride film is disposed on the amorphous film and is in contact with a surface of the amorphous film.

The present application relates to an energy conversion apparatus. The energy conversion apparatus comprises: an upper conductive layer; a lower conductive layer, which is arranged below the upper conductive layer; and at least one piezoelectric micro/nano unit and a fluid, which are arranged between the upper conductive layer and the lower conductive layer, wherein the piezoelectric micro/nano unit has a piezoelectric property and is immersed in the fluid. The present application further relates to a preparation method for an energy conversion apparatus and the use thereof.

The present application relates to an energy conversion apparatus. The energy conversion apparatus comprises: an upper conductive layer; a lower conductive layer, which is arranged below the upper conductive layer; and at least one piezoelectric micro/nano unit and a fluid, which are arranged between the upper conductive layer and the lower conductive layer, wherein the piezoelectric micro/nano unit has a piezoelectric property and is immersed in the fluid. The present application further relates to a preparation method for an energy conversion apparatus and the use thereof.

A method for manufacturing a monocrystalline piezoelectric material layer includes providing a donor substrate made of the piezoelectric material, providing a receiving substrate, transferring a so-called “seed layer” of the donor substrate onto the receiving substrate, and using epitaxy of the piezoelectric material on the seed layer until the desired thickness for the monocrystalline piezoelectric layer is obtained.