In a piezoelectric element, shift of a resonance point to a low-pitched sound side is achieved. A resonance point of a piezoelectric element moves to a low-pitched sound side when an active region is configured to be surrounded by an inactive region as in the configuration of the piezoelectric element. According to the piezoelectric element whose resonance point is moved to a low-pitched sound side, the piezoelectric element can realize a sound pressure that is sufficiently high for practical use when it is applied to an acoustic device.

A semiconductor structure is provided. The semiconductor structure includes a substrate, a first piezoelectric layer, and a first dummy layer. The first piezoelectric layer is over the substrate, and the first piezoelectric layer has a first top surface. The first dummy layer is over the first piezoelectric layer, and the first dummy layer has a second top surface. And an average roughness of the first top surface is greater than an average roughness of the second top surface. A method for manufacturing the semiconductor structure is also provided.

An acoustic wave device includes a piezoelectric substrate made of LiNbO.sub.3 or LiTaO.sub.3 and including first and second main surfaces that face each other, an IDT electrode provided on the first main surface of the piezoelectric substrate, and a Li.sub.2CO.sub.3 layer provided on the second main surface of the piezoelectric substrate.

Provided is a piezoelectric actuator, a linear driving device, and an electronic device that achieve displacement of a drive shaft of a given magnitude even in a case where a low voltage is applied. A piezoelectric actuator includes a piezoelectric material composed of a stack of plate-shaped piezoelectric elements, the piezoelectric material being expandable and contractable in a direction of a plate surface thereof; an elastic plate having the piezoelectric material formed on a plate surface of the elastic plate, and a drive shaft having one end fixed to either the piezoelectric material or the elastic plate in a direction perpendicular to the plate surface of the piezoelectric material.

A plurality of conductive via connections are fabricated on a substrate located at positions where MTJ devices are to be fabricated, wherein a width of each of the conductive via connections is smaller than or equivalent to a width of the MTJ devices. The conductive via connections are surrounded with a dielectric layer having a height sufficient to ensure that at the end of a main MTJ etch, an etch front remains in the dielectric layer surrounding the conductive via connections. Thereafter, a MTJ film stack is deposited on the plurality of conductive via connections surrounded by the dielectric layer. The MTJ film stack is etched using an ion beam etch process (IBE), etching through the MTJ film stack and into the dielectric layer surrounding the conductive via connections to form the MTJ devices wherein by etching into the dielectric layer, re-deposition on sidewalls of the MTJ devices is insulating.

A piezoelectric element includes a piezoelectric element body including a first principal surface and a second principal surface opposing each other, and a plurality of external electrodes disposed on the first principal surface. A vibration member includes a third principal surface opposing the second principal surface. The piezoelectric element is joined to the third principal surface. A wiring member is electrically connected to the piezoelectric element. The wiring member includes a region located on the plurality of external electrodes and joined to the plurality of external electrodes. The region of the wiring member monolithically covers the plurality of external electrodes when viewed from a direction orthogonal to the first principal surface.

An actuator device has an electroactive polymer actuator (35) and an integrated piezoelectric transformer (30) whose primary side (32) and secondary side (34) are formed from different electroactive polymer materials. At least the secondary side (34) of the transformer shares a piezoelectric electroactive polymer layer (36) with the electroactive polymer actuator, so that lower external voltages can be applied to the device.

A piezoelectric element including a piezoelectric layer having a perovskite structure including lead, zirconium, and titanium, and an electrode provided on the piezoelectric layer is provided. In the piezoelectric layer, in a range of 50 nm or smaller from an interface between the piezoelectric layer and the electrode in a thickness direction, a ratio c/a of a lattice spacing a in a direction perpendicular to the thickness direction and a lattice spacing c in the thickness direction satisfies 0.986≤c/a≤1.014.

An ultrasonic fingerprint recognition sensor and a manufacturing method thereof, and a display device are disclosed. The ultrasonic fingerprint recognition sensor includes a resonant cavity, a receiver electrode, a drive electrode, and a piezoelectric thin film layer between the receiver electrode and the drive electrode, the resonant cavity is on a side, closer to the piezoelectric thin film layer, of the receiver electrode, and is configured to increase vibration amplitude of the piezoelectric thin film layer.

An object of the present invention is to provide a piezoelectric film capable of realizing an electroacoustic conversion film or the like in which the durability is high and a sufficient sound pressure with respect to an input operating voltage is obtained. The object is achieved by providing a piezoelectric film including a polymer-based piezoelectric composite material which contains piezoelectric particles in a matrix containing a polymer material, and electrode layers which are provided on both surfaces of the polymer-based piezoelectric composite material, in which in a case where a cross section of the film in a thickness direction is observed with a scanning electron microscope, the polymer-based piezoelectric composite material is divided into ten equal regions in the thickness direction, area ratios of the piezoelectric particles in two most distant regions are measured, and the area ratio of the piezoelectric particles in the region with a lower area ratio is set as 1, the area ratio of the piezoelectric particles in the region with a higher area ratio is 1.2 or greater.