An RF integrated circuit device can includes a substrate and a High Electron Mobility Transistor (HEMT) device on the substrate including a ScAlN layer configured to provide a buffer layer of the HEMT device to confine formation of a 2DEG channel region of the HEMT device. An RF piezoelectric resonator device can be on the substrate including the ScAlN layer sandwiched between a top electrode and a bottom electrode of the RF piezoelectric resonator device to provide a piezoelectric resonator for the RF piezoelectric resonator 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 ultrasonic device according to an aspect of the present disclosure includes a substrate in which an opening section piercing through the substrate in a thickness direction is provided, a vibration plate provided on the substrate to close the opening section, a piezoelectric element provided in a position corresponding to the opening section on a first surface at the opposite side of the substrate side of the vibration plate, and an elastic layer provided in contact with a second surface at the substrate side of the vibration plate at the inner side of the opening section of the substrate. The elastic layer includes a curved surface recessed to the vibration plate side at the opposite side of the vibration plate side.

The present invention relates to a heterostructure, in particular, a piezoelectric structure, comprising a cover layer, in particular, a layer of piezoelectric material, the material of the cover layer having a first coefficient of thermal expansion, assembled to a support substrate, the support substrate having a second coefficient of thermal expansion substantially different from the first coefficient of thermal expansion, at an interface wherein the cover layer comprises at least a recess extending from the interface into the cover layer, and its method of fabrication.

An omnidirectional electroacoustic transducer capable of reproducing a sound with high acoustic quality and sufficient sound volume in a wide frequency band is provided with a small number of components. The electroacoustic transducer includes: two or more electroacoustic transduction units each including an electroacoustic transduction film and an elastic supporter, the electroacoustic transduction film having a polymer composite piezoelectric body in which piezoelectric body particles are dispersed in a viscoelastic matrix formed of a polymer material having viscoelasticity at a normal temperature, and two thin film electrodes laminated on both surfaces of the polymer composite piezoelectric body, and the elastic supporter being disposed to be closely attached to one principal surface of the electroacoustic transduction film so as to cause the electroacoustic transduction film to be bent, in which the two or more electroacoustic transduction units are disposed so that the electroacoustic transduction films face outward and form some or all of faces of a polyhedron.

An imaging device includes a two dimensional array of piezoelectric elements. Each piezoelectric element includes: a piezoelectric layer; a bottom electrode disposed on a bottom side of the piezoelectric layer and configured to receive a transmit signal during a transmit mode and develop an electrical charge during a receive mode; and a first top electrode disposed on a top side of the piezoelectric layer; and a first conductor, wherein the first top electrodes of a portion of the piezoelectric elements in a first column of the two dimensional array are electrically coupled to the first conductor.

An electronic device may include a first electrode, a first piezoelectric layer electrically coupled to the first electrode, a first magnetostrictive layer above the first piezoelectric layer, a first tunnel barrier layer above the first magnetostrictive layer, and a ferromagnetic layer above the first ferroelectric layer. The electronic device may further include a second electrode electrically coupled to the ferromagnetic layer a second tunnel barrier layer above the ferromagnetic layer, a second magnetostrictive layer above the second tunnel barrier layer, a second piezoelectric layer above the second magnetostrictive layer, and a third electrode electrically coupled to the second piezoelectric layer. The first piezoelectric layer may be strained responsive to voltage applied across the first and second electrodes, and the second piezoelectric layer may be strained responsive to voltage applied across the second and third electrodes.

Provided is a laminated piezoelectric element is formed by folding back and laminating a piezoelectric film having an electrode layer and a protective layer on both sides of a piezoelectric layer in which piezoelectric particles are dispersed in a matrix. In the laminated two layers of the piezoelectric film, in a case where a thickness of a central portion thereof is a center thickness and a position up to twice the center thickness in a direction from the folded side end part toward the center is the folded-back portion, there is a position at which the thickness is greater than the center thickness in the folded-back portion, and there is an air gap in the folded-back portion or the air gap is filled with a cementing agent. The laminated piezoelectric element is able to prevent peeling of the electrode layer and the like in the folded-back portion in the laminated piezoelectric element in which the piezoelectric film is folded back and laminated. An electroacoustic transducer uses the laminated piezoelectric element.

The invention relates to a method for manufacturing an electroacoustic resonator comprising the steps of: Providing a first substrate having a first side and an opposite second side; depositing a diamond layer having a first side and an opposite second side on said first substrate, wherein the second side of the diamond layer is in contact with said first side of the first substrate; removing the first substrate; forming a piezoelectric layer on the second side of the diamond layer; applying a second substrate to the first side of the diamond layer.

A piezoelectric device includes a piezoelectric single crystal body with a homogeneous polarization state and of which at least a portion flexurally vibrates, an upper electrode on an upper surface of the piezoelectric single crystal body, a lower electrode on a lower surface of the piezoelectric single crystal body, and a supporting substrate below the piezoelectric single crystal body. A recess extends from a lower surface of the supporting substrate toward the lower surface of the piezoelectric single crystal body.