A piezoelectric micromachined ultrasonic transducer (PMUT) device includes a layer of piezoelectric material that is activated and sensed by an electrode and a conductive plane layer. The conductive plane layer may be electrically connected to processing circuitry by a via that extends through the piezoelectric layer. One or more isolation trenches extend through the conductive plane layer to isolate the conductive plane layer from other conductive plane layers of adjacent PMUT devices of a PMUT array.

An MEMS device includes: a first member; a second member forming a sealed space with the first member therebetween; and a third member disposed between the first member and the second member and joined to the first member and the second member, in which the third member has lower rigidity than rigidity of the first member and the second member, and the third member is provided with a communication portion that establishes communication between the sealed space and an external space.

There are provided a laminated piezoelectric element in which a stress applied to an interface between a cover layer and a stacked body is reduced, and an injection device and a fuel injection system provided with the laminated piezoelectric element. A laminated piezoelectric element includes a stacked body in which piezoelectric layers and internal electrode layers are alternately laminated; and a cover layer disposed so as to surround a side face of the stacked body, and the cover layer has a two-layer structure with an annular boundary when viewed in a section perpendicular to a stacking direction of the stacked body.

A MEMS component having increased integration density and a method for manufacturing such a component are specified. The component comprises a base wafer and a cover wafer arranged over this. A first cavity is arranged between the base wafer and the cover wafer. A second cavity is arranged over the cover wafer, below a thin-layer covering. The cavities contain component structures.

Provided is a piezoelectric element vibration apparatus that generates vibration by applying a driving voltage to a piezoelectric vibrator, wherein a piezoelectric element layer is arranged on an electrode substrate made of a conductive material, an insulation member for preventing the applied driving voltage from leaking is formed on the piezoelectric element layer, and the piezoelectric element vibration apparatus has various types of forms in order to attach and install the piezoelectric vibrator. As a result, the piezoelectric element vibration apparatus has the effects wherein: installation is possible simply by attachment, thereby simplifying the assembly process; installation in any position is possible because the thickness of the piezoelectric element vibration device is made to be thin; the vibration volume can increase and the vibration noise can decrease while minimizing the thickness.

Provided is a laminated piezoelectric element capable of suppressing a short circuit between piezoelectric films in a laminated piezoelectric element in which a plurality of layers of a piezoelectric film formed by interposing a piezoelectric layer between an electrode layer and a protective layer are laminated. The laminated piezoelectric element is formed by laminating a plurality of layers of piezoelectric films each having a piezoelectric layer, two electrode layers between which the piezoelectric layer is interposed, and two protective layers respectively covering the electrode layers. At least a part of each end side of the adjacent piezoelectric films is located at a different position in a plane direction.

A process for producing a piezoelectric sensor includes the following steps: a step of providing a housing made of stainless steel; a step of producing a solution of a compound comprising a metal or metalloid element; a step of depositing a layer of the solution over at least one inner surface of the housing; a step of oxidizing the deposited layer of solution; a step of placing a piezoelectric element inside the housing; a step of closing the housing. A piezoelectric sensor obtained by such a process and comprising a closed steel housing, a piezoelectric element arranged inside the housing and a layer of a solution of a compound comprising a metal or metalloid element that is arranged over at least one inner surface of the housing.

An actuator includes a deformable thin-film member having an opening, an electromechanical conversion element disposed at a periphery of the opening of the deformable thin-film member, an insulating film covering the electromechanical conversion element, a protective film over a surface of the insulating film, the protective film covering the surface of the insulating film and a surface of an electrode wiring connected to the electromechanical conversion element, and an adhesion improving film disposed between the electrode wiring and the protective film.

Bulk acoustic wave (BAW) resonators and particularly top electrodes with step arrangements for BAW resonators are disclosed. Top electrodes on piezoelectric layers are disclosed that include a border (BO) region with a dual-step arrangement where an inner step and an outer step are formed with increasing heights toward peripheral edges of the top electrode. Dielectric spacer layers may be provided between the outer steps and the piezoelectric layer. Passivation layers are disclosed that extend over the top electrode either to peripheral edges of the piezoelectric layer or that are inset from peripheral edges of the piezoelectric layer. Piezoelectric layers may be arranged with reduced thickness portions in areas that are uncovered by top electrodes. BAW resonators as disclosed herein are provided with high quality factors and suppression of spurious modes while also providing weakened BO modes that are shifted farther away from passbands of such BAW resonators.

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.