Provided is a lead-free piezoelectric material reduced in dielectric loss tangent, and achieving both a large piezoelectric constant and a large mechanical quality factor. A piezoelectric material according to at least one embodiment of the present disclosure is a piezoelectric material including a main component formed of a perovskite-type metal oxide represented by the general formula (1): Na.sub.x+s(1−y)(Bi.sub.wBa.sub.1−s−w).sub.1−yNb.sub.yTi.sub.1−yO.sub.3 (where 0.84≤x≤0.92, 0.84≤y≤0.92, 0.002≤(w+s)(1−y)≤0.035, and 0.9≤w/s≤1.1), and a Mn component, wherein the content of the Mn is 0.01 mol % or more and 1.00 mol % or less with respect to the perovskite-type metal oxide.

A layered portion includes, at least above an opening, a first single-crystal piezoelectric body layer, a second single-crystal piezoelectric body layer, an intermediate electrode layer, a lower electrode layer, and an upper electrode layer. The first single-crystal piezoelectric body layer includes a material that produces a difference in etching rate between a positive side and a negative side of a polarization charge. The polarization charge of the first single-crystal piezoelectric body layer is negative on a side of the intermediate electrode layer and positive on a side of the lower electrode layer.

A thin-film transistor may include an amorphous semiconductor channel layer, an organic material piezoelectric stress gate layer formed adjacent to the amorphous semiconductor channel layer, a source electrode coupled to the organic material piezoelectric stress gate layer, a drain electrode coupled to the organic material piezoelectric stress gate layer and a gate electrode coupled to the organic material piezoelectric stress gate layer. In some embodiments, the amorphous semiconductor channel layer may be amorphous indium gallium zinc oxide. In some embodiments, the organic material piezoelectric stress gate layer may be organic polyvinylidene fluoride. In some embodiments, the amorphous semiconductor channel layer may be formed on a flexible substrate.

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.

A layered portion includes, at least above an opening, a first single-crystal piezoelectric body layer, a second single-crystal piezoelectric body layer, an intermediate electrode layer, a lower electrode layer, and an upper electrode layer. The first single-crystal piezoelectric body layer includes a material that produces a difference in etching rate between a positive side and a negative side of a polarization charge. The polarization charge of the first single-crystal piezoelectric body layer is positive on a side of the intermediate electrode layer and negative on a side of the lower electrode layer

A piezoelectric actuator including an upper piezoelectric bimorph beam having a first upper piezoelectric layer, a second upper piezoelectric layer and at least three upper electrode layers extending between a first end and a second end of the upper piezoelectric bimorph beam; a lower piezoelectric bimorph beam having a first lower piezoelectric layer, a second lower piezoelectric layer and at least three lower electrode layers extending between a first end and a second end of the lower piezoelectric bimorph beam, and wherein the first end of the lower piezoelectric bimorph beam is coupled to the first end of the upper piezoelectric bimorph beam by a first joint, and the second end of the lower piezoelectric bimorph beam is coupled to second end of the upper piezoelectric bimorph beam; and a base member coupled to a center region of the lower piezoelectric bimorph beam.

PMUT acoustic transducer formed in a body of semiconductor material having a face and accommodating a plurality of first buried cavities, having an annular shape, arranged concentrically with each other and extending at a distance from the face of the body. The first buried cavities delimit from below a plurality of first membranes formed by the body so that each first membrane extends between a respective first buried cavity of the plurality of first buried cavities and the face of the body. A plurality of piezoelectric elements extend on the face of the body, each piezoelectric element extending above a respective first membrane of the plurality of first membranes. The first membranes have different widths, variable between a minimum value and a maximum value.

In a chip-on-array approach, acoustic and electronic modules are separately formed. The acoustic stack is connected to one interposer, and the electronics are connected to another interposer. Different connection processes (e.g., using low temperature bonding for the acoustic stack and higher temperature-based interconnect for the electronics) may be used. This arrangement may allow for different pitches of the transducer elements and the I/O of the electronics by staggering vias in the interposers. The two interposers are then connected to form the chip-on-array.

A piezoelectric vibrating device includes a piezoelectric layer composed of a bulk piezoelectric material, a lower electrode on a first surface of the piezoelectric layer and a supporting substrate bonded with the lower electrode.

A piezoelectric element includes a support member, a vibrator, a through electrode and a seed layer. The vibrator is disposed on an insulation film of the support member, and includes a piezoelectric film and an electrode coating film electrically connected to the piezoelectric film. The vibrator has a support region and a vibration region. The through electrode is electrically connected to the electrode coating film at the support region, and is disposed in a stacking direction of the support member and the vibrator. Between the piezoelectric film and the insulation film, the seed layer is disposed at a portion of the electrode coating film facing another portion of the electrode coating film connected to the through electrode in the stacking direction. The seed layer is made of material having a lattice constant closer to the piezoelectric film or material easier to cause the piezoelectric film to be self-aligned.