A piezoelectric element includes a piezoelectric layer, a first electrode layer, and a second electrode layer. The piezoelectric layer includes first and second surfaces opposed to each other. The first electrode layer is located on the first surface. The second electrode layer is located on the second surface. At least a portion of the second electrode layer faces the first electrode layer with the piezoelectric layer interposed therebetween. The second electrode layer mainly includes silicon. The piezoelectric layer is monocrystalline.

A method for manufacturing a film on a support having a non-flat surface comprises: providing a donor substrate having a non-flat surface, forming an embrittlement zone in the donor substrate so as to delimit the film to be transferred, forming the support by deposition on the non-flat surface of the film to be transferred, and detaching the donor substrate along the embrittlement zone, so as to transfer the film onto the support.

A piezoelectric element includes a piezoelectric layer, a first electrode layer, a second electrode layer, and a coupling electrode. At least a portion of the second electrode layer faces the first electrode layer with the piezoelectric layer interposed therebetween. The second electrode layer includes a coupling area. The coupling area meets a through hole in a region of the second electrode layer not facing the first electrode layer. The coupling electrode is on the coupling area. Between the coupling area and the surface of the second electrode layer on the piezoelectric layer side excluding the coupling area, the difference in position is about 5 nm or less.

An embodiment piezoelectric element includes a piezoelectric composite layer including a polymer and a piezoelectric ceramic, a backing layer disposed on a rear surface of the piezoelectric composite layer and configured to limit vibration of the piezoelectric composite layer, and an adhesive layer bonding the piezoelectric composite layer and the backing layer.

Producing a semiconductor or piezoelectric on-insulator type substrate for RF applications which is provided with a porous layer under the BOX layer and under a layer of polycrystalline semiconductor material.

The occurrence of cracking in a functional layer is suppressed, while maintaining flexibility of a layered structure. The layered structure includes a polymer substrate, and a crystalline functional layer formed on the first surface of the substrate. The surface roughness of the first surface of the substrate is 3 nm or less in terms of arithmetic mean roughness (Ra).

The disclosed method of diffusion bonding of a lead zirconate titanate piezoelectric crystal to a metal wear plate, for the fabrication of an ultrasonic transducer operable at high temperatures and able to withstand repeated thermal cycling, comprises depositing noble metal coatings on both bonding surfaces, bringing the surfaces into contact, and heating under pressure at a temperature ranging from 270 to 400° C.

A method for manufacturing a hybrid structure comprising an effective layer of piezoelectric material having an effective thickness and disposed on a supporting substrate having a substrate thickness and a thermal expansion coefficient lower than that of the effective layer includes: a) a step of providing a bonded structure comprising a piezoelectric material donor substrate and the supporting substrate, b) a first step of thinning the donor substrate to form a thinned layer having an intermediate thickness and disposed on the supporting substrate, the assembly forming a thinned structure; c) a step of heat treating the thinned structure at an annealing temperature; and d) a second step, after step c), of thinning the thinned layer to form the effective layer. The method also comprises, prior to step b), a step a′) of determining a range of intermediate thicknesses that prevent the thinned structure from being damaged during step c).

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.

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.