A joining method is for producing a sound transducer system. The method includes: providing a piezoelectric material and a plurality of components, each of the components being characterized by a solidus temperature; arranging the piezoelectric material and the plurality of components in the form of a stack, so that adjacent to a front face of the piezoelectric material there is a front stack part and adjacent to a rear face of the piezoelectric material there is a rear stack part; and consolidating the stack by the introduction of heat and pressure for a predetermined period of time, none of the solidus temperatures of the plurality of components being exceeded during the consolidation; and, during the consolidation, the piezoelectric material being directly acoustically coupled to an immediately adjacent component of the front and/or rear stack part.

A piezoelectric substrate according to the present disclosure includes: a base body; an electrode formed at the base body; and a piezoelectric layer formed at the electrode and containing potassium, sodium, and niobium. A value of IR2/IR1 obtained by dividing an integrated intensity IR2 at a peak 2 by an integrated intensity IR1 at a peak 1, when a surface of the piezoelectric layer is measured by Fourier transform infrared spectroscopy, is less than 0.086. Here, the peak 1 has a strongest area intensity among peaks detected at wavenumbers of 475 cm.sup.?1 to 700 cm.sup.?1, and the peak 2 has an area intensity that is a sum of area intensities of peaks detected at wavenumbers of 1200 cm.sup.?1 to 1645 cm.sup.?1.

A piezoelectric substrate according to the present disclosure includes: a base body; an electrode formed at the base body; and a piezoelectric layer formed at the electrode and containing potassium, sodium, and niobium. A value of IR2/IR1 obtained by dividing an integrated intensity IR2 at a peak 2 by an integrated intensity IR1 at a peak 1, when a surface of the piezoelectric layer is measured by Fourier transform infrared spectroscopy, is less than 0.086. Here, the peak 1 has a strongest area intensity among peaks detected at wavenumbers of 475 cm.sup.?1 to 700 cm.sup.?1, and the peak 2 has an area intensity that is a sum of area intensities of peaks detected at wavenumbers of 1200 cm.sup.?1 to 1645 cm.sup.?1.

A piezoelectric material contains: a first component which is a rhombohedral crystal in a single composition, has a Curie temperature Tc1, and is a lead-free-system composite oxide having a perovskite-type structure; a second component which is a crystal other than the rhombohedral crystal in a single composition, has a Curie temperature Tc2<Tc1, and is a lead-free-system composite oxide having a perovskite-type structure; and a third component which is a crystal other than the rhombohedral crystal in a single composition similar to the second component, has a Curie temperature Tc3Tc1, and is a lead-free-system composite oxide that has a perovskite-type structure and is different from the second component. When a molar ratio of the third component to the sum of the second component and the third component is and Tc3+(1)Tc2 is Tc4, |Tc4Tc2|50 C.

A method for producing a plurality of piezoelectric ultrasound transducer elements, the method comprising providing or depositing a piezoelectric material on at least part of a surface of a sheet of substrate to form a layered member; and forming the one or more piezoelectric ultrasound transducer elements from the layered member.

[Object] An object of the present invention is to provide a method for manufacturing an oxide single crystal substrate having less dispersion in characteristics within the substrate surface. [Means to solve the Problems] In the manufacture method of the present invention, a powder containing a Li compound is dispersed in a medium to form a slurry, and heat is applied while the slurry is in contact with the surface of the oxide single crystal substrate, so as to diffuse Li into the substrate from the surface thereof to effect a modification of the substrate; or after the slurry is brought into contact with the surface of the oxide single crystal substrate, the oxide single crystal substrate is buried in a powder containing the Li compound, and heat is applied to effect the diffusion of Li in the substrate from the surface thereof whereby a modification of the substrate occurs.

Provided is a piezoelectric element including a first electrode provided above a substrate, a piezoelectric layer including a plurality of crystal grains containing potassium, sodium, and niobium and provided above the first electrode, and a second electrode provided above the piezoelectric layer. An atom concentration N.sub.K1 (atm %) of potassium contained in grain boundaries of the crystal grains and an atom concentration N.sub.K2 (atm %) of potassium contained in the crystal grains satisfy a relationship of 1.0<N.sub.K1/N.sub.K22.4.

A subtractive forming method that includes providing a material stack including a samarium and selenium containing layer and an aluminum containing layer in direct contact with the samarium and selenium containing layer. The samarium component of the samarium and selenium containing layer of the exposed portion of the material stack is etched with an etch chemistry comprising citric acid and hydrogen peroxide that is selective to the aluminum containing layer. The hydrogen peroxide reacts with the aluminum containing layer to provide an oxide etch protectant surface on the aluminum containing layer, and the citric acid etches samarium selectively to the oxide etch protectant surface. Thereafter, a remaining selenium component of is removed by elevating a temperature of the selenium component.

A method of forming a monolithic integrated PMUT and CMOS with a coplanar elastic, sealing, and passivation layer in a single step without bonding and the resulting device are provided. Embodiments include providing a CMOS wafer with a metal layer; forming a dielectric over the CMOS; forming a sacrificial structure in a portion of the dielectric; forming a bottom electrode; forming a piezoelectric layer over the CMOS; forming a top electrode over portions of the bottom electrode and piezoelectric layer; forming a via through the top electrode down to the bottom electrode and a second via down to the metal layer through the top electrode; forming a second metal layer over and along sidewalls of the first and second via; removing the sacrificial structure, an open cavity formed; and forming a dielectric layer over a portion of the CMOS, the open cavity sealed and an elastic layer and passivation formed.

Disclosed is a silicon nanowire pressure sensor including a lower substrate with a diaphragm recess in a lower surface thereof, an upper substrate having a first surface attached to an upper surface of the lower substrate, silicon nanowires formed on the first surface of the upper substrate, resistive portions exposed on a second surface of the upper substrate, and a diaphragm region formed by etching a center portion of the second surface of the upper substrate so as to be aligned with the resistive portions, in which the diaphragm recess is larger than the diaphragm region.