A method for producing an at least partially transparent device is provided, including producing, on a first substrate, first and second separation layers one against the other; producing, on the second separation layer, an at least partially transparent functional layer; making the functional layer integral with a second at least partially transparent substrate; forming a mechanical separation at an interface between the separation layers; removing the second separation layer; producing a first at least partially transparent electrode layer on the functional layer; where the materials of the stack are chosen such that the interface between the separation layers corresponds to that, among all the interfaces of the stack, having the lowest adherence force.

A composite wafer has an oxide single-crystal film transferred onto a support wafer, the film being a lithium tantalate or lithium niobate film, and the composite wafer being unlikely to have cracking or peeling caused in the lamination interface between the film and the support wafer. More specifically, a method of producing the composite wafer, includes steps of: implanting hydrogen atom ions or molecule ions from a surface of the oxide wafer to form an ion-implanted layer inside thereof; subjecting at least one of the surface of the oxide wafer and a surface of the support wafer to surface activation treatment; bonding the surfaces together to obtain a laminate; heat-treating the laminate at 90 C. or higher at which cracking is not caused; and applying ultrasonic vibration to the heat-treated laminate to split along the ion-implanted layer to obtain the composite wafer.

Provided is a composite wafer (c-wafer) having an oxide single-crystal film transferred onto a support wafer (s-wafer), the film being a lithium tantalate or lithium niobate film, and c-wafer being unlikely to have cracking or peeling caused in the lamination interface between the film and s-wafer. More specifically, provided is a method of producing c-wafer, including steps of: implanting hydrogen atom ions or molecule ions from a surface of the oxide wafer (o-wafer) to form an ion-implanted layer inside thereof; subjecting at least one of the surface of o-wafer and a surface of s-wafer to surface activation; bonding the surfaces together to obtain a laminate; providing at least one of the surfaces of the laminate with a protection wafer having thermal expansion coefficient smaller than that of o-wafer; and heat-treating the laminate with the protection wafer at 80 C. or higher to split the laminate along the layer to obtain c-wafer.

A substrate for a surface acoustic wave device or bulk acoustic wave device, comprising a support substrate and an piezoelectric layer on the support substrate, wherein the support substrate comprises a semiconductor layer on a stiffening substrate having a coefficient of thermal expansion that is closer to the coefficient of thermal expansion of the material of the piezoelectric layer than that of silicon, the semiconductor layer being arranged between the piezoelectric layer and the stiffening substrate.

A diaphragm for a piezoelectric micromachined ultrasonic transducer (PMUT) is presented having resonance frequency and bandwidth characteristics which are decoupled from one another into independent variables. Portions of at least the piezoelectric material layer and backside electrode layer are removed in a selected pattern to form structures, such as ribs, in the diaphragm which retains stiffness while reducing overall mass. The patterned structure can be formed by additive, or subtractive, fabrication processes.

A method can be used for producing ceramic multilayer components. The method includes providing green layers for the ceramic multilayer components, stacking the green layers into a stack, and subsequently compressing the stack to form a block. Furthermore, the method includes isolating the block into partial blocks that each have a longitudinal direction, thermally treating the partial blocks, subsequently mechanically machining surfaces of the partial blocks, and providing the partial blocks with outer electrodes and isolating the partial blocks in each case transversely to the longitudinal direction into individual ceramic multilayer components.

A substrate for a surface acoustic wave device or bulk acoustic wave device, comprising a support substrate and an piezoelectric layer on the support substrate, wherein the support substrate comprises a semiconductor layer on a stiffening substrate having a coefficient of thermal expansion that is closer to the coefficient of thermal expansion of the material of the piezoelectric layer than that of silicon, the semiconductor layer being arranged between the piezoelectric layer and the stiffening substrate.

A piezoelectric element includes: a piezoelectric part; a first substrate and a second substrate, provided at both sides of the piezoelectric part, respectively; a first electrode layer, located between the first substrate and the piezoelectric part; and a second electrode layer, located between the electrode substrate and the piezoelectric part, wherein a surface of at least one of the first substrate and the second substrate close to the piezoelectric part is provided with a convex portion.

A manufacturing method of a vibrator includes processing a tip of a contact part arranged on an elastic body of the vibrator by lapping or grinding processing so that part of the tip has a plane shape in part of a spherical shape.

A method for producing an at least partially transparent device is provided, including producing, on a first substrate, first and second separation layers one against the other; producing, on the second separation layer, an at least partially transparent functional layer; making the functional layer integral with a second at least partially transparent substrate; forming a mechanical separation at an interface between the separation layers; removing the second separation layer; producing a first at least partially transparent electrode layer on the functional layer; where the materials of the stack are chosen such that the interface between the separation layers corresponds to that, among all the interfaces of the stack, having the lowest adherence force.