A bonded body includes a supporting substrate, a piezoelectric single crystal substrate and a bonding layer provided between the supporting substrate and piezoelectric single crystal substrate. The bonding layer has a composition of Si.sub.(1-x)O.sub.x (x represents an oxygen ratio). The oxygen ratio x at a central part in a thickness direction of the bonding layer is higher than an oxygen ratio x at an end part of the bonding layer on a side of the piezoelectric single crystal substrate and an oxygen ratio x at an end part of the bonding layer on a side of the supporting substrate. The oxygen ratio at the central part in the thickness direction of the bonding layer is 0.013 or higher and 0.666 or lower.

The present disclosure provides a resonator and its fabrication method. The method includes providing a first substrate; forming a piezoelectric stacked layer-structure on the first substrate; forming a sacrificial layer covering the piezoelectric stacked layer-structure on a working region; providing a second substrate; forming an adhesive layer on the second substrate; attaching a second back surface of the adhesive layer to the sacrificial layer and the piezoelectric stacked layer-structure exposed by the sacrificial layer, where the adhesive layer covers sidewalls of the sacrificial layer and is filled between the second substrate and the piezoelectric stacked layer-structure; removing the first substrate to expose a first front surface of the piezoelectric stacked layer-structure; forming release holes passing through the piezoelectric stacked layer-structure, or forming release holes passing through the second substrate; and removing the sacrificial layer through the release holes to form a cavity.

An electronic device includes a first substrate and a second substrate. A side wall joins the first substrate to the second substrate. The side wall includes a first alloy layer of a first metal and a second metal bonded directly to an upper surface of the first substrate and a second alloy layer of the first metal and a third metal disposed on top of the first alloy layer and bonded directly to a lower surface of the second substrate, the second metal and the third metal being different from each other and from the first metal. An electronic circuit is disposed on the lower surface of the second substrate within a cavity defined by the lower surface of the first substrate, the upper surface of the second substrate, and the side wall.

A piezoelectric transducer includes beam portions each with a fixed end portion and extending in a direction away from the fixed end portion. A base portion is connected to the fixed end portion of each of the beam portions. The beam portions extends in a same plane, and respective extending directions of at least two beam portions are different from each other. The beam portions each include a single crystal piezoelectric layer having a polarization axis in a same direction, an upper electrode layer, and a lower electrode layer. A polarization axis has a polarization component in the plane. An axial direction of an orthogonal axis that is orthogonal to the polarization axis and extends in the above-described plane intersects with an extending direction of each of the plurality of beam portions.

An ultrasonic transducer includes a delay line substrate, a piezoelectric element, a metal conductive layer between the delay line substrate and the piezoelectric element, and a backing layer applied to the piezoelectric element. The delay line substrate and the piezoelectric element are acoustically joined, configured to couple ultrasonic waves from the piezoelectric element into the delay line substrate or from the delay line substrate into the piezoelectric element. The backing layer includes a metal film, the metal film has a thickness and an acoustic impedance, and the thickness and the acoustic impedance each have value sufficient to provide acoustic damping. The backing layer has a substantially columnar cross-sectional morphology with a substantially granular surface morphology.

Exemplary embodiments relate to a skin-adherable electronic device including a semiconductor circuit unit including a circuit element including an electrode and an interconnect, and a semiconductor device including an insulating layer and an active layer; and a flexible patch that can adhere to skin and including a plurality of through-holes, wherein the insulating layer includes a plurality of through-holes corresponding to the plurality of through-holes of the flexible patch, and a method of manufacturing the same. When the active layer is made of a piezoelectric material, the electronic device may be used as a skin sensor that can acquire skin deformation and/or elasticity information.

Fingerprint identification modules, methods for forming the fingerprint identification modules and electronic devices are provided. The method may include providing a substrate, containing a signal process circuit formed therein; providing a carrier substrate; forming one or more piezoelectric transducers on the carrier substrate, wherein a piezoelectric transducer of the one or more piezoelectric transducers includes a first electrode, a piezoelectric layer on the first electrode and a second electrode on the piezoelectric layer; forming a permanent bonding layer, containing one or more cavities, on one of the carrier substrate and the substrate; bonding the carrier substrate with the substrate using the permanent bonding layer, wherein the permanent bonding layer is between the one or more piezoelectric transducers and the substrate, and each piezoelectric transducer covers one cavity; and removing the carrier substrate.

A wafer has a layer containing silicon, a layer of polycrystalline diamond deposited on the silicon-containing layer, and a bow-compensation layer on the other side of the silicon-containing layer for reducing wafer-bow. A method of making a bonded structure includes an activation process for creating dangling bonds on the surface of one substrate, followed by contact-bonding the surface to a second substrate at low temperature. A bonded structure may include two substrates contact bonded to each other, one substrate including a layer containing silicon, a layer of polycrystalline diamond, a bow-compensation layer for reducing wafer-bow of the first substrate, and the other substrate including gallium nitride, silicon carbide, lithium niobate, lithium tantalate, gallium arsenide, indium phosphide, or another suitable material other than diamond.

A microphone device may include: a substrate wafer, a support member bonded to a front surface of the substrate wafer, a single-crystal piezoelectric film provided over the support member, a top electrode and a bottom electrode. The single-crystal piezoelectric film may have a first surface and an opposing second surface. The top electrode may be arranged adjacent to the first surface of the single-crystal piezoelectric film. The bottom electrode may be arranged adjacent to the second surface of the single-crystal piezoelectric film. The substrate wafer may have a through-hole formed therein. The through-hole of the substrate wafer may be at least substantially aligned with at least one of the top electrode and the bottom electrode.

A semiconductor device may include: a substrate wafer, a bonding layer at least partially covering a front surface of the substrate wafer, a plurality of silicon pillars bonded to the front surface of the substrate wafer by the bonding layer, a single-crystal piezoelectric film having a first surface and an opposing second surface, a top electrode arranged adjacent to the first surface of the single-crystal piezoelectric film, and a bottom electrode arranged adjacent to the second surface of the single-crystal piezoelectric film. The single-crystal piezoelectric film may be supported by the plurality of silicon pillars such that the second surface of the piezoelectric film and the front surface of the substrate wafer enclose a cavity therebetween.