An object of the present invention is to provide a piezoelectric element formed of a piezoelectric film including an electrode layer provided on each of both surfaces of a piezoelectric layer and a protective layer provided on the surface of the electrode layer, in which the electrode layer and a conductive member such as a lead wire can be connected to each other with high productivity and the resistance of the connection is also low. The object thereof is achieved by opening through-holes in the protective layer of the piezoelectric film and the conductive member, allowing both through-holes to at least partially overlap each other, filling the through-hole of the protective layer with a conductive filling member, and allowing the filling member to reach the through-hole of the conductive member.

An object of the present invention is to provide a piezoelectric element formed of a piezoelectric film including an electrode layer provided on each of both surfaces of a piezoelectric layer and a protective layer provided on the surface of the electrode layer, in which the electrode layer and a conductive member such as a lead wire can be connected to each other with high productivity and the resistance of the connection is also low. The object thereof is achieved by opening through-holes in the protective layer of the piezoelectric film and the conductive member, allowing both through-holes to at least partially overlap each other, filling the through-hole of the protective layer with a conductive filling member, and allowing the filling member to reach the through-hole of the conductive member.

A micro-electrical-mechanical system (MEMS) guided wave device includes a piezoelectric layer including multiple thinned regions of different thicknesses each bounding in part a different recess, different groups of electrodes on or adjacent to different thinned regions and arranged for transduction of lateral acoustic waves of different wavelengths in the different thinned regions, and at least one bonded interface between the piezoelectric layer and a substrate. Optionally, a buffer layer may be intermediately bonded between the piezoelectric layer and the substrate. Methods of producing such devices include locally thinning a piezoelectric layer to define multiple recesses, bonding the piezoelectric layer on or over a substrate layer to cause the recesses to be bounded in part by either the substrate or an optional buffer layer, and defining multiple groups of electrodes on or over the different thinned regions.

A method for manufacturing a monocrystalline piezoelectric material layer includes providing a donor substrate made of the piezoelectric material, providing a receiving substrate, transferring a so-called “seed layer” of the donor substrate onto the receiving substrate, and using epitaxy of the piezoelectric material on the seed layer until the desired thickness for the monocrystalline piezoelectric layer is obtained.

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.

An energy harvester includes a frame having a base, a first side member affixed to the base, and a second side member affixed to the base and spaced apart from the first side member. A beam is coupled between the first side member of the frame and the second side member of the frame. The beam has a substrate layer with a first end affixed to the first side member of the frame, a second end affixed to the second side member of the frame, a first face, and a second face opposite to the first face. The substrate is elastically deformable in response to the vibratory force. The beam further includes a first piezoelectric layer joined to the first face of the substrate layer and having a terminal for electrical connection to a load, the first piezoelectric layer comprising at least one piezoelectric patch.

A bonded body having a supporting substrate and piezoelectric material layer is provided. The supporting substrate is composed of mullite, and the material of the piezoelectric material layer is LiAO.sub.3 where A represents one or more element selected from the group consisting of niobium and tantalum. An interface layer is present along an interface between the supporting body and piezoelectric material layer, and a supporting substrate-side intermediate layer is present between the interface layer and supporting substrate. Each of the interface layer and supporting substrate-side intermediate layer contains oxygen, aluminum, silicon and one or more element selected from the group consisting of niobium and tantalum as main components.

An acoustic wave device includes a piezoelectric material substrate, an intermediate layer on the piezoelectric material substrate and composed of one or more materials selected from the group consisting of silicon oxide, aluminum nitride and sialon. A bonding layer is on the intermediate layer and is composed of one or more materials selected from the group consisting of tantalum pentoxide, niobium pentoxide, titanium oxide, mullite, alumina, and a high resistance silicon and hafnium oxide. A supporting body is composed of a polycrystalline ceramic and is bonded to the bonding layer by direct bonding, and an electrode is on the piezoelectric material substrate.

Techniques for joining dissimilar materials in microelectronics are provided. Example techniques direct-bond dissimilar materials at an ambient room temperature, using a thin oxide, carbide, nitride, carbonitride, or oxynitride intermediary with a thickness between 100-1000 nanometers. The intermediary may comprise silicon. The dissimilar materials may have significantly different coefficients of thermal expansion (CTEs) and/or significantly different crystal-lattice unit cell geometries or dimensions, conventionally resulting in too much strain to make direct-bonding feasible. A curing period at ambient room temperature after the direct bonding of dissimilar materials allows direct bonds to strengthen by over 200%. A relatively low temperature anneal applied slowly at a rate of 1° C. temperature increase per minute, or less, further strengthens and consolidates the direct bonds. The example techniques can direct-bond lithium tantalate LiTaO.sub.3 to various conventional substrates in a process for making various novel optical and acoustic devices.

An acoustic wave device includes: a piezoelectric substrate bonded on a support substrate, a surface including protruding portions and/or recessed portions being interposed between the piezoelectric substrate and the support substrate; a first acoustic wave resonator that includes first electrode fingers with a first average pitch and is disposed on the piezoelectric substrate in a first region where an average interval between the protruding portions and/or the recessed portions in a direction in which the first electrode fingers are arranged is a first interval; and a second acoustic wave resonator that includes second electrode fingers with a second average pitch different from the first average pitch, and is disposed on the piezoelectric substrate in a second region where an average interval between the protruding portions and/or the recessed portions in a direction in which the second electrode fingers are arranged is a second interval different from the first interval.