A film structure includes a substrate (11) which is a silicon substrate including an upper surface (11a) composed of a (100) plane, an alignment film (12) which is formed on the upper surface (11a) and includes a zirconium oxide film which has a cubic crystal structure and is (100)-oriented, and a conductive film (13) which is formed on the alignment film (12) and includes a platinum film which has a cubic crystal structure and is (100)-oriented. An average interface roughness of an interface (IF1) between the alignment film (12) and the conductive film (13) is greater than an average interface roughness of an interface (IF2) between the substrate (11) and the alignment film (12).

Provided is a piezoelectric film including an AlN crystal, and a first element and a second element doped to the AlN crystal. The first element is an element having an ionic radius larger than an ionic radius of Al. The second element is an element having an ionic radius smaller than the ionic radius of Al. Also provided are piezoelectric film laminated body including an underlayer and a piezoelectric film including ScAlN, and a method of manufacturing the same. The underlayer has a crystal lattice having six-fold symmetry or three-fold symmetry. Also provided are a piezoelectric film including ScAlN having a laminated structure of a hexagonal crystal and a cubic crystal, and a method of manufacturing the same. The cubic crystal is doped with an element other than trivalent element.

A piezoelectric device has a good piezoelectric characteristic, while suppressing a leakage current between electrodes. The piezoelectric device has a first substrate, a first conductive film provided on the first substrate, a piezoelectric layer formed of an inorganic material and provided on the first conductive film, an adhesive layer provided on the piezoelectric layer, and a second conductive film provided on the adhesive layer.

A method for producing a piezoelectric transducer device is provided, including a membrane including at least one silicon and/or silicon nitride layer; a piezoelectric layer including at least one piezoelectric material with crystalline perovskite structure and arranged on the membrane; first and second electrodes electrically in contact with the piezoelectric layer; and in which the piezoelectric layer is in direct contact with the silicon and/or silicon nitride layer, or in which the piezoelectric layer is in contact with the silicon and/or silicon nitride layer solely through one or more metal layers.

A method for producing a piezoelectric transducer device is provided, including a membrane including at least one silicon and/or silicon nitride layer; a piezoelectric layer including at least one piezoelectric material with crystalline perovskite structure and arranged on the membrane; first and second electrodes electrically in contact with the piezoelectric layer; and in which the piezoelectric layer is in direct contact with the silicon and/or silicon nitride layer, or in which the piezoelectric layer is in contact with the silicon and/or silicon nitride layer solely through one or more metal layers.

There are provided a method for manufacturing a substrate excellent in heat dissipation with a small loss in radio frequencies with no need of a high temperature process in which a metal impurity is diffused, and a substrate of high thermal conductivity. A composite substrate according to the present invention is a composite substrate having a piezoelectric single crystal substrate, a support substrate, and an intermediate layer provided between the piezoelectric single crystal substrate and the support substrate. The intermediate layer is a film formed of an inorganic material, and at least a part of the film is thermally synthesized silica. The intermediate layer may be separated into at least two layers along the bonding surface of the composite substrate. The first intermediate layer in contact with the support substrate may be a layer including thermally synthesized silica.

There are provided a method for manufacturing a substrate excellent in heat dissipation with a small loss in radio frequencies with no need of a high temperature process in which a metal impurity is diffused, and a substrate of high thermal conductivity. A composite substrate according to the present invention is a composite substrate having a piezoelectric single crystal substrate, a support substrate, and an intermediate layer provided between the piezoelectric single crystal substrate and the support substrate. The intermediate layer is a film formed of an inorganic material, and at least a part of the film is thermally synthesized silica. The intermediate layer may be separated into at least two layers along the bonding surface of the composite substrate. The first intermediate layer in contact with the support substrate may be a layer including thermally synthesized silica.

A device includes a substrate, a first layer of getter material, a first electrode, an insulator element, a second electrode, a first input-output electrode, and a second input-output electrode. The first layer of getter material is deposited on the substrate. The first electrode is formed in a first conductive layer deposited on the first layer of getter material. The first layer of getter material has a getter capacity for hydrogen that is higher than the first electrode. The insulator element is formed in a piezoelectric layer deposited on the first electrode. The second electrode is formed in a second conductive layer deposited on the insulator element. The first input-output electrode is conductively connecting to the first layer of getter material. The second input-output electrode is conductively connecting to the second electrode.

A manufacturing method of a piezoelectric element includes: forming a first conductive film on a vibration plate as a substrate; etching a first conductive film; forming a second conductive film on the first conductive film; etching the second conductive film to form a first electrode having a step region as a step formed by the second conductive film and the first conductive film at ends thereof; forming a seed layer as an orientation control layer covering the first electrode by a liquid phase method; forming a piezoelectric film on the seed layer; etching the piezoelectric film to form a piezoelectric body; and forming a second electrode covering the piezoelectric body.

A manufacturing method of a piezoelectric element includes: forming a first conductive film on a vibration plate as a substrate; etching a first conductive film; forming a second conductive film on the first conductive film; etching the second conductive film to form a first electrode having a step region as a step formed by the second conductive film and the first conductive film at ends thereof; forming a seed layer as an orientation control layer covering the first electrode by a liquid phase method; forming a piezoelectric film on the seed layer; etching the piezoelectric film to form a piezoelectric body; and forming a second electrode covering the piezoelectric body.