National Institute of Advanced Industrial Science and Technology

Agency of Industrial Science and Technology

Ube Industries, Inc.

Japan Science and Technology Agency

Japan as Represented by Director General of Agency of Industrial Science

Co-Op Chemical Co., Ltd.

Hiroshi Tateyama

Morito Akiyama

Naohiro Ueno

Kunio Kimura

Kiichi Ikeda

Kazuhiko Jinnai

Tetsuo Yamada

Kazuhiro Nonaka

Chao-Nan Xu

Keigo Nagao

Chisen Hashimoto

Hideharu Hirosue

Toshihiro Kamohara

Noriyuki Kuwano

Kinue Tsunematsu

Takashi Furusawa

Yoshitaka Sunagawa

Yoshihiro Umeuchi

Keiichiro Jinushi

A thin film made of a wurtzite structure compound is manufactured by a reactive sputtering using a metal material as a target, and a nitrogen gas or oxygen gas as a reactive gas. By optimizing film-forming conditions when manufacturing the film, it is possible to obtain a wurtzite thin film whose polarization directions of crystal grains are aligned in a uniform direction. There is provided a laminate including a first wurtzite crystalline layer made of a wurtzite crystalline structure compound is formed in advance between a substrate and a functional material layer that is a ground. Thus it is possible to improve the crystallinity and crystalline orientation of a second wurtzite crystalline layer on the functional material layer.

Wurtzite thin film, laminate containing wurtzite crystalline layer and their manufacturing methods

A lower electrode is formed on a silica glass substrate or a stainless substrate. Through a sputtering process, a thin film of aluminum nitride and/or zinc oxide is formed on the lower substrate so that the degree of dipole-orientation becomes 55% or more, and thereby a piezoelectric thin film is formed. And an upper electrode is formed on the piezoelectric thin film. A piezoelectric device has a piezoelectric layer made of aluminum nitride and/or zinc oxide. Aluminum nitride and zinc oxide with a crystal structure have inborn piezoelectric characteristics because their crystal structures are not symmetrical, they do not have Curie temperature unlike ferroelectrics, and in aluminum nitride and zinc oxide, magnetic transition does not occur even at high temperature, so that they never lose piezoelectric characteristics until crystal melts or sublimates.

Piezoelectric element and method for manufacturing

A stacked structure () includes an electrostriction layer () including an electric inductive distortion material and a stress light-emitting layer () including a stress light-emitting material. When applying a voltage to the electrostriction layer () in the stacked structure (), the electric inductive distortion material deforms, thereby the electrostriction layer () deforms. The deformation of the electrostriction layer () causes an external force to act on the stress light-emitting material of the stress light-emitting layer (), and the stress light-emitting layer () emits light, accordingly. That is, by applying the voltage to the stacked structure (), the stacked structure () can emit the light.

Light-emitting device, display device, and stress sensor

The present invention has an objective to provide a high performance piezoelectric element in which is formed an aluminum nitride thin film free from hillocks, cracks, and peeling which exhibits superhigh c-axis orientation, by forming a bottom electrode from a W layer with no intervening adhesive layer on a glass or other cheap substrate. The piezoelectric element of the present invention is a piezoelectric element using a superhigh-oriented aluminum nitride thin film characterized in that the piezoelectric element is free from hillocks, cracks, and peeling and includes a stack structure in which a bottom electrode, a piezoelectric body thin film, and a top electrode are sequentially formed on a substrate; the bottom electrode is made of an oriented W layer of which a (111) plane of W is parallel to a surface of the substrate; and the piezoelectric body thin film is formed of a c-axis-oriented aluminum nitride thin film having a rocking curve full width half maximum (RCFWHM) not exceeding 2.5&#xb0;.

Piezoelectric device comprising ultrahighly-oriented aluminum nitride thin film and its manufacturing method

A piezoelectric sensor arranged so as to includes: a transparent piezoelectric element having a piezoelectric property; and a pair of transparent conductor film layers opposed to each other with the piezoelectric element therebetween, the transparent piezoelectric element and the transparent conductor film layers are formed between a pair of transparent substrates, opposed to each other, which serve as pressure transmission means. Consequently, the transparent piezoelectric sensor has an excellent durability. A piezoelectric sensor comprises a piezoelectric element with a piezoelectric property which is made of a piezoelectric material having no Curie point and has a dipole orientation degree of not less than 75%. Consequently, the piezoelectric sensor having an excellent durability and a simple structure is provided at low cost.

Piezoelectric sensor and input device including same

A thin film bulk acoustic resonator comprises a substrate () of a silicon single crystal, a base film () formed on the substrate () and composed of a dielectric film mainly containing silicon oxide, and a piezoelectric stacked structure () formed on the base film (). A vibratory section () composed of a part of the base film () and a part of the piezoelectric stacked structure (). The piezoelectric stacked structure () includes a lower electrode (), a piezoelectric film (), and an upper electrode () formed in this order from below. The substrate () had a via hole () in the region corresponding to the vibratory section (). The via hole forms a space for allowing vibration of the vibratory section (). The piezoelectric film () is an aluminum nitride thin film containing 0.2 to 3.0 atom % of alkaline earth metal and/or a rare earth metal. Thus, the thin film bulk acoustic resonator has a high performance such as a large electromechanical coupling coefficient, an excellent acoustic quality factor (Q) and an excellent frequency-temperature characteristic.

Film bulk acoustic resonator

A thin pressure sensor includes: a pair of external electrodes, which are respectively made of conductive thin films that are respectively provided with piezoelectric layers on inner sides; and a single internal electrode, made of a conductive thin film, which is sealed between the pair of external electrodes, one of the pair of external electrodes having a conducting window that conducts to said internal electrode. The thin pressure sensor has a simple and thin structure with sufficient durability and mechanical strength.

Thin pressure sensor and biological information measuring device using same, and biological information measuring method

Disclosed is a high-sensitivity flexible ceramic sensor for detecting mechanical shocks and vibrations, which comprises a metal foil of a specified thickness as a substrate, a single-crystalline thin film of a piezoelectric ceramic material such as aluminum nitride and zinc oxide having a specified thickness formed on the substrate, a metallic electrode formed on the thin ceramic film and an external circuit connecting the metal foil and the electrode with insertion of an electric meter for measuring the piezoelectric voltage changes induced in the ceramic thin film.

High-sensitivity flexible ceramic sensor

The present invention is a method for producing swellable or nonswellable fluorine mica at a relatively lower temperature by heating a powdery mixture comprising 10 to 35% by weight of an alkali silicofluoride as the main component optionally together with an alkali fluoride and the balance of talc. This fluorine mica is used for pigments, etc.

Method for producing fluorine mica

Ultra-fine hollow glass spheres suitable as a filler in light-weight composite materials for building use and the like can be prepared from a fine powder of volcanic glass even when the starting powder has a particle size as fine as 20 .mu.m or smaller. The inventive method comprises an acid-leaching treatment of the starting powder using hydrochloric or sulfuric acid under hydrothermal conditions at 150.degree.-200.degree. C. to modify the chemical composition in the surface layer of the particles and a subsequent heat treatment of the acid-treated particles at a specified high temperature to effect expansion by the water vapor produced from the structural water in the softened particles. By virtue of the modified composition in the surface layer and in contrast to the prior art method without the acid treatment, a good balance can be obtained between the rate of water vapor release and softening of the particles even when the particle size is extremely small to facilitate expansion of the particles.

Growing community of inventors

Tosu, Japan

Hiroshi Tateyama