Toyoda Gosei Co., Ltd.

National Institute for Materials Science

Sharp Kabushiki Kaisha Corporation

Centre National De La Recherche Scientifique

Yasuo Koide

Masanori Murakami

Naoki Shibata

Toshiya Uemura

Nobuaki Teraguchi

Meiyong Liao

Jun Ito

Yoshitaka Tomomura

Shizuyo Noiri

Makoto Asai

Jean-Paul Kleider

Satoshi Koizumi

Shunichi Hishida

Jose Antonio Alvarez

Shunsuke Murai

Tokuyuki Teraji

Jose Alvarez

Antonio Alvarez Jose

Osamu Nakatsuka

Ryohei Konishi

Ryuichi Yasukochi

Naoki c/o Toyoda Gosei Co Ltd Shibata

The utilization of single crystal diamond in a nano- or micro-machine (N/MEMS) device is difficult, and there has been no report on such utilization. The reason for this resides in that it is difficult to grow single crystal diamond on an oxide which is a sacrifice layer. In a conventional technique, a cantilever or the like is produced by forming polycrystalline diamond or nanodiamond on an oxide as a sacrifice layer, but the mechanical performance, vibration characteristics, stability, and reproducibility of the produced cantilever or the like are unsatisfactory. In the present invention, utilizing the fact that the high concentration ion-implanted region in a diamond substrateis modified into graphite, the layermodified into graphite as a sacrifice layer is removed by electrochemical etching to obtain the diamond layer remaining on the resultant substrate as a movable structure. The produced cantileverexhibited high frequency resonance. The use of single crystal diamond makes it possible to improve the N/MEMS device in mechanical performance and stability as well as electric properties.

Method for producing single-crystal diamond movable structure

A method of manufacturing a diamond UV sensor element improved with a UV/visible light blind ratio using a diamond single crystal as a light receiving portion and detecting a light based on the change of electric resistance caused by a light irradiated to the light receiving portion is provided, the method, including (1) a step of hydrogenating the surface of the diamond single crystal in an atmosphere substantially containing hydrogen, and (2) a step of forming a light receiving portion by exposing the hydrogenated surface of the diamond single crystal into an atmosphere containing ozone or active oxygen.

Diamond UV-sensor element and manufacturing method thereof, UV-sensor unit, and method of treating diamond single crystal

The diamond semiconductor device is a diamond semiconductor device where a pair of electrodes are fixed on a diamond substrate, and wherein at least one interface to the electrode on the surface of the diamond substrate has a hydrogen termination and at least the surface of the substrate between the pair of two electrodes is controlled to have a larger electric resistivity value than inside the substrate. Accordingly, a diamond semiconductor device can be realized, capable of attaining the device work stability, especially the device work stability in severe environments such as high temperature with exhibiting the function of the hydrogen termination thereof to the utmost extent.

Diamond semiconductor device

Au base electrode materials have fatal disadvantages, such as inferior adhesion to diamond, low mechanical strength, and low thermal stability. A diamond UV sensor is provided which includes a photoconductive or Schottky optical sensor element having two-terminal electrodes and detects light irradiating a light-receiving portion according to the changes in electrical resistance or photo-induced current of the material of the light-receiving portion. The sensor element includes diamond having a surface from which a conductive surface layer has been removed, and the surface of the diamond is used as the light-receiving portion and a junction interface with the electrodes. The electrodes include a rectifying and an ohmic electrode. The rectifying electrode is transparent electrode capable of transmitting light and is defined by a single layer made of a nitride of a refractory metal element. The ohmic electrode includes a first layer made of a reactive elementary metal that can react with diamond to form a carbide or a carbon-containing solid solution, and a second layer made of a nitride of a refractory metal element.

Diamond UV-Ray sensor

An object of the present invention is to obtain greater reduction in resistance between an n-electrode and an n-type layer made of a Group III nitride compound semiconductor. According to the present invention, the n-electrode is formed with a first electrode material made of at least one member selected from the group consisting of vanadium (V), titanium (Ti), zirconium (Zr) and tungsten (W), a second electrode material made of at least one member selected from the group consisting of palladium (Pd), platinum (Pt), gold (Au), silver (Ag) and copper (Cu), and a third electrode material made of at least one member selected from the group consisting of aluminum (Al), silicon (Si) and germanium (Ge).

n-Electrode for III group nitride based compound semiconductor element

In a conventional ultraviolet sensing device using a diamond semiconductor in a light-receiving unit, an Au-based electrode material is used for both a rectifier electrode and an ohmic electrode. However, the Au-based electrode material has fatal defects, such as poor adhesion to diamond, low mechanical strength, and furthermore poor thermal stability. While avoiding complication of the device structure and exploiting the characteristics of a photoconductive sensing device, by using a carbide compound (TiC, ZrC, HfC, VC, NbC, TaC, CrC, MoC, and WC) of a high melting metal having a high mechanical strength for a rectifier electrode and/or a ohmic electrode, there is provided an extremely heat-stable diamond ultraviolet sensor having a light-receiving sensitivity to ultraviolet light having a wavelength of 260 nm or less.

Diamond ultraviolet sensor

An AlN buffer layer; a silicon (Si)-doped GaN high-carrier-concentration nlayer; an Si-doped n-type AlGaN n-cladding layer; an Si-doped n-type GaN n-guide layer; an active layerhaving a multiple quantum well (MQW) structure, and including a GaInN well layer(thickness: about 2 nm) and a GaInN barrier layer(thickness: about 4 nm), the layersandbeing laminated alternately; an Mg-doped GaN p-guide layer; an Mg-doped AlGaN p-cladding layer; and an Mg-doped GaN p-contact layerare successively formed on a sapphire substrate. A p-electrodeis formed of a film of titanium nitride (TiN) or tantalum nitride (TaN) (thickness: 50 nm). The contact resistance of this electrode is reduced through heat treatment.

Group III nitride compound semiconductor device and method for forming an electrode

An object of this invention is to provide an electrode for p-type SiC which can provide improved surface morphology and less thermal damage for a semiconductor crystal layer due to formation of an electrode. In this invention, a p-type electrode is manufactured to contain at least one selected from the group consisting of nickel (Ni), cobalt (Co), palladium (Pd) and platinum (Pt).

Electrode for p-type SiC

An AlN buffer layer ; a silicon (Si)-doped GaN high-carrier-concentration n layer ; an Si-doped n-type Al Ga N n-cladding layer ; an Si-doped n-type GaN n-guide layer ; an active layer having a multiple quantum well (MQW) structure, and including a Ga In N well layer (thickness: about 2 nm) and a Ga In N barrier layer (thickness: about 4 nm), the layers and being laminated alternately; an Mg-doped GaN p-guide layer ; an Mg-doped Al Ga N p-cladding layer ; and an Mg-doped GaN p-contact layer are successively formed on a sapphire substrate. A p-electrode is formed of a film of titanium nitride (TiN) or tantalum nitride (TaN) (thickness: 50 nm). The contact resistance of this electrode is reduced through heat treatment.

III nitride compound semiconductor element an electrode forming method

A layer comprising cobalt (Co) is formed on a p layer by vapor deposition, and a layer comprising gold (Au) is formed thereon. The two layers are alloyed by a heat treatment to form a light-transmitting electrode. The light-transmitting electrode therefore has reduced contact resistance and improved light transmission properties, and gives a light-emitting pattern which is stable over a long time. Furthermore, since cobalt (Co) is an element having a large work function, satisfactory ohmic properties are obtained.

GaN related compound semiconductor and process for producing the same

Process for producing GaN related compound semiconductor

A layer comprising cobalt (Co) is formed on a p,layer by vapor deposition, and layer comprising gold (Au) is formed thereon. The two layers are alloyed by a heat treatment to form a light-transmitting electrode. The light-transmitting electrode therefore has reduced contact resistance and improved light transmission properties, and gives a light-emitting patten which is stable over a long time. Furthermore, since cobalt (Co) is an element having a large work function, satisfactory ohmic properties are obtained.

GaN related compound semiconductor light-emitting device

A II-VI group compound semiconductor device includes a semiconductor substrate, a Zn.sub.X Mg.sub.1-X S.sub.Y Se.sub.1-Y (0.ltoreq.X.ltoreq.1, 0.ltoreq.Y.ltoreq.1) semiconductor layer formed on the semiconductor substrate, and an electrode layer formed on the semiconductor layer, the electrode layer containing an additive element of Cd or Te and a metal which can form a eutectic alloy with the additive element, thus achieving an electrode layer having a small contact resistance, especially an electrode layer with an ohmic contact.

Method for making II-VI group compound semiconductor device

A II-VI group compound semiconductor device having a p-type Zn.sub.x Mg.sub.1-x S.sub.y Se.sub.1-y (0.ltoreq.x.ltoreq.1, 0.ltoreq.y.ltoreq.1) semiconductor layer, on which an electrode layer is formed with at least metallic nitride layer lying between the semiconductor layer and the electrode layer.

II-VI group compound semiconductor device and method for manufacturing

A II-VI group compound semiconductor device comprising a Zn.sub.X Mg.sub.1-X S.sub.Y Se.sub.1-Y (0.ltoreq.X.ltoreq.1, 0.ltoreq.Y.ltoreq.1) semiconductor layer, an intermediate layer comprising a compound of an element constituting the semiconductor layer and an additive element of Cd, Te or Hg formed on the semiconductor layer, and an electrode layer containing Ni, Pt or Pd formed on the intermediate layer.

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Tsukuba, Japan

Yasuo Koide