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Kenichi Ohtsuka, Tokyo JP

Kenichi Ohtsuka, Tokyo JP

Patent application numberDescriptionPublished
20090020766POWER SEMICONDUCTOR DEVICE - A power semiconductor device less prone to cause a reaction between a metal material for interconnection and an electrode or the like connected to a semiconductor region during the high-temperature operation thereof and less prone to be strained during the high-temperature operation thereof. The power semiconductor device can be an SiC power device or the like in which a first metal layer containing at least one selected from the group consisting of Pt, Ti, Mo, W and Ta is formed on a source electrode formed on the semiconductor region, such as a source region or the like. A second metal layer containing at least one selected from the group consisting of Mo, W and Cu is formed on the first metal layer. A third metal layer containing at least one selected from the group consisting of Pt, Mo and W is formed on the second metal layer.01-22-2009
20090098719METHOD FOR MANUFACTURING SILICON CARBIDE SEMICONDUCTOR DEVICE - An object of the invention is to provide a method for manufacturing a silicon carbide semiconductor device having constant characteristics with reduced variations in forward characteristics. The method for manufacturing the silicon carbide semiconductor device according to the invention includes the steps of: (a) preparing a silicon carbide substrate; (b) forming an epitaxial layer on a first main surface of the silicon carbide substrate; (c) forming a protective film on the epitaxial layer; (d) forming a first metal layer on a second main surface of the silicon carbide substrate; (e) applying heat treatment to the silicon carbide substrate at a predetermined temperature to form an ohmic junction between the first metal layer and the second main surface of the silicon carbide substrate; (f) removing the protective film; (g) forming a second metal layer on the epitaxial layer; and (h) applying heat treatment to the silicon carbide substrate at a temperature from 400° C. to 600° C. to form a Schottky junction of desired characteristics between the second metal layer and the epitaxial layer.04-16-2009
20090134404SILICON CARBIDE SEMICONDUCTOR DEVICE - On a major surface of an n-type silicon carbide inclined substrate (05-28-2009
20090140389NITRIDE SEMICONDUCTOR DEVICE AND METHOD OF MANUFACTURING THE SAME - A nitride semiconductor device with a p electrode having no resistance between itself and other electrodes, and a method of manufacturing the same are provided. A p electrode is formed of a first Pd film, a Ta film, and a second Pd film, which is an antioxidant film for preventing oxidation of the Ta film, and on a p-type contact layer of a nitride semiconductor. On the second Pd film, a pad electrode is formed. The second Pd film as an antioxidant film is formed on the entire upper surface of the Ta film which forms the p electrode, to prevent oxidation of the Ta film. This inhibits the resistance between the p electrode and the pad electrode, thereby preventing a failure in contact between the p electrode and the pad electrode and providing the low-resistance p electrode.06-04-2009
20090142871METHOD OF MANUFACTURING SEMICONDUCTOR DEVICE - A method of manufacturing a semiconductor device provides a semiconductor device with a gallium-nitride-based semiconductor structure that allows long-term stable operation without degradation in device performance. After formation of an insulation film on a surface other than on a ridge surface, an oxygen-containing gas such as O06-04-2009
20090170304METHOD OF MANUFACTURING SEMICONDUCTOR DEVICE - A method of manufacturing a semiconductor device is provided, which can reduce the contact resistance of an ohmic electrode to a p-type nitride semiconductor layer and can achieve long-term stable operation. In forming, in an electrode forming step, a p-type ohmic electrode of a metal film by successive lamination of a Pd film which is a first p-type ohmic electrode and a Ta film which is a second p-type ohmic electrode on a p-type GaN contact layer, the metal film is formed to include an oxygen atom. In the presence of an oxygen atom in the metal film, then in a heat-treatment step, the p-type ohmic electrode of the metal film is heat-treated in an atmosphere that contains no oxygen atom-containing gas.07-02-2009
20090173997MOSFET AND METHOD FOR MANUFACTURING MOSFET - The present invention provides a MOSFET and so forth that offer high breakdown voltage and low on-state loss (high channel mobility and low gate threshold voltage) and that can easily achieve normally OFF. A drift layer 07-09-2009
20090190622SEMICONDUCTOR LASER - A semiconductor laser comprises: a semiconductor substrate and a lower cladding layer, an active layer, and an upper cladding layer on the semiconductor substrate. The layers form a resonator having opposed end surfaces. A ridge includes part of the upper cladding layer. The upper cladding layer in the ridge, proximate the resonator end surfaces, is thicker than the upper cladding layer in the ridge at a central part of the resonator.07-30-2009
20100314629SILICON CARBIDE SEMICONDUCTOR DEVICE - In order to obtain a silicon carbide semiconductor device that ensures both stability of withstand voltage and reliability in high-temperature operations in its termination end-portion provided for electric-field relaxation in the perimeter of a cell portion driven as a semiconductor element, the termination end-portion is provided with an inorganic protection film having high heat resistance that is formed on an exposed surface of a well region as a first region formed on a side of the cell portion, and an organic protection film having a high electrical insulation capability with a little influence by electric charges that is formed on a surface of an electric-field relaxation region formed in contact relation to an outer lateral surface of the well region and apart from the cell portion, and on an exposed surface of the silicon carbide layer.12-16-2010
20110001209SEMICONDUCTOR DEVICE - In a termination structure in which a JTE layer is provided, a level or defect existing at an interface between a semiconductor layer and an insulating film, or a minute amount of adventitious impurities that infiltrate into the semiconductor interface from the insulating film or from an outside through the insulating film becomes a source or a breakdown point of a leakage current, which deteriorates a breakdown voltage. A semiconductor device includes: an n01-06-2011
20110012133SILICON CARBIDE SEMICONDUCTOR DEVICE AND METHOD FOR MANUFACTURING THE SAME - A silicon carbide MOSFET that exhibits a high source-to-drain withstand voltage and that involves a smaller difference between gate-to-drain capacitance achieved in an activated state and gate-to-drain capacitance achieved in a deactivated state. A silicon carbide drift layer of a first conductivity type is provided on a silicon carbide substrate of a first conductivity type; a pair of base regions are provided in a surface layer portion of the silicon carbide drift layer and exhibit a second conductivity type; a pair of source regions are provided in interiors of surface layer portions of the pair of base regions and exhibit a first conductivity type; and semi-insulating regions are provided between the silicon carbide substrate and the pair of base regions.01-20-2011

Patent applications by Kenichi Ohtsuka, Tokyo JP