Abstract: There are provided a high-quality semiconductor device having stable characteristics and a method for manufacturing such a semiconductor device. The semiconductor device includes: a substrate having a main surface; and a silicon carbide layer formed on the main surface of the substrate and including a side surface inclined relative to the main surface. The side surface substantially includes a {03-3-8} plane. The side surface includes a channel region.

Abstract: A method of fabricating a SiC semiconductor device includes the steps of preparing a silicon carbide semiconductor including a first surface having impurities implanted at least partially, forming a second surface by dry etching the first surface of the silicon carbide semiconductor using gas including hydrogen gas, and forming an oxide film constituting the silicon carbide semiconductor device on the second surface.

Abstract: There is provided a method for manufacturing a SiC semiconductor device achieving improved performance. The method for manufacturing the SiC semiconductor device includes the following steps. That is, a SiC semiconductor is prepared which has a first surface having at least a portion into which impurities are implanted. By cleaning the first surface of the SiC semiconductor, a second surface is formed. On the second surface, a Si-containing film is formed. By oxidizing the Si-containing film, an oxide film constituting the SiC semiconductor device is formed.

Abstract: A method of manufacturing an SiC semiconductor device includes the steps of forming a first oxide film on a first surface of an SiC semiconductor, removing the first oxide film, and forming a second oxide film constituting the SiC semiconductor device on a second surface exposed as a result of removal of the first oxide film in the SiC semiconductor. Between the step of removing the first oxide film and the step of forming a second oxide film, the SiC semiconductor is arranged in an atmosphere cut off from an ambient atmosphere.

Abstract: A MOSFET includes a silicon carbide substrate, an active layer, a gate oxide film, and a gate electrode. The active layer includes a p type body region in which an inversion layer is formed when the gate electrode is fed with a voltage. The inversion layer has an electron mobility ? dependent more strongly on an acceptor concentration Na of a channel region of the p type body region, as compared with a dependency of the electron mobility ? being proportional to the reciprocal of the acceptor concentration Na. The acceptor concentration Na in the channel region of the p type body region is not less than 1×1016 cm?3 and not more than 2×1018 cm3. The channel length (L) is equal to or smaller than 0.43 ?m. The channel length (L) is equal to or longer than a spreading width d of a depletion layer in the channel region. The spreading width d is expressed by d=D·Na?C.

Abstract: A MOSFET includes: a silicon carbide substrate having a main surface having an off angle of not less than 50° and not more than 65° relative to a {0001} plane; an active layer; a gate oxide film; a p type body region having p type conductivity and formed to include a region of the active layer, the region being in contact with the gate oxide film; an n+ region having n type conductivity and formed in the p type body region to include a main surface of the active layer opposite to the silicon carbide substrate; and a source contact electrode formed on the active layer in contact with the n+ region, the p type body region having a p type impurity density of 5×1017 cm?3 or greater, the source contact electrode and the p type body region being in direct contact with each other.

Abstract: A method of cleaning an SiC semiconductor includes the steps of forming an oxide film on a surface of an SiC semiconductor and removing the oxide film. In the step of removing the oxide film, the oxide film is removed with halogen plasma or hydrogen plasma. In the step of removing the oxide film, fluorine plasma is preferably employed as halogen plasma. The SiC semiconductor can be cleaned such that good surface characteristics are achieved.

Abstract: A cleaning method for a SiC semiconductor includes the step of forming an oxide film on a front surface of a SiC semiconductor, and the step of removing the oxide film, and oxygen plasma is used in the step of forming the oxide film. Hydrogen fluoride may be used in the step of removing the oxide film. Thereby, a cleaning effect on the SiC semiconductor can be exhibited.

Abstract: A method of cleaning a SiC semiconductor includes the steps of forming an oxide film at the surface of a SiC semiconductor, and removing the oxide film. At the step of forming an oxide film, an oxide film is formed using ozone water having a concentration greater than or equal to 30 ppm. The forming step preferably includes the step of heating at least one of the surface of the SiC semiconductor and the ozone water. Thus, there can be obtained a method of cleaning a SiC semiconductor that can exhibit cleaning effect on the SiC semiconductor.

Abstract: A MOSFET includes a silicon carbide substrate including a main surface having an off angle of not less than 50° and not more than 65° with respect to a {0001} plane, a buffer layer and a drift layer formed on the main surface, a gate oxide film formed on and in contact with the drift layer, and a p type body region of a p conductivity type formed in the drift layer to include a region in contact with the gate oxide film. The p type body region has a p type impurity density of not less than 5×1016 cm?3.

Abstract: A method of cleaning an SiC semiconductor capable of exhibiting an effect of cleaning an SiC semiconductor is provided. An SiC semiconductor and an SiC semiconductor device capable of achieving improved characteristics are provided. The method of cleaning an SiC semiconductor includes the steps of forming an oxide film on a surface of an SiC semiconductor (step S2) and removing the oxide film (step S3). In the forming step (step S2), the oxide film is formed in a dry atmosphere at a temperature not lower than 700° C. that contains O element. The SiC semiconductor is an SiC semiconductor having a surface and the surface has metal surface density not higher than 1×1012 cm?2. The SiC semiconductor device includes an SiC semiconductor and an oxide film formed on a surface of the SiC semiconductor.

Abstract: A silicon carbide layer is provided on a substrate, has a hexagonal single-crystal structure, and has a surface at which a depletion layer is formed. A protective film is insulative and provided on the silicon carbide layer to directly cover the surface. The surface thus directly covered with the protective film includes a portion having an off angle of not more than 10° relative to the {0-33-8} plane of the silicon carbide layer. This results in reduced leakage current flowing in an interface between the protective film and the semiconductor layer.

Abstract: An IGBT, which is capable of reducing on resistance by reducing channel mobility, includes: an n type substrate made of SiC and having a main surface with an off angle of not less than 50° and not more than 65° relative to a plane orientation of {0001}; a p type reverse breakdown voltage holding layer made of SiC and formed on the main surface of the substrate; an n type well region formed to include a second main surface of the reverse breakdown voltage holding layer; an emitter region formed in the well region to include the second main surface and including a p type impurity at a concentration higher than that of the reverse breakdown voltage holding layer; a gate oxide film formed on the reverse breakdown voltage holding layer; and a gate electrode formed on the gate oxide film. In a region including an interface between the well region and the gate oxide film, a high-concentration nitrogen region is formed to have a nitrogen concentration higher than those of the well region and the gate oxide film.

Abstract: A MOSFET, which is capable of reducing on resistance by reducing channel mobility even when a gate voltage is high, includes: an n type substrate made of SiC and having a main surface with an off angle of 50°-65° relative to a {0001} plane; an n type reverse breakdown voltage holding layer made of SiC and formed on the main surface of the substrate; a p type well region formed in the reverse breakdown voltage holding layer distant away from a first main surface thereof; a gate oxide film formed on the well region; an n type contact region disposed between the well region and the gate oxide film; a channel region connecting the n type contact region and the reverse breakdown voltage holding layer; and a gate electrode disposed on the gate oxide film. In a region including an interface between the channel region and the gate oxide film, a high-concentration nitrogen region is formed.

Abstract: This invention discloses a novel cold-inducible promoter which induces gene expression at low temperatures in potato tubers but which is scarcely induced in organs other than tuber or at normal temperature, which induces gene expression for a long time not less than five months.

Abstract: A hypercholesterolemia therapeutic agent containing lycopene as an effective ingredient. The hypercholesterolemia therapeutic agent comprises a soft-capsulated drug, and the soft-capsulated drug comprises a soft capsule which comprises gelatin and glycerin, and contents which comprise lycopene, .beta.-carotene, .alpha.-carotene, d-.alpha. tocopherol and a mixture of a wheat germ oil and a vegetable oil, which contents are packed into the soft capsule.

Abstract: A DNA encoding cold stable PFK, a recombinant vector which can express a cold stable PFK in a host cell, and a method for changing sugar content in plant cells under low temperature using the recombinant vector are disclosed. The present invention provides a DNA encoding ATP dependent fructose 6-phosphate 1-phosphotransferase originating from a plant, as well as a recombinant vector comprising the DNA and a plant transformed with the DNA.

Abstract: A hypercholesterolemia therapeutic agent containing lycopene as an effective ingredient. The hypercholesterolemia therapeutic agent comprises a soft-capsulated drug, and the soft-capsulated drug comprises a soft capsule which comprises gelatin and glycerin, and contents which comprise lycopene, .beta.-carotene, .alpha.-carotene, d-.alpha. tocopherol and a mixture of a wheat germ oil and a vegetable oil, which contents are packed into the soft capsule.