Abstract: An epitaxial wafer includes a silicon carbide film having a first main surface. A groove portion is formed in the first main surface. The groove portion extends in one direction along the first main surface. Moreover, a width of the groove portion in the one direction is twice or more as large as a width of the groove portion in a direction perpendicular to the one direction. Moreover, a maximum depth of the groove portion from the first main surface is not more than 10 nm.

Abstract: An epitaxial wafer includes a silicon carbide film having a first main surface. A groove portion is formed in the first main surface. The groove portion extends in one direction along the first main surface. Moreover, a width of the groove portion in the one direction is twice or more as large as a width of the groove portion in a direction perpendicular to the one direction. Moreover, a maximum depth of the groove portion from the first main surface is not more than 10 nm.

Abstract: A silicon carbide epitaxial substrate includes: a silicon carbide single crystal substrate; and an epitaxial layer. The silicon carbide single crystal substrate has a diameter of not less than 100 mm. The epitaxial layer has a thickness of not less than 10 ?m. The epitaxial layer has a carrier concentration of not less than 1×1014 cm?3 and not more than 1×1016 cm?3. A ratio of a standard deviation of the carrier concentration in a plane of the epitaxial layer to an average value of the carrier concentration in the plane is not more than 10%. The epitaxial layer has a main surface. The main surface has an arithmetic mean roughness Sa of not more than 0.3 nm. An area density of pits originated from a threading screw dislocation is not more than 1000 cm?2. Each of the pits has a maximum depth of not less than 8 nm.

Abstract: An epitaxial wafer includes a silicon carbide film having a first main surface. A groove portion is formed in the first main surface. The groove portion extends in one direction along the first main surface. Moreover, a width of the groove portion in the one direction is twice or more as large as a width of the groove portion in a direction perpendicular to the one direction. Moreover, a maximum depth of the groove portion from the first main surface is not more than 10 nm.

Abstract: An epitaxial wafer includes a silicon carbide film having a first main surface. A groove portion is formed in the first main surface. The groove portion extends in one direction along the first main surface. Moreover, a width of the groove portion in the one direction is twice or more as large as a width of the groove portion in a direction perpendicular to the one direction. Moreover, a maximum depth of the groove portion from the first main surface is not more than 10 nm.

Abstract: A method for manufacturing a silicon carbide epitaxial substrate includes: a step of placing a silicon carbide single crystal substrate within a chamber and reducing a pressure within the chamber; a step of increasing a temperature within the chamber to a first temperature; a step of introducing hydrogen gas into the chamber and adjusting the pressure within the chamber; a step of introducing hydrocarbon gas into the chamber; a substrate reforming step of increasing the temperature within the chamber to a second temperature and holding the temperature at the second temperature for a predetermined time, with the adjusted pressure within the chamber and a flow rate of the hydrogen gas being maintained and the hydrocarbon gas being introduced; and a step of growing an epitaxial layer on the silicon carbide single crystal substrate by introducing silane gas into the chamber with the second temperature being maintained.

Abstract: A step of preparing a silicon carbide substrate (S11), a step of forming a first silicon carbide semiconductor layer on the silicon carbide substrate using a first source material gas (S12), and a step of forming a second silicon carbide semiconductor layer on the first silicon carbide semiconductor layer using a second source material gas (S13) are provided. In the step of forming a first silicon carbide semiconductor layer (S12) and the step of forming a second silicon carbide semiconductor layer (S13), ammonia gas is used as a dopant gas, and the first source material gas has a C/Si ratio of not less than 1.6 and not more than 2.2, the C/Si ratio being the number of carbon atoms to the number of silicon atoms.

Abstract: A method for manufacturing a silicon carbide epitaxial substrate includes: a step of placing a silicon carbide single crystal substrate within a chamber and reducing a pressure within the chamber; a step of increasing a temperature within the chamber to a first temperature; a step of introducing hydrogen gas into the chamber and adjusting the pressure within the chamber; a step of introducing hydrocarbon gas into the chamber; a substrate reforming step of increasing the temperature within the chamber to a second temperature and holding the temperature at the second temperature for a predetermined time, with the adjusted pressure within the chamber and a flow rate of the hydrogen gas being maintained and the hydrocarbon gas being introduced; and a step of growing an epitaxial layer on the silicon carbide single crystal substrate by introducing silane gas into the chamber with the second temperature being maintained.

Abstract: A method for manufacturing a silicon carbide substrate is a method for manufacturing a silicon carbide semiconductor substrate, in which epitaxial growth is carried out in a reaction chamber, and includes the steps of arranging a base substrate composed of silicon carbide in the reaction chamber and forming an epitaxially grown film on the base substrate. In the step of forming an epitaxially grown film, the base substrate is heated while a reaction gas in which a first gas containing ammonia and a second gas containing a halide but not containing ammonia have been mixed with each other is supplied toward the base substrate. The first gas is mixed with the second gas after the first gas is heated no that ammonia contained in the first gas can be thermally decomposed.

Abstract: An epitaxial wafer includes a silicon carbide film having a first main surface. A groove portion is formed in the first main surface. The groove portion extends in one direction along the first main surface. Moreover, a width of the groove portion in the one direction is twice or more as large as a width of the groove portion in a direction perpendicular to the one direction. Moreover, a maximum depth of the groove portion from the first main surface is not more than 10 nm.

Abstract: A step of preparing a silicon carbide substrate (S11), a step of forming a first silicon carbide semiconductor layer on the silicon carbide substrate using a first source material gas (S12), and a step of forming a second silicon carbide semiconductor layer on the first silicon carbide semiconductor layer using a second source material gas (S13) are provided. In the step of forming a first silicon carbide semiconductor layer (S12) and the step of forming a second silicon carbide semiconductor layer (S13), ammonia gas is used as a dopant gas, and the first source material gas has a C/Si ratio of not less than 1.6 and not more than 2.2, the C/Si ratio being the number of carbon atoms to the number of silicon atoms.

Abstract: A step of preparing a silicon carbide substrate, a step of forming a first silicon carbide semiconductor layer on the silicon carbide substrate using a first source material gas, and a step of forming a second silicon carbide semiconductor layer on the first silicon carbide semiconductor layer using a second source material gas are provided. In the step of forming a first silicon carbide semiconductor layer and the step of forming a second silicon carbide semiconductor layer, ammonia gas is used as a dopant gas, and the first source material gas has a C/Si ratio of not less than 1.6 and not more than 2.2, the C/Si ratio being the number of carbon atoms to the number of silicon atoms.

Abstract: A method for manufacturing a silicon carbide semiconductor substrate is provided to offer a silicon carbide semiconductor substrate having a highly flat surface at low cost. The method includes: a step of preparing a silicon carbide substrate as a seed substrate; a step of performing vapor phase etching onto a main surface of the silicon carbide substrate; and a step of epitaxially growing silicon carbide on the main surface. A carbon-atom containing gas is supplied to silicon carbide substrate from a point of time in the step of performing the vapor phase etching.

Abstract: A method for manufacturing a silicon carbide semiconductor substrate is provided to offer a silicon carbide semiconductor substrate having a highly flat surface at low cost. The method includes: a step of preparing a silicon carbide substrate as a seed substrate; a step of performing vapor phase etching onto a main surface of the silicon carbide substrate; and a step of epitaxially growing silicon carbide on the main surface. A carbon-atom containing gas is supplied to silicon carbide substrate from a point of time in the step of performing the vapor phase etching.

Abstract: A silicon carbide epitaxial substrate having a main surface (second main surface) includes: a base substrate; and a silicon carbide epitaxial layer formed on the base substrate and including the main surface (second main surface), the second main surface having a surface roughness of 0.6 nm or less, a ratio of standard deviation of a nitrogen concentration in the silicon carbide epitaxial layer at a surface layer including the main surface (second main surface) within a plane of the silicon carbide epitaxial substrate to an average value of the nitrogen concentration in the silicon carbide epitaxial layer at the surface layer within the plane of the silicon carbide epitaxial substrate being 15% or less.

Abstract: A step of preparing a silicon carbide substrate, a step of forming a first silicon carbide semiconductor layer on the silicon carbide substrate using a first source material gas, and a step of forming a second silicon carbide semiconductor layer on the first silicon carbide semiconductor layer using a second source material gas are provided. In the step of forming a first silicon carbide semiconductor layer and the step of forming a second silicon carbide semiconductor layer, ammonia gas is used as a dopant gas, and the first source material gas has a C/Si ratio of not less than 1.6 and not more than 2.2, the C/Si ratio being the number of carbon atoms to the number of silicon atoms.

Abstract: A silicon carbide epitaxial substrate having a main surface (second main surface) includes: a base substrate; and a silicon carbide epitaxial layer formed on the base substrate and including the main surface (second main surface), the second main surface having a surface roughness of 0.6 nm or less, a ratio of standard deviation of a nitrogen concentration in the silicon carbide epitaxial layer at a surface layer including the main surface (second main surface) within a plane of the silicon carbide epitaxial substrate to an average value of the nitrogen concentration in the silicon carbide epitaxial layer at the surface layer within the plane of the silicon carbide epitaxial substrate being 15% or less.

Abstract: A silicon carbide epitaxial substrate having a main surface (second main surface) includes: a base substrate; and a silicon carbide epitaxial layer formed on the base substrate and including the main surface (second main surface), the second main surface having a surface roughness of 0.6 nm or less, a ratio of standard deviation of a nitrogen concentration in the silicon carbide epitaxial layer at a surface layer including the main surface (second main surface) within a plane of the silicon carbide epitaxial substrate to an average value of the nitrogen concentration in the silicon carbide epitaxial layer at the surface layer within the plane of the silicon carbide epitaxial substrate being 15% or less.

Abstract: Substrates are mounted on a plurality of susceptors respectively. The plurality of susceptors on which respective substrates are mounted are placed on a rotational mechanism so that the susceptors are vertically spaced at a predetermined interval. The rotational mechanism on which the plurality of susceptors are placed is rotated. The plurality of susceptors on which the substrates are mounted respectively are heated. Semiconductor thin-films are deposited by supplying a source gas to each of the susceptors that are heated while being rotated, the source gas having been heated while passing through gas flow paths of respective path lengths substantially equal to each other.

Abstract: A buffer layer is provided on a substrate, is made of silicon carbide containing an impurity, and has a thickness larger than 1 ?m and smaller than 7 ?m. A drift layer is provided on the buffer layer and is made of silicon carbide having an impurity concentration smaller than that of the buffer layer. In this way, there can be provided a silicon carbide semiconductor device having the drift layer having a desired impurity concentration and a high crystallinity.