Abstract: A silicon carbide epitaxial substrate has a silicon carbide single-crystal substrate and a silicon carbide layer. An average value of carrier concentration in the silicon carbide layer is not less than 1×1015 cm?3 and not more than 5×10 cm?3. In-plane uniformity of the carrier concentration is not more than 2%. The second main surface has: a groove 80 extending in one direction along the second main surface, a width of the groove in the one direction being twice or more as large as a width thereof in a direction perpendicular to the one direction, and a maximum depth of the groove from the second main surface being not more than 10 nm; and a carrot defect. A value obtained by dividing a number of the carrot defects by a number of the grooves is not more than 1/500.

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 semiconductor stack includes a substrate made of silicon carbide, and an epi layer disposed on the substrate and made of silicon carbide. An epi principal surface, which is a principal surface opposite to the substrate, of the epi layer is a carbon surface having an off angle of 4° or smaller relative to a c-plane. In the epi principal surface, a plurality of first recessed portions having a rectangular circumferential shape in a planar view is formed. Density of a second recessed potion that is formed in the first recessed portions and is a recessed portion deeper than the first recessed portions is lower than or equal to 10 cm?2 in the epi principal surface.

Abstract: A silicon carbide epitaxial substrate includes a silicon carbide single crystal substrate and a silicon carbide layer. The silicon carbide single crystal substrate has a first main surface. The silicon carbide layer is on the first main surface. The silicon carbide layer includes a second main surface opposite to a surface thereof in contact with the silicon carbide single crystal substrate. The second main surface has a maximum diameter of more than or equal to 100 mm. The second main surface includes an outer peripheral region which is within 3 mm from an outer edge of the second main surface, and a central region surrounded by the outer peripheral region. The central region has a haze of less than or equal to 75 ppm.

Abstract: A semiconductor stack includes a substrate made of silicon carbide, and an epi layer disposed on the substrate and made of silicon carbide. An epi principal surface, which is a principal surface opposite to the substrate, of the epi layer is a carbon surface having an off angle of 4° or smaller relative to a c-plane. In the epi principal surface, a plurality of first recessed portions having a rectangular circumferential shape in a planar view is famed. Density of a second recessed portion that is formed in the first recessed portions and is a recessed portion deeper than the first recessed portions is lower than or equal to 10 cm?2 in the epi principal surface.

Abstract: A semiconductor stack includes a substrate made of silicon carbide, and an epi layer disposed on the substrate and made of silicon carbide. An epi principal surface, which is a principal surface opposite to the substrate, of the epi layer is a carbon surface having an off angle of 4° or smaller relative to a c-plane. In the epi principal surface, a plurality of first recessed portions having a rectangular circumferential shape in a planar view is famed. Density of a second recessed portion that is formed in the first recessed portions and is a recessed portion deeper than the first recessed portions is lower than or equal to 10 cm?2 in the epi principal surface.

Abstract: A method for manufacturing a silicon carbide epitaxial substrate includes epitaxially growing a first layer on a silicon carbide single crystal substrate, and forming a second layer at an outermost surface of the first layer. The second layer has a chemical composition or density different from that of the first layer. A ratio of a thickness of the second layer to a thickness of the first layer is more than 0% and less than or equal to 10%.

Abstract: A silicon carbide epitaxial substrate includes a silicon carbide single crystal substrate and a silicon carbide layer. The silicon carbide single crystal substrate has a first main surface. The silicon carbide layer is on the first main surface. The silicon carbide layer includes a second main surface opposite to a surface thereof in contact with the silicon carbide single crystal substrate. The second main surface has a maximum diameter of more than or equal to 100 mm. The second main surface includes an outer peripheral region which is within 3 mm from an outer edge of the second main surface, and a central region surrounded by the outer peripheral region. The central region has a haze of less than or equal to 75 ppm.

Abstract: A silicon carbide epitaxial substrate includes: a silicon carbide single crystal substrate; a first silicon carbide layer on the silicon carbide single crystal substrate, the first silicon carbide layer having a first concentration of carriers; and a second silicon carbide layer on the first silicon carbide layer, the second silicon carbide layer having a second concentration of carriers. A transition region in which the concentration of the carriers is changed between the first concentration and the second concentration has a width of less than or equal to 1 ?m. A ratio of a standard deviation of the second concentration to an average value of the second concentration is less than or equal to 5%, the ratio being defined as uniformity of the second concentration in a central region. The central region has an arithmetic mean roughness of less than or equal to 0.5 nm.

Abstract: A silicon carbide epitaxial substrate includes a silicon carbide single crystal substrate and a silicon carbide layer. In a direction parallel to a central region, a ratio of a standard deviation of a carrier concentration of the silicon carbide layer to an average value of the carrier concentration of the silicon carbide layer is less than 5%. The average value of the carrier concentration is more than or equal to 1×1014cm?3 and less than or equal to 5×1016cm?3. In the direction parallel to the central region, a ratio of a standard deviation of a thickness of the silicon carbide layer to an average value of the thickness of the silicon carbide layer is less than 5%. The central region has an arithmetic mean roughness (Sa) of less than or equal to 1 nm. The central region has a haze of less than or equal to 50.

Abstract: A silicon carbide epitaxial substrate has a silicon carbide single-crystal substrate and a silicon carbide layer. An average value of carrier concentration in the silicon carbide layer is not less than 1×1015 cm?3 and not more than 5×1016 cm?3. In-plane uniformity of the carrier concentration is not more than 2%. The second main surface has: a groove 80 extending in one direction along the second main surface, a width of the groove in the one direction being twice or more as large as a width thereof in a direction perpendicular to the one direction, and a maximum depth of the groove from the second main surface being not more than 10 nm; and a carrot defect. A value obtained by dividing a number of the carrot defects by a number of the grooves is not more than 1/500.

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: A semiconductor device has a semiconductor layer and a substrate. The semiconductor layer constitutes at least a part of a current path, and is made of silicon carbide. The substrate has a first surface supporting the semiconductor layer, and a second surface opposite to the first surface. Further, the substrate is made of silicon carbide having a 4H type single-crystal structure. Further, the substrate has a physical property in which a ratio of a peak strength in a wavelength of around 500 nm to a peak strength in a wavelength of around 390 nm is 0.1 or smaller in photoluminescence measurement. In this way, the semiconductor device is obtained to have a low on-resistance.

Abstract: A silicon carbide semiconductor substrate includes a first main surface and a second main surface opposite to the first main surface. The first main surface has a maximum diameter of more than 100 mm, and the silicon carbide semiconductor substrate has a thickness of not more than 700 ?m. A dislocation density is not more than 500/mm2 at an arbitrary region having an area of 1 mm2 in a region within 5 mm from an outer circumferential end portion of the first main surface toward a center of the first main surface. Accordingly, there is provided a silicon carbide semiconductor substrate allowing for suppression of generation of cracks.

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 semiconductor device has a semiconductor layer and a substrate. The semiconductor layer constitutes at least a part of a current path, and is made of silicon carbide. The substrate has a first surface supporting the semiconductor layer, and a second surface opposite to the first surface. Further, the substrate is made of silicon carbide having a 4H type single-crystal structure. Further, the substrate has a physical property in which a ratio of a peak strength in a wavelength of around 500 nm to a peak strength in a wavelength of around 390 nm is 0.1 or smaller in photoluminescence measurement. In this way, the semiconductor device is obtained to have a low on-resistance.

Abstract: A method for manufacturing a silicon carbide epitaxial substrate includes epitaxially growing a first layer on a silicon carbide single crystal substrate, and forming a second layer at an outermost surface of the first layer. The second layer has a chemical composition or density different from that of the first layer. A ratio of a thickness of the second layer to a thickness of the first layer is more than 0% and less than or equal to 10%.

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: The silicon carbide layer includes a second main surface opposite to a surface in contact with the silicon carbide single crystal substrate. The second main surface corresponds to a plane inclined relative to a {0001} plane in an off direction. The second main surface has a maximum diameter of not less than 100 mm. The second main surface has an outer circumferential region and a central region, the central region being surrounded by the outer circumferential region. The central region is provided with a first dislocation array of first half loops along a straight line perpendicular to the off direction. Each of the first half loops includes a pair of threading edge dislocations exposed at the second main surface. An area density of the first dislocation array at the central region is not more than 10/cm2.