Abstract: A silicon carbide epitaxial substrate includes a silicon carbide substrate, a silicon carbide epitaxial film. The silicon carbide epitaxial film is on the silicon carbide substrate. The first extended defect is in the silicon carbide epitaxial film. The first extended defect includes a particle, a triangular defect extending from the particle along an off-direction, and a basal plane dislocation originating from the particle and having a portion extending along a direction perpendicular to each of a thickness direction of the silicon carbide substrate and the off-direction. In the direction perpendicular to each of the thickness direction of the silicon carbide substrate and the off-direction, an extended width of the basal plane dislocation is twice or more a base width of the triangular defect. In a second main surface, an area density of the basal plane dislocation included in the first extended defect is 3/cm2 or less.

Abstract: When an area density of a first protrusion present in a central region is denoted by Xa, an area density of a second protrusion present in the central region is denoted by Xb, an area density of a third protrusion present in the central region is denoted by Xc, an area density of a fourth protrusion present in an outer circumferential region is denoted by Ya, an area density of a fifth protrusion present in the outer circumferential region is denoted by Yb, and an area density of a sixth protrusion present in the outer circumferential region is denoted by Yc, as viewed in a thickness direction of a silicon carbide substrate, the first protrusion and the fourth protrusion each have an area of 100 ?m2 or more and less than 1,000 ?m2.

Abstract: A first main surface is a (000-1) plane or a plane inclined by an angle of less than or equal to 8° relative to the (000-1) plane. A reaction chamber has a cross-sectional area of more than or equal to 132 cm2 and less than or equal to 220 cm2 in a plane perpendicular to a direction of movement of a mixed gas. When an X axis indicates a first value and a Y axis indicates a second value, the first value and the second value fall within a hexagonal region surrounded by first coordinates, second coordinates, third coordinates, fourth coordinates, fifth coordinates and sixth coordinates in XY plane coordinates, where the first coordinates are (0.038, 0.0019), the second coordinates are (0.069, 0.0028), the third coordinates are (0.177, 0.0032), the fourth coordinates are (0.038, 0.0573), the fifth coordinates are (0.069, 0.0849), and the sixth coordinates are (0.177, 0.0964).

Abstract: A method of manufacturing a silicon carbide epitaxial substrate includes: preparing a silicon carbide single-crystal substrate having a polytype of 4H and having a principal surface inclined at an angle ? from a {0001} plane in a <11-20> direction; growing a silicon carbide epitaxial layer on the principal surface having a basal plane dislocation, the basal plane dislocation having a portion extending in a <1-100> direction and a portion extending in a <11-20> direction; and irradiating the silicon carbide epitaxial layer with an ultraviolet light having a predetermined power and a predetermined wavelength for a predetermined period of time to stabilize the basal plane dislocation. After the irradiating, the basal plane dislocation does not move even when the basal plane dislocation is irradiated with an ultraviolet light having a power of 270 mW and a wavelength of 313 nm for 10 seconds.

Abstract: A silicon carbide epitaxial wafer includes a single crystal silicon carbide substrate of 4H polytype having a major surface thereof inclined at an angle ? to a {0001} plane toward a <11-20> direction, and a silicon carbide epitaxial layer of a thickness t formed on the major surface, wherein a diameter of the single crystal silicon carbide substrate is greater than or equal to 150 mm, wherein the angle ? exceeds 0°, and is less than or equal to 6°, wherein one or more pairs of a screw dislocation pit and a diagonal line defect situated at a distance of t/tan? from the pit are present in a surface of the silicon carbide epitaxial layer, and wherein a density of the pairs of a pit and a diagonal line defect is less than or equal to 2 pairs/cm2.

Abstract: A silicon carbide epitaxial layer includes a first silicon carbide layer, a second silicon carbide layer, a third silicon carbide layer, and a fourth silicon carbide layer. A nitrogen concentration of the second silicon carbide layer is increased from the first silicon carbide layer toward the third silicon carbide layer. A value obtained by dividing, by a thickness of the second silicon carbide layer, a value obtained by subtracting a nitrogen concentration of the first silicon carbide layer from a nitrogen concentration of the third silicon carbide layer is less than or equal to 6×1023 cm?4. Assuming that the nitrogen concentration of the third silicon carbide layer is N cm?3; and a thickness of the third silicon carbide layer is X ?m, X and N satisfy a Formula 1.

Abstract: A first main surface is a (000-1) plane or a plane inclined by an angle of less than or equal to 8° relative to the (000-1) plane. A reaction chamber has a cross-sectional area of more than or equal to 132 cm2 and less than or equal to 220 cm2 in a plane perpendicular to a direction of movement of a mixed gas. When an X axis indicates a first value and a Y axis indicates a second value, the first value and the second value fall within a hexagonal region surrounded by first coordinates, second coordinates, third coordinates, fourth coordinates, fifth coordinates and sixth coordinates in XY plane coordinates, where the first coordinates are (0.038, 0.0019), the second coordinates are (0.069, 0.0028), the third coordinates are (0.177, 0.0032), the fourth coordinates are (0.038, 0.0573), the fifth coordinates are (0.069, 0.0849), and the sixth coordinates are (0.177, 0.0964).

Abstract: The composite defect includes an extended defect and a basal plane dislocation. The extended defect includes a first region extending in a <11-20> direction from an origin located at a boundary between the silicon carbide substrate and the silicon carbide epitaxial film, and a second region extending along a <1-100> direction. The first region has a width in the <1-100> direction that increases from the origin toward the second region. The basal plane dislocation includes a third region continuous to the origin and extending along the <1-100> direction, and a fourth region extending along a direction intersecting the <1-100> direction. When an area of the main surface is a first area, and an area of a quadrangle circumscribed around the composite defect is a second area, a value obtained by dividing the second area by the first area is not more than 0.001.

Abstract: A first main surface is a (000-1) plane or a plane inclined by an angle of less than or equal to 8° relative to the (000-1) plane. A substrate placement surface has an area of more than or equal to 697 cm2 and less than or equal to 1161 cm2. When an X axis indicates a first value and a Y axis indicates a second value, the first value and the second value fall within a hexagonal region surrounded by first coordinates, second coordinates, third coordinates, fourth coordinates, fifth coordinates and sixth coordinates in XY plane coordinates, where the first coordinates are (0.038, 0.0019), the second coordinates are (0.069, 0.0028), the third coordinates are (0.177, 0.0032), the fourth coordinates are (0.038, 0.0573), the fifth coordinates are (0.069, 0.0849), and the sixth coordinates are (0.177, 0.0964).

Abstract: A silicon carbide epitaxial wafer includes a single crystal silicon carbide substrate of 4H polytype having a major surface thereof inclined at an angle ? to a {0001} plane toward a <11-20> direction, and a silicon carbide epitaxial layer of a thickness t formed on the major surface, wherein a diameter of the single crystal silicon carbide substrate is greater than or equal to 150 mm, wherein the angle ? exceeds 0°, and is less than or equal to 6°, wherein one or more pairs of a screw dislocation pit and a diagonal line defect situated at a distance of t/tan? from the pit are present in a surface of the silicon carbide epitaxial layer, and wherein a density of the pairs of a pit and a diagonal line defect is less than or equal to 2 pairs/cm2.

Abstract: A silicon carbide epitaxial substrate includes: a silicon carbide single-crystal substrate having a polytype of 4H and having a principal surface inclined at an angle ? from a {0001} plane in a <11-20> direction; and a silicon carbide epitaxial layer provided on the principal surface and having a basal plane dislocation, wherein even when the basal plane dislocation is irradiated with an ultraviolet light having a power of 270 mW and a wavelength of 313 nm for 10 seconds, the basal plane dislocation does not move.

Abstract: A silicon carbide epitaxial film has a plurality of arc-shaped or annular basal plane dislocations and a plurality of threading dislocations. The plurality of threading dislocations have a first threading dislocation which is surrounded by the plurality of basal plane dislocations and a second threading dislocation which is not surrounded by the plurality of basal plane dislocations, when viewed from a direction perpendicular to a main surface. The plurality of basal plane dislocations and the first threading dislocation constitute an annular defect. An area density of the plurality of threading dislocations in the main surface is more than or equal to 50 cm?2. A value obtained by dividing an area density of the annular defect when viewed from the direction perpendicular to the main surface by the area density of the plurality of threading dislocations in the main surface is more than or equal to 0.00002 and less than or equal to 0.004.

Abstract: A silicon carbide epitaxial film has a plurality of arc-shaped or annular basal plane dislocations and a plurality of threading dislocations. The plurality of threading dislocations have a first threading dislocation which is surrounded by the plurality of basal plane dislocations and a second threading dislocation which is not surrounded by the plurality of basal plane dislocations, when viewed from a direction perpendicular to a main surface. The plurality of basal plane dislocations and the first threading dislocation constitute an annular defect. An area density of the plurality of threading dislocations in the main surface is more than or equal to 50 cm?2. A value obtained by dividing an area density of the annular defect when viewed from the direction perpendicular to the main surface by the area density of the plurality of threading dislocations in the main surface is more than or equal to 0.00002 and less than or equal to 0.004.