Silicon carbide epitaxial wafer
A silicon carbide epitaxial wafer includes a single crystal silicon carbide substrate of 4H polytype having a major surface thereof inclined at an angle θ 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 θ 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/tanθ 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.
1. A silicon carbide epitaxial wafer, comprising:
a single crystal silicon carbide substrate of 4H polytype having a major surface thereof inclined at an angle θ to a {0001} plane toward a <11-20>direction,
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 θ exceeds 0°, and is less than or equal to 6°,
wherein one or more pairs of a screw dislocation pit and a diagonal an oblique line defect situated at a distance of t/tanθ 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/cm 2 .
2. The silicon carbide epitaxial wafer as claimed in claim 1 , wherein a line width of the diagonal line defect is greater than or equal to 1 μm and less than or equal to 5μm.
3. The silicon carbide epitaxial wafer as claimed in claim 1 , wherein the diagonal line defect is situated on a side of the pit that forms a pair with the diagonal line defect, the side being in a direction in which the surface of the silicon carbide epitaxial layer and the {0001} plane of the silicon carbide epitaxial layer come closer to each other.
4. The silicon carbide epitaxial wafer as claimed in claim 2 , wherein the diagonal line defect is situated on a side of the pit that forms a pair with the diagonal line defect, the side being in a direction in which the surface of the silicon carbide epitaxial layer and the {0001} plane of the silicon carbide epitaxial layer come closer to each other.
5. The silicon carbide epitaxial wafer as claimed in claim 1 , wherein the density of the pairs of a pit and a diagonal line defect relative to a density of screw dislocations in the single crystal silicon carbide substrate is less than or equal to 0.11%.
6. A silicon carbide epitaxial wafer, comprising:
a single crystal silicon carbide substrate of 4H polytype having a major surface thereof inclined at an angle θ 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 θ exceeds 0°, and is less than or equal to 6°,
wherein one or more pairs of a screw dislocation pit and a diagonal an oblique line defect situated at a distance of t/tan θ from the pit are present in a surface of the silicon carbide epitaxial layer,
wherein a density of the pairs of a pit and a diagonal an oblique line defect is less than or equal to 2 pairs/cm 2 ,
wherein a line width of the diagonal oblique line defect is greater than or equal to 1 μm and less than or equal to 5 μm,
wherein the diagonal line defect is situated on a side of the pit that forms a pair with the diagonal line defect, the side being in a direction in which the surface of the silicon carbide epitaxial layer and the {0001} plane of the silicon carbide epitaxial layer come closer to each other, and
wherein the density of the pairs of a pit and a diagonal line defect relative to a density of screw dislocations in the single crystal silicon carbide substrate is less than or equal to 0.11%.
7. The silicon carbide epitaxial wafer as claimed in claim 2 , wherein the density of the pairs of a pit and a diagonal line defect relative to a density of screw dislocations in the single crystal silicon carbide substrate is less than or equal to 0.11%.
8. The silicon carbide epitaxial wafer as claimed in claim 3 , wherein the density of the pairs of a pit and a diagonal line defect relative to a density of screw dislocations in the single crystal silicon carbide substrate is less than or equal to 0.11%.
9. The silicon carbide epitaxial wafer as claimed in claim 4 , wherein the density of the pairs of a pit and a diagonal line defect relative to a density of screw dislocations in the single crystal silicon carbide substrate is less than or equal to 0.11%.