Silicon carbide epitaxial substrate and method for manufacturing silicon carbide semiconductor device

A silicon carbide epitaxial substrate comprising:

• a silicon carbide single-crystal substrate having a first main surface;
• and
• a silicon carbide layer on the first main surface,
• the silicon carbide layer including a surface in contact with the silicon carbide single-crystal substrate, and a second main surface opposite to the surface,
• the second main surface being a plane inclined at an off angle in an off direction relative to a {0001} plane,
• a thickness of the silicon carbide layer is 5 μm or more and 100 μm or less,
• the off angle is greater than 0° and smaller than or equal to 8°, the second main surface having one or more defects, and
• assuming that the one or more defects satisfying relations of Formula 1 and Formula 2 are first defects, and the one or more defects satisfying relations of Formula 3 and Formula 2 are second defects, where the off angle is θ°, the thickness of the silicon carbide layer in a direction perpendicular to the second main surface is W μm, a width of each of the one or more defects in a direction parallel to a direction obtained by projecting the off direction onto the second main surface is L μm, and a width of each of the one or more defects in a direction perpendicular to the off direction and parallel to the second main surface is Y μm, then a value obtained by dividing a number of the second defects by a sum of a number of the first defects and the number of the second defects being greater than 0.8:
• L
• Y
• ≦
• 1
• Formula
• 
• 
• 1
• 0.8
• ×
• W
• tan
• 
• 
• θ
• <
• L
• <
• 1.2
• ×
• W
• tan
• 
• 
• θ
• Formula
• 
• 
• 2
• 1
• <
• L
• Y
• Formula
• 
• 
• 3