SILICON CARBIDE EPITAXIAL SUBSTRATE AND METHOD OF MANUFACTURING SILICON CARBIDE SEMICONDUCTOR DEVICE
A silicon carbide epitaxial substrate includes a silicon carbide substrate and a silicon carbide epitaxial layer. The silicon carbide epitaxial layer is on the silicon carbide substrate. The silicon carbide epitaxial layer has a main surface located opposite to an interface between the silicon carbide substrate and the silicon carbide epitaxial layer. An area density of a pit in the main surface is 1/cm 2 or less. An area density of a bump in the main surface is less than 0.7/cm 2 . An area of the pit is 100 μm 2 or less, and an area of the bump is 100 μm 2 or less when viewed in a direction perpendicular to the main surface. A depth of the pit is 0.01 μm to 0.1 μm and a height of the bump is 0.01 μm to 0.1 μm in the direction perpendicular to the main surface.
1 . A silicon carbide epitaxial substrate comprising:
a silicon carbide substrate; and
a silicon carbide epitaxial layer on the silicon carbide substrate,
wherein the silicon carbide epitaxial layer has a main surface located opposite to an interface between the silicon carbide substrate and the silicon carbide epitaxial layer,
an area density of a pit in the main surface is 1/cm 2 or less,
an area density of a bump in the main surface is less than 0.7/cm 2 ,
an area of the pit is 100 μm 2 or less and an area of the bump is 100 μm 2 or less when viewed in a direction perpendicular to the main surface, and
a depth of the pit is 0.01 μm to 0.1 μm and a height of the bump is 0.01 μm to 0.1 μm in the direction perpendicular to the main surface.
2 . The silicon carbide epitaxial substrate according to claim 1 , wherein the silicon carbide epitaxial layer has a thickness of 15 μm or more.
3 . The silicon carbide epitaxial substrate according to claim 1 ,
wherein the silicon carbide epitaxial layer has a thickness of less than 15 μm,
the area density of the bump in the main surface is 0.1/cm 2 or less, and
the area density of the pit in the main surface is 0.5/cm 2 or less.
4 . The silicon carbide epitaxial substrate according to claim 1 , wherein an area density of a three-dimensional oblique defect in the main surface is 0.006/cm 2 to 0.2/cm 2 .
5 . The silicon carbide epitaxial substrate according to claims 1 ,
wherein an area density of a scratch in the main surface is 1/cm 2 or less,
a width of the scratch is 10 μm or less and a length of the scratch is 150 mm or less when viewed in the direction perpendicular to the main surface, and
a depth of the scratch is 0.2 μm or more in the direction perpendicular to the main surface.
6 . A silicon carbide epitaxial substrate comprising:
a silicon carbide substrate; and
a silicon carbide epitaxial layer on the silicon carbide substrate,
wherein the silicon carbide epitaxial layer has a main surface located opposite to an interface between the silicon carbide substrate and the silicon carbide epitaxial layer, and
an area density of a three-dimensional oblique defect in the main surface is 0.006/cm 2 to 0.2/cm 2 .
7 . A method of manufacturing a silicon carbide semiconductor device, the method comprising:
preparing the silicon carbide epitaxial substrate according to claim 1 ; and
processing the silicon carbide epitaxial substrate.