| abstract |
A silicon carbide semiconductor substrate capable of reducing basal plane dislocations in a silicon carbide epitaxial layer and a method for manufacturing the same are provided. Two layers of the same conductivity type as a drift layer are provided between a first semiconductor layer serving as a drift layer, which is a layer for forming components of a semiconductor device, and a base substrate made of a silicon carbide single crystal wafer. A buffer layer constituted by the above semiconductor layers is provided by epitaxial growth. A donor concentration step is provided at the interface between the drift layer and the buffer layer, between the semiconductor layers constituting the buffer layer, and at the interface between the buffer layer and the base substrate. The donor concentration on the drift layer side is lower than that on the base substrate side. By doing so, more basal plane dislocations can be converted into threading edge dislocations than when the drift layer is a single layer or when a single buffer layer is provided. [Selection] Figure 4 |