Silicon carbide semiconductor wafer, manufacturing method of silicon carbide semiconductor wafer, and silicon carbide semiconductor device

A manufacturing method of a silicon carbide semiconductor wafer having a disk shape and having a center portion and an outer edge portion, the manufacturing method comprising:

• preparing a silicon carbide semiconductor substrate;
• and
• epitaxially growing a silicon carbide semiconductor layer on the silicon carbide semiconductor substrate, wherein
• the epitaxially growing of the silicon carbide semiconductor layer includes forming a first layer and forming a second layer,
• the forming of the first layer includes doping with an element that controls a conductivity type of the silicon carbide semiconductor layer and an element that does not control the conductivity type of the silicon carbide semiconductor layer such that, within a plane of the first layer, a concentration of the element that controls the conductivity type is different at the center portion and the outer edge portion, and a concentration of the element that does not control the conductivity type is uniform at the center portion and the outer edge portion, one of the elements substitutes for Si sites and another of the elements substitutes for C sites, and
• the forming of the second layer includes doping with the element that controls the conductivity type, and not doping with the element that does not control the conductivity type or doping with the element that does not control the conductivity type at a lower concentration than the first layer such that, within a plane of the second layer, a high and low concentration relationship of the element that controls the conductivity type at the center portion and the outer edge portion is reversed from that in the first layer.

A silicon carbide semiconductor device comprising:

• a silicon carbide semiconductor substrate;
• and
• a silicon carbide semiconductor layer formed of an epitaxially grown layer on the silicon carbide semiconductor substrate, and forming a buffer layer, wherein
• the silicon carbide semiconductor layer includes a first layer and a second layer,
• the first layer is doped with an element that controls a conductivity type of the silicon carbide semiconductor layer and an element that does not control the conductivity type of the silicon carbide semiconductor layer, one of the elements substitutes for Si sites and another of the elements substitutes for C sites, and
• the second layer is doped with the element that controls the conductivity type, and is not doped with the element that does not control the conductivity type or is doped with the element that does not control the conductivity type at a lower concentration than the first layer.