Silicon carbide semiconductor element and method for manufacturing same

A silicon carbide semiconductor element comprising a plurality of unit cells, each of the plurality of unit cells includes

• a substrate having a first main surface and a second main surface,
• a silicon carbide semiconductor layer of a first conductivity type disposed on the first main surface of the substrate,
• a body region of a second conductivity type that is in contact with a surface of the silicon carbide semiconductor layer,
• a source region of the first conductivity type that is in contact with the body region,
• a channel layer comprising a silicon carbide semiconductor, the channel layer being disposed above the silicon carbide semiconductor layer so as to be in contact with at least a part of the body region,
• a gate insulating film disposed above the channel layer, and
• a gate electrode disposed above the gate insulating film,
• wherein
• the channel layer has a multilayer structure, the multilayer structure including a higher-concentration impurity layer containing impurities of the first conductivity type in a concentration ranging from 1×1018/cm3 to 1×1019/cm3 inclusive, a first medium-concentration impurity layer containing impurities of the first conductivity type in a concentration ranging from more than or equal to 1×1017/cm3 to less than 1×1018/cm3, and a first lower-concentration impurity layer containing impurities of the first conductivity type in a concentration of less than 1×1017/cm3, and
• the first lower-concentration impurity layer is disposed closer to the body region than the higher-concentration impurity layer and the first medium-concentration impurity layer are.