A semiconductor device of an embodiment includes, an n-type SiC substrate that has first and second faces, and contains a p-type impurity and an n-type impurity, the p-type impurity being an element A, the n-type impurity being an element D, the element A and the element D being a combination of Al (aluminum), Ga (gallium), or In (indium) and N (nitrogen), and/or a combination of B (boron) and P (phosphorus), the ratio of the concentration of the element A to the concentration of the element D in the combination(s) being higher than 0.40 but lower than 0.95, the concentration of the element D forming the combination(s) being not lower than 1×1018 cm−3 and not higher than 1×1022 cm−3, an SiC layer formed on the first face, a first electrode formed on the first face side, and a second electrode formed on the second face.