Patent ID: 8766413

Claim:
A semiconductor device comprising: a first first-conductivity-type semiconductor layer; a second second-conductivity-type semiconductor layer that is provided on one main surface of the first semiconductor layer and has an impurity concentration more than that of the first semiconductor layer; a third first-conductivity-type semiconductor layer that is provided on the other main surface of the first semiconductor layer and has an impurity concentration more than that of the first semiconductor layer; and a first-conductivity-type broad buffer region that is provided in the first semiconductor layer and has an impurity concentration more than that of the first semiconductor layer and in which a local maximum value of an impurity concentration distribution is less than the impurity concentration of the second semiconductor layer and the third semiconductor layer, wherein the total amount of the net doping concentration of the broad buffer region is equal to or more than 4.8×10 11 atoms/cm 2 and equal to or less than 1.0×10 12 atoms/cm 2 , and wherein the resistivity ρ 0 (Ωcm) of the first semiconductor layer satisfies 0.12V 0 ≦ρ 0 ≦0.25V 0 with respect to a rated voltage V 0 (V).