US Patent 7859048 Semiconductor device having super junction

A semiconductor device includes: a first semiconductor layer; a PN column layer having first and second column layers; and a second semiconductor layer. Each of the first and second column layers includes first and second columns alternately arranged along with a horizontal direction. The first and second column layers respectively have first and second impurity amount differences defined at a predetermined depth by subtracting an impurity amount in the second column from an impurity amount in the first column. The first impurity amount difference is constant and positive. The second impurity amount difference is constant and negative.