A semiconductor device having a wide depletion region for increasing the breakdown voltage of the device includes an epitaxial layer of a first conductive type. An anode electrode and a cathode electrode are arranged on the epitaxial layer to be separated from each other. A first drift layer of the first conductive type formed in the epitaxial layer. A Schottky contact area is at a region of contact between the anode electrode and the first drift layer. An impurity region of a second conductive type is different from the first conductive type at the epitaxial layer. An insular impurity region is formed below the Schottky contact area.