Semiconductor device and method of manufacturing the same

摘要

A semiconductor device formed by decreasing thickness of a substrate by grinding, and performing ion implantation. In a diode in which a P anode layer and an anode electrode are formed at a side of a right face of an N^- drift layer, and an N⁺ cathode layer and a cathode electrode are formed at a side of a back face of the N^- drift layer, an N cathode buffer layer is formed thick compared with the N⁺-type cathode layer between the N^--type drift layer and the N⁺ cathode layer, the buffer layer being high in concentration compared with the N^- drift layer, and low compared with the N⁺ cathode layer. When a reverse bias voltage is applied, a depletion layer is stopped in the middle of the N cathode buffer layer, and thus prevented from reaching the N⁺ cathode layer, so that the leakage current is suppressed.