Semiconductor device

A semiconductor device comprising:

• a first semiconductor layer of a first conductivity type having a first face and a second face opposite to the first face;
• a second semiconductor layer of a second conductivity type disposed above the first face of the first semiconductor layer;
• control electrodes facing the first and second semiconductor layers via insulating layers, and extending to a first direction parallel to the first face of the first semiconductor layer;
• third semiconductor layers of the first conductivity type and fourth semiconductor layers of the second conductivity type alternately disposed along the first direction above the second semiconductor layer;
• and
• a fifth semiconductor layer of the first conductivity type disposed below the second semiconductor layer or disposed at a position surrounded by the second semiconductor layer, and extending to the first direction, the fifth semiconductor layer alternately including maximum points and minimum points of effective impurity concentration of impurities of the first conductivity type along the first direction.