| 摘要 |
PROBLEM TO BE SOLVED: To provide a planar semiconductor device having high long term reliability by relaxing concentration of field thereby preventing the breakdown strength of an element from deteriorating. SOLUTION: In the peripheral breakdown strength structure of a diode comprising an n+ cathode layer, an n drift layer 12 of high specific resistance, a p-anode region 13, an anode electrode 15, and a cathode electrode 16, a plurality of conductive rings 20 are arranged concentrically on a field insulation film 17 between an outermost circumferential guard ring 14a and the peripheral electrode 18 at a terminal end part. |
