PURPOSE: To avoid the generation of current leakage even when a contact hole becomes partly off a diffused region by a method wherein only the contact hole on a diffused layer region regarded as having a potential different from that of the peripheral semiconductor layer including the diffused layer region is provided with a poly Si, which is then electrically coupled with a metallic wiring layer.

CONSTITUTION: A poly Si electrode 7 doped with phosphorus, an N type impurity, is grown only on the diffused layer 2 where a potential different from that of the substrate 1 is given, the surface of which electrode is then oxidized, and an the same time phosphorus is diffused to the substrate 1 through the contact hole, thus forming the diffused layer region 2a. Thereby, even when the contact hole becomes partly off the N+ diffused layer 2, a complete P-N including the hole is formed, and the leakage does not generate. Next, after an interlayer insulation film 8 is formed, an aluminum wiring 9 connected to the electrode 7 and an aluminum wiring 10 connected to an N+ diffused layer 3 are formed. Even when the contact hole of the N+ diffused layer 3 becomes off the diffused layer region, the substrate 1 and diffused layer region 3 are not under electric bad influences because of having the same potential. Besides, the electrode 7 and the wiring 10 are insulated by the inter insulation film 8 and do not short-circuit.