To prevent short-circuiting between the edge of a diffusion mask and an electrode of second conductivity type even in an impurity diffusion region with a small diffusion depth, by extending part of a layer insulating film from a first insulating film to an opening side wall to part of the impurity diffusion region.
An impurity diffusion region 13 of first conductivity type, for example, p-type, is formed on a base 11 made of a n-type semiconductor. In addition, a first insulating film 15 and a layer insulating film 17 are formed on the base 11 in this order. A p-type electrode 19 that is electrically connected with the impurity diffusion layer 13 and extends to the layer insulating film 17, is formed. However, part of the first insulating film 15 is gibbously expanded in an opening in the direction of lead-out of the electrode 19 of the first conductive type. Part of the layer insulating film 17 extends from the first insulating film 15 to at least part of the expanded portion 13 in the impurity diffusion layer. Thus the portion P of the first insulating film 15 in proximity to the opening 17a is covered with the portion 17x of the layer insulating film on the impurity diffusion layer without fail.
OGIWARA MITSUHIKO
SHIMIZU TAKAATSU
