| 摘要 |
PURPOSE:To prevent the generation of an inversion layer and to improve an interelement isolation by a method wherein, when an element isolation region is provided on a first conductivity type semiconductor substrate using a first conductivity type impurity-containing channel stopper region as an underlay, the central part of the stopper region is kept heavily doped and other part of the stopper region is kept lightly doped. CONSTITUTION:A buffer oxide film 11 and an Si3N4 film 12 are laminated and adhered on a P-type Si substrate 1 and the film 12 on a channel stopper forming region is removed by patterning. In such a way, the end part 13 of the film 12 is specified to the end part of an element isolation regions 3 which is formed afterwards and the exposing surface of the film 11 is lightly etched back and made thinner. After that, low-concentration ions are implanted in the surface of the substrate 1 through the film 11 which became thinner, a poly Si layer is deposited on here and the Si layer is remained only at the end part 13 as a sidewall 14 by etching back. Then, high-concentration ions are implanted using this and the film 12 as masks to obtain a stopper region 4 including a P<+> region and the element isolation region 3 is provided thereon.
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