Method of making semiconductor integrated circuit device

Abstract

The invention relates to a method of making a semiconductor integrated circuit device, and aims at diminishing the size of the isolating region which isolates the adjacent semiconductor elements from each other. The method of the invention has the steps of forming on a substrate a deposition layer of diffused impurities of different conductivity type from that of the substrate, forming a masking film having apertures on the deposition layer, effecting an etching through making use of the masking film as the diffusion mask, so as to etch the portions of the deposition layer and the substrate under the apertures, thereby to form grooves which divide the deposition layer into island-like deposition layer sections, and stretching and diffusing the impurities in each island-like deposition layer section to form a diffusion layer which constitutes a part of a semiconductor element.