Method of manufacturing semiconductor devices with local oxidation of

Abstract

An improved method of manufacturing a semiconductor device employs a local oxidation process in which an oxide isolation region is formed by locally oxidizing a silicon epitaxial layer, using a nitride-oxide double layer for masking purposes, with a P.sup.+ type region being formed by the diffusion of an impurity into the silicon epitaxial layer using the oxide isolation region, which has an 'oxide beak', as a diffusion mask. An additional region of the same conductivity type as the P.sup.+ type diffused region is provided to be contiguous to the P.sup.+ type diffused region, so that a PN junction terminates at a silicon surface remote from the electrode to be connected to the P.sup.+ diffused region. As a result, disadvantages caused by the oxide beak, such as the imperfect protection of the PN junction and short-circuiting between the electrode and the epitaxial layer through pin holes in the oxide beak can be eliminated.