ELEMENT ISOLATING STRUCTURE OF SEMICONDUCTOR DEVICE SUITABLE FOR HIGH DENSITY INTEGRATION

摘要

An element isolating structure employed for isolating the elements of a semiconductor substrate has an impurity region having a concentration lower than that of a source/drain and a channel stop region, between the source/drain of an MOS transistor formed in an active region, and the channel stop region formed under an LOCOS film. A field shield isolating structure has a low concentrated impurity region between the source/drain of an MOS transistor formed in the active region and the substrate surface region covered by a field shield electrode layer. The low concentrated impurity region improves its junction breakdown voltage in the boundary region with the element isolating region. An improved LOCOS film is formed into an amorphous region on the surface of the substrate by an oblique rotating ion implanting method, and the amorphous region is formed by thermal oxidation. The method suppresses the emergence of a bird's beak.