JPS5637679A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To prevent the short-circuit between source and drain regions and gate region when forming electrodes in a semiconductor device by coating a semiconductor layer on the boundary end between the gate insulating film and the gate region. CONSTITUTION:A field Si oxide film 10 and a gate Si oxide film 11 are formed on a monocrystalline Si substrate 9. Then, a polycrystalline Si layer 12 is then grown as doped with impurity thereon. A gate region 12 is formed subsequently by a photoetching process, with the region 12 as a mask the film 11 is etched, and the substrabe 9 is exposed on the portion 13 forming source and drain regions. Thereafter, a polycrystalline Si layer 14 including no impurity is grown on the entire surface, and impurity is selectively introduced to the layer 14 grown in contact with the film 11. Subsequently, the layer 14 is thermally oxidized, thereby converting it to an Si oxide film. At this time the polycrystalline Si layer 14a including no impurity becomes a thin Si oxide film 15a, and the polycrystalline Si layer 14b including impurity becomes a thick Si oxide film 15b. Thus, since the boundary between the gate oxide film 10b and the gate region 12 is coated with the film 15b, it can prevent the short-circuit of the gate.