JPS6477931A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To form a thin source-drain having a conductivity type reverse to one conductivity type semiconductor substrate by a method wherein a gate electrode is shaped onto a thin insulating film formed onto the substrate, a thin semiconductor layer is shaped, ions are implanted to the thin semiconductor layer, a reverse conductivity type impurity is introduced and oxidation is conducted. CONSTITUTION:A thick insulating film 11 and a gate insulating film 2 acquired by thinly oxidizing the surface of a substrate 1 are formed in an element isolation region in a p-type semiconductor substrate such as the silicon substrate 1, a polycrystalline silicon film, etc., are shaped onto the insulating film 2, and the polycrystalline silicon film, etc., are patterned and a gate electrode 3 is formed. A polycrystalline silicon film 21 is shaped onto the whole surface. Ions are implanted by implantation energy in an extent that ions are not penetrated through the film 21, and a reverse conductivity type (an n-type) impurity is introduced into the film 21. A piling-up phenomenon is generated through oxidation, and the introduced reverse conductivity type impurity is penetrated through the gate insulating film 2, and diffused onto the surface layer of the p-type silicon substrate 1, thus shaping source-drain 41. Consequently, the thickness of the source-drain 41 is thinned extremely. The polycrystalline silicon film 21 is changed into an silicon oxide film 22 in the process, and turned into an insulating film for the gate electrode 3.