Method for fabricating a semiconductor device

Abstract

The invention provides a method for fabricating a semiconductor device comprising the steps of: forming an insulating layer on a semiconductor substrate; selectively forming an oxidation preventive film on the surface of said insulating layer; depositing polycrystalline silicon on the entire surface of said substrate including said oxidation preventive film; selectively etching said polycrystalline silicon so as to leave said polycrystalline silicon only around the sides of said oxidation preventive film by an etching method having a directivity perpendicular to the surface of said substrate; ion-implanting an impurity for preventing inversion in said substrate using as a mask said oxidation preventive film and said polycrystalline silicon remaining therearound; and forming a field insulator film including an oxide of said polycrystalline silicon by oxidizing the surface of said substrate. A higher integration and a higher reliability of elements may be attained according to the method of the invention.

Dependencies are inferred from the claim text.