Method of fabricating an insulated gate field effect device

Abstract

This invention provides a method of making an improved gate structure in which the gate electrode is self-aligned with respect to the field isolation oxide regions. Gate constituting layers are formed on a substrate prior to formation of the field isolation oxide regions. An oxidation barrier layer is provided on such layers, also covering the other regions which should be formed into the source and drain regions, etc. By etching off the oxidation barrier layer above the field isolation regions, the boundary edges of the gate on the field isolation regions are formed. Then oxidation is performed using the oxidation barrier as a masking pattern to form the field isolation oxide regions. The field isolation oxide regions and the gate thus formed completely coincide with each other at their boundary edges.