Process for producing silicide or silicon gates for an integrated circuit having elements of the gate-insulator-semiconductor type

Claim 1

A process for producing closely spaced gate electrodes on a silicon semiconductive substrate for an integrated circuit comprising: depositing on the top surface of the substrate successively, layers of silicon oxide, polycrystalline silicon, a metal which can be converted to a silicide, an oxide and a masking material, patterning the masking layer to provide openings where there is exposed the underlying oxide layer, etching the oxide layer isotropically to undercut the masking layer to obtain overhang, thereby exposing portions of the metal layer larger than the openings in the masking layer, etching the exposed portions of the metal layer, for exposing the underlying polycrystalline silicon, depositing through the openings in the masking layer a layer of a metal which can be converted into a silicide on only the central portion of the exposed polycrystalline layer, corresponding essentially to the opening in the masking layer, annealing the substrate for converting the metal in the portions contacting the polycrystalline layer to silicide, and removing both the layers the silicide portions and the unconverted polycrystalline silicon portions between the silicide portions to define the silicide gates.