Semiconductor device having improved gate capacitance and manufacturing method therefor

Claim 1

A semiconductor device comprising: source and drain regions, formed on one principal surface of a semiconductor substrate of one conductivity type, with the opposite conductivity type; a gate oxide film formed on said semiconductor substrate surface between said source and drain regions; a gate electrode formed on said gate oxide film consisting of a laminated layer structure of a poly­crystalline silicon layer and a refractory metal silicide layer having a topmost layer of a polycrystalline silicon layer thereon; an insulating film formed on said polycrystalline silicon layer in the topmost layer of said gate electrode; and an electrically conductive layer formed on said insulating film.

Claim 15

A method of manufacturing a semiconductor device comprising the steps of: forming a gate oxide film on a surface of a semi-­conductor substrate of one conductivity type; forming a first polycrystalline silicon layer on said gate oxide layer; forming a refractory metal silicide layer on said polycrystalline silicon layer; forming a second polycrystalline silicon layer on said refractory metal silicide layer; patterning said first and second polycrystalline silicon layers and said refractory metal silicide layer in a predetermined form; introducing impurities of opposite conductivity type into said semiconductor substrate with said first and second polycrystalline silicon layers and said refractory metal silicide layer that are patterned as a mask; exposing the surface of said second polycrystalline silicon layer by applying an anisotropic etching after forming an oxide film over the surface; introducing impurities of the opposite conductivity type into said semiconductor substrate with said first and second polycrystalline silicon layers and said refractory metal silicide layer that are pattern and said oxide film left on side faces of said layers as the mask; forming a thermal oxide film by applying a thermal oxidation to the surface of said second polycrystalline silicon layer; and forming an electrically conductive layer on said thermal oxide film.

Claim 16

A method of manufacturing a semiconductor device comprising the steps of: forming a gate oxide film on a surface of a semi-­conductor substrate of one conductivity type; forming a first polycrystalline silicon layer on said gate oxide layer; forming a refractory metal silicide layer on said polycrystalline silicon layer; forming a second polycrystalline silicon layer on said refractory metal silicide layer; patterning said first and second polycrystalline silicon layers and said refractory metal silicide layer in a predetermined form; introducing impurities of opposite conductivity type into said semiconductor substrate with said first and second polycrystalline silicon layers and said refractory metal silicide layer that are patterned as a mask; exposing the surface of said second polycrystalline silicon layer by applying an anisotropic etching after forming an oxide film over the surface; introducing impurities of the opposite conductivity type into said semiconductor substrate with said first and second polycrystalline silicon layers and said refractory metal silicide layer that are pattern and said oxide film left on side faces of said layers as the mask; forming a thermal oxide film by applying a thermal oxidation to the surface of said second polycrystalline silicon layer; and forming an electrically conductive layer on said thermal oxide film.