Method of fabricating recessed gate static induction transistors

Claim 1

The method of fabricating a semiconductor device comprising providing a substrate of silicon of one conductivity type of relatively low resistivity having a flat, planar surface; growing an epitaxial layer of silicon of the one conductivity type of relatively high resistivity on said surface of the substrate, said epitaxial layer having a flat, planar surface parallel to the interface of the epitaxial layer and the substrate forming a body of silicon; introducing conductivity type imparting material of the one conductivity type into said epitaxial layer from said surface to form a layer of silicon of the one conductivity type of relatively low resistivity in said epitaxial layer adjacent to said surface; forming a layer of protective material on the surface of the body; removing portions of said layer of protective material to expose a plurality of parallel areas of said surface; removing silicon at the exposed areas to form a plurality of grooves in said body of silicon providing interposed ridges of silicon having surfaces in said surface of the body, said grooves extending through said layer of silicon of the one conductivity type of relatively low resistivity into the underlying layer of the one conductivity type of relatively high resistivity, each of said grooves having side walls formed by the adjacent ridges of silicon and an end wall; introducing conductivity type imparting material of the opposite conductivity type into the silicon at the end walls of said grooves to convert zones of silicon of the one conductivity type of relatively high resistivity to the opposite conductivity type; removing all protective material to expose the silicon at the side walls and end walls of said grooves and at the surfaces of said ridges; forming a layer of silicon oxide on the side walls and end walls of said grooves and on said surfaces of said ridges; removing the layer of silicon oxide from the end walls of said grooves and from said surfaces of said ridges to expose the silicon at said end walls of the grooves and at said surfaces of said ridges while leaving silicon oxide overlying the side walls of said grooves; depositing a silicide-forming metal overlying the silicon oxide at the side walls of the grooves, the silicon at the end walls of the grooves, and the silicon at the surfaces of the ridges; heating to cause the silicide-forming metal to react with the underlying silicon to form metal silicide in ohmic contact with the silicon at the end walls of the grooves and at the surfaces of the ridges, the silicide-forming metal not reacting with the underlying silicon oxide layer on the side walls; and removing the unreacted silicide-forming metal overlying the silicon oxide layer on the side walls while leaving the metal silicide in ohmic contact with the silicon at the end walls of the grooves and at the surfaces of the ridges.

Claim 2

The method of fabricating a semiconductor device comprising providing a substrate of silicon of one conductivity type of relatively low resistivity having a flat, planar surface; growing an epitaxial layer of silicon of the one conductivity type of relatively high resistivity on said surface of the substrate, said epitaxial layer having a flat, planar surface parallel to the interface of the epitaxial layer and the substrate forming a body of silicon; introducing conductivity type imparting material of the one conductivity type into said epitaxial layer from said surface to form a layer of silicon of the one conductivity type of relatively low resistivity in said epitaxial layer adjacent to said surface; forming a layer of protective material on the surface of the body; removing portions of said layer of protective material to expose a plurality of parallel areas of said surface; removing silicon at the exposed areas to form a plurality of grooves in said body of silicon providing interposed ridges of silicon having surfaces in said surface of the body, said grooves extending through said layer of silicon of the one conductivity type of relatively low resistivity into the underlying layer of the one conductivity type of relatively high resistivity, each of said grooves having side walls formed by the adjacent ridges of silicon and an end wall; introducing conductivity type imparting material of the opposite conductivity type into the silicon at the end walls of said grooves to convert zones of silicon of the one conductivity type of relatively high resistivity to the opposite conductivity type; removing all protective material to expose the silicon at the side walls and end walls of said grooves and at the surfaces of said ridges; forming a layer of silicon oxide on the side walls and end walls of said grooves and on said surfaces of said ridges; removing the layer of silicon oxide from the end walls of said grooves and from said surfaces of said ridges to expose the silicon at said end walls of the grooves and at said surfaces of said ridges while leaving silicon oxide overlying the side walls of said grooves; depositing a silicide-forming metal overlying the silicon oxide at the side walls of the grooves, the silicon at the end walls of the grooves, and the silicon at the surfaces of the ridges; heating to cause the silicide-forming metal to react with the underlying silicon to form metal silicide in ohmic contact with the silicon at the end walls of the grooves and at the surfaces of the ridges, the silicide-forming metal not reacting with the underlying silicon oxide layer on the side walls; and removing the unreacted silicide-forming metal overlying the silicon oxide layer on the side walls while leaving the metal silicide in ohmic contact with the silicon at the end walls of the grooves and at the surfaces of the ridges.