Method for producing a floating gate memory device including implanting ions through an oxidized portion of the silicon film from which the floating gate is formed

Claim 1

A method for producing a nonvolatile semiconductor memory device comprising the steps of: forming a field insulating film on an isolation region on a semiconductor substrate and forming a tunneling oxide film on an active region; depositing a silicon film on the semiconductor substrate; forming stripe-shaped silicon portions including a plurality of first portions to be used as a plurality of floating gates and a plurality of second portions interposed between two adjacent portions of the plurality of first portions by patterning the silicon film; forming an insulating film so as to cover at least the stripe-shaped silicon portions; forming a conductive film so as to cover the insulating film; forming a control gate so as to cover the plurality of first portions of the stripe-shaped silicon portions by patterning the conductive film; converting the plurality of second portions of the stripe-shaped silicon portions into a silicon oxide film, and forming the plurality of floating gates from the plurality of first portions by thermally oxidizing the plurality of second portions; and implanting impurity ions through the silicon oxide film into the active region on the semiconductor substrate by using the control gate as a mask, thereby forming a source region and a drain region in the active region.

Claim 2

A method for producing a nonvolatile semiconductor memory device comprising the steps of: forming a field insulating film on an isolation region on a semiconductor substrate and forming a tunneling oxide film on an active region; depositing a silicon film on the semiconductor substrate; forming stripe-shaped silicon portions including a plurality of first portions to be used as a plurality of floating gates and a plurality of second portions interposed between two adjacent portions of the plurality of first portions by patterning the silicon film; forming an insulating film so as to cover at least the stripe-shaped silicon portions; forming a conductive film so as to cover the insulating film; forming a control gate so as to cover the plurality of first portions of the stripe-shaped silicon portions by patterning the conductive film; converting the plurality of second portions of the stripe-shaped silicon portions into a silicon oxide film, and forming the plurality of floating gates from the plurality of first portions by thermally oxidizing the plurality of second portions; and implanting impurity ions through the silicon oxide film into the active region on the semiconductor substrate by using the control gate as a mask, thereby forming a source region and a drain region in the active region.

Claim 7

A method for producing a nonvolatile semiconductor memory device according to claim i, wherein the insulating film is an ONO film constituted by a first oxide film, a nitride film and a second oxide film.

Claim 9

A method for producing a nonvolatile semiconductor memory device comprising the steps of: forming a field insulating film on an isolation region on a semiconductor substrate and forming a tunneling oxide film on active regions, each of the active regions extending in a first direction; depositing a silicon film on the semiconductor substrate; forming stripe-shaped silicon portions including a plurality of first portions to be used as a plurality of floating gates and a plurality of second portions interposed between two adjacent portions of the plurality of first portions by patterning the silicon film, the stripe-shaped silicon portions covering the active regions; forming an insulating film so as to cover at least the stripe-shaped silicon portions; forming a conductive film so as to cover the insulating film; forming a plurality of control gates so as to cover the plurality of first portions of the stripe-shaped silicon portions by patterning the conductive film, the control gates extending in a second direction which is perpendicular with the first direction; converting the plurality of second portions of the stripe-shaped silicon portions into silicon oxides, and forming the plurality of floating gates from the plurality of first portions by thermally oxidizing the plurality of second portions; and implanting impurity ions through the silicon oxides into the active regions on the semiconductor substrate by using each of the control gates as a mask, thereby forming a source region and a drain region in each of the active regions.

Claim 10

A method for producing a nonvolatile semiconductor memory device comprising the steps of: forming a field insulating film on an isolation region on a semiconductor substrate and forming a tunneling oxide film on active regions, each of the active regions extending in a first direction; depositing a silicon film on the semiconductor substrate; forming stripe-shaped silicon portions including a plurality of first portions to be used as a plurality of floating gates and a plurality of second portions interposed between two adjacent portions of the plurality of first portions by patterning the silicon film, the stripe-shaped silicon portions covering the active regions; forming an insulating film so as to cover at least the stripe-shaped silicon portions; forming a conductive film so as to cover the insulating film; forming a plurality of control gates so as to cover the plurality of first portions of the stripe-shaped silicon portions by patterning the conductive film, the control gates extending in a second direction which is perpendicular with the first direction; converting the plurality of second portions of the stripe-shaped silicon portions into silicon oxides, and forming the plurality of floating gates from the plurality of first portions by thermally oxidizing the plurality of second portions; and implanting impurity ions through the silicon oxides into the active regions on the semiconductor substrate by using each of the control gates as a mask, thereby forming a source region and a drain region in each of the active regions.