Patent ID: 6294427
Filing Date: 2001-09-25
Classification: H01L

Abstract:
A method of fabricating a non-volatile semiconductor memory device comprising a semiconductor substrate and a memory element provided with a floating gate and a control gate, said method including steps of:forming a first well in said semiconductor substrate;forming a second well within said first well, said second well having a conductivity opposite to that of said first well;forming a tunnel insulation film on said semiconductor substrate;forming a floating gate on said tunnel insulation film;forming a dielectric film so as to cover said floating gate;selectively removing said dielectric film to form a contact hole through which said second well is exposed;forming a conductive film that will become said control gate on said dielectric film, in such a manner as to be in contact with said second well through said contact hole; andthermally processing said conductive film to diffuse impurities contained within said conductive film into said second well to form a first conductive layer.