METHOD FOR FABRICATING A SEMICONDUCTOR MEMORY DEVICE HAVING FLOATING GATE WITH IMPROVED INSULATION FILM QUALITY

摘要

A method for manufacturing a flash EPROM includes a primary gate insulating film 24a, a secondary gate insulating film 24b, and a secondary gate insulating film 24b on a semiconductor substrate so as to cover the primary and secondary device regions, respectively. Forming; Providing a primary conductive layer 28 to cover both the primary device region covered with the primary gate insulating film and the secondary device region covered with the secondary gate insulating film; Patterning the primary conductive layer to form a floating gate electrode 28a corresponding to the primary device region; Oxidizing the surface of the primary conductive layer to form the capacitor insulating film 30c so that the capacitor insulating film covers the floating gate electrode; Providing a secondary conductive layer over the primary conductive layer by asking the floating gate electrode covered by the capacitor insulating film below; Patterning a secondary conductive layer over the primary device region to form a control gate electrode; Exposing a primary conductive layer corresponding to the secondary device region; And patterning the primary conductive layer remaining over the secondary device region to form the gate electrode of the peripheral transistor.