Method for fabricating a semiconductor memory device having a floating gate with improved insulation film quality

摘要

A method for fabricating a flash-EPROM comprises the steps of forming a first gate insulation film and a second gate insulation film on a semiconductor substrate so as to respectively cover first and second device regions, providing a first conductor layer so as to cover both the first device region and the second device region, patterning the first conductor layer to form a floating gate electrode in correspondence to the first device region, oxidizing a surface of the first conductor layer to form a capacitor insulation film surrounding the floating gate electrode, providing a second conductor layer on the first conductor layer as to bury underneath the floating gate electrode covered by the capacitor insulation film, patterning the second conductor layer on the first device region to form a control gate electrode, exposing the first conductor layer in correspondence to the second device region, and patterning the first conductor layer remaining on the second element region to form a gate electrode of a peripheral transistor.