Semiconductor memory device, method of manufacturing the same and method of driving the same

摘要

The present invention relates to a dual bit nonvolatile programmable read/write memory containing a semiconductor memory element having one conductivity type semiconductor substrate including at least one convex portion. A pair of opposite conductivity source/drain regions are formed on a surface of the semiconductor substrate an opposing sides of the convex portion, and a first insulating film covers the upper surface of the convex portion. Second insulating films cover the side surfaces of the convex portion and the source/drain regions. A pair of floating gates abut opposing side surfaces of the convex portion and the source/drain regions through the second insulating films. Third insulating films are formed on the floating gates. A control gate covers the upper surface of the convex portion through the first insulating film and the floating gates through the third insulating films.