Nonvolatile semiconductor memory with raised source and drain

Claim 1

A nonvolatile semiconductor memory device comprising: a semiconductor substrate of a first conductivity type; an element isolation insulating film formed in said semiconductor substrate so as to define an active region in said semiconductor substrate; a pair of first polycrystalline silicon layers including impurities of a second conductivity type different from said first conductivity type and formed on a said active region of said semiconductor substrate, said pair of first polycrystalline silicon layers being separated from each other by a small gap: a pair of diffusion layers of said second conductivity type formed in those regions of said semiconductor substrate which are in contact with said pair of first polycrystalline silicon layers by diffusing the impurities included in said first polycrystalline silicon layers, respectively; an interlayer insulating film formed to cover said pair of second conductivity type first polycrystalline silicon layers and a part of said semiconductor substrate which is exposed to an outside at said small gap between said first polycrystalline silicon layers, a portion of said interlayer insulating film which covers the part of said semiconductor substrate exposed to the outside at said small gap serving as a first gate insulating film; a floating gate electrode formed on said interlayer insulating film so as to cover said very small gap; a second insulating film formed on said floating gate electrode; and a control gate electrode formed on said second gate insulating film.