SPLIT-GATE TYPE MEMORY CELL

PROBLEM TO BE SOLVED: To obtain a split-gate type memory cell having superior erasure characteristics. SOLUTION: This split-gate type memory cell 1 comprises a source region 2, drain region 3, channel region 4, floating gate electrode 5, and control gate electrode 6. The floating gate electrode 5 comprises three layers of film 5a-5c formed in the direction perpendicular to a substrate 7, where the film 5b has left and right end parts projecting from the films 5a, 5c and forming protrusions 5d of the floating gate electrode 5. A tunnel insulation film 10 is made thin on the side of the protrusions 5d of the floating gate electrode 5, and protrusions 6d are formed at the parts of the control gate electrode 6 facing the protrusions 5d via the tunnel insulation film 10. At the time of erasure operation, field concentrates between the protrusions 5d, 6d and electrons in the floating gate electrode 5 jump out from the protrusions 5d to move toward the protrusions 6d of the control gate electrode 6.