| 摘要 |
PROBLEM TO BE SOLVED: To provide a nonvolatile semiconductor memory device having high endurance characteristics capable of preventing deterioration of the conductance of a transistor, without increasing the manufacturing man-hours. SOLUTION: In the floating gate nonvolatile semiconductor memory device equipped with a sidewall 8, a drain diffused layer 7 is partially overlapped with a floating gate electrode 3. Upon removing electron from the floating gate electrode to a semiconductor substrate 1, tunnelling current is employed in which electrons pass through the whole surface of a gate insulation film 2. Further, upon readout operation, the concentration of impurities in the drain diffused layer is set on the surface of the semiconductor substrate, so that a depletion layer 9 generated in the connecting part of the semiconductor substrate and the drain diffused layer do not reach the parts immediately below the edge and the sidewall of the floating gate electrode. COPYRIGHT: (C)2004,JPO
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