| 摘要 |
A nonvolatile semiconductor memory device including a semiconductor substrate 1, a plurality of memory cells 1a on the semiconductor substrate including transistors having floating gate electrodes and control gate electrodes. Source lines 30 are formed in a self-alignment manner with respect to a control gate electrodes. The surface of the semiconductor substrate 1 has such a periodical unevenness along the source lines 30 which has a diffusion layer 30a that an impurity is distributed along the surface of the semiconductor substrate 1 and a buried diffusion layer 30b that an impurity is distributed at a position deeper than said diffusion layer 30a. The buried diffusion layer 30b connects a plurality of portions of the diffusion layers 30a under the bottom surface 5b of the recess portion 5 to each other.
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