| 摘要 |
PROBLEM TO BE SOLVED: To provide a semiconductor memory device that achieves suppression of deterioration in writing characteristics without deteriorating characteristics of peripheral circuits other than a memory-cell transistor element. SOLUTION: The semiconductor memory device 101 of a writing method by hot electron injection, for example, includes a P+ semiconductor substrate 10, a P- epitaxial layer 11 (a semiconductor layer) being a P- epitaxial layer (a semiconductor layer) formed on the P+ semiconductor substrate 10 and having higher resistance than that of the P+ semiconductor substrate 10, a memory-cell transistor element 20 formed on the P- epitaxial layer 11, and a P+ impurity diffusion region 12 being a P+ impurity diffusion region 12 formed in the P- epitaxial layer 11 below the memory-cell transistor element 20 at a depth that its bottom reaches the P+ semiconductor substrate 10 and having lower resistance than that of the P- epitaxial layer 11. COPYRIGHT: (C)2011,JPO&INPIT
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