| 摘要 |
A nonvolatile semiconductor memory device in one embodiment includes a select gate switch transistor having a gate insulating film formed on a semiconductor substrate, a gate electrode formed on the gate insulating film, and first and second source/drain regions provided in the semiconductor substrate so as to face each other across the gate electrode. The first source/drain region includes a first n-type impurity layer and a second n-type impurity layer which has a higher impurity concentration and has a shallower depth than the first n-type impurity layer. The second source/drain region has a third n-type impurity layer which has a lower impurity concentration and has a shallower depth than the first n-type impurity layer and a fourth n-type impurity layer which has a higher impurity concentration and has a deeper depth than the third n-type impurity layer.
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