| 摘要 |
PROBLEM TO BE SOLVED: To provide a non-volatile semiconductor storage device wherein coupling ratio is increased and a write voltage is lowered by controlling impurity concentration of a polysilicon layer of a floating gate electrode and a polysilicon layer of a control gate electrode, and a manufacturing method thereof. SOLUTION: A non-volatile semiconductor storage device has a first insulation film 104 formed on a substrate, a first polysilicon layer 106 containing impurities on the first insulation film 104, a second insulation film 107 on the floating gate electrode, a control gate electrode with a second polysilicon layer 108 containing impurities on the second insulation film 107, and a third insulation film on the control gate electrode. The first polysilicon film 106 of the non- volatile semiconductor storage device is formed of polysilicon whose impurity concentration is higher in the second insulation film 107 side than in the first insulation film 104 side.
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