| 摘要 |
PROBLEM TO BE SOLVED: To enhance writing speed by preventing the generation of variations in transistor threshold. SOLUTION: In the nonvolatile semiconductor storage device, the film thickness of a control gate electrode 106a is made to be thinner than that of an upper gate electrode 106b so as to have the relation of Hsg×8/9>Hcell≥Hsg×7/9-Heb×11/9, where the thickness of the control gate electrode 106a above a floating gate electrode 104a of a memory cell transistor 1 is Hcell, a film thickness of an upper gate electrode 106b of a selection transistor 2 is Hsg, and the difference between the height of an upper surface of the floating gate electrode 104a and the height of an upper surface of an element isolation region 107 is Heb. COPYRIGHT: (C)2009,JPO&INPIT
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