| 摘要 |
PROBLEM TO BE SOLVED: To provide a technique which can prevent an electric field concentration due to birds beaks and can suppress demerits of the birds beaks. SOLUTION: This invention relates to a semiconductor device having bit lines and word lines, characterized by comprising: a substrate in which there are provided plural first trenches extending in the bit-line direction and there are formed the birds beaks at upper edges of side surfaces constituting sidewalls of the first trenches; a first gate insulating film formed on the substrate between the first trenches; a floating gate formed on the first gate insulating film between the first trenches and located between second trenches extending in the word-line direction, wherein any birds beaks are not formed at lower edges of the side surfaces facing sides of the first trenches; a second gate insulating film formed on the floating gate between the second trenches; and a control gate formed on the second gate insulating film between the second trenches. COPYRIGHT: (C)2009,JPO&INPIT
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