| US 7,489,006 B2 | ||
| Nonvolatile semiconductor storage device and manufacturing method therefor | ||
| Hiroshi Watanabe, Yokohama (Japan); Atsuhiro Kinoshita, Kamakura (Japan); Akira Takashima, Tokyo (Japan); and Daisuke Hagishima, Tokyo (Japan) | ||
| Assigned to Kabushiki Kaisha Toshiba, Tokyo (Japan) | ||
| Filed on Sep. 13, 2005, as Appl. No. 11/224,049. | ||
| Claims priority of application No. 2005-086803 (JP), filed on Mar. 24, 2005. | ||
| Prior Publication US 2006/0214217 A1, Sep. 28, 2006 | ||
| Int. Cl. H01L 29/788 (2006.01) | ||
| U.S. Cl. 257—317 | 7 Claims |
| 1. A nonvolatile semiconductor storage device comprising:
a semiconductor substrate;
a plurality of isolation regions formed in the semiconductor substrate;
an element-forming region formed between adjacent isolation regions;
a first gate insulating film provided on the element-forming region;
a floating gate electrode provided on the first gate insulating film;
a second gate insulating film provided on the floating gate electrode; and
a control gate electrode provided on the second gate insulating film,
wherein a recess is provided on a side surface of the element-forming region, so that a width of at least a part of the element-forming
region under a top surface of the element-forming region is narrower than a width of the top surface of the element-forming
region in a section taken in a direction perpendicular to a direction in which the isolation regions extend.
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