| 摘要 |
PROBLEM TO BE SOLVED: To provide a nonvolatile semiconductor storage having excellent electric characteristics and a manufacturing method thereof. SOLUTION: The semiconductor device has a semiconductor substrate 1 having two grooves 2a, 2b, separating oxide films 5a, 5b formed in the insides of the grooves 2a, 2b, floating gate electrodes 7a-7c, an ONO (oxide-nitride-oxide) film 8, and a controlling gate electrode 9. Regions 33 of the top surfaces of the separating oxide films 5a, 5b have the shapes of convex curved surfaces to down sides. The floating gate electrode 7b is extended from the upside of the principal surface of the semiconductor substrate 1 interposed between the two grooves to the upsides of the two separating oxide films 5a, 5b, and has a flat top surface. The ONO film 8 is extended from the upsides of the top surfaces of the floating gate electrodes to the upsides of the side surfaces of the floating gate electrodes 7a-7c. The controlling gate electrode 9 is so formed on the ONO film 8 as to extend it from the upsides of the top surfaces of the floating gate electrodes 7a-7c to the upsides of the side surfaces of the floating gate electrodes 7a-7c. COPYRIGHT: (C)2004,JPO&NCIPI
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