| 摘要 |
PROBLEM TO BE SOLVED: To provide a high-density nonvolatile semiconductor storage device capable of reducing an element isolation width of a memory cell by reducing the embedding aspect of an element insolation insulating film. SOLUTION: In the nonvolatile semiconductor storage device having an element isolation region 23 in which element isolation insulating films are embedded in a plurality of trench grooves, a plurality of semiconductor regions 30 electrically isolated by the element isolation region 23, a charge accumulation layer 27 formed on the semiconductor region 30 via a first gate insulating film 24, and a control gate 29 formed on the charge accumulation layer 27 via a second gate insulating film 28, the charge accumulation layer 27 has a laminated structure consisting of two or more conductive layers, the side end position of a conductive layer 25 that is the lowermost layer of the structure coincides with the trench groove wall position, the width of a conductive layer 26 that is the uppermost layer is greater than the width of the lowermost conductive layer 25, and the top surface of the element isolation insulating film and the top surface of the uppermost layer of the charge accumulation layer 27 coincide with each other. COPYRIGHT: (C)2008,JPO&INPIT
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