| 摘要 |
PROBLEM TO BE SOLVED: To form a fine memory cell, while securing an overlapping area of a floating gate and an impurity diffused layer, and to reduce irregularity on an F-N tunnel phenomenon between bits that is resulted from a fine memory cell. SOLUTION: A nonvolatile semiconductor memory comprises a first conductivity type semiconductor substrate 1, including grooves formed in one direction, a first gate insulating film 8 formed entirely on the interior walls of the grooves, floating gates 9 which are placed into the grooves and whose upper parts protrude from a surface of the semiconductor substrate, second conductivity type impurity diffused layers 6 which are formed on both sidewalls of the grooves so as to oppose the floating gates via the first gate insulating film 8, and a control gate 12 which extends from the semiconductor substrate to the floating gate 9 via a second gate insulating film 10 on the floating gate 9 and via an oxide film, which provides insulation from the semiconductor substrate, and the second gate insulating film on the semiconductor substrate.
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