| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a nonvolatile semiconductor memory device capable of improving data holding characteristics and reducing erasure time. <P>SOLUTION: A bit line is connected to one end of a memory unit, a word line is connected to a control gate of a memory transistor and a control gate line is connected to a gate of a selection transistor. A control circuit controls an erase operation to erase data of the memory transistor by applying a predetermined voltage to the bit line, word line and control gate line, a correction write operation to move an erase threshold level of the memory transistor to a positive threshold level after the erase operation, and a correction write verify operation to determine whether or not a threshold level of the result of the correction write operation reaches a predetermined value. In the correction write operation, the control circuit simultaneously executes the correction write operation with respect to a plurality of memory units connected to the common bit lines and sequentially executes the correction write verify operation with respect to a plurality of memory units in which the correction write operation is executed. <P>COPYRIGHT: (C)2012,JPO&INPIT |
