| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a nonvolatile semiconductor memory device provided with a discrimination function for erroneous write and excessive write. <P>SOLUTION: The device is provided with a cell array storing a first logic state of which a threshold value is a first value or less and a second logic state of which a threshold value is a second value or more in a nonvolatile state, a data holding circuit holding write data to the cell array and sensing read data, and a controller controlling write of the cell array. The controller is provided with a write control function by which data of a selected cell is shifted to the second logic state from the first logic state on the basis of the write data loaded onto the data holding circuit, a write verify-control function confirming that data of the selected cell is shifted to the second logic state, an erroneous write verify-control function confirming that threshold voltage of the cell to be held in the first logic state is not shifted exceeding a third value being the supremum value of variation of the first logic state, and an excessive write verify-control function confirming that threshold voltage of the selected cell shifted to the second logic state is not shifted exceeding a fourth value being the supremum value. <P>COPYRIGHT: (C)2003,JPO</p> |
