| 摘要 |
<P>PROBLEM TO BE SOLVED: To decrease the probability of erroneous reading. <P>SOLUTION: A nonvolatile semiconductor storage device 1 includes a memory cell array 2 which is connected to a plurality of word lines and a plurality of bit lines and has a plurality of memory cells capable of storing an n value (n is a natural number of 3 or more), and a control circuit 9 for controlling voltages of the word lines and the bit lines according to write data, performing a writing operation for writing data in the memory cells, and performing a verifying operation for determining threshold voltages of the memory cells. When writing a first memory cell in a first threshold voltage, the control circuit 9 performs the verifying operation using a first determination voltage and a second determination voltage. When the threshold voltage of the first memory cell is the first determination voltage or more and less than the second determination voltage, the control circuit 9 determines to complete the writing operation of the first memory cell or to continue the writing operation thereof on the basis of write data of a second memory cell adjacent to the first memory cell. <P>COPYRIGHT: (C)2013,JPO&INPIT |
