| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a writing method of a nonvolatile semiconductor storage device capable of making a threshold voltage distribution a narrow band. <P>SOLUTION: A flash memory precharges each bit-line GBL corresponding to a memory cell MC of a writing target, discharges each bit-line GBL corresponding to a memory cell MC of a writing non-target, verifies the bit-line GBL to detect a memory cell MC of a low threshold voltage (S7) and additionally performs writing to the detected memory cell MC (S8, S9). Then, verification can be performed without being affected by current caused to flow to the memory cell MC of the writing non-target, and threshold voltage of the entire memory cells MC can be correctly set. <P>COPYRIGHT: (C)2007,JPO&INPIT</p> |
