| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To suppress data corruption caused by a verify-error or the like due to raising of a source potential. <P>SOLUTION: The apparatus has a memory array and a control circuit. The memory array has a plurality of nonvolatile memory transistors of which the threshold voltage can be changed electrically. The control circuit can store data of two bits or more in the one nonvolatile memory transistor by changing the threshold voltage. The control circuits performs verifying again for the nonvolatile memory transistor of a processing unit being passed once by application of a high voltage pulse for storing data and verifying (S41, S47), and adds light application of the high voltage pulse for the nonvolatile memory transistor being made fail in verifying again (S46, S52). Thereby, correction is performed even if a state of erroneous verifying is caused. The occurrence of data corruption can be suppressed easily even if actual threshold voltage is varied by an RTS phenomenon or the like after that. <P>COPYRIGHT: (C)2007,JPO&INPIT</p> |
