| 摘要 |
An operating method of a nonvolatile memory device is provided to minimize a data error rate by changing a read voltage according to a change of threshold voltage distribution of memory cells. An erasing operation about a memory cell is performed(S401). A page program operation about the memory cell is performed(S403). A data stored to the memory cell is read by using a present read voltage(S405). An intermediate value and sigma distribution of the threshold voltage distribution of the memory cell are determined(S407). A whole error rate is calculated by using the intermediate value and the sigma distribution of the threshold voltage distribution, and the read voltage(S409). The read voltage is changed in order to minimize the whole error rate(S411). The intermediate value and the sigma distribution of the threshold voltage distribution, and the read voltage are stored(S413). |
