| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a nonvolatile memory device, a memory system including it, and its programming method and reading method. <P>SOLUTION: A reading method of a nonvolatile memory device includes a step for reading an initial threshold voltage value from threshold voltage information cells that store the initial threshold voltage value of an index cell, a step for reading a current threshold voltage value from the index cell, a step for comparing the initial threshold voltage value and the current threshold voltage value to calculate a shifted threshold voltage level of the index cell, and a step for reading user data by changing reading voltage by the shifted threshold voltage level. <P>COPYRIGHT: (C)2009,JPO&INPIT |
