| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain high-speed rewriting characteristics by minimizing variations in a threshold voltage distribution after programming.SOLUTION: A nonvolatile semiconductor memory device comprises: a nonvolatile memory cell array; and a control circuit that controls writing to the memory cell array. Before erasure processing for erasing data of a memory cell for writing, the control circuit detects a program speed of writing to the memory cell array; determines a program start voltage corresponding to the program speed for each block or each word line; stores the determined program start voltage in the memory cell array; and reads the program start voltage from the memory cell array and writes predetermined data.</p> |
