| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To increase data write speed by achieving a high-speed verify operation. <P>SOLUTION: A memory cell MC stores data by the first to n-th threshold voltage (n is a natural number of two or more). A control circuit 7 writes the first to n-th threshold voltage in the memory cell according to input data. The control circuit 7 writes data into the memory cell to k-value threshold voltages of the n-th threshold voltage, the (n-1)th threshold voltage to the (n-k+1)th threshold voltage in the first write operation, writes data into the memory cell to k-value threshold voltages of the (n-k)th threshold voltage, the (n-k-1)th threshold voltage to the (n-2k+1)th threshold voltage in the second write operation, and writes data into the memory cell to (k-1) value threshold voltages of the kth threshold voltage, the (k-1)th threshold voltage to the second threshold voltage in the n/k-th write operation. <P>COPYRIGHT: (C)2011,JPO&INPIT</p> |
