| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To write data so that the number of times of reading each page data is averaged. <P>SOLUTION: The semiconductor memory device executes a write operation to a data sequence of the same digit of 2<SP>x</SP>pieces of (x)-bit data corresponding to the arrangement of 2<SP>x</SP>threshold distribution wherein only one bit in (x)-bit data allocated to the adjacent threshold distribution is different based on a first bit allocation pattern containing at least two change points of "0" and "1" in the write operation. The semiconductor memory device sets the aggregate of bit data of the same digit of (x)-bit data stored in the memory cells connected to a word line as a page, applies a read voltage corresponding to the change points of "0" and "1" to the word line by page, and determines (x)-bit data stored in the memory cells by in the read operation. <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
