| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a nonvolatile semiconductor memory device capable of limiting effects of threshold voltage variations due to interference between adjacent cells. <P>SOLUTION: A nonvolatile semiconductor memory device relating to one embodiment comprises: a memory cell array which includes NAND cell units with tandemly-connected multiple memory cells that respectively include control gates and charge accumulation layers, and in which each control gate of the memory cells is connected to each word line; and a control circuit that executes writing operation for setting threshold voltage according to data by applying predetermined writing voltage to the word lines multiple times and controlling an accumulated charge amount in each charge accumulation layer of the memory cells. The control circuit increases the writing voltage by first step-up voltage when repeatedly applying the writing voltage in a first period after starting the writing operation, and it controls the writing voltage so as to increase the writing voltage by second step-up voltage lower than the first step-up voltage in a second period after the first period. <P>COPYRIGHT: (C)2013,JPO&INPIT |
