| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a sufficient read margin stably in a nonvolatile semiconductor memory device constituted so that an average current of two reference cells is set as a reference current. <P>SOLUTION: This memory is a nonvolatile semiconductor memory device comprising a memory cell array, a reference cell including a first reference cell and a second reference cell, and a data decision control section which determines the average reference current from the first reference cell and the second reference cell, and which decides read data by comparing the magnitudes of the average reference current and the read current of each memory cell of the memory cell array. The device further comprises a reference cell setting section which determines a distribution of the threshold of each memory cell by carrying out program verification of the memory cell array based on the first reference cell, and which sets the second reference cell based on a distribution of obtained threshold. <P>COPYRIGHT: (C)2004,JPO&NCIPI</p> |
