| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a flash memory device including a plurality of stack gate type memory cells that can shorten a time required for simultaneous erasing operation by eliminating writing operation before erasing and also shorten a time required for rewriting data. <P>SOLUTION: In erasing, electrons are simultaneously injected into floating gates 1005 from sources 1003 of a plurality of memory cells. Thus, the threshold voltages of the plurality of memory cells are increased. In programming, electrons are emitted from the floating gate 1005 of a selected memory cell to a drain 1002. Thus, the threshold voltage of the selected memory cell is reduced. <P>COPYRIGHT: (C)2006,JPO&NCIPI</p> |
