| 摘要 |
<p>PURPOSE:To enhance reliability and realize high integration by simultaneously achieving the increase in junction withstand voltage of drain and source and also preventing punch through. CONSTITUTION:At the time of writing information in memory, the potential of a source 26 and bit lines 32 other than a selected bit line 32 is set to less than 1 V positive potential, for instance, and all bit lines 32 are set to a positive potential of less than 3 V, for example, when erasing the whole information stored. At this time, since the substrate potential is set to 0 V, a substrate bias is practically being applied, and punch through hardly occurs at an MOS transistor 25 and a parasitic MOS transistor even though the impurity concentration of a channel stopper is low and the junction withstand voltage of a drain 27 and the source 26 is high.</p> |
