| 摘要 |
<p>PURPOSE:To obtain the title write method wherein many bits can be written simultaneously and the time for a collective write operation is shortened by a method wherein a positive voltage which is lower than a positive voltage for a control gate electrode is applied in common to a drain region and a source region. CONSTITUTION:A first voltage is applied to a control gate 4 for a memory cell transistor, a common position voltage which is lower than the first voltage is applied to a source 2 and a drain 3, and a write operation in which electrons are injected into a floating gate electrode 5 by an F-N tunnel effect is executed. Thereby, the second positive voltage is applied in common to the source region 2 and the drain region 3. As a result, when data is written by injecting the electrons into the floating gate electrode 5, a channel current does not flow to the memory transistor. Consequently, since a small write current required for every transistor and a small write current as a whole are sufficient, a write operation can be performed simultaneously in many memory transistors, and the time for a collective write operation can be shortened.</p> |
