| 摘要 |
PURPOSE:To improve writing characteristics without increasing the size of a memory cell by a method wherein, in the diffused regions of the memory cell insulators or semiconductors with different polarities are provided in a channel region near a drain region and the gate width is narrowed at the boundary of the channel region and the drain region only. CONSTITUTION:A region A forms one memory cell. A source region 4 and a drain region 6 are surrounded by field oxide films 16. The field oxide films 16 invade the boundary of the drain region 6 and a channel region 24 as insulating region 26 to narrow the width W of a gate at the boundary of the drain region 6 and the channel region 24. With this constitution, the writing characteristics of the memory cell can be improved. In other words, the difference between a threshold voltage before writing in the memory cell and a threshold voltage after writing can be enlarged. |
