| 摘要 |
PURPOSE:To enable a trench type memory cell to withstand scaling by forming the gate electrode of a MIS type field effect transistor constituting the transfer gate of the charge for storing information in the memory node into the shape of a loop. CONSTITUTION:A MOSFET having a gate electrode shaped in a loop consists of a second gate electrode 6 buried in the upper portion of the groove via an insulating film, a second gate oxide film 5 formed in the side wall of an epitaxial layer 2, and an n<+> diffusion layer 7 formed in the surface of the epitaxial layer. The second gate electrode 6 acts not only as the gate electrode of the switching transistor of the memory cell, but also as device isolation at the surface portion of the epitaxial layer 2. With this, a memory cell capable of withstanding scaling can be realized. |
