| 摘要 |
PURPOSE:To use a trench for both element isolation and a capacitor and to make it possible to miniaturize a memory cell and to increase density of a DRAM by providing a data storing capacitor on the side wall of the trench for isolating a transfer gate transistor. CONSTITUTION:An insulating film 9 is formed at the bottoms of trenches 2a and 2b. The connection between side wall diffused layers 6 is prevented at the insulating film 9 and the bottom of the trench 2a. An embedded layer 10 comprising an insulator is embedded in the gap parts in the trenches 2a and 2b for flattening the surfaces. A capacitor is not formed at the side wall part of the trench 2b. The trench 2b is used for element isolation. The trench 2a is used for both applications as a capacitor and element isolation. In this way, two capacitors are formed at the two side wall parts of the trench, and the trench is used for the element isolation. Thus, the required area per one cell can be reduced. |
