| 摘要 |
PROBLEM TO BE SOLVED: To provide a high-density cross point DRAM cell with a fold-up bit line trench and a cell area of only 4 lithographic square units. SOLUTION: Access devices (transistor elements) 18, 5, 6, and 13 are provided vertically on a side face of a trench. Polysilicon spacer word lines 6 and 7 are used in a preferred embodiment. By enlarging the depth of a trench 16, the width of the word lines 6 and 7 are increased without increasing the cell area. The word lines 6 and 7 have a smaller RC time constant, and thereby access speed of the cell becomes higher. In addition, a diffusion point 13 to a memory node and an access element is provided on one side face of the trench 16. Especially, a mutual interaction between adjoining nodes on account of scaling is suppressed to a minimum. |
