| 摘要 |
PURPOSE:To improve data retaining characteristics by making a trench contiguous to one source-drain region of a MOS transistor in a semiconductor substrate and forming a second lower electrode covering the inner face of the trench and a first lower electrode thereby preventing formation of a scooped part susceptible to field concentration. CONSTITUTION:A P<+> impurity layer 32 is formed surrounding the inner face of a trench 21. A poly-Si film 24 is then formed on the entire surface including the inner face of the trench 21 by CVD and phosphorus is diffused into the poly-Si film 24. The poly-Si film 24 is then patterned to cover a poly-Si film 31. The poly-Si film 24 contacts an impurity layer 15 on the side face of the trench 21 and also contacts with the poly-Si film 31 thus forming a second lower electrode of a capacitor 27. The contact part eliminates the need of planar region and reduces the memory area thus facilitating fabrication of high density, high integration semiconductor memory device. |
