| 摘要 |
PURPOSE:To attain a large capacitance and to prevent signal coupling with the upper wiring, by splitting a trench formed in a semiconductor substrate with a separating insulation film arrayed on the bottom, and by forming first and second capacitors on both the splitted side faces. CONSTITUTION:First and second capacitors belonging to neighboring memory cells are formed by utilizing both the side faces of a trench formed in a substrate 1. Both the capacitors are separated with a P<+> separation region 9 on the trench bottom, and a thick insulating film 2 is formed over the P<+> separation region 9, preventing signal coupling with the Al alloy wiring layer 12. Moreover, the insulating film 2 is arrayed partially on the bottom center of the trench so as not to cover the trench side faces. Accordingly, the insulating film 5 can be formed thick enough to reach the top of the planar section positioned at the top of the trench while the capacitors can be formed by utilizing the entire side faces, so that tradeoff between the thickness of the separating insulation film at the trench bottom and the capacitance of the trench capacitors which has been the drawback of an FCC structure can be overcome. |
