| 摘要 |
PURPOSE:To manufacture a semiconductor device which is excellent in holding characteristics and free of a tunnel current by a method wherein a thick insulating film is selectively formed on the base of a trench. CONSTITUTION:A first holding film 2 and a second holding film 3 are formed on a semiconductor substrate 1, and a mask insulating film 4 is deposited. A first groove 5 is formed using the insulating film 4 as a mask. A resist 29 is patterned so as to enable a part of the groove 5 and an element region 26 to be exposed at the same time. Ions 31 are implanted using the resist 29 and the mask insulating film 4 as a mask to form a first N<+> layer 27. Then, ions 31 are implanted into the surface of the semiconductor substrate l to form a second N<+> layer 28 only on the base of the first groove 5. Then, the resist 29 is removed, an insulating film 6 used for the formation of the side wall material of the first groove 5 is deposited on the part where the resist 29 has been removed, and the insulating film 6 is left unremoved only on the side face of the first groove 5 to serve as a first groove side wall material 7. A part inside the first groove 5 where the surface of the substrate l is kept exposed is etched deep to form a second groove 8. Then, using the insulating film 4 and the first groove side wall material. 7 as a mask, an N<+> layer 19 serving as a node electrode is formed only on the side wall of the second groove 8. In succession, a first insulating film serving as a second capacitor insulating film 32 is deposited. |
