Loading patent…
AssigneeNippon Telegraph & Telephone Public Corporation
InventorsTakashi Morie, Kazushige Minegishi, Shigeru Nakajima
Estimating the term…
A semiconductor memory device has a semiconductor substrate of one conductivity type in which a plurality of memory cells are formed, each of the plurality of memory cells including at least one capacitor and having a trench which is formed from one major surface of the semiconductor substrate so as to surround at least one memory cell, wherein a first insulating film having element isolation properties is formed on a bottom and most areas of side wall surfaces of the trench, a first conductive film serving as one electrode of the capacitor is formed on the side wall of the first insulating film and an exposed portion of the semiconductor substrate which is not covered with the first insulating film, a second insulating film is formed on the first conductive film, and a second conductive film serving as the other electrode of the capacitor is formed on the second insulating film.
A semiconductor memory device comprising a semiconductor substrate of a first conductivity in which a plurality of memory cells are formed, each of said plurality of memory cells including at least one capacitor, a switching element and a trench being disposed on a major surface of said substrate, and switching element being disposed on a flat surface of said substrate which is surrounded by said trench, wherein a first insulating film is formed at least on most areas of side wall surfaces of said trench, said capacitor and first insulating film being disposed within a region defined by said trench, said first insulating film having a window near the opening of said trench so that a portion of said substrate is exposed, a diffusion region is formed in a portion of said substrate corresponding to said window, a first conductive film serving as one electrode of said capacitor is formed on said first insulating film and an exposed portion, said exposed portion being disposed in corresponding relationship to said window, said first conductive film and said diffusion region extending into said window and being in contact with one another thereat, wherein among adjacent memory cells, the first conductive film of each adjacent memory cell are disposed upon side wall of said trench and are isolated from one therewithin, and wherein a second insulating film is formed on said first conductive film, a second conductive film serving as the other common electrode of said capacitor of each adjacent memory cell is formed between said first insulating and said second insulating film, at the bottom of said trench so that the first conductive film of each adjacent memory cell is electrically separated from each other by the second insulating films, and wherein one terminal of said switching element contacts to said first conductive film through said window.
Dependencies are inferred from the claim text.