Appeal No. 96-1536
Application 08/136,241
side-walls and a bottom. Subsequently, an outer electrode is
formed along said four side-walls in the trench by implanting
ions into each side-wall, serially, after rotating the
semiconductor 90E with respect to each previous implantation.
Thereafter, an insulating layer is formed within the trench
along the outer electrode. Finally, an inner electrode is
formed within the trench along the insulating layer.
At column 4, lines 47 through 50 of their patent,
appellants describe their technique of doping by rotating the
semiconductor in planarity four times in 90E increments as
useful for doping the side-walls of deep trenches in dynamic
RAM cell capacitors. In column 6, lines 20 through 42,
appellants describe the preparation of one cell of a dynamic
RAM. At lines 27 through 30 of column 6, the formation of a
deep trench (68) is described with reference to Figure 9(b).
To form n-type regions (72, 74) in the side-walls, which
regions form one of the electrodes, each side-wall is, in
succession, doped with As+ ions (column 6, lines 30 through
34). In the next step, which step is depicted in Figure 9(c),
a thin insulation film (76) is formed on the inner wall of the
deep trench (68) and the other electrode (78) is formed by
doped polysilicon (column 6, lines 34 through 37). We find
6
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