Appeal No. 2002-0677
Application 09/257,899
in the art,2 and relies upon Fazan for a teaching of forming
hemispherical grains on a polysilicon layer (answer, page 4).
Fazan, however, teaches that his polycrystalline silicon-
germanium alloy grains are deposited as macroscopic islands
having diameters which are sufficiently large relative to a
subsequently-applied dielectric layer that the dielectric layer
does not bridge the gaps between the islands (col. 4, line 46 -
col. 5, line 5). Fazan does not disclose etching the macroscopic
islands.
2 In support of this argument the examiner relies upon the
above-discussed portion of Hirota and also Hirota’s fourth,
fifth, thirteenth and fourteenth embodiments (answer, page 4).
In the fourth embodiment a doped polysilicon film is annealed and
then etched with phosphoric acid to form microrecesses in the
film (col. 11, lines 18-48). In the fifth embodiment a method
similar to that in the fourth embodiment is disclosed, and a
method is disclosed wherein an amorphous silicon film is annealed
to form silicon crystal grains and the film is then etched with
phosphoric acid to produce microrecesses therein (col. 11,
line 50 - col. 12, line 11). In the thirteenth embodiment a
porous silicon is annealed to recrystallize the silicon and
thereby form grains which, compared to the original grains, have
larger sizes and larger microrecesses between them (col. 17,
lines 5-24). In the fourteenth embodiment an amorphous silicon
film which has been formed partially on a single crystal silicon
substrate and partially on a silicon oxide film is annealed to
form hemispherical grains and is then etched with phosphoric acid
to decrease the microrecess size and increase the surface area
(col. 17, line 26 - col. 18, line 9).
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