Appeal No. 1997-3696 Page 9
Application No. 08/473,419
Rejection of Claim 65 over Ciszek in View of Naumann and Bult
Claim 65 is directed to a method of making silicon (Si) and germanium (Ge) crystals by placing
one of Si and Ge and water containing boron oxide in a vessel and cooling to crystallize the Si or Ge.
The cooling progresses in a predominately horizontal direction from the bottom center of the vessel to
the inner walls and then predominately vertically from the bottom toward the top of the vessel to form
the crystal. According to the specification, at page 9, this progressive cooling is accomplished by
imposing a cold spot on the bottom center of a crucible having a tapered bottom and tapered sides so
that nucleation of the melt occurs at the bottom center. A uniform thermal gradient across the furnace
and perpendicular to the crucible vertical axis is then imposed on the melt to accomplish crystallization
in the vertical direction.
Ciszek describes a process of growing Si crystals using a vertical temperature gradient cooling
process. Appellant’s sole argument is that the combination of prior art does not teach or suggest the
horizontal and vertical progressive cooling step of the claimed process. We agree with the examiner
that such a cooling progression would have necessarily occurred in the process of Ciszek. Ciszek
describes maintaining a vertical temperature gradient on the melt so that the molten Si solidifies from
bottom to top (col. 2, lines 27-31, Figure 1, col. 3, lines 43-44). Ciszek also discloses forming the
container with a conical bottom recess for a seed to be placed therein (col. 3, lines 5-7). The point of
the conical bottom contains the seed and therefore crystallization will begin at the bottom center of the
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