Appeal No. 96-3475
Application 08/245,775
freezing point and has a useful vapor pressure in chemical vapor deposition systems ( col. 2, lines
30-35). Thus liquid triisopropylindium is said to offer a "substantial advantage" (col. 4, line 62)
over the solid trimethylindium in terms of transport properties, and provides a constant and
controllable quantity of indium to a chemical vapor deposition reactor when a carrier gas is
bubbled through the liquid (col. 4, lines 53-63 and col. 2, lines 20-24). In light of the disclosures
in Gedridge, one of ordinary skill in the art, motivated by the desire to solve the prior art
"transport problem", would have been led to use triisopropylindium as a liquid dopant precursor
source with a reasonable expectation that a constant and controllable quantity of indium would be
provided for the doping of II/VI semiconductor materials.
Appellants state in their specification that just because a given compound may
demonstrate acceptable results when used as a source compound for semiconductor materials
does not lead one to the conclusion that the same compound can be used as a dopant source for
semiconductor materials with equally good results. See the specification at page 3, lines 3-6.
However, in light of the disclosures in the Gedridge patent, why such equally good results would
not have been expected for the liquid compound, triisopropylindium, has not been adequately
explained by appellants. Moreover, we observe that trimethylindium, the prior art solid source
material, has provided acceptable results both as a source compound for semiconductor materials
and as dopant source for II/VI semiconductor materials such as mercury cadmium telluride at
16 -3
least at dopant concentrations in the mid 10 cm range. Again see the specification at page 2,
lines 20-22. Further, as the examiner has accurately pointed out in the answer, appellants have
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