Appeal No. 96-3475
Application 08/245,775
Relying on appellants’ admissions (specification, page 2, lines 7-11) and Chen’s disclosure
that triisopropylindium has a much lower decomposition temperature than trimethylindium, the
examiner contends that it would have been obvious to a person with ordinary skill in the art to
utilize the claimed source in place of the trimethylindium precursor to effectively reduce the
temperature of the doping processing. With respect to the admitted prior art doping processes
involving the interdiffused multilayer process and directed alloy growth process for the doping of
mercury cadmium telluride, however, doping temperature ranges are not disclosed. Thus there is
no objective or factual support explaining why one of ordinary skill in the art would desire to
lower the effective doping temperature or why there would be any advantage for doping II/VI
semiconductor materials at lower temperatures. Accordingly, the rationale of the examiner’s
stated rejection is not adequately factually supported. For the reasons below, however, we agree
with the examiner’s conclusion that the claimed subject matter would have been obvious.
As indicated above, the use of trimethylindium presents transport problems when used as a
low level n-type dopant in the chemical vapor deposition of II/VI semiconductor materials, such
as mercury cadmium telluride. Thus, because it is a solid at or below room temperature, its
effective vapor pressure changes with time, and thus it does not provide a constant quantity of
indium during the prior art doping processes. The Gedridge patent relates to the use of the
claimed material, triisopropylindium as an alternative precursor for the chemical vapor deposition
growth (not doping) of indium-containing semiconductor materials, i.e. III/V semiconductors.
More particularly, however, Gedridge indicates that triisopropylindium is a liquid with a low
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