Appeal No. 2006-1176
Application No. 09/926,202
determined by skilled persons.
To account for the epitaxial layer deposition temperature
and oxygen concentration in units of atoms/cm3 missing in
Wijranakula, the examiner refers to the teachings of Wolf. We
find that Wolf teaches at page 59 that the oxygen content
(10 ppma - 50 ppma) described in Wijranakula embraces the claimed
oxygen content defined in units of atoms/cm3. Specifically, Wolf
teaches that “the most abundant impurity in Czochralski (CZ) Si
crystal is oxygen, with concentrations typically ranging from
5X1017-1X1018 atoms/cm3 (or 10-20 ppma).” See page 59. We find
that Wolf also teaches at pages 135 and 136, Figures 12, 13 and
14 that conventional epitaxial layer deposition temperatures
include 1000o C and greater, which according to column 2, lines
1-7, of Wijaranakula “drive off oxygen near their surfaces...”
We find that Wolf further teaches that:
The growth rate of the epitaxial film depends on
several parameters: a)chemical source; b) deposition
temperature and c) mole fraction of reactants.
Given the above teachings, we concur with the examiner that
the employment of the conventional epitaxial layer deposition
temperatures and oxygen concentrations implicitly and/or
explicitly taught in Wijaranakula, as explained by Wolf, in the
semiconductor silicon-wafer making process of Wijaranakula would
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