Appeal No. 2001-2590
Application No. 09/449,063
teaches implanting oxygen into the substrate through a silicon
nitride (high dielectric constant) layer and into the substrate
and annealing to form an interfacial oxide layer. (Id., lines 12-
16).
The examiner then concludes that it would have been obvious
to form the interfacial oxide layer of Mogami in the primary
reference of Hsu to prevent boron from entering the channel of the
device which leads to premature transistor failure. (Id., lines
17-20).
The appellants, on the other hand, assert that Mogami teaches
doping oxygen into the silicon nitride layer, not through. This,
it is urged, creates an oxygen-rich layer along an interface
between the silicon nitride and the substrate, not an oxygen-
implanted region as claimed. (Appeal Brief, page 7, line 24-page
8, line 1).
We agree with the appellants. Mogami expressly states that
the oxygen implantation forms an oxygen-doped silicon nitride film
(column 3, lines 15-19, see also column 9, lines 2-5), not that
the oxygen is implanted into the substrate as claimed.
The examiner has stated that “inherently a portion of the
layer will be formed in the substrate since silicon must be taken
from the substrate in order to form the layer.” (Examiner’s
Answer, page 5, lines 15-16). While this may be true in terms of
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