Appeal No. 1999-2576
Application 08/836,960
region does not function as the "base contact." Instead, that
function is performed by N+ POLY region 26 (col. 4, l. 50),
which is coupled to base 6 through the N+ buried layer 4.
Moreover, McFarlane gives this as the reason the alternative
embodiment shown in Figure 12 omits the refractory layer 45b
over N+ POLY layer 24 (col. 4, ll. 60-65). Nevertheless,
Appellant's observation that
N+ POLY region does not function as the base terminal does not
undercut the rejection, because claim 1 does not specify that
the "diffusion barrier" separates the "base region" from the
"base terminal region." Instead, the claim specifies that the
"diffusion barrier" separates the "base region" from a "base
electrode," which is satisfied when the term "base electrode"
is read on N+ POLY region 24.
The examiner relies on Yorikane as broadly teaching "the
use of [a] silicon nitride layer for the purpose of preventing
diffusion of impurities between impurity doped regions."
Answer at 3. Yorikane's Figure 6 reproduced below, shows a
prior art transistor structure including an N-type substrate
201, a P-type base layer 204, an N-type emitter region 209, a
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