Appeal No. 2005-0285 5
Application No. 09/881,675
the interlayer insulating film, base region, emitter regions, and
under the emitter electrode.
The examiner relies on the Japanese document, specifically
Figure 2, for a teaching of a barrier metal layer 21 of
molybdenum silicide with a thickness of more than 60nm formed to
continuously contact an interlayer insulating film 12, base
region 2, emitter regions 3, and under an emitter electrode 20 of
aluminum. From this teaching, the examiner concludes that it
would have been obvious to modify Sakurai’s structure by forming
the emitter electrode 12 of aluminum and providing a barrier
metal layer having a thickness of more than 60 nm “so that the
emitter electrode of aluminum provides relatively low resistivity
and low cost, and the barrier metal layer continuously contacts
said interlayer insulating film, base region, and emitter regions
to eliminate silicon residue and prevent aluminum diffusion into
the silicon substrate” (answer-page 4).
The examiner recognized that this modified structure of
Sakurai still did not disclose a barrier metal layer formed of
titanium nitride, but, asserts the examiner, molybdenum silicide
and titanium nitride are “barrier materials known in the art and
routinely used to form barrier metal layer in semiconductor
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