Appeal No. 2001-2540
Application No. 09/240,395
comprises a layer 14 comprising silicon, a transition layer 16
disposed on the layer containing silicon, and a conductive layer
18 disposed on the transition layer 16.
As the examiner recognized, Lur fails to disclose that the
transition layer 16 is a “metal boride layer,” as required by
instant claims 1 and 14. The examiner turned to Thomas for a
teaching, at column 5, lines 39-44, of the patent, of using
either a metal nitride or a metal boride as a diffusion barrier
to silicon from an underlying junction.
The examiner then concluded that it would have been obvious,
within the meaning of 35 U.S.C. 103, to incorporate the metal
boride barrier layer of Thomas into the gate stack of Lur in
order to achieve “a highly stable gate stack” since the artisan
would have recognized “that the gate stack itself is simply a
conductive structure often used to interconnect other elements on
the integrated circuit” [answer-pages 4-5].
Appellants argue that neither Lur nor Thomas suggests the
use of a transition metal boride layer in a gate stack; that
Thomas teaches away from the claimed invention in that Thomas
avoids the formation of a barrier layer in a gate stack and that
this is not a mere oversight but, rather, explicitly contemplated
by Thomas by employing the barrier layer, e.g., 227 in direct
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