Appeal No. 96-1271
Application No. 08/190,388
determined by more than merely the use of a silicide. Rather,
the contact resistance is shown to be proportional to a
barrier height at an interface between the metal and the
silicon. As pointed out by appellant, at pages 4-5 of the
reply brief, since the value of the barrier height varies with
the type of material employed, “the contact resistance is not
necessarily reduced by using a silicide as alleged by the
Examiner.”
Moreover, as pointed out by appellant, at page 8 of the
reply brief, and as supported by the objective evidence
provided by Publication No. (4) attached to the principal
brief in Exhibit A, the “snowplow effect” of palladium or
platinum silicide appears to stop the movement of implanted
impurities (e.g., arsenic). Therefore, since palladium and
platinum silicide layers appear to prevent the diffusion of
implanted impurities into the metal silicide layer, the
impurity concentration at the interface region is not lowered.
Thus, unlike the result achieved by the instant claimed
invention, the artisan would not have expected the
concentration of the impurity region in Lechaton to drop after
7
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Last modified: November 3, 2007