Appeal No. 2005-0323 Page 10
Application No. 09/577,835
spacers extending to the height of the vertically extending
sidewalls of the gate stack, we would have found that Gardner
anticipated appellants claims.
Turning to Mogami, we find that from Mogami's teaching of
having spacers extend to a point above the top of the vertically
extending sidewalls of the gate stack, in order to prevent short
circuit between the silicide layer on the gate electrode and the
source/drain regions, that an artisan would have been motivated
to increase the height of the sidewall the difference, if any,
necessary to reach the top of the sidewall. We observe that in
Mogami, the spacer extends above the top of the vertically
extending sidewalls of the gate stack, and do not stop at the
top. However, from the “comprising” language of the claims, we
find no language in the claims that would preclude the spacers
from extending above the top of the sidewalls of the gate stack.
Turning back to Gardner, we recall that the spacers 114, 116
extend close to the top of the silicide layer. With this in
mind, we return to Mogami. Mogami discloses that as MOS devices
have scaled down to improve performance, the gate length of the
gate electrode has been shortened and the junction depth of the
source/drain diffusion regions has been shallowed, resulting in
decreased drain current. To suppress the decrease in drain
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