Appeal 2007-0378
Application 10/212,895
additional precursors. That is, the limitation is fully met by forming the seed
layer and overlying paraelectric layer using a common precursor,
notwithstanding the use of additional precursors.
With this interpretation in mind, we turn to the prior art. As the
Examiner indicates, Norga’s PZT layer 35 comprises two sub-layers: (1) a
first PZT sub-layer adjacent to the bottom electrode 34, and (2) a second
PZT sub-layer on the first sub-layer. The first sub-layer has Ti concentration
higher than the second sub-layer (Norga, ¶ 0062).
We disagree with Appellants that the first sub-layer is not a seed layer
as claimed. First, we see no reason why the first sub-layer in Norga cannot
function as a seed layer, particularly since it is disposed adjacent to the
bottom electrode 34 – an arrangement commensurate with the seed layer
disclosed in the present application. See Fig. 2 of the present application
(showing seed layer 45 adjacent to electrode 44). Moreover, Appellants
have provided no evidence on this record establishing that the first sub-layer
is incapable of functioning as a seed layer.
Second, even if we assume, without deciding, that Norga provides a
seed layer in addition to the two sub-layers of PZT layer 35 as Appellants
seem to suggest, such an additional seed layer is not required. Rather, an
additional seed layer is merely recommended for certain PZT layers with
Zr/Zr+Ti concentrations greater than 0.2 to improve crystallinity of the
formed layers (Norga, ¶ 0063). In our view, the first sub-layer in Norga
reasonably constitutes a seed layer as claimed giving the term its broadest
reasonable interpretation.
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