Appeal 2007-0378
Application 10/212,895
Although Norga is silent regarding the specific precursors used to
form these respective PZT sub-layers, Roeder teaches depositing PZT layers
utilizing multiple vaporizers (vaporizers 18 and 20) that vaporize certain
liquid precursors that are directed to the corresponding vaporizer (Roeder,
col. 9, ll. 14-34; col. 9, l. 58 – col. 10, l. 49; Fig. 1).
In one embodiment, a seed layer 212 of PbTiO3 is first deposited
using only the vaporizer 18. That is, only the precursor vaporized by
vaporizer 18 is used. Next, a PbZrTiO3 layer 214 is formed on the seed
layer using both vaporizers 18 and 20 (i.e., the second vaporizer’s “run
valve” is opened to admit Zr precursor to the CVD reactor) (Roeder, col. 11,
ll. 24-47; Fig. 3).3 That is, the layer 214 is formed using both precursors
(i.e., precursors vaporized by both vaporizers 18 and 20). Since both layers
212 and 214 are formed using a common precursor (i.e., the precursor
vaporized by vaporizer 18), the layers are therefore formed using the same
precursor as claimed, notwithstanding the use of an additional Zr precursor
for layer 214. Moreover, we find this teaching reasonably combinable with
Norga’s deposition process of PZT layers in a capacitor. Such a system
would not only facilitate precisely applying the same precursor to multiple
layers as noted above, but would also facilitate precisely controlling the
application of multiple, incompatible precursors with separate vaporizers.
See, e.g., Roeder, col. 6, ll. 40-63.
3 Significantly, these same compositions are cited in the present application
as exemplary seed and ferroelectric layers. See Specification 5:5-10 (noting
that the composite ferroelectric layers 36, 46 are reactive seed layers
including, among other things, PbTiO3 disposed under PZT (PbZrxTi(1-x)O3).
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