Appeal No. 1997-2041
Application No. 08/337,131
ordinary skill in the art at the time of the invention by the
appellant, to modify the EPROM device taught by Mazzali by
using the state-of-the-art monocrystalline silicon material for
the substrate and by forming the source/drain regions prior to
forming the floating gate layer, as taught in column 2 of
Guterman and columns 3 and 4 of Woo. In our opinion, the
incentive for forming the source/drain regions prior to the
formation of the floating gate is explicitly taught in Guterman
which teaches that forming the source/drain regions prior to
the floating gate layer allows one to use the thick oxide that
covers the source/drain region as the mask, rather than relying
upon the polysilion layer as the mask to define the floating
gate members. The instructions in the paragraph bridging
columns 3 and 4 of Woo guide the artisan to the fact that the
order of formation of the floating gate with respect to the
formation of the source/drain does not change the resulting
structure and that the floating gate could be formed either
before or after the source/drain regions. We note that there
is no evidence presented by the appellant in the instant record
which indicates that the particular order of the steps produces
unexpected results or results differing in any way from those
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