Appeal No. 2001-0776
Application 09/276,043
nitride layer less than the tunneling thickness of the silicon
nitride layer.
On page 4 of the brief, appellants also argue that even if
Ek teaches a silicon layer of 5 nm or less, this is not a
teaching or suggestion to provide such a layer in the combination
as claimed and for the purpose as claimed. We again refer to In
re Kemps, supra. We also find that Ek teaches the formation of a
silicon layer having a thickness of between 2 nm and 500 nm,
which encompasses the claimed value of “less than 5 nm”. See
column 3 lines 15-30 of Ek.
With regard to the use of a CVD method for depositing the
tungsten layer in Contreras, we agree with the examiner’s finding
that Mendonca teaches that the CVD method is a well known method
for depositing tungsten.
In view of the combination of teachings (which have been
properly combined as discussed, supra), we determine that it
would have been obvious to optimize the thickness of the silicon
layer of Contreras in view of Urquhart such that, upon nitriding,
the resultant silicon nitride layer has a thickness less than the
tunneling thickness such that a tunnel current can flow. We
especially make this determination in the absence of a showing of
unexpected results. We also determine that the use of the CVD
method to deposit tungsten is well known and therefore obvious.
In view of the above, we affirm the rejection.
II. The rejection of claims 11, 13 and 14
We consider claim 11 in this rejection.
Upon our review of the combination of Chow in view of
Mendonca, we note that Chow is directed to a silicon substrate 10
having formed thereon a gate oxide 19, and then a polysilicon
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