Appeal No. 95-5148 Page 3
Application 08/121,794
reviewing the rejection as stated. In re Hoch, 428 F.2d 1341,
1342 n.3, 166 USPQ 406, 407 n.3 (CCPA 1970).
The admitted prior art teaches all of the essential claim
limitations in the claimed relationships except a barrier
layer "composed of a" high melting point metallic nitride
(claim 1, emphasis added) "with an amorphous structure"
(claim 5). According to the specification, "metallic nitrides
having high melting points assume amorphous structures"
(Paper 1 at 4:15-16), so the only remaining question is
whether Yamagishi teaches or suggests adding or substituting a
barrier layer composed of a metallic nitride having a high
melting point.
Yamagishi is directed to a Schottky junction (p. 3), not
an ohmic contact. Although the fields of endeavor are related
(metal/semiconductor junctions), they are distinct.4
Yamagishi notes that both silicides and nitrides have been
used to form gate electrodes for self-matching field-effect
transistors (FETs). (p. 3.) His refinement is to use two
nitrides--tungsten nitride (WN) and tantalum nitride (TaN)--as
a laminate to form the gate. (p. 4-5; Fig. 2(b).)
4 Wittmer indicates, however, that the barrier height
of Schottky junctions is "a very sensitive indicator of
interfacial changes" at the metal/semiconductor interface.
(p. 276.)
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