Appeal No. 96-4103
Application 08/363,479
the emitter layer. The examiner asserts that it would have
been
obvious to add Ohshima’s graded layer to Yokoyama’s transistor
to improve the cut-off frequency of the bipolar transistor
[answer, page 5].
Appellants argue that neither Yokoyama nor Ohshima
even remotely suggests the structure of a ballast resistor
layer and an active emitter layer as recited in claim 21. The
examiner responds that the ballast resistor layer is met by
Yokoyama’s layer 14 of Al Ga As, and the active emitter layer
0.5 0.5
is met by Ohshima’s graded layer (wherein x=0 to 0.3) when
added to Yokoyama’s transistor as discussed above [answer,
page 13].
Although neither Yokoyama nor Ohshima discloses that
an Al Ga As layer should operate as both a ballast resistor
x 1-x
and an active emitter layer, we note that claim 21 merely
recites two such Al Ga As layers with each layer having a
x 1-x
different range of the value of x. We also note that
appellants’ own disclosure basically indicates that the dual
functions of ballast resistor and active emitter result
entirely from the selection of a larger aluminum mole fraction
for the Al Ga As layer. Thus, regardless of whether either
x 1-x
10
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