Appeal No. 96-4103
Application 08/363,479
Yokoyama or Ohshima recognized the dual functions of ballast
resistor and active emitter, the claimed two layers of Al Ga
x 1-
xAs are clearly suggested by Yokoyama’s layer of Al Ga As 0.5 0.5
modified with Ohshima’s graded layer of Al Ga As between the
x 1-x
emitter layer and the base layer.
The examiner’s analysis goes somewhat awry, however,
when she indicates that the graded layer has a value of x
ranging from 0 to 0.3. While this is true for the graded
layer of Ohshima, these values are dictated by the emitter
layer in Ohshima which is made of Al Ga As. In other words,
0.3 0.7
the mole fraction of aluminum at the boundary between the
graded layer and the emitter layer is selected to be the same
at the boundary. Therefore, if a graded layer were added to
Yokoyama’s transistor as proposed by the examiner, the graded
layer would range from a value of x=0.5 at the emitter layer
boundary to a value of x=0 at the base layer boundary.
Thus, if Yokoyama’s transistor is provided with a
graded layer as taught by Ohshima, the graded layer would have
an aluminum mole fraction which is greater that 0.4 near the
emitter layer but would be less than 0.4 near the base layer.
The recitation of claim 21 would be met by a portion of the
graded layer but would not be met by all of the graded layer.
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