Appeal No. 1996-4050
Application No. 08/410,375
Note that, as here claimed, the “third
columnar regions” are not the P type substrate (the
P type substrate extends throughout the
semiconductor device, it is not in the form of
“columnar regions” only where the bipolar
transistors are. (Answer-page 5.)
The specification states:
The Bipolar column, shown at the left of Fig. 3,
of the cell contains two bipolar transistors. The
first bipolar transistor B1 has a surface collector
region B11, a base region B12 and an emitter region
B13 within the base region B12; the second bipolar
transistor B2 has a surface collector region B21, a
base region B22 and an emitter region B23 within the
base region B22. Both transistors have a buried
collector region which extends below the base
regions B12 and B22 respectively, as is common in
integrated circuit bipolar transistor structures.
The base region B22 of the second transistor B2 has
an extension, a lightly doped region B24, which can
act as a resistor. Finally the Bipolar column has a
heavily doped P-type tap region T5 which makes an
electrical connection to the lightly doped P-type
substrate. In this embodiment the bipolar
transistors are NPN-type. Thus the collector and
emitter regions are N-type, and the base and
resistive extension region B24 P-type. All of these
collector, base and emitter regions of the two
bipolar transistors are vertically aligned, together
with the region B24 and the tap region T5. (Page
11, line 29-page 12, line 12.) (Emphasis added.)
We agree with Appellants that the transistor structure
described supra is common in the art, and as such is presented
in an enabling manner. When T5 is used to reverse bias the
5
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