Appeal No. 1997-3444
Application 08/268,728
different way. The Examiner takes the position that operation
of a bipolar transistor in the avalanche region as shown in
the Handbook (pages 42 and 63-64) inherently meets the terms
of the claims because there are two stable states, one of
which is a stable point in the avalanche region called
latch-up (page 64), and which is caused by impact ionization
(page 65).
There is some evidence of record that RBC and classical
bipolar snapback having a latch-up condition represent the
same physical mechanism. See Hayden et al., A Comparison of
Base Current Reversal and Bipolar Snapback in Advanced n-p-n
Bipolar Transistors, IEEE Electron Device Letters, Vol. 12,
No. 8, August 1991, pp. 407-409 (Paper 11 in Exhibit 2 filed
with the Preliminary Amendment to predecessor Application
08/035,205, Paper No. 6); Ishimaru et al., A Reverse Base
Current under High Level Injection, IEDM, 1991, pp. 91-865 to
91-868, at 91-865 (right col. description of Figure 2: "A
snapback phenomenon was observed, which is caused by the
existence of the reverse base current.") (Paper 13 in
Exhibit 2 filed with the Preliminary Amendment to predecessor
Application 08/035,205, Paper No. 6).
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