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Summary: Current gain in bipolar transistors with a field
plate over the base surface
V. Anantharam and K.N. Bhat
Indexing terms: Bipolar transistors, Analogue simulation, Carrier lifetime, Minority carriers.
Abstract: Vertical n-p-n and lateral p-n-p transistor structures of an integrated circuit are studied using an
electrolytic tank analogue and it is shown that the presence of a proper field plate extending from the
collector-base junction over most of the base surface will improve the current-gain factor considerably.
Experimental results of the analogue study, simulating typical carrier lifetimes and typical overall dimensions,
are presented with various geometrical dimensions as parameters.
1 Introduction
Recently, a 2-dimensional electrolytic tank analogue1
simu-
lating volume recombination in the base region of bipolar
transistors has been reported. The studies1
'2
have shown
that the current gain of transistors is limited by the excess
stored charge in the transverse region of the base and also
by the transverse diffusion of minority carriers into the base
contact. This simulation study has also been adopted for
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