
58 Semiconductors: Integrated Circuit Design for Manufacturability
[24], accidental forward biasing of a normally off diode can create a ood of
carriers, changing the bias state of other reverse-biased junctions between
V
cc
and V
ss
. As a result, latchup is a key electrical transient effect in the semi-
conductor substrate, depending on a combination of biasing conditions and
external sources of electron-hole pairs [25].
An IC coming out of a manufacturing line contains considerably more
devices than necessary for its function and reected in its schematic. These
extra devices (transistors, diodes, and capacitors), called the parasitics,
resu ...