zener breakdown and avalanche breakdown?

zener breakdown and avalanche breakdown?


1 Answers

Mukesh Sharma
askIITians Faculty 43 Points
9 years ago
Zener Breakdown
1.This occurs at junctions which being
heavily doped have narrow depletion
2. This breakdown voltage sets a
very strong electric field across
this narrow layer.
3. Here electric field is very strong
to rupture the covalent bonds
thereby generating electronhole
pairs. So even a small
increase in reverse voltage is
capable of producing large
number of current carriers. ie
why the junction has a very low
resistance. This leads to Zener
Avalanche breakdown
1. This occurs at junctions which
being lightly doped have wide
depletion layers.
2. Here electric field is not strong
enough to produce Zener
3. Her minority carriers collide
with semi conductor atoms in
the depletion region, which
breaks the covalent bonds and
electron-hole pairs are
generated. Newly generated
charge carriers are accelerated
by the electric field which
results in more collision and
generates avalanche of charge
carriers. This results in
avalanche breakdown.
Thanks & Regards
Mukesh Sharma
AskIITians Faculty

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