What is meant by ZENER and AVALANCHE breakdown>How are they different from each other. Based on KTU Engineerin(Basic ELECTRONiCS engineering).Umay get the video explanation in the link below
https://youtu.be/VzGs0WEZbW4
3. AVALANCHE BREAKDOWN
When the Reverse voltage increases, Velocity of the carriers increases
which leads to higher kinetic energy of the carriers .
These carriers moving with high kinetic energy collide with other atoms to
break their covalent bonds thus generating more carriers .
This cumulative effect therefore results in multiplication of carriers called
Avalanche multiplication.
The process thus creates a large number of carriers & thus a large amount
of current which eventually leads to break down of the diode.This is called
Avalanche breakdown .
It happens at about 6V or more reverse voltage
4.
5. Avalanche breakdown
Impact ionisation
Multiplication of carriers
For Lightly/Moderately
doped diodes
Occurs for Higher
voltages(6V)
6. ZENER BREAKDOWN
ZENER Breakdown occurs in heavily doped junctions(high impurity).
With high reverse voltage Electric field at the junction increases .
This High electric field is strong enough to break the covalent bonds of
the other atoms
This results in breaking up of more covalent bonds resulting in higher
number of charge carriers & eventually a large amount of current leading
to breakdown
7. Difference between Zener and Avalanche breakdown
ZENER BREAKDOWN
Heavily doped diodes
Occurs at a voltage in the range of 4V to 6V.
Field Ionisation
High electric field results in breaking up of covalent bonds
resulting in many free carriers.
Zener diodes exhibit negative temperature coefficient
(Breakdown voltage decreases with temperature)
AVALANCHE BREAKDOWN
Lightly/moderately doped diodes
Occurs at a high voltage -6V or more.
Impact Ionisation
High reverse voltage leads to avalanche
multiplication resulting in many free carriers.
Avalanche diodes exhibit positive
temperature coefficient (Breakdown voltage
increases with temperature)
8.
9. Comparison PN Junction Diode Zener Diode
Definition
Symbol
It is a semiconductor diode which
conducts only in one direction, i.e., in
forward direction.
The diode which allows the current to
flow in both the direction i.e., forward
and reverse, such type of diode is
known as the Zener diode.
VI Characteristics
Reverse Current Effect Damage the junction. Do not damage the junction.
Doping Level Low/Moderate doping Heavy doping
Breakdown Occurs in higher voltage. Occur in lower voltage.
Ohms Law Obey Do not obey.