Question
Question: Distinguish between Avalanche breakdown and Zener breakdown....
Distinguish between Avalanche breakdown and Zener breakdown.
Solution
Hint: In this question use the concept that although both the zener as well as avalanche breakdown occurs in the reverse biased region of a diode but avalanche breakdown occurs at more negative reverse biasing potential that is more towards left side of negative x-axis as compared to the zener breakdown. This will help approach the solution.
Complete step-by-step answer:
The difference between the Avalanche breakdown and Zener breakdown are as follows:
S.No | Avalanche breakdown | Zener breakdown |
---|---|---|
1 | It will occur in the diodes that are lightly doped. | It will occur in the diodes that are highly doped. |
2 | The VI characteristics of an Avalanche breakdown has not a very sharp curve. | The VI characteristics of a Zener breakdown has a very sharp curve. |
3 | The increase in temperature increases the breakdown voltage. | The increase in temperature decreases the breakdown voltage. |
4 | The process of applying the high voltage and increasing the free electrons or electric current in the semiconductor and insulating materials are called avalanche breakdown. | The process in which the electrons move through the barrier from the valence band of the p type material into the conduction band of the n type material is known as Zener breakdown. |
5 | Avalanche breakdown occurs because of the collision of free electrons with the atoms. | Zener breakdown occurs only because of the high electric field in reverse bias condition. |
6 | This is observed in Zener diodes having Zener breakdown voltage Vz greater than -8 volts. | This is observed in Zener diodes having Zener breakdown voltage Vz between -5 to -8 volts. |
So this is the required difference between the avalanche breakdown and Zener breakdown.
Note – Avalanche breakdown is a non-destructive and a reversible process, that means if we decrease the voltage down the current eventually decreases and crossing a certain point may cause a breakdown but however if we increase the potential again then increase in the current can be seen.