Zener and Avalanche Breakdown: Zener and avalanche breakdown are two distinct mechanisms that contribute to the breakdown of a PN junction diode in an exter...
Zener and Avalanche Breakdown:
Zener and avalanche breakdown are two distinct mechanisms that contribute to the breakdown of a PN junction diode in an external circuit. These mechanisms play a crucial role in determining the breakdown voltage and current rating of a diode.
Zener Breakdown:
Zener breakdown is caused by an applied voltage exceeding the breakdown voltage.
When a reverse voltage is applied across the PN junction, the holes and electrons are separated, forming a depletion region.
As the reverse voltage increases, the depletion region grows, eventually reaching a point where it can conduct current.
This process results in the sudden increase in current and the subsequent breakdown of the diode.
An example of a Zener breakdown is when a high-voltage power supply is connected to a circuit containing a PN junction diode.
Avalanche Breakdown:
Avalanche breakdown is caused by the high-energy impact of high-energy electrons or holes on the PN junction.
When a reverse-biased PN junction is struck by an electron or hole, the energy of the impact ionizes an electron or hole, creating a large amount of free charge carriers.
This avalanche process quickly generates a large current, leading to a sudden breakdown of the diode.
Avalanche breakdown is often observed in semiconductors that are heavily doped or heavily strained.
These two breakdown mechanisms differ in their mechanisms and characteristics:
Zener breakdown is typically linear, while avalanche breakdown is often non-linear.
Zener breakdown is typically caused by a high-voltage pulse, while avalanche breakdown is caused by a reverse-biased pulse.
Avalanche breakdown is generally more efficient than Zener breakdown