Explain the difference between Zener breakdown and Avalanche breakdown?

Answer and Explanation:

Zener Breakdown:

The Zener breakdown occurs when high intensity electric field is developed across a very thin and narrow depletion region having higher numbers of free electrons as a result of application of reverse bias.

The increase in intensity of electric field results in increased kinetic energy of the charge carriers due to which these carriers start crossing the junction jumping from one region to another and collide with the semiconductor atoms to generate more electron-hole pairs resulting in reverse current which leads to Zener breakdown.

Avalanche Breakdown:

Avalanche breakdown occurs as a result of development of reverse saturation current across the junction.

When reverse bias is applied, electrical field across the junction intensifies due to which the velocity of minority carrier crossing the junction also increases. This results in the collision of atoms of the crystal with the charge carriers generating more electron-hole pairs.

The process continues until the electric field intensifies so much so that a reverse saturation current is set up across the p-n junction leading to Avalanche breakdown.