Avalanche Avalanche breakdown

Avalanche breakdown

• We know that when the diode is reverse biased a small reverse saturation current I0 flows across the junction because of the minority cariers in the depletion region.

• The velocity of the minority charge carriers is directly proportional to the applied voltage. Hence when the reverse bias voltage is increased, the velocity of minority charge carriers will also increase and consequently their energy content will also increase.

• When these high energy charge carriers strikes the atom within the depletion region they cause other charge carriers to break away from their atoms and join the flow of current across the junction as shown above. The additional charge carriers generated in this way strikes other atoms and generate new carriers by making them to break away from their atoms.

• This cumulative process is referred to as avalanche multiplication which results in the flow of large reverse current and this breakdown of the diode is called avalanche breakdown.