SOLUTION

The voltage where the avalanche occurs is called the breakdown voltage.

Avalanche Breakdown

• When the reverse-bias voltage is increased, a greater amount of energy is provided to minority carriers (electrons in the P-type region and holes in the N-type region) and they diffuse across the junction.
• Due to the further increase in reverse-bias voltage, the minority carriers get a large amount of energy.
• When the minority carriers have a collision with silicon or germanium atoms within the crystal structure, the minority carriers obtain sufficient energy to break a covalent bond and generate additional carriers (electron-hole pairs).
• Subsequently, these additional carriers get energy from the applied external voltage and generate more carriers. Hence, the reverse current increases very rapidly.
• If this cumulative process of carrier generation continues, a large current flows through the junction in the reverse direction. This type of junction breakdown is called avalanche breakdown.
• This is also known as avalanche multiplication.