Question

Zener breakdown occurs in a p-n junction having p and n both :

• A. lightly doped and have narrow depletion layer.
• B. lightly doped and have wide depletion layer.
• C. heavily doped and have narrow depletion layer.
• D. heavily doped and have wide depletion layer.

Hint:

Zener breakdown happens at low voltages ($< 6\text{V}$) due to tunneling, whereas Avalanche breakdown happens at high voltages due to collision-driven ionization.

Answer 1

The Correct Option is C

Step 1: Zener breakdown occurs due to high electric field intensity across the junction.
Step 2: Heavy doping increases the concentration of charge carriers, which results in a very narrow depletion layer.
Step 3: A narrow layer creates a massive electric field ($E = V/d$) even at low voltages, enabling electrons to tunnel through.