Multiple choice

Compared to a p-n junction with NA=ND=1014/cm3, which one of the following statements is TRUE for a p-n junction with NA=ND=1020/cm3?

  1. Reverse breakdown voltage is lower and depletion capacitance is lower.

  2. Reverse breakdown voltage is higher and depletion capacitance is lower.

  3. Reverse breakdown voltage is lower and depletion capacitance is higher.

  4. Reverse breakdown voltage is higher and depletion capacitance is higher.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Reverse bias breakdown or Zener effect oauts in highly doped PN junction through tunneling mechanism. In a highly doped PN Junction, the conduction and valence beads on opposite tides of the junction are sufficiently doe. dogleg raven. bias that electron may tunnel directly from the valence hand on the p-side into the conduction bend on n-side.

Breakdown voltage $V_B \propto \dfrac{1}{N_AN_D}$

So, breakdown voltage decreases as concentration increases

Depletion capacitance $C = \left[ \dfrac{\epsilon_0 N_AN_D}{2(V_{be} + V_R) (N_A + N_D) } \right]^{8/x} $

Thus $C \propto N_AN_D$

Depletion capacitance increases as concentration increases

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