Question

The CT for an abrupt PN junction diode is ________

(a) CT = K/(V0+VB)^1/2

(b) CT = K/(V0+VB)^-1/2

(c) CT = K/(V0+VB)^1/3

(d) CT = K/(V0+VB)^-1/3

I had been asked this question by my college professor while I was bunking the class.

This interesting question is from Diode Capacitances topic in portion Semiconductor-Diode Characteristics of Electronic Devices & Circuits

Answer 1

Right choice is (a) CT = K/(V0+VB)^1/2

The explanation: For an abrupt PN junction diode, CT = K/(V0+VB)^n. Here,  n=1/2 for abrupt PN junction diode and 1/3  for  linear PN junction diode. When the doping concentration of a diode varies within a small scale of area, then the diode is called as an abrupt diode.