How can I estimate depletion thickness of silicon from C/V measurement? I can calculate the doping density N, but the depletion thickness is a function of both inbuilt voltage and bias voltage. Any ideas?
In reverse biased condition, the effective bias on the junction is the sum of the applied voltage and the built-in potential (Va+Vbi). The depletion layer width in the lighter doped region of the junction will be approximately correspond to (Va+Vbi). You can also find Vbi from your C-V experiment. The intercept (obtained by linear extrapolation) on the voltage axis of the 1/C^2 ~ V plot should give you Vbi. So, you can find the depletion width due to the applied voltage.