ELE533 Bipolar Devices

ELE533 Mid Term Question 3

Design a pn junction with a breakdown voltage of 20 Volts.

Specify doping levels.

Answer

Ec = [2q(Vbi + Vbd)Nd/e]^1/2

where e = the permitivity of silicon , e = 10^-12

Vbd = 20V > > Vbi

Nd = eEc²/2qVbd = 1.4x10¹⁶

Na > > Nd

Na = 5x10¹⁸