Q:

A silicon diode called to be 1mA device displays a forward voltage of 0.7 Volts at a 1mA current. Estimate the value of junction scaling constant I_s in the event that n is either can be 1 or 2 .What scaling constant would apply for a 1A diode of the similar manufacture that conducts 1A at 0.7Volts.

Solution:

                        As

                                                  i =I_se^v/nVT

            So

                                                I_s = ie^-v/nVT

                         In the 1mA diode:

                                     if n=1 : I_s = 10-3 e ^-700/25

                                                I_s = 6.9 x10¹⁶A

                                    If n =2: I_s =10^-3 e^-700/50

                                                 I_s = 8.3 x10^-10 A

The diode conducting 1A at 0.7Volts correspond to 1000mA in parallel along a net junction area 1000 times greater. Therefore I_s is also 1000 times greater.