What is the dependence of reverse saturation current in a P-N diode on applied voltage and temperature?

Answer 1

In a PN junction diode, the reverse current is due to the diffusive flow of minority electrons from the p-side to the n-side and the minority holes from the n-side to the p-side. Hence IS, reverse saturation current depends on the diffusion coefficient of electrons and holes. The minority carriers are thermally generated so the reverse saturation current is almost unaffected by the reverse bias but is highly sensitive to temperature changes. so , as the temperature increases the density of minority charge carriers increases creating a slight increase in the amount of IC.

so, the inference is reverse current is directly proportional to temperature

In the reverse biased condition the PN diode is least dependent on voltage till certain limit called breakdown voltage, till that voltage the increase in V is not actually increasing the current it is just increasing the heat at the junction which in turn raises the temperature and so the minority charge carriers.

But if the voltage increases the breakdown voltage the pn junction is lost and all the holes and electrons will start acting like charge carriers , such avalanche of charge carriers increases the current sharply to several hundred times. This phenomena is called as zener or avalanche breakdown

so if applied voltage less than breakdown voltage

no significant change in reverse current(only due to minority charge carriers)

and if applied voltage greater than breakdown voltage

the pn junction break and current increases sharply (both due to minority and majority charge carriers)

Answer 2

1/T