Semiconductors Question Please provide detailed answers Than

Semiconductors Question! Please provide detailed answers! Thank you

There is a p^+ -n junction with some nominal n-doping. If the n dopants are reduced by half determine how each of the following will be affected. State if there will be an increase or decrease and explain your reasoning. a) Junction capacitance b) Built-in potential c) Breakdown voltage

Solution

Doping means adding impurities to thesemiconductor to improve its electrical conductivity. When we add large amount of impurities to the semiconductor, it will produces large number of free electrons in the n-type semiconductor and large number of holes in the p-type semiconductor.

The large number of free electrons in the n-type semiconductor repels from each other and try to move towards p-side. However, before entering into p-side, the free electrons meet positive ions at the depletion region. We know that positive ions are ready to accept extra electrons. When the positive ions accept the extra electrons, they become neutral atoms. In this manner large number of free electrons fills the holes in positive ions and makes them neutral.

If dopants reduced carriers reduced then depletion length increases

Then junction capacitance increases

Built in potential increases

Breakdown voltage decreases