Question

Phosphorus atoms are to be diffused into a silicon wafer. What is the purpose of this process?

1) To increase the conductivity of the silicon wafer
2) To decrease the conductivity of the silicon wafer
3) To create a barrier layer on the surface of the silicon wafer
4) To remove impurities from the silicon wafer

Answer 1

The diffusion of phosphorus atoms into a silicon wafer is done to increase its conductivity by creating an n-type semiconductor with excess electrons serving as charge carriers. Option 1 is correct.

Step-by-step explanation:

The purpose of diffusing phosphorus atoms into a silicon wafer is to increase its conductivity, which is essential in the manufacture of semiconductors. By incorporating atoms like phosphorus, which has one more valence electron than silicon, extra electrons are introduced into the crystal lattice.

This extra electron, being loosely bound to the phosphorus atom, is easily excited into the conduction band at room temperature, thus significantly increasing the semiconductor's conductivity. This process is called doping, and it results in the creation of an n-type semiconductor, where 'n' stands for negative due to the negatively charged electrons that serve as the primary charge carriers.

The purpose of diffusing phosphorus atoms into a silicon wafer is to increase the conductivity of the silicon wafer. When phosphorus atoms, which have one more valence electron than silicon atoms, are diffused into the silicon wafer, they introduce extra electrons into the conduction band, making it easier for current to flow through the material. This process is known as doping and it is commonly used in the production of semiconductors like silicon.