Solid state electronics (III)

Zookeeper

When a small amount of impurity is added to a semiconductor, the semiconductor will show excellent properties, such as the ability to change silicon from an insulator to a semiconductor or even a conductor.

Doping theory applies to all semiconductor materials.

 

The donor impurity in silicon is the fifth element, and the outermost layer has 5 valence electrons, such as phosphorus and arsenic. Each donor yard is ionization with a free electron for conducting electricity, and itself becomes a charge with + q power, which is fixed in a certain position in the lattice and cannot be moved.

 

The primary impurity in silicon is the third element, and the outermost layer is one electron less than that in silicon. The most common recipient impurity is B. Because B has only three electrons in the outermost layer and There is one vacancy in the interaction bond, the adjacent electrons can easily fill this vacancy. In this case, another vacancy is formed, in this way, the space is moved in the lattice. An impurity atom receives an electron ionization and becomes a charge with a-Q power, which is fixed in a certain position in the lattice and cannot be moved.

 

In semiconductor doping, the hole concentration is no longer equal to the electron concentration. If n> P, it becomes n-type semiconductor. If n <p, It is P-type semiconductor.

In intrinsic semiconductors, the product of electrons and holes is a constant. This formula is true even for Doped Semiconductors in heat balance. (I think this formula is very important)

In N-type semiconductors, the concentration of free electrons can be considered to be equal to the concentration of the donor impurity;

In P-type semiconductors, the hole concentration can be considered to be equal to the concentration of the main impurity.

(BOTH conclusions have theoretical basis. We only need to remember the conclusions)

Appendix:

All these contents are based on textbooks.

Because textbooks have too many formulas, they are obscure. At the same time, we do not need to study it too deeply.

Therefore, I will write my understanding of books in the future.

Solid state electronics (III)