Concept of Doping

Semiconductors are the type of materials that are highly important for optical activity. Because of the semiconductors, the silicon industry can thrive and work efficiently. Doping is synonymous with semiconductors as some impurities are added to them to increase their efficiency and output. There are two types of semiconductors present. One is n-type, and the other is p-type. The n-type and the p types of semiconductors are named as per the impurity type added to it.

Understanding the semiconductors and their usage

A semiconductor is a material made up of silicon that conducts more electricity than an insulator, such as a glass slab and less than a pure conductor, for example, a copper slab.

The properties and the conductivity of a semiconductor can be altered by a phenomenon known as Doping, in which impurities are added to enhance their conducting power.

Doping is highly needed because semiconductors are also used in electronic devices in which silicon-based products are used extensively. Also known as semis, these semiconductors are found in thousands of products such as computers, laptops, pen drives, microchips, smartphones, gaming gadgets, medical equipment, etc.

There are mainly two types of semiconductors:

N-type: N-type semiconductor is an extrinsic semiconductor doped with the excess amount of electron donors. Hence the name is N-type. In n-type semiconductors, the majority of the charge carriers are negatively charged electrons. As a result, the number of electrons is higher than the number of holes.

P-type: In p-type semiconductors, it is just the reverse. In p-type semiconductors, the electron acceptors are added. As a result, the number of holes is higher than the number of electrons present.

What is doping?

Doping is when impurities are added to the semiconductors to increase their efficiency.

A doped semiconductor is an intentionally doped semiconductor that is doped to increase its magnitude and efficiency by the addition of the impurities, its conductivity increases.

In the structure of the semiconductors, there are holes present in the crystal lattice that gets filled when an impurity is added to it. In the case of N-type semiconductors, the electron donors are added. As a result, the number of electron donors is higher than the number of holes. In the case of P-type semiconductors, Electron acceptors are added to and get settled in the crystal lattice.

As there are two types of semiconductors present, the doping for each type of semiconductor is different.

N – doping

In this type of doping, adding the element with an excess of electrons is done to a Silicon-based semiconductor. For example, an element like P or As is added to the Si. Since P or As has free electrons, they can behave like Si plus the extra electrons fill the holes. The addition of these extra electrons to the Si skeleton increases the overall conductivity of the semiconductors.

Here the impurity that is added is pentavalent. Therefore, the impurity that is added can sufficiently increase the metallic conductivity of the semiconductor.

As the number of dopant atoms is higher than the Si atoms, it can be concluded that the number of electron carriers is higher than the number of holes present in it.

The donor level created by the substitution of P or as just lies below the bottom of the conduction band. The thermal energy is sufficient to bring these electrons to the conduction band.

P-type doping

In p-type doping, the Si atom of the silicon skeleton is substituted by a neighbouring atom of an electron that possesses one less electron than Si. The example of such elements is for B or Al. Boron or Aluminum is added to substitute the Silicon. These dopant atoms create a “hole” around them and can jump from one site to another. The hopping of a hole in one direction leads to the jumping of an electron in the opposite direction. The process of conduction is dominantly governed by the doping atoms.

Conclusion

Semiconductors find their place in all the daily usage of the materials. Semiconductors are also called integrated circuits (ICs) or microchips because they are typically made up of silicon or germanium or other compounds such as gallium arsenide. In a doped semiconductor, small amounts of impurities are added to the Silicon-based Skeleton of the semiconductors, causing a large increase in the conductivity of the semiconductors.

Due to their role in the enhancement of electronic devices, semiconductors find their essential usage in our lives. No one can imagine life without electronic devices. That’s why doping is important in semiconductors for a better performance of the devices.