Semiconductors and How They Work

Overview

Semiconductors are the central building block of all modern electronics. This article gives a brief overview about the basic principle that semiconductors work with and what the chemical elements are relied on most commonly nowadays. 

Article Highlights

  • Semiconductors can conduct current, but only partially.
  • There are 2 types of semiconductor impurities, the N-type and the P-type that are charged negatively and positively.
  • Silicon is the basis material for the impurities and hence current differences.

Semiconductors are a solid chemical element or compound, which can conduct electricity under some conditions. It can conduct current, but only partially. Its conductivity is in between that of an insulator, which has no conductivity, and a conductor, which has full capacity. Most semiconductors are crystals; an example would be silicon.

Silicon, just like Carbon and Germanium are common periodic table elements that are used for semiconductor. They have four electrons in their outer orbital, which form covalent bonds with their neighboring atoms and form a lattice formation. The crystalline form of carbon would be a diamond whilst Silicon crystalline form would be a silvery, metallic substance. Metals are commonly used as conductors due to their free electrons, where electricity can flow easily. On the other hand, silicon is not metallic, they form covalent bonds which disallows them to move, in fact, pure silicon is considered an insulator which only allows few electricity to flow. But, by adding impurities to it, it changes its behavior and allows electricity to flow, which is why it can be used as a semiconductor. Impurities such as phosphorous, arsenic, boron, or gallium, allows silicon to be a semiconductor.

There are 2 types of impurities, the N-type and the P-type. N-type. For the N-type, phosphorous and arsenic is added to silicon in copious amounts. It only takes a copious amount of impurity for free electrons to allow an electric current to flow through silicon. It is called the N-type due to the electrons having a negative charge. The P-type of the other hand uses boron or gallium. When added to silicon, they form holes in the lattice formation of silicon allowing a bond to occur. Since there is an absence of an electron, it creates the effect of a positive charge, thus called P-type. The positive holes in the P-type silicon get attracted to the negative terminal of the battery. These 2 types both create a good conductor, not a strong one but enough for electricity to flow within. When voltage is applied to either an N-type or a P-type semiconductor, current flows. The result is that the random electron and hole movement that is present in a semiconductor becomes organized in one direction, creating measurable electric current.

Most semiconductor chips and transistors are now created with silicon and that is why silicon is called the heart of any electronic device. Nowadays, children as young as two play with electronic devices. These devices include television, smart phones, computers, video games, etc. The electronics market has been growing rapidly, and increasing the number of competitors. The competition relies on the design and quality of each unique device. The manufacturers use semiconductors in these devices, which is why they are an important component. Without these, there would be no radios, no TV’s, no computers, no video games, and poor medical diagnostic equipment. The developments in semiconductor technology during the years have made electronic devices smaller, faster, and more reliable.

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