Silicon

Position of silicon in the periodic table.

Silicon sample.

Silicon is a chemical element with the symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic luster, and is a metalloid. It is relatively unreactive.

Uses

Most silicon is used commercially without being separated, often with very little processing of the natural minerals. Such use includes industrial construction with clays, silica sand, and stone. Silicates are used in Portland cement for mortar and stucco, and mixed with silica sand and gravel to make concrete. They are also used in whiteware ceramics such as porcelain, and in traditional silicate-based soda-lime glass and many other specialty glasses.

Silicon compounds such as silicon carbide are used as abrasives and components of high-strength ceramics. Silicon is the basis of the widely used synthetic polymers called silicones. The small portion of very highly purified elemental silicon used in semiconductor electronics is essential to the transistors and integrated circuit chips used in most modern technology such as smartphones and other computers.

Electrical uses

Silicon is widely used in many electrical components and is fundamental to many circuits, both analog and digital, due to its semiconducting properties. To properly use these electrical properties, the silicon must be pure and in a monocrystalline form. To make use of its semiconducting behavior, silicon needs to be doped: with an acceptor element (usually boron or aluminum) to form P-type silicon or with a donor element (usually phosphorus or arsenic) to form N-type silicon Fusing the two types together creates different types of junctions. The simplest of these is the P-N junction, which forms a diode. A diode allows current to flow in only one direction and is used to rectify alternating current or to block it in one direction. Another important component is the transistor. One type can be made by sandwiching a P-doped slice of silicon between two N-doped layers (or the other way around), making an NPN or PNP transistor. Transistors are used to create electrical controls, analog devices, and digital circuits, as they act like switches. For example, current passes between a PNP transistor’s P-doped sides when current isn’t passing into the N-doped area. Note that silicon on its own is not conductive.

Dependencies

• Silicon
  • Ceramic
  • Clay
  • Glass
  • Stone
• Gravel
• Sand
  • Concrete

See also

• Arsenic
• Boron
• Chemical elements

References

This article uses material from the Wikipedia article Silicon, which is released under the Creative Commons Attribution-ShareAlike 3.0 Unported License (view authors).