However, in nature, silicon exists in the form of compounds with oxygen, aluminum, and magnesium. Therefore, the silicon element must be extracted from these compounds and purified. Silicon used in semiconductors, such as for integrated circuits (ICs), requires an ultra-high purity level of "99.999999999%" (commonly referred to as "11 nines") in a single-crystal structure, which is achieved through various refinement processes after extraction.
A single-crystal structure is a configuration in which atoms are arranged in an orderly pattern in three-dimensional space. This orderly arrangement is known as a lattice. A single crystal consists of a continuously ordered lattice. The silicon lattice features a diamond cubic crystal structure with a repeating pattern of eight atoms. Each silicon atom forms bonds with four neighboring silicon atoms. Silicon is a very common element and is used as a raw material for semiconductors due to its stable structure.
The purification of silicon consumes a significant amount of electricity. In Japan, refined silicon ingots with a purity of at least 98% are imported from countries where electricity is relatively inexpensive, such as Australia, China, and Brazil.
The physical properties of silicon
Silicon is a brittle and hard crystalline solid with a bluish-grey metallic luster. Compared to neighboring elements on the periodic table, silicon is relatively inert. Its symbol is Si, with an atomic number of 14. Silicon has high melting and boiling points. Under standard conditions, silicon also forms extensive covalent structures, akin to other Group 14 elements on the periodic table.
The chemical properties of silicon
At room temperature, pure silicon acts as an insulator. Under standard temperature and pressure, silicon functions as a semiconductor. In its crystalline form at low temperatures, silicon is inert. Its electrical conductivity increases with rising temperature. Silicon readily reacts with oxygen and can react with air at temperatures above 900 degrees Celsius. Molten silicon becomes highly reactive and must be stored in inert refractory materials to prevent any chemical reactions.
In addition to being a crucial material for semiconductors, silicon has many other widespread applications:
l Silicon minerals are used as structural compounds，such as clay, silica sand, building mortar, plaster, and building stones.
l Silicon minerals are also employed in the production of concrete.
l Silicon dioxide is used to manufacture refractory bricks for furnace linings.
l It is utilized in the production of white ceramics like soda-lime glass and porcelain.
l Silicon dioxide is essential in making optical fibers, which are widely used in telecommunications and computer networks.
l It is used to produce fiberglass and glass wool, which are crucial for structural support and insulation.
l Silicon is used to manufacture mechanical seals and waterproof materials.
l Wax and high-temperature lubricants are made from silicon.
l For medical purposes, silicon is used in breast implants and contact lenses.
l Silicon is used to make high-temperature alloys.
l Silicon is essential for producing silicon wafers, which have extensive applications in the semiconductor industry.
l Silicon is also vital for human health; the density of human skin, nails, hair, and bones depends on the silicon content.
l Silicone resins are synthetic polymers produced from silicon.
l Solar cells, semiconductor detectors, transistors, and other semiconductor devices used in the computer industry are all made from silicon.
l Silicon is a crucial component of integrated circuits (ICs), which are fundamental to our electronic devices, such as computers and mobile phones.
l Free silicon is used in the cast aluminum and steel refining industries.
