Silicon is the most common metalloid. It is a chemical element, which has the symbol Si and atomic number 14. A tetravalent metalloid, silicon is less reactive than its chemical analog carbon. As the eighth most common element in the universe by mass, silicon very rarely occurs as the pure free element in nature, but is more widely distributed in dusts, planetoids and planets as various forms of silicon dioxide (silica) or silicates.
Amorphous silicon (a-Si or α-Si) is the non-crystalline allotropic form of silicon. It can be deposited in thin films at low temperatures onto a variety of substrates, which offers some unique capabilities in a variety of electronics.
Nanocrystalline silicon (nc-Si), sometimes also known as microcrystalline silicon (μc-Si), is a form of porous silicon . It is an allotropic form of silicon with paracrystalline structure—is similar to amorphous silicon (a-Si), in that it has an amorphous phase. Where they differ, however, is that nc-Si has small grains of crystalline silicon within the amorphous phase.
Silica gel is a granular, vitreous, highly porous form of silica and naturally formed from the silica plant. Silica gel is most commonly encountered in everyday life as beads packed in a vapor-permeable plastic. In this form, it is used as a desiccant to control local humidity in order to avoid spoilage or degradation of some goods. Because of poisonous dopants (see below) and their very high absorption of moisture, silica gel packets usually bear warnings for the user not to eat the contents.
Liquid crystal on silicon (LCOS or LCoS) is a "micro-projection" or "micro-display" technology typically applied in projection televisions. It is a reflective technology similar to DLP projectors; however, it uses liquid crystals instead of individual mirrors. By way of comparison, LCD projectors use transmissive LCD chips, allowing light to pass through the liquid crystal.
Silicone resins are a type of silicone material which is formed by branched, cage-like oligosiloxanes with the general formula of RnSiXmOy, where R is a non reactive substituent, usually Me or Ph, and X is a functional group H, OH, Cl or OR. These groups are further condensed in many applications, to give highly crosslinked, insoluble polysiloxane networks.
Nisil is an alloy of nickel and silicon. Typically, the alloy is mostly nickel alloyed with 4.4% silicon. Nisil melts at 1341 °C and has a density of 8.55 g/cm³. It is often used in conjunction with Nicrosil in type N thermocouples. In this use, it serves as the negative leg of the thermocouple.
Strained silicon is a layer of silicon in which the silicon atoms are stretched beyond their normal interatomic distance. This can be accomplished by putting the layer of silicon over a substrate of silicon germanium.
Silex, in modern usage, most frequently refers to a finely ground, nearly pure form of silica or silicate. The first known use occurs circa 1590 as a post-medieval/Early Modern Era term in Latin for (presumably) powdered or ground up "Flints" (i.e.
Silicon (Si) has numerous known isotopes, with mass numbers ranging from 22 to 44. Si (the most abundant isotope, at 92.23%), Si (4.67%), and Si (3.1%) are stable; Si is a radioactive isotope produced by cosmic ray spallation of argon. Its half-life has been determined to be approximately 170 years (0.21 MeV), and it decays by beta emission to P (which has a 14.28 day half-life) and then to S. The standard atomic mass is 28.0855(3) u
Silicothermic reactions are thermic chemical reactions using silicon as the reducing agent at high temperature (800-1400°C). The most prominent example is the Pidgeon process for reducing magnesium metal from ores. Other processes include the Bolzano process and the magnetherm process. All three are commercially used for magnesium production. The silicothermic process for magnesium production was developed commercially in Canada during the second World War.
Dissolved silica (DSi) is the form of water soluble silica as silicon hydroxide (equivalent to the old term silicic acid), which can be measured by standard analyses (e.g. Strickland and Parsons, 1972). However, The term dissolved silica is different from the silicate occurring as silicate minerals, which is a class of minerals forming rings, sheets, chains, and tetrahedrons. Likewise, the term dissolved silica is different from the term silicone, which is organic polymers of silicon.
In microfabrication, thermal oxidation is a way to produce a thin layer of oxide on the surface of a wafer (semiconductor). The technique forces an oxidizing agent to diffuse into the wafer at high temperature and react with it. The rate of oxide growth is often predicted by the Deal-Grove model. Thermal oxidation may be applied to different materials, but this article will only consider oxidation of silicon substrates to produce silicon dioxide.
The World Ocean Atlas (WOA) is a data product of the Ocean Climate Laboratory of the National Oceanographic Data Center. The WOA consists of a climatology of fields of in situ ocean properties for the World Ocean. It was first produced in 1994 (based on the earlier Climatological Atlas of the World Ocean), with later editions at roughly four year intervals in 1998, 2001 and 2005.
Nicrosil is a nickel alloy containing 14.4% chromium, 1.4% silicon, and 0.1% magnesium. Nicrosil is used as the positive leg of type N thermocouples. In this application, another nickel alloy, Nisil, is used as the negative leg.
Becancour Silicon is a Canadian company in Bécancour, Quebec which produces silicon for photovoltaics. It is a subsidiary of Timminco Ltd. , which is based in Toronto and is majority-owned by AMG Advanced Metallurgical Group N.V. of the Netherlands.
Black silicon is a semiconductor material, a surface modification of silicon with very low reflectivity and correspondingly high absorption of visible light. The modification was discovered in the 1980's as an unwanted side effect of reactive ion etching (RIE). Another method for forming a similar structure was developed in Eric Mazur's laboratory at Harvard University (1998).