From Quartz Sand to Electronic Grade Silicon
Silicon in the Universe and on Earth
Hydrogen and helium dominate the visible matter of the universe, the mass fraction of silicon is less than 0.1 %. This element mainly arises from the fusion of two oxygen nuclei (2 16O -> 28Si + 4 He) at temperatures > 109 K inside stars with more than eight solar masses.
Metallurgical-Grade Silicon Production
Quartz sand is reduced with carbon in an electric arc furnace at temperatures > 1900°C to metallurgical grade silicon (> 98 % pure). The major part of the world production (2008: approx. 6 million tons) is used for manufacturing alloys with aluminium and steel, and as raw material for polysiloxane production.
Purification of Silicon
The impurity concentration in metallurgical-grade silicon is many orders of magnitude too high for an application in photovoltaics and microelectronics, thus the silicon has to be purified.
The polycrystalline silicon formation is performed in the so-called Siemens-Process (fig. right): The purified trichlorosilane mixed in hydrogen is thermally decomposed on the surface of a heated (approx. 1100°C) silicon rod via
Our Technical Wafer Brochure
Our technical wafer brochure with information on the production and specification of silicon, quartz, fused silica and borosilicate glass wafers can be downloaded or ordered (for free) here.