Silicon dioxide (SiO2) is quartz glass and occurs naturally as quartz silica. This impure, non-crystalline silicon dioxide is contained in quartz sand and is used for the production of quartz and, after processing into high-purity, monocrystalline silicon, in chip manufacturing and in photovoltaics for the production of solar cells.
Silicon dioxide has a permittivity of 3.9 and a band gap of 8.9 electron volts( eV). The density of silicon dioxide is 2.3 g/cm3, and the refractive index is 1.46. The single- crystal silicon dioxide is used, among other things, in chip manufacturing in an extremely thin layer that lies on the silicon substrate of the wafer.