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, crystalline silicon, in chip manufacture, in photovoltaics
for theproduction of solar cells
. Silicon dioxide has a permittivity of 3.9 and a band gap of 8.9 electron volts (eV). The material is used, among other things, in chip manufacture in an extremely thin layer that lies on the silicon substrate of the wafer.