Process for the production of undoped and fluorine-doped quartz glass

摘要

Quartz glass has hitherto usually been produced from silicon tetrachloride at very high temperatures by the CVD process. These glasses contain a high chlorine ion concentration and metallic impurities in the base material. Quartz glass produced by the novel process has a very low concentration of chlorine ions and metallic impurities and thus has lower attenuation in the UV region. The novel process operates at lower temperatures and does not allow any toxic compounds to be formed. The starting material used is high-purity silane (SiH4), from which the quartz glass is obtained by the OVD and VAD processes. Subsequent treatment in a chlorine gas/helium atmosphere reduces the OH content. Quartz glass for optics and fibres for wavelengths below 600 nm.