Oxidation is a key step in which layers of glass (SiO2) are grown on the surface of silicon wafers. This is done by a chemical process where silicon wafers are heated in an environment of oxygen:
Si + O2 => SiO2
This takes place in temperatures between 850°C and 1200°C. Oxidation rate can be enhanced by adding water vapor.
(CLICK HERE to view a companion webpage showing ALL of the steps required to fabricate a microchip transistor).