There are various processing techniques to grow or deposite silicon dioxide available.
PECVD deposited silicon dioxide in the ccp system is produced by the reaction between silane (5% silane in He) and N2O. In the HDP system the reactants are silane and O2.
LPCVD deposited silicon dioxide is a high deposition rate, low temperature process (compared to thermally grown oxides). Either silane or TEOS (Tetra EthOxy Silane or Tetra Ethyl OrthoSilicate) can be used as a precursor for SiO2.