Laser-induced fluorescence of OH and SiO molecules during thermal chemical vapour deposition of SiO 2 from silane-oxygen mixtures

Abstract

During low-pressure chemical vapour deposition of SiO 2 from thermally activated mixtures of silane and oxygen, laser-induced fluorescence is observed from OH and SiO molecules. From these measurements the rotational and vibrational temperatures are derived. The continuous nature of the observed oxygen chemiluminescence might be explained by a high vibrational temperature, which is not in equilibrium with the rotational temperature. Oxygen molecules are probably excited in the gas-phase reaction step SiO+O+O 2→SiO 2+O 2 *.