Fabrication of a silicon oxide film by ozone and 1,1,1,3,3,3- hexamethyldisilazane (HMDS): Infrared Absorption analysis on a photochemical reaction in the gas phase

Fourier-Transformed Infrared absorption spectroscopy (FT-IR) was applied to analysis of initial photochemical reaction of ozone (O₃) and 1,1,1,3,3,3-hexamethyldisilazane (HMDS) at room temperature in the gas phase under the irradiation of an ultraviolet (UV) light, as the side reaction during the fabrication of a silicon oxide (SiO₂) film by photo-assisted chemical vapor deposition (CVD). FT-IR spectrum indicated the photodissociation of O₃ by the UV light, shown by the decreases in the intensity of peaks assigned to an O₃ molecule in the spectrum. Under the confirmation of this photodissociation of an O₃ molecule, while the UV light is known to induce no photochemical reaction of HMDS, FT-IR spectrum indicated the photochemical reaction of HMDS by its scission of Si-N-Si bond and formation of C = O bond and SiO₂ in a mixture of O₃ and HMDS gases, thus showing that direct reaction of photodissociated species from O₃, possibly atomic oxygen, with HMDS.