Open air deposition of SiO2 films by an atmospheric pressure line-shaped plasma

A line-shaped atmospheric pressure filamentary plasma is developed to carry out the open air deposition of silicon oxide films from N-2/hexamethyldisoxane (HMDSO) mixtures with/without adding oxygen. FT-IR, XPS, SEM, and ellipsometry were used to analyse the samples. It is found that the deposited films present mainly inorganic characteristics even without an oxygen admixture in the open air system. Smooth, continuous, and uniform films can be formed at relatively low monomer content. By increasing the monomer content for a fixed power density or oxygen in the input gases, the deposition rates increase and then show a plateau, suggesting that there exists saturation values for the deposition rates corresponding to the monomer and oxygen content. By the comparison of films deposited in the open air device and in a controlled nitrogen atmosphere in the same device, the important role of the oxygen in the open air reactor has been shown. This study exhibits a potential of open air deposition at atmospheric pressure to form SiO2 films for large-scale deposition.