Silica nanofilms deposited by atmospheric pressure plasma liquid deposition

Silica coatings were deposited onto pure silicon surfaces by a deposition technique known as atmospheric pressure plasma liquid deposition using liquid tetraethylorthosilicate (TEOS) as a precursor. Deposition parameters were varied, including power, TEOS flow rate, helium flow rate, and substrate distance, in order to assess their influence on the growth rates and refractive index as well as the formation of surface particulates and organic content of the coatings. Growth rates were accurately controlled in the range of 0.5 nm s− 1 to 7.2 nm s− 1, with thin-films having refractive indices ranging from 1.1 to 1.4, indicative of layers with different levels of porosity. The results suggest that, with careful selection of deposition parameters, this (atmospheric pressure) plasma-based deposition technique could be used to achieve coherent, particulate free, smooth dense inorganic silica coatings.