On the relationship between the structure and the barrier performance of plasma deposited silicon dioxide-like films

Silicon dioxide-like barrier films were deposited by plasma enhanced chemical vapor deposition from different siloxane and silane precursors. The variation of the precursor was investigated as a route to obtain silicon dioxide-like films with different structures, densities and hence barrier performances. Although the films were characterized by the same elemental composition, some differences in film density and porosity were evidenced from optical properties measurements and from the shift of the SiOSi infrared absorption band position. These differences were correlated with film microstructure and in turn with barrier performances. The results confirmed that films with high density and low porosity performed better as single inorganic barrier layers for food-packaging.