Deposition of functional coatings on polyethylene terephthalate films by magnetronplasma-enhanced chemical vapour deposition

Magnetron-plasma enhanced chemical vapour deposition (PECVD) is a process tool which allows the deposition of plasma polymer coatings at process pressures below 1 Pa. The striking features of this technology are the relatively easy realisation of large area deposition as well as the possibility of the combination with sputtering processes for multilayer coating designs. SiOxCy coatings were deposited on polymer film in a roll-to-roll deposition machine. Dynamic deposition rates as high as 120 nm*m/min were achieved. The process was set up with both the monomer hexamethyldisiloxane and the monomer tetraethylorthosilicate (TEOS) and with mixtures thereof. The coatings were analysed by Fourier transform infrared spectroscopy. This method identifies the existence of different types of Si–O bonding in the layer. The results show how the layer properties are linked to the plasma parameters of the deposition process. The properties were compared to sputtered SiO2 and to layers obtained by other PECVD processes. Elastic recoil detection analysis (ERDA) was used in order to determine the composition of the samples. Both IR spectroscopy and ERDA revealed that the usage of TEOS provided more SiO2-like layers. The process was applied to the deposition of optical multilayer coating in a roll-to-roll coating system.