Apparatus and method for plasma enhanced chemical vapour deposition

The present invention relates to a process for simultaneous deposition onto two opposite sides of a sheetlike substrate using a plurality of linear plasma sources, comprising the steps: g) providing a reaction chamber comprising a gaseous atmosphere; and at least two linear plasma sources positioned in the chamber, h) introducing a sheetlike substrate comprising two elongate sides into the reaction chamber, and moving the substrate between the at least two linear plasma sources at a first velocity; i) supplying power to the linear plasma sources to generate linear plasmas in the vicinity of each side of the substrate; j) introducing at least one reactant mixture, at a first gas flow rate, into the reaction chamber on each of the respective opposite sides of the substrate, the composition of the mixture being such that, upon contact with the plasma, the reactant mixture decomposes and generates a chemical reactant species capable of being deposited as a film onto the corresponding side of the substrate; k) allowing the chemical reactant species to simultaneously be deposited onto the first and second opposite sides of the substrate at the same position with respect to the substrate movement direction; to obtain a substrate comprising a coated homogeneous film of desired thickness on the opposite sides of the substrate.