Plasma 2D modeling and diagnostics of DLC deposition on PET

The possibility to apply two dimensional (2D) emission spectra of short-lived excited species for estimating the uniformity of production of ions and radicals that have an important role in the deposition of diamond-like coatings on polymeric substrates was investigated. Images of the α-balmer line of atomic hydrogen in CH4/H2 discharges were recorded under various total gas pressures and substrate bias voltages to reveal that the increase of the total gas pressure enhances radial non-uniformities of the electron population with energy higher than 16 eV. A comparison between these images and the results of a 2D simulator of CH4/H2 discharges shows that the most abundant ions (H3+, CH5+) and radicals with high reactivity in the gas phase (CH2, CH, C) present similar axial and radial distribution with these emission maps.