Reactive pulse magnetron sputtered SiOxNy coatings on polymers

Amorphous SiO2, Si3N4 and SiOxNy single layers have been deposited on silicon, glass and PETG substrates by reactive pulse magnetron sputtering. Apart from the expected correlation between refractive index, coating density and nitrogen content in the reactive gas mixture new results have been found about mechanical stress and humidity barrier property of these thin films. The lowest compressive stress was observed in the coatings deposited with nitrogen contents of around 29% to 50% in the reactive gas mixture. The humidity barrier effect of the thin films begins to increase significantly already at low nitrogen contents of below 20% in the reactive gas. Additional investigations regarding coating adhesion, environmental stability and hardness complement this work with the main focus to optimize these materials for optical multilayer systems on polymer substrates.