Carbon-free SiOx films deposited from octamethylcyclotetrasiloxane (OMCTS) by an atmospheric pressure plasma jet (APPJ)

The deposition of carbon-free, silicon oxide (SiOx) films with a non-thermal, RF capillary jet at 27.12 MHz at normal pressure is demonstrated. The gas mixture for film deposition is constituted of argon, oxygen and small admixtures of octamethylcyclotetrasiloxane (Si4O4C8H24, 0.4 ppm). Surface analysis of the deposited films reveals their exceptionally low carbon content. The XPS atom percentage stays at 2% and less, which is near detection limit. The parametric study reported here focuses on the optimization of the deposition process with regard to the chemical and morphological surface properties of the coating by varying oxygen feed gas concentration (0-0.2%) and substrate temperature (10-50 A degrees C).