Chemical Composition of SiOx Films Deposited by an Atmospheric Pressure Plasma Jet (APPJ)

SiOx films are deposited with an APPJ (27 MHz) using Ar, O-2 and OMCTS [Si4O4(CH3)(8)]. An experimental study on the influence of the O-2 versus OMCTS concentration on the chemical composition of the films and their radial gradients over the static deposition profile is carried out by means of XPS and ATR-FTIR. The films are characterized by dominating SiO IR absorption and the absence of CH2 and CH3 bands, indicating the inorganic SiOx character. From the absorbance differences of the three SiO IR bands present in the spectra, the existence of different structural phases is derived. Over the examined parameter field, three different structural phases are distinguished. Their occurrence can be seen as a marker for the film quality and allows formulating optimal deposition conditions for defined structures of organosilicon films.