Silicon nitride and oxynitride films deposited from organosilicon plasmas: ToF-SIMS characterization with multivariate analysis

In this work bis(dimethylamino)dimethylsilane (BDMADMS) has been utilized as precursor for plasma enhanced chemical vapour deposition (PECVD) of silicon nitride-like and silicon oxynitride-like thin films. The effect of input power and O2/BDMADMS ratio on the film surface chemistry has been investigated by time-of-flight secondary ion mass spectrometry (ToF–SIMS) and principal component analysis (PCA). Changes in surface composition have been correlated to infrared (FT-IR) and X-ray photoelectron spectroscopy (XPS) analyses. The results show that the PCs profile obtained by increasing input power during the deposition is correlated to the transition from an organic to an inorganic silicon nitride-like coating while at high input power, if the oxygen concentration in the feed is increased, the following transition occurs: inorganic silicon nitride-like→oxynitride-like→oxide-like.