In this study, we investigated the atmospheric plasma polymerization of allyl methacrylate (AMA), n-propyl methacrylate (nPMA), and propyl isobutyrate (PiB), whose chemistry mainly differs by their number of unsaturations. The resulting material is characterized using X-ray photoelectron spectroscopy (XPS) and infrared reflection absorption spectroscopy (IRRAS) while the thickness of the coatings is determined by visible spectroscopic ellipsometry (Vis-SE). The results show that the concentration of ester groups at the surface of the plasma polymers, as well as their deposition rate strongly depends on the surrounding unsaturations present in the precursor. A stabilization of the ester groups and an increase in the deposition rate due to the carbon-carbon double bonds is suggested.

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This work deals with the plasma‐deposition of allyl methacrylate (AMA) and acrylic acid (AA) on metallic substrates. The plasma setup used is an atmospheric pressure radio frequency (RF) torch. Infrared reflection absorption spectroscopy (IRRAS) and X‐ray photoelectron spectroscopy (XPS) are used as characterization tools. In addition, spectroscopic ellipsometry (SE) has been used to control the thickness and calculate the corresponding deposition rates. Whereas the surface chemistry of plasma deposited AMA does not seem to be influenced by the plasma power, acrylic acid based coatings are strongly degraded with the increasing power. AMA seems to allow an efficient polymerization, while at the same time is particularly resistant to plasma induced fragmentation in the range of power used.

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Silicon nitride thin films were deposited by reactive DC magnetron sputtering on different substrates in a home-made planar DC sputtering system. The sputtering was performed from a silicon target in a sputtering atmosphere of (Ar, H 2 , N 2 ) mixture. The gas composition could be varied from 0 to 100% for Ar and N 2 , and from 0 to 10% for H 2 . The structure and purity of the coatings have been investigated as a function of the process parameters, such as the composition of the sputtering atmosphere and the total pressure. The deposited films were characterised by optical interferometry (thickness measurement), Fourier transformed infrared spectroscopy (FTIR), X-ray diffraction (XRD) and XPS. The XPS spectra indicated that Si 3 N 4 was obtained for a molar fraction of nitrogen larger than 0.1, and also indicated that the sputtered silicon nitride films were uncontaminated with oxygen and carbon. The N/Si ratio of the nitride films could be tuned between 0.56 and 1.33 depending on the deposition conditions. The presence of the transverse optical (TO) and longitudinal optical (LO) phonons in infrared reflection absorption spectroscopy (IRRAS) attest for the presence of Si-N bonds. For the stoichiometric films no change in the LO phonon peak position was observed, indicating that there is no variation in the film composition.

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