The interaction of (3-Aminopropyl)triethoxysilane (APTES) with pulsed late Ar-O 2 afterglow is characterized by the synthesis of OH, CO and CO 2 in the gas phase as main by-products. Other minor species like CH, CN and C 2 H are also produced. We suggest that OH radicals are produced in a first step by dehydrogenation of APTES after interaction with oxygen atoms. In a second step, the molecule is oxidized by any O 2 state, to form peroxides that transform into by-products, break thus the precursor CC bonds. If oxidation is limited, i.e. a low duty cycle, fragmentation of the precursor is limited and produced nanoparticles keep the backbone structure of the precursor, but contain amide groups produced from the amine groups initially available in APTES. At high duty cycle, silicon-containing fragments contain some carbon and react together and produce nanoparticles with a non-silica-like structure.

From results of in situ FTIR absorption and optical emission spectroscopy, the interaction of (3‐aminopropyl)triethoxysilane (APTES) with late ArN2 afterglow is shown to occur mainly with N atoms. They react preferentially with carbon from CHx groups in the precursor, leading to the synthesis of CN bonds. No production of NH radical is observed, demonstrating the lack of direct reaction between active nitrogen and APTES. The NH2 group is not affected by the afterglow. One of the CC bonds of the propylamine group in the APTES is likely broken. These nanoparticles present secondary amides due to reactions with active nitrogen. They are amorphous and react in air to produce a salt.

This article reports the use of pulsed remote Ar-O 2 microwave plasma assisted chemical vapor deposition with an −NH 2 containing organosilicon precursor ((3-Aminopropyl)triethoxysilane: APTES). It is shown that modifying the plasma pulses duration (ton) and the plasma off duration (toff) allows to finely tune the deposited layer composition. In addition, the results of this work demonstrate that an important film growth occurs during toff, which results in an increased −NH 2 density. Besides, high resolution MALDI-ORBITRAP Mass spectrometry analysis clearly points out that APTES oligomers up to eight base units, including silsesquioxanes (cages), and cyclosiloxanes (rings) molecules with intact−NH 2 groups are embedded into the as grown pp-APTES thin film.