Synthesis of Ti–Al–Si–N nanocomposite films using liquid injection PECVD from alkoxide precursors

Abstract

A series of nitride films of the Ti–Al–Si system have been synthesized at about 750 °C using the liquid injection plasma-enhanced chemical vapor deposition technique from corresponding alkoxide precursors. The composition and structure of the films were characterized by X-ray photoelectron spectroscopy, X-ray diffraction, and scanning and transmission electron microscopy. Amorphous SiN x and crystalline AlN and TiN films were formed in their individual cases, while the SiN x -containing (Ti/Al)Si–N composite films showed a two-phase microstructure consisting of amorphous SiN x matrix and embedded TiN, AlN, or TiAlN nanocrystals. The Si-rich nanocomposite films demonstrated superior high-temperature oxidation resistance. After two hours of air exposure at 900 °C, no elemental segregation was observed in the nitride films and their structures remained basically unaffected. The fundamental mechanism is discussed in terms of the chemically high inertness of amorphous SiN x interfacial phase and thereby the high thermal stability of the composite nitride films with unique nanostructures.