Silicides and Nitrides Formation in Ti Films Coated on Si and Exposed to (Ar-N2-H2) Expanding Plasma

Abstract

Abstract:The physical properties including the mechanical, optical and electrical properties of Ti nitrides and silicides are very attractive for many applications such as protective coatings, barriers of diffusion, interconnects and so on. The simultaneous formation of nitrides and silicides in Ti films improves their electrical properties. Ti films coated on Si wafers are heated at various temperatures and processed in expanding microwave (Ar-N 2 -H 2 ) plasma for various treatment durations. The Ti-Si interface is the centre of Si diffusion into the Ti lattice and the formation of various Ti silicides, while the Ti surface is the centre of N diffusion into the Ti film and the formation of Ti nitrides. The growth of silicides and nitrides gives rise to two competing processes which are thermodynamically and kinetically controlled. The effect of thickness on the kinetics of the formation of silicides is identified. The metastable C 49 TiSi 2 phase is the main precursor of the stable C 54 TiSi 2 phase, which crystallizes at about 600 • C, while TiN crystallizes at about 800 • C.

Expanding Plasma Process for Nitriding Mo–Ti Bilayer Thin Films

“…A longer exposure time up to 3 h results in a decrease of both TiN and TiO 2 reflection line intensities ( Figure 4b). Hydrogen species as NH x radicals and/or H atoms produced in (Ar-N 2 -H 2 ) plasma have a reducing effect on oxide species, which form in the surface layers of metal films such as Ti [15]. However, as far as TiN is concerned, hydrogen species could also have an etching effect on TiN during the first stages of crystallization.…”

“…Raman spectroscopy measurements carried out on Mo-Ti bilayer films processed at 600 and 800 • C confirm the XRD results ( Figure 5). as low as 400 °C , before various titanium silicides are formed at higher temperatures [15], interdiffusions of Si and Mo occurred at the Mo-Si interface and MoSi2 crystallizes at substrate temperatures of 800 °C . TiO2 in rutile phase is detected in the film instead of anatase phase (Figure 4c).…”

“…The broad band located around 450 cm −1 could be a convolution of the vibrational modes of TiN at 464 cm −1 and TiO 2 at 446 cm −1 whereas the shoulder identified at the high wave number side of TiN band, located at about 550 cm −1 is due to the presence of TiO 2 . TiO 2 in the rutile phase usually shows the most intense E g and A 1g modes at 446 and 612 cm −1 [15].…”

Effects of the Prefabricated Cu-Ti Film on the Microstructure and Mechanical Properties of the Multiphase Coating by Thermo Plasma Nitriding on C17200 Cu Alloy

“…The good affinity between the O atoms and the active Fe atoms prompts the formation of Fe 3 O 4 (FeO·Fe 2 O 3 ), as illustrated by the XPS result in Figure 15. It was reported that the formation of iron oxide contributes to the improvement of the friction coefficient [25,26]. Nitrogen elements were not detected in the E and F regions for the modified F3 film, and the higher Cu content in the film layer indicates the existence of Cu-Ti intermetallics of higher Cu/Ti atomic ratios and the Cu grains, which are of lower hardness, so the WC ball penetrates into the substrate during the sliding test.…”

“…The good affinity between the O atoms and the active Fe atoms prompts the formation of Fe3O4 (FeO·Fe2O3), as illustrated by the XPS result in Figure 15. It was reported that the formation of iron oxide contributes to the improvement of the friction coefficient [25,26]. In addition, the high O content might result from the oxidation of Ti-N compounds, which also led to the decreasing amounts of Ti-N compounds [5], as well as the formation of the iron oxide (Fe 3 O 4 ) during the plasma nitrating process and the wear-test process.…”