Synthesis and characterization of superhard Ti-Si-N films obtained in an inductively coupled plasma enhanced chemical vapor deposition (ICP-CVD) with magnetic confinement

Using a novel inductively coupled plasma enhanced chemical vapor deposition (ICP-CVD) with magnetic confinement system, Ti-Si-N films were prepared on single-crystal silicon wafer substrates by sputtering Ti and Si (5 at.%:1 at.%) alloyed target in argon/nitrogen plasma. High-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), X-ray diffractometer (XRD), field emission scanning electron microscope (FESEM), atomic force microscopy (AFM) and Nano Indenter XP tester were employed to characterize nanostructure and performances of the films. These films were essentially composed of TiN nanocrystallites embedded in an amorphous Si3N4 matrix with maximum hardness value of 44 GPa. Experimental results showed that the film hardness was mainly dependent on the TiN crystallite size and preferred orientation, which could be tailored by the adjustment of the N2/Ar ratio. When the N2/Ar ratio was 3, the film possessed the minimum TiN size of 10.5 nm and the maximum hardness of 44 GPa.