Micro-tribo-mechanical properties of nanocrystalline TiN thin films for small scale device applications

Nanocrystalline titanium nitride (TiN) thin films were deposited on Si (100) substrates using reactive DC magnetron sputtering. Microstructure of the film was modified by adjusting the N2 flow rate during the deposition. At low flow rate, hexagonal-closed-packed (HCP)-Ti and α-Ti2N phases were formed. At higher N2 flow rate, the FCC-TiN single phase was formed predominantly. FCC-TiN film showed high hardness and elastic modulus due to covalently bonded TiN cubic phase and grain size refinement. In humid atmosphere, ultra-low friction coefficient ~0.025 with high wear resistance was measured in the film consisting of HCP-Ti and α-Ti2N phases while the hardness was 12.7 GPa.