Growth of Ti-C nanocomposite films by reactive high power impulse magnetron sputtering under industrial conditions

Titanium carbide (TiC) films were deposited employing high power impulse magnetron sputtering (HiPIMS) and direct current magnetron sputtering (DCMS) in an Ar–C2H2 atmosphere of various compositions. Analysis of the structural, bonding and compositional characteristics revealed that the deposited films are either TiC and hydrogenated amorphous carbon (a-C:H) nanocomposites, nanocrystalline TiC, or Ti/TiC, depending on the C/Ti ratio. It was found that Ti-C films grown by HiPIMS show a C/Ti ratio of close to 1 for a wide C2H2 flow range (4–15 sccm), with free C ranging from 0 to 20%. Thus, films ranging from near stoichiometric single phase TiC to TiC/a-C:H nanocomposites can be synthesized. This was not the case for DCMS, where films grown using similar deposition rates as for HiPIMS formed larger fractions of amorphous C matrix, thus being nanocomposites in the same C2H2 (above 4 sccm) flow range. For a C/Ti ratio of 1 the resistivity is low (4–8 × 102 μΩ cm) for the HiPIMS films, and high (> 100 × 102 μΩ cm) for the DCMS films. The hardness also shows a big difference with 20–27 and 6–10 GPa for HiPIMS and DCMS grown films, respectively.