Microstructure and composition of TiC/a-C:H nanocomposite thin films deposited by a hybrid IPVD/PECVD process

Titanium containing amorphous carbon (TiC/a-C:H) films were deposited by a hybrid IPVD/PECVD (Ionized Physical Vapor Deposition/Plasma Enhanced Chemical Vapor Deposition) process combining titanium target magnetron sputtering and PECVD in an Ar–CH4 plasma. Films with various carbon contents have been deposited by variation of the composition of the Ar–CH4 plasma mixture. The films were characterized by XPS, EDX, XRD and TEM. The film characterization was focused on the effect of the argon ion bombardment on the surface composition measured by in situ XPS. This ion erosion allows enhancing the XPS signal coming from the TiC crystallites on the surface. The evolution of the microstructure as a function of carbon content in the films was studied. A transition from percolated TiC nanocrystallites with a preferential (111) crystalline orientation to isolated nanocrystallites TiC embedded in amorphous carbon was observed with an increasing carbon content in the films. This evolution was coupled with the variation of the electrical resistivity, measured by a four probe method.