Synthesis and characterization of Ti-Si-C compounds for electrical contact applications

We present a growth study of Ti-Si-C thin films on Cu and Al substrates for contact resistance studies. The films were grown by magnetron sputtering from Ti₃SiC₂ compound targets at temperatures from 100 °C to 300 °C. The films consist of TiC_x nanocrystallites embedded in an amorphous SiC matrix. Mechanically, the Ti-Si-C films exhibit a nanoindentation hardness of 20 GPa and an elastic modulus of 290 GPa, reflecting a carbidic nature but with a remarkable ductile behavior. In electrical contact studies, the contact resistance of the Ti-Si-C films, deposited on Ni-plated Al washers at 300 °C, against Ag was comparable to that of Ag against Ag at high contact forces (6 μΩ, and 3.2 μΩ, respectively, at 800 N). At lower forces the difference is significant due to the formation of surface oxides. In a crossed cylinder setup, the contact resistance of Ti-Si-C films deposited on Ni-plated Cu cylinders is typically a factor 5 higher than that of Ag against Ag. Encouragingly, Ti-Si-C films deposited at 100 °C exhibited contact resistances less than double of that of films deposited at 300 °C. We conclude that, while significant work remains on process optimization and analysis, Ti-Si-C has high potential in general electrical contact applications.