Structural, electrical, and mechanical properties of nc-TiC/a-SiC nanocomposite thin films

We have synthesized Ti-Si-C nanocomposite thin films by dc magnetron sputtering from a Ti3SiC2 compound target in an Ar discharge on Si(100), Al2O3(0001)- and Al substrates at temperatures from room temperature to 300 degrees C. Electron microscopy, x-ray diffraction, and x-ray photoelectron spectroscopy showed that the films consisted of nanocrystalline (nc-) TiC and amorphous (a-) SiC, with the possible presence of a small amount of noncarbidic C, The growth mode was columnar, yielding a nodular film-surface morphology. Mechanically, the films exhibited a remarkable ductile behavior. Their nanoindentation hardness and E-modulus values were 20 and 290 GPa, respectively, The electrical resistivity was 330 mu Omega cm for optimal Ar pressure (4 mTorr) and substrate temperature (300 degrees C). The resulting nc-TiC/a-SiC films performed well as electrical contact material. These films' electrical-contact resistance against Ag wits remarkably low, 6 mu Omega at a contact force of 800 N compared to 3.2 mu Omega for Ag against Ag. The chemical stability of the nc-TiC/a-SiC films was excellent, as shown by a Battelle flowing mixed corrosive-gas test, with no N, Cl, or S contaminants entering the bulk of the films. (c) 2005 American Vacuum Society.