Carbon based Si- and Cr-containing thin films: Chemical and nanomechanical properties

Si- and Cr-containing C films were deposited by magnetron sputtering combined with CVD onto silicon wafers. The composition and chemical structure were characterized by X-ray Photoelectron Spectroscopy (XPS) and nanomechanical properties by depth-sensing hardness and scratch techniques.The incorporated Si and Cr are preferentially bonded to carbon, in accordance with simplified thermodynamic calculations and as manifested by the XPS chemical shifts. At relatively high Cr- and low Si-content silicides (Cr_xSi) may also form as indicated by X-ray induced Auger electron spectroscopy. The chromium content in the C–Si–Cr films varied between 1 and 55 at% while the silicon content in the same films between 25 and 0 at%. For comparison two-component films of Si–C and Cr–C were also deposited with Si-content up to 42 at% and Cr-content up to 55 at% by varying the input power of the magnetrons.The nanohardness (H) and reduced modulus (E) were higher for all the films than that of the silicon substrate being 10 GPa, 127 GPa, respectively. Interestingly, the H and E of the three-component CrSiC films were almost invariant of the changes of the components' concentration within the indicated range and varied between 13–16 GPa and 120–140 GPa. H and E values for the two-component Cr–C films were much higher, reaching about 22 GPa and 170 GPa, respectively.