Different substrate materials effect on structure of ta-C films by Raman spectroscopy for magnetic recording sliders

Raman spectra, using visible (514 nm) and ultraviolet (244 nm) excitation, of tetrahedral amorphous carbon (ta-C) films of thickness of 5 nm have been studied as a function of different substrates materials. These materials are Fe–Co (Fe: 67 at.%, Co: 33 at.%) alloy, Fe–Ni alloy (Fe: 18 at.%, Ni: 82 at.%), Au and Al2O3–TiC (Al2O3: 64 at.%, TiC: 36 at.%), which are mainly used in magnetic recording sliders. The spectra show that the films deposited on Al2O3–TiC contain the highest sp3 content, with a lower sp3 content observed in films deposited to Fe–Co and Fe–Ni alloys. The lowest sp3 content was observed in films on the Au substrate. The results also indicate that the anti-wear performance of ta-C film on different substrates varies as Al2O3–TiC (the best) > Fe–Co and Fe–Ni alloy > Au (the worst). Also mechanisms are proposed to explain the effect of substrate material on these thin film properties.