The mechanical and structural properties of Si doped diamond-like carbon prepared by reactive sputtering

초록

Silicon doped diamond-like carbon (Si-DLC) thin films were synthesized on silicon substrates using a reactive sputtering system. A plasma composed of the decomposition of a CH(4) and SiH(4) gas mixture and RF magnetron sputtering of a graphite target by Ar gas was used. The Si content in the films was controlled by adjusting the alpha-ratio (input fraction of SiH(4)) ranging from 0 to 15 at.%. The Raman spectra revealed that the G peak position shifted to a lower wavenumber and the I(D)/I(G) ratio decreased with increasing Si content, indicating that Si incorporation reduced the average size of sp(2)-bonded clusters and promoted sp(3) bond formation. It was found that the hardness increased and residual stress decreased as the Si content was increased. The changes of the structural and mechanical properties might be explained by the existence of 5 run beta-SiC crystallites embedded in an amorphous matrix.

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