Correlation between structural and mechanical properties of silicon doped DLC thin films

Silicon doped diamond like carbon (Si-DLC) thin films were deposited on SiO2/Si substrates with different H-2 flow rate. The deposited Si-DLC films were characterized by field emission scanning electron microscopy (FESEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and nanoindentation characterizations. The FESEM images reveal the smooth Si-DLC thin films at lower H-2 flow rate, however, increased surface roughness with increasing H-2 flow rate. The Raman spectroscopy of Si-DLC thin films confirmed carbon nanocluster decreasing from 60.4 to 49.3 nm with increasing of H-2 flow rates. The Raman signature at 796, 968 and 1530 cm(-1) correspond to transverse optic (TO), longitudinal optic (LO) and Si attachment to graphitic carbon respectively in the Si-DLC thin films. The maximum hardness and Young's modulus were 17.95 GPa and 186.65 GPa for 70 sccm and 90 sccm H-2 flow rate respectably. The XPS results reveal Si at.% decreased from 18.91 to 14.15 of the Si-DLC thin films within creased by H-2 flow rate.