Amorphous C films of several thicknesses were prepared by graphite sputtering onto crystalline Si substrate. The samples were depth profiled with positron annihilation spectroscopy for open-volume measurements and characterized for their residual internal stress. It was found that after film growth the substrate presented vacancy-like defects decorated by O in a layer extending in the substrate by several tens of nanometers beyond the film/Si interface. The width of the defected layer and the decoration of vacancy-like defects were directly and inversely proportional to the measured intensity of the residual stress, respectively. These findings indicated the existence of a relaxation mechanism of the stress in the films that deeply involved the substrate. The decorated vacancy-like defects were suggested to be bounded to dislocations induced in the substrate by the stress relaxation.

Amorphous Carbon Film Growth on Si - Correlation between Stress and Generation of Defects into the Substrate. R.S.Brusa, C.Macchi, S.Mariazzi, G.P.Karwasz, N.Laidani, R.Bartali, M.Anderle: Applied Physics Letters, 2005, 86[22], 221906 (3pp)