Internal stress reduction by incorporation of silicon in diamond-like carbon films

Si-containing diamond-like carbon (DLC) films deposited using CH4+SiH4 by an electron beam excited plasma (EBEP) CVD system were investigated for internal stress, dynamic hardness and structural properties. As the SiH4 flow ratio was varied from 0 to 36.4%, the internal compressive stress linearly decreased from 2.5 to 1.0 GPa while the dynamic hardness remained nearly constant. From the correlations between the internal stress and the structural properties, it is suggested that SiH bonds formed by silicon incorporation can play the role of reducing the compressive stress. Also, the formation of SiH bonds is accompanied by a reduction in unbound hydrogen, which may cause the compressive stress reduction.