Microstructure and property changes induced by substrate rotation in titanium/silicon dual-doped a-C:H films deposited by mid-frequency magnetron sputtering

Ti and Si dual-doped hydrogenated amorphous carbon (a-C:H) films were synthesized by mid-frequency (MF) magnetron sputtering with stationary and rotary substrates. The effects of substrate rotation on the microstructure, surface morphology, internal stress and mechanical properties were investigated. The results show that substrate rotation plays an important role in the growth of the a-C:H films. The film deposited on rotary substrate has a higher sp2 content with high degree of bond disorder and relatively low H content, thus resulting in much lower compressive stress and high hardness. The structural changes induced by the substrate rotation are discussed in terms of subplantation and migration roles of incident species in growth of the films. Moreover, the film deposited on rotary substrate shows smoother surface with small and dense particles, which is attributed to suppressing the shadowing effect by rotating substrate.