The influence of the thickness of silicon- and oxygen-doped hydrogenized carbon films on their surface properties

Hydrogenized carbon films 0.5–7.0 $\mu$m thick doped with silicon (11.9 $\pm$ 0.4 at.%) and oxygen (1.7 $\pm$ 0.1 at.%) have been grown on VT-6 titanium and silicon substrates in an externally heated arc discharge plasma. The hardness, internal stresses, surface morphology, wettability, and surface potential of the films against their thickness have been studied. It has been found that as the film gets thicker, the allowable load on the material and its hardness grow. It has been shown that the films have low internal stresses (below 600 MPa) and the water contact angle is 75$^\circ$–80$^\circ$. It have turned out that an increase in film thickness raises the negative surface potential from 50 to 670 mV.