Synthesis of the silicon and silicon oxide doped a-C:H films from hexamethyldisiloxane vapor by DC ion beam

In this research silicon and silicon oxide doped hydrogenated amorphous carbon films have been synthesized by direct ion beam deposition from hexamethyldisiloxane (HMDSO) vapor mixture with hydrogen (H2) or acetylene (C2H2) gas. Adherent and stable coatings of the thickness up to 0.8 μm were deposited onto the stainless steel and tooling steel. Presence of a few atomic percents of Si was enough to achieve stable coatings. In the HMDSO + C2H2 film silicon is found in the form of the SiC while in HMDSO + H2 film Si presents as silicon oxide (SiOx). Raman spectra of the deposited films were typical for diamond like carbon (DLC). Films deposited from mixture with hydrogen gas had higher optical transparency (E04 bandgap 3.1 vs. 1.6 eV for film deposited from mixture with acetylene gas) and lower refractive index (1.7 vs. 2.1 at 632.8 nm wavelength). However, more transparent SiOx doped DLC films had more disordered structure as well.