XPS and XRR studies on microstructures and interfaces of DLC films deposited by FCVA method

Diamond-like carbon (DLC) films have been deposited at room temperature using a filtered cathodic vacuum arc technique. The influence of the negative bias voltage applied to the substrate from 0 to −250 V on the sp3 hybridized carbon fraction is studied by Raman spectroscopy, which is also compared with the result obtained from X-ray photoelectron spectroscopy (XPS) for C 1s core peak. Based on the depth profiles for C 1s, Si 2p, and O 1s XPS peaks, the DLC film is modeled as a structure having three different layers, such as surface, bulk, and interface. In addition, the X-ray reflectivity is proposed as a method for estimating the density, surface roughness, and thickness of the layers constituting the DLC film. The estimated thickness of DLC film shows good agreement with the result obtained from the transmission electron microscope measurement.