Arc evaporation processes are connected with the emission of small particles which are incorporated in the growing film on the substrate. SEM, AFM and optical microscopy indicate a size increase of such objects during film growth. Because of their cone-like shape we call them cone-like nodules. Using conventional measurement methods that can determine the structure, it is hard to explain the behaviour and properties of those nodules, as they do not provide clear information about their nature. Square resolved Raman measurements show a mixture of graphitic and diamond-like structures, that allows to conclude that the nodule consists of a graphitic particle originated at the cathode, covered by an amorphous carbon film. We propose a new model that describes the growth of cone-like nodules in the homogeneous carbon film very well. It is based on the dependence of the DLC film properties on the incidence angle of ions. The cone-like shape and the growth behaviour at perpendicular and grazed ion incidence was simulated using a simple computer program. A comparison of the simulated data and the SEM-images show a good qualitative and quantitative agreement.
- Diamond-like carbon
- Nodular growth