Plasma biasing to control the growth conditions of diamond-like carbon

• Published in: Surface & coatings technology 2007-01, Vol.201 (8), p.4628-4632
• Main Authors: Anders, André, Pasaja, Nitisak, Lim, Sunnie H.N., Petersen, Tim C., Keast, Vicki J.
• Format: Article
• Language: English
• Subjects: Cross-disciplinary physics: materials science; rheology; Diamond-like carbon films; Electron energy loss spectroscopy; Exact sciences and technology; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Other topics in materials science; Physics; Plasma bias; Substrate bias; Transmission electron microscopy
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2006.09.313

It is well known that the structure and properties of diamond-like carbon, and in particular the sp 3/sp 2 ratio, can be controlled by the energy of the condensing carbon ions or atoms. In many practical cases, the energy of ions arriving at the surface of the growing film is determined by the bias applied to the substrate. The bias causes a sheath to form between substrate and plasma in which the potential difference between plasma potential and surface potential drops. In this contribution, we demonstrate that the same results can be obtained with grounded substrates by shifting the plasma potential. This “plasma biasing” (as opposed to “substrate biasing”) is shown to work well with pulsed cathodic carbon arcs, resulting in tetrahedral amorphous carbon (ta-C) films that are comparable to the films obtained with the conventional substrate bias. To verify the plasma bias approach, ta-C films were deposited by both conventional and plasma bias and characterized by transmission electron microscopy (TEM) and electron energy loss spectrometry (EELS). Detailed data for comparison of these films are provided.