The mechanical and biocompatibility properties of DLC-Si films prepared by pulsed DC plasma activated chemical vapor deposition

• Published in: Diamond and related materials 2007-08, Vol.16 (8), p.1616-1622
• Main Authors: Bendavid, A., Martin, P.J., Comte, C., Preston, E.W., Haq, A.J., Magdon Ismail, F.S., Singh, R.K.
• Format: Article
• Language: English
• Subjects: Biocompatibility; Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Diamond-like carbon; Exact sciences and technology; Fullerenes and related materials; diamonds, graphite; Materials science; Mechanical and acoustical properties; Mechanical properties; Methods of deposition of films and coatings; film growth and epitaxy; Physical properties of thin films, nonelectronic; Physics; Plasma CVD; Specific materials; Structure and morphology; thickness; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology
• ISSN: 0925-9635; 1879-0062
• DOI: 10.1016/j.diamond.2007.02.006

Films of diamond-like carbon containing up to 22 at.% silicon (DLC-Si) were deposited on to silicon substrates by low-frequency pulsed DC plasma activated chemical vapor deposition (PACVD). The influence of silicon doping on deposition rate, composition, bonding structure, hardness, stress, surface roughness and biocompatibility was investigated and correlated with silicon content. A mixture of methane and tetramethylsilane (TMS) was used for the deposition of DLC-Si films at a pressure of 200 Pa. The deposition rate increased with increasing TMS flow. The addition of silicon into the DLC film leads to an increase of sp 3 bonding, as measured by Raman spectroscopy, and also resulted in lower stress and hardness values. The RMS surface roughness of the films was measured by atomic force microscopy and increased from 0.35 nm for DLC to 6.7 nm for DLC-Si (14 at.% Si) due to the surface etching by the H atoms. Biocompatibility tests were performed using MG-63 osteoblast-like cell cultures that were left to grow for 3 days and their proliferations were assessed by scanning electron microscopy. The results indicated a homogeneous and optimal tissue integration for both the DLC and the DLC-Si surfaces. This pulsed PACVD technique has been shown to produce biocompatible DLC and DLC-Si coating with potential for large area applications.