Structural analysis of Si-containing diamond-like carbon

• Published in: Diamond and related materials 2006-04, Vol.15 (4), p.1004-1010
• Main Authors: Iseki, T., Mori, H., Hasegawa, H., Tachikawa, H., Nakanishi, K.
• Format: Article
• Language: English
• Subjects: Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Materials science; Mechanical and acoustical properties; Methods of deposition of films and coatings; film growth and epitaxy; NMR; Physical properties of thin films, nonelectronic; Physics; Silicon-containing DLC; Sp 2; Sp 3; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties)
• ISSN: 0925-9635; 1879-0062
• DOI: 10.1016/j.diamond.2005.12.020

We have investigated the structures of silicon-containing diamond-like carbon (DLC-Si) films with various silicon contents. The DLC-Si films were deposited on steel substrates at 773 K by direct current plasma-enhanced chemical vapour deposition (DC-PECVD). The Si content in the films was controlled in the range of 4–28 at.% by adjusting the ratio of methane (CH 4) and tetramethylsilane (Si(CH 3) 4) as the precursor gases. Several typical spectroscopic measurements provided the film information: elastic recoil detection analysis (ERDA), hydrogen content; electron probe microanalysis (EPMA), carbon and silicon content; Fourier transform infrared (FT-IR), chemical bonding; and Raman scattering, networking due to the sp 2 carbon (Csp 2). In addition, solid-state 13C nuclear magnetic resonance (NMR) measurements were able to quantify the two types of hybridized carbon atoms, Csp 2 and Csp 3. The cross-polarization technique provided more precise environments for the carbon atoms bonded to hydrogen atoms, suggesting that the environment of Csp 2 is quite different depending on the silicon content. The 29Si NMR measurement was also carried out to provide the circumstance of the four-coordinate Si atoms. In addition, the mechanical property of the films (hardness) was evaluated by the nanoindentation method in order to compare it with the film structure.