Fabrication of Transparent Protective Diamond-Like Carbon Films on Polymer

Si doped hydrogenated amorphous carbon (Si-DLC) films as a candidate protection coating for polycarbonate (PC) were prepared using a pulse-biased inductively coupled plasma chemical vapor deposition (ICP-CVD) system with a gas mixture of acetylene (C2H2) and tetramethylsilane [Si(CH3)(4)]. The effects of Si incorporation on the structure and optical properties of the Si-DLC films were investigated. In addition, plasma pretreatments with O-2, N-2, and Ar gases were carried out to enhance the adhesion strength of Si-DLC films on polycarbonate. Structural characterization through Raman and X-ray photoelectron spectroscopy (XPS) analyses showed that the incorporation of Si atoms in DLC films leads to an increase in the optical band gap (E-opt) with the formation of sp(3) C-Si bonds. O-2 plasma pretreatment improved the strength of adhesion of the Si-DLC films to polycarbonate, while Ar and N-2 plasma treatments did not. This can be explained by the formation of an activated dense interfacial layer by O-2 plasma pretreatment. (C) 2011 The Japan Society of Applied Physics