INFLUENCE OF PLASMA PRETREATMENT IN THE FORMATION OF DIAMOND-LIKE CARBON THIN FILMS
ABSTRACT Plasma-enhanced chemical vapor deposition has been used to synthesize diamond-like carbon (DLC) thin films. High purity argon and methane gases were used as precursors for the fabrication of the DLC films. The influence of plasma pretreatment on the growth of the DLC films has been studied by subjecting one of the substrates to plasma pretreatment prior to deposition of the DLC films, while maintaining the other substrate as the control. The structural properties of the DLC films have been characterized using atomic force microscopy and Raman spectroscopy. The film grown on the pretreated substrate shows a more uniform coating as compared to the film grown on non-pretreated silicon substrate. The results are discussed based on diffusivity of carbon on silicon and the effect of the plasma pretreatment.
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ABSTRACT: The diamond like carbon (DLC) films have been grown by radio frequency plasma enhanced chemical vapor deposition (RF-PECVD) in methane–argon plasma. In PECVD, the plasma sheath potential drop arising due to argon plasma was utilized to grow the DLC film on silicon (100) substrate at low temperature without using any external negative bias voltage. The growth process of the DLC film has been studied completely starting from nucleation to continuous film by atomic force microscopy. It was seen that the DLC film nucleates around surface defects on the substrate and that the film growth occurs by both adatom deposition and coalescence between nucleated islands. Raman spectrum confirms that the DLC film nucleates excessively in sp2 hybridized state and that during the growth process the fraction of sp3 CHx (x=1−3) increases which leads to the amorphous nature of the film. Long range uniformity of the film was identified using scanning electron microscope.Journal of Non-Crystalline Solids 04/2011; 357(7):1710-1715. · 1.72 Impact Factor