Diamond-like carbon (DLC) coatings were successfully produced on the silicon wafer by a microwave plasma enhanced chemical vapor deposition (MPECVD) with the precursor gases of methane, hydrogen and argon. High resolution transmission electron microscopy (HRTEM) was applied to analyze the nano-particles in the coating. Both diamond and silicon carbide (SiC) nano-clusters of sizes ranging from 2 to 5 nm were observed in the DLC films. The dispersion of nano-clusters of diamond and SiC improves the film quality in terms of crystallinity and hardness of the DLC coating significantly.