Substrate bias effect on amorphous nitrogenated carbon films deposited by filtered arc deposition

Abstract

The effect of substrate bias and nitrogen incorporation on the structure and hardness properties of amorphous carbon (a-C) films is characterized in terms of its composition, sp3 bonding fraction, and Raman spectra. The films’ properties were analyzed using Raman spectroscopy, Auger electron spectroscopy (AES), and nanoindentation system (NIS). Experimental results indicate that a-C films were found to possess the highest hardness when deposited at a substrate bias ranging from −50 to −100 V. In addition, the hardness values do not correlate well with the Raman I(D)/I(G) ratio. The hardness of films increases with their sp3 bonds fraction. Furthermore, nitrogen content increases with increasing substrate bias on amorphous nitrogenated carbon (a-C:N) films, and influences the growth of small graphitic crystallines.