Diamond like carbon (DLC) thin films: Preparation and Characterization

Diamond-like carbon (DLC) thin films are prepared using plasma enhanced chemicalvapour deposition (PECVD) process at different bias voltage. We have studied their microstructuraland electrical properties using Raman spectroscopy and current (I) – voltage (V) relationships.Electrical conductivity is gradually decreases with bias voltage as the films are becoming more andmore diamond like carbon as observed from Raman spectroscopy results. Raman spectroscopyresult shows that the ID/IG ratio gradually decreases indicating formation of more diamond likecarbon films that responsible for the decrease of conductivity of the films. The full width halfmaximum of G peak increase with increase the bias voltage indicating the ring-like sp2 transformsto sp2 chains and raises the amount of sp3-chains. The structural disorder arises from the bond angle and bond length distortions in amorphous carbon films. Thus the structural disorder and mechanical properties such as hardness and elastic modulus increase with bias voltage