Diamond like Carbon (DLC) Thin Films: Preparation and Characterization

Abstract

Diamond-like carbon (DLC) thin films are prepared using plasma enhanced chemical vapour deposition (PECVD) process at different bias voltage. We have studied their microstructural and 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 and more diamond like carbon as observed from Raman spectroscopy results. Raman spectroscopy result shows that the ID/IG ratio gradually decreases indicating formation of more diamond like carbon films that responsible for the decrease of conductivity of the films. The full width half maximum of G peak increase with increase the bias voltage indicating the ring-like sp2 transforms to 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.