Unhydrogenated diamond-like carbon films prepared by dc plasma chemical vapor deposition at room temperature

Unhydrogenated diamond-like carbon films were prepared at room temperature by a simple dc plasma chemical vapor deposition system with a low overall power consumption. A gaseous mixture of methane and argon (1:9) was used as a material gas with the intent of bombarding the growing film with Ar+ ions. The bombardment of the depositing species with Ar+ ions present in the plasma leads to (i) removal of hydrogen from the carbon atoms and (ii) a preferential resputtering of weakly bonded graphite precursors from the film surface giving rise to diamond-like properties of the films. The progressive thermal annealing of the films induces graphitization, and promotes growth of the crystallites at higher anneal temperatures (≥500 °C)