Annealing of nonhydrogenated amorphous carbon films prepared by filtered cathodic arc deposition

The effect of postdeposition annealing to 600 degrees C in vacuum on the ha rdness, modulus, film stress, and sp(3) content of nonhydrogenated amorphou s carbon was studied. The films were deposited using a filtered cathodic ar c source and the film properties were varied by controlling the substrate b ias. In films with an initial sp(3) content of greater than 80% a significa nt decrease (from 10.5 GPa to less than 2 GPa) in the level of compressive stress was observed without deterioration of the mechanical properties. In films with an initial sp(3) content of 50%, the stress and hardness remaine d constant. Films with lower sp(3) content showed a significant increase in the level of stresses and only a marginal decrease in hardness. The evolut ion of stresses and hardness with annealing is discussed in light of a prop osed microstructure of these amorphous films. (C) 2000 American Institute o f Physics. [S0021-8979(00)03618-5].