Hardness and structure of a-CNx films synthesized by chemical vapor deposition

Mechanically hard a-CNx films were synthesized using a combination of ion b ombardment and the chemical vapor deposition process using the dissociative excitation reaction of BrCN with Ar metastable atoms. Nanoindentation test s disclosed that the indentation hardness, Young's modulus and elastic reco very increased with increasing ion-accelerating voltage. Moreover, the degr ee of flow among clusters decreased in the ion-bombarded sample. The D (dis ordered)-band absorption on an infrared absorption spectrum was replaced by a C-N absorption assigned to the tertiary aromatic amine. These results su ggest that the internal and external structures of the carbon nitride clust er change from the two-dimensional order to the three-dimensional order of C-N. The structure of hard a-CNx is clearly distinguishable from nitrogen-c ontaining diamond-like carbon.