Hardening mechanisms in graphitic carbon nitride films grown with N-2/Ar ion assistance

Amorphous carbon nitride films have been grown by ion beam assisted deposit ion (IBAD) under different process conditions. The films were found to be g raphitic, with pi bonds between C and N atoms and a [N]/[C] ratio below 0.3 . There is a relationship between the contribution of electrons from C and N atoms to the pi bonds and the mechanical properties of the films. This is consistent with the arrangement of the basal planes, the softer films cons isting in the pileup of weakly; interacting graphitic planes and the harder films consisting in a superstructure of interconnected and corrugated basa l planes. Aiming toward the synthesis of nongraphitic hard phases, we have studied the bombardment with mixtures of nitrogen! argon ions to enhance mo mentum transfer in the collisions. The hardest films are obtained when usin g a single type of ions. The hardness is reduced in the case of the N-2/Ar mixture, indicating competitive mechanisms of cross-linking of basal planes .