Polymerization of dual ion beam deposited CNx films with increasing N content

Carbon nitride (CNx) films with 0-22.8 at. % N were prepared using dual ion beam deposition With increasing N content in this range, more N-containing pyridinelike rings, and single, double, and triple bends between C and N w ere formed, resulting in polymerization of the film structure. Consequently , the films became more transparent in the infrared region, and the hardnes s dropped from 24.2 to 12 GPa. Furthermore, nanoscratch tests showed that l ess debris was produced along the scratch track on the film containing high N content, indicating that the film was less brittle following the polymer ization of the film structure. in addition, the minimum (critical) normal l oad for damaging the films dropped from 7.8 to 4 mN, reflecting that the ad hesion between the firms and substrates was weakened, thereby resulting in delamination of the films from the substrates. Finally, the room temperatur e electrical conductivity was found to be reduced by a factor of 100, consi stent with the more pronounced polymerlike nature of the films at high N co ntents. (C) 1999 American Vacuum Society: [S0734-2101(99)03902-0].