Carbon nitride films deposited by reactive sputtering and pulsed laser ablation

Carbon nitride films were deposited by reactive sputtering process and by pulsed laser ablation process with substrate bias. By applying the RF bias, it enables the ion irradiation on to the depositing film surface continuously. ECR plasma source was used for reactive sputtering. Nd:YAG laser (λ=532 nm, 210 mJ) was used to ablate a graphite target in the nitrogen atmosphere. The film properties were examined by XPS, Raman, nanoindentation measurement, and FE-SEM. It was shown that the films deposited by reactive sputtering had smooth surface and its hardness of approximately 30 GPa. However, the films deposited by pulsed laser ablation had uneven surface and low hardness. Both processes, the atomic composition ratio of N/C and sp³ bonding ratio increased with ion bombardment energy up to 100-150 eV, and level off above it. The maximum atomic composition ratio of N/C was 0.35 for reactive sputtering and 0.24 for laser ablation.