Correlation between structure and hardness of magnetron sputtering deposited CNx films

Carbon nitride films are deposited on Si(001) substrates by reactive de mag netron sputtering graphite in a pure N-2 discharge. The structure of carbon nitride films has been probed using Fourier transformation infrared, near edge X-ray absorption fine structure (NEXAFS) and high resolution electron microscopy (HREM), and the hardness has been evaluated in nanoindentation e xperiments. FTIR spectra show that N atoms are bound to sp(1), sp(2), and s p(3) hybridized C atoms. C1s NEXAFS spectra show that the intensity of pi* resonance is the lowest for the film grown at substrate temperature T-S = 3 50 degrees C, with a turbostratic-like structure and high hardness, while i t is the highest for the film grown at T-S = 100 degrees C, with an amorpho us structure and low hardness. The correlation between the structure and ha rdness of carbon nitride films has been discussed.