Chemical bonding, structure, and hardness of carbon nitride thin films

Carbon nitride films are deposited on Si(001) substrates by reactive d.c. m agnetron sputtering graphite in a pure N-2 discharge. The chemical bonding and structure of carbon nitride films were probed using Fourier transformat ion infrared (FTIR) and near edge X-ray absorption fine structure (NEXAFS), and the hardness was evaluated using nanoindentation experiments. The stru cture and hardness for the films are dependent on the substrate temperature (T-s). FTIR and NEXAFS spectra show that N atoms are bound to sp(1), sp(2) and sp(3) hybridized C atoms, and the intensity of pi* resonance for Cls N EXAFS spectra is the lowest for the film grown at T-s = 350 degrees C, havi ng a turbostratic-like structure, high hardness and stress. The correlation between the structure and hardness of carbon nitride films is discussed. ( C) 2000 Elsevier Science S.A. All rights reserved.