The effect of thermal annealing on reactive radio-frequency magnetron-sputtered carbon nitride films

Carbon nitride (CN) thin films were deposited on Si(111) substrates by reactive radio-frequency magnetron sputtering. The effect of thermal annealing on the structural properties of the films has been studied by Fourier-transform infrared spectroscopy (FTIR) and x-ray photoelectron spectroscopy (XPS). Both FTIR and XPS results show that the amount of the CN phase decreases upon annealing and that it is eliminated by annealing at C. Increasing the annealing temperature leads to the formation of a more prominent peak corresponding to the tetrahedral CN bonds in the FTIR absorption spectra. XPS N 1s peaks indicate that the third component due to the CN bonding state is significantly weaker than the others, relatively speaking. These results reveal that annealing causes a substantial decrease in the number of weakly bound nitrogen and carbon dangling bonds. The C-N phase is stable with respect to thermal treatment at C.