Characterization of titanium nitride films sputter deposited from a high-purity titanium nitride target

Abstract

Titanium nitride films (100–300 nm) were sputter deposited from a high-purity titanium nitride target (nominal purity 99.99%) in an experimental dc-magnetron system. The gold-colored target, 5 cm in diameter, had a density of 92% of the theoretical value. X-ray diffraction indicated that the target material matched the simulated stoichiometric TiN pattern, while the deposited films showed a shift in the crystallographic plane spacing of the (111) and (200) Bragg reflections. Rutherford backscattering spectrometry (RBS) performed on titanium nitride films which were deposited on amorphous carbon substrates indicated the presence of titanium, nitrogen, and oxygen as principal components of the films. No argon was detected in the films within the sensitivity of the RBS technique. Titanium to nitrogen atomic ratios in the films varied from 0.83 to 1.02 according to the RBS results. The binding energy measured by x-ray photoelectron spectrometry (XPS) indicated that Ti and N were present in compound form. The effect of substrate temperature deposition, dc bias, and nitrogen content in the sputtering gas were correlated to the stoichiometry and resistivity of the films. High rates of deposition (3.8 nm/s) on hot Si(100) substrates produced films with a resistivity as low as 40 μΩ cm. The performance of the TiN films as a diffusion barrier was evaluated in a Al/TiN/TiSi2/Si(100) layered structure.