The passivating effect of plasma-enhanced chemical vapor deposited nitride was evaluated by using secondary ion mass spectrometry and atomic absorption spectrometry. From the results, it was deduced that a large amount of Cu diffused through the films during metallization heat treatments. This was attributed to rapid diffusion along micro-defects in the films. On the other hand, Cu contamination was hardly detectable in current-voltage data and bias-temperature stress results for Cu/SiN/SiO2/Si capacitors, because the leakage current through the SiN films increased slightly as a result of Cu diffusion. This was explained in terms of an electric-field relaxation which was caused by large numbers of electrons that were trapped in the SiN films. Their negative charge compensated the positive charge of the Cu ions.

H.Miyazaki, H.Kojima, K.Hinode: Journal of Applied Physics, 1997, 81[12], 7746-50