The mechanism of so-called spiking was investigated by using high-resolution transmission electron microscopy and electron dispersive spectroscopy. It was found that the nitride was saturated with Al by annealing at 550C. It was noted that Si also diffused through the nitride and dissolved in the Al. Spikes formed at the Si substrate upon annealing at 550C. Electron dispersive spectroscopy revealed that the spike phase was Al3Ti which contained a considerable amount of Si. The results indicated that spiking through the nitride was due to the formation and growth of Al3Ti following Al saturation at the bottom of the nitride.

A Study of the Failure Mechanism of a Titanium Nitride Diffusion Barrier H.J.Lee, R.Sinclair, P.Li, B.Roberts: Journal of Applied Physics, 1999, 86[6], 3096-103