GRAIN-BOUNDARY DIFFUSION AND GROWTH OF TITANIUM SILICIDE LAYERS ON SILICON

A kinetics study of titanium silicide formation is described. The results show that a fine grained precursor layer exist in between the well developed C-54 silicide layer and the unreacted titanium film. This layer is a mixture of C49-TiSi2 and unreacted titanium. The fact that no C54-TiSi2 formed from the Ti-Si reaction suggests that the nucleation of C49-TiSi2 is easier than that of C54-TiSi2 under our annealing conditions. The silicide layer growth has a non-t1/2 dependence and is much better described by a grain boundary diffusion limited model giving different kinetics. This indicates that grain boundary diffusion is the major atomic transportation mechanism. The growth rate depends on both the grain boundary diffusion coefficient and the silicide grain growth rate.