Migration into an underlying Si substrate, from CoSi2 layers which had been implanted with As and B ions, was studied by using a high-resolution carrier delineation technique. In the early stages of diffusion, the junction shape followed the silicide/silicon interface in the case of B. It was deeper near to the CoSi2 grain boundaries in the case of As. The differing behaviors were attributed to the differing diffusion mechanisms of As and B in the silicide layer. By using 2-step annealing, or a thin silicide diffusion source, a laterally uniform junction was also obtained with As-implanted CoSi2. The diffusion coefficients of As and B in Si could be measured by using this technique (figure 2). The activation energies for B and As diffusion were 3.8 and 4.05eV, respectively. It was found that the present diffusivity values were very similar to published data.

F.La Via, C.Spinella, E.Rimini: Semiconductor Science and Technology, 1995, 10[10], 1362-7