An advanced model for dopant diffusion in polycrystalline silicon during rapid thermal annealing

We have investigated and modelled the diffusion of boron implanted into polycrystalline silicon. A one-dimensional two stream diffusion model adapted to the granular structure of polysilicon and to the effects of the strong-concentrations has been developed. This model includes dopant clustering in grains as well as in grain boundaries. The grains-growth and energy barrier height are coupled with the dopant diffusion coefficients and the process temperature based on thermodynamic concepts. The simulation well reproduces the experimental profiles when crystallisation and clustering are considered. The trapping-emission mechanism between grains and grain boundaries and segregation are the major effects during annealing process.