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. Growth of grains and energy barrier height are coupled with the dopant diffusion coefficients and the process temperature based on thermodynamic concepts. The adjustment of the simulated profiles with the experimental SIMS profiles for short treatment times ranging between 1 and 30 minutes at temperature of 700°C; allowed the validation of this model. Growth of grains and strong-concentrations phenomena are the major effects during annealing processes. They play a significant role for the precise determination of the diffusion profiles.
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