Boron diffusion in silicon in the presence of other species

We model B diffusion in the category of equilibrium diffusivity in the presence of other species using ab initio calculations. The result shows that in the presence of other atoms X (X=F, N, C, Al, Ga, In, and Ge), the migration energy for B along the migration pathway is larger than the case if X=Si (0.33 eV). This suggests the reduction of B diffusion. If another B occupies that position (X=B), then a smaller migration energy is observed and enhanced diffusion is expected. The simulation results are consistent with experiments. The reason for the migration energy difference can be understood in terms of electronic and strain effects. Estimates of the enthalpy of bond formation agree with the simulation except for the low-enthalpy cases where the strain effect caused by atom-size misfit dominates.