Theoretical Model for Radiation Enhanced Diffusion and Redistribution of Impurities. Comparison with Experiments

The redistribution of boron in silicon through high temperature proton irradiation is described. It is interpreted with a two-species model, where the impurity can exist either as a slow or as a fast diffuser, the transformation between these two species being induced through interaction with radiation defects. The two species could be the substitutional and the interstitial boron. The influence of experimental parameters, especially impurity concentration, beam current, temperature is studied and interpreted by taking into account the formation of impurity—defect complexes and direct vacancy—interstitial recombination. The following thermodynamical parameters are proposed for interstitial boron: Em = 1.2 eV, Sm = 0.14 k, D0 = 4 × 10−3 cm2/s. The self interstitial—vacancy and boron—interstitial capture radius would then be 1.4a and 4a respectively.