The diffusion of antimony atoms into silicon was performed under the following conditions: diffusion temperatures 1150° and 1050°C, surface concentrations of antimony atom , using antimony‐doped oxides as the diffusant source. The distribution of the diffusant in silicon deviated from the well‐known erfc curve when the diffusion was carried out for a longer time at the higher diffusion temperature and the higher surface concentration of antimony. In that case, the diffusion coefficient of antimony was determined by the Boltzmann‐Matano method. It showed a considerable dependence on the local concentration of antimony and was interpreted in terms of the generation of diffusion‐induced dislocations and the excess vacancies introduced from the surface during the diffusion.