The depth profiles of bulk stacking fault radius formed under the annealed specimen surface of Czochralski silicon wafers have been obtained. It is clearly shown that the depth profiles have been well predicted by the theoretical result. The curve fitting gives the diffusion coefficient of the responsible point defects expressed byD=257 exp[−(2.84±0.66)eV/kT] in the temperature range between 1080 and 1270 °C. It is strongly suggested that vacancies, not self‐interstitials, dominate the growth of the bulk stacking faults.