The present invention provides a method for producing a nitrogen-doped
annealed wafer, wherein before a wafer sliced from a silicon single
crystal doped with at least nitrogen and polished is subjected to a high
temperature heat treatment at 1100.degree. C. to 1350.degree. C. in an
atmosphere of argon, hydrogen or a mixed gas thereof, a step of
maintaining the wafer at a temperature lower than the treatment
temperature of the high temperature heat treatment is conducted to allow
growth of oxygen precipitation nuclei having such a size that the nuclei
should be annihilated by the high temperature heat treatment to such a
size that the nuclei should not be annihilated by the high temperature
heat treatment, and then the high temperature heat treatment is
performed. Thus, there are provided a nitrogen-doped annealed wafer with
reducing variation of the BMD density after the annealing among silicon
single crystal wafers sliced from various positions of the silicon single
crystal without being affected by concentration of nitrogen doped in a
silicon single crystal and a method for producing the same.