Patent ID: 7326658

Claim:
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° C. to 1350° C. in an atmosphere of argon, hydrogen or a mixed gas thereof, a step of maintaining the wafer within a temperature region of from 700° C. to 900° C. for 60 minutes to 200 minutes is conducted to allow growth of oxygen precipitation nuclei 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, the step of maintaining the wafer within the temperature region of from 700° C. to 900° C. for 60 to 200 minutes being performed with a rate of increasing temperature of 3° C./min or less for the temperature region of from 700° C. to 900° C.