| 摘要 |
PROBLEM TO BE SOLVED: To provide a nitrogen doped annealed wafer which has a little variation in a BMD density after annealing, in silicon single crystal wafers which is sliced from various portions of a silicon single crystal without the influence of the doped nitrogen concentration, and to provide its manufacturing method. SOLUTION: Before applying a high temperature heat treatment at 1,100 to 1,350 deg.C in argon, hydrogen, or a mixing gas of these for a silicon wafer which is sliced from a nitrogen-doped silicon single crystal and polished at least, the wafer is held at a temperature less tan the said temperature in the high temperature heat treatment. Thereby, oxygen-separating nucleuses are grown up to the size that the nucleuses do not disappear at the said temperature in the high temperature heat treatment although the original oxygen-separating nucleuses disappear at the said temperature in the high temperature heat treatment, and then the said high temperature heat treatment is applied for the wafer.
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