METHOD FOR PREPARING NITROGEN-DOPED AND ANNEALED WAFER AND NITROGEN-DOPED AND ANNEALED WAFER

摘要

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°C to 1350°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.