| 摘要 |
PROBLEM TO BE SOLVED: To reduce time for an intrinsic gettering heating operation by performing an oxygen deposition nuclei growing operation in a gas atmosphere containing chlorine. SOLUTION: An oxygen deposition nucleus growing operation is performed in an atmosphere containing chlorine. Namely, with a batch heating furnace such as an oxidizing furnace, an external dispersion heating operation of an initial step is performed at a temperature such as 1100 deg.C or more, preferably 1100 to 1200 deg.C for about 2 to 5 hours, and the oxygen deposition nucleus growing treatment is performed at 500 to 700 deg.C for several hours to 50 hours. Next, a wafer, on which the external dispersion heating operation and the oxygen deposition nucleus growing operation have been carried out, is subjected to an oxygen deposition nucleus growing operation. Instead of a conventional gas atmosphere containing a substance such as nitrogen and argon, the operation is performed in an atmosphere containing chlorine. The atmosphere containing chlorine includes hydrogen chloride gas and silicon chloride gas. In the case of hydrogen chloride gas, the concentration is preferably 0.5 to 5% relative to hydrogen gas.
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