| 摘要 |
A process is disclosed for preparing silicon wafers having a high quality, high lifetime surface layer and a bulk region characterized by a low lifetime and by a high density of precipitated oxygen gettering sites. A wafer having a relatively high concentration of interstitial oxygen is heated in a reducing ambient at a sufficiently high temperature and a sufficiently long time to cause a surface layer to be denuded of oxygen related defects and dislocations. The temperature is then ramped down to a lower temperature and the wafer is maintained at this lower temperature for a sufficient time to allow precipitation of oxygen within the bulk of the wafer.
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