Process for the preparation of silicon wafers having a controlled distribution of oxygen precipitate nucleation centers
AssigneeMEMC Electronic Materials, Inc.
InventorRobert Falster
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Abstract
A process for the preparation of silicon wafers having a non-uniform distribution of oxygen precipitate nucleation centers. Silicon wafers having a controlled distribution of oxygen precipitate nucleation centers are prepared by heating the wafer in a manner to create a temperature gradient across the thickness of the wafer for a period of time. Upon a subsequent oxygen precipitation heat treatment, those regions of the wafer which were rapidly heated to a temperature in excess of about 900.degree. C. will form a denuded zone whereas those regions of the wafer which did not achieve a temperature in excess of about 900.degree. C. during the rapid heating will form oxygen precipitates.
Claims11
A process for the preparation of a silicon wafer having a non-uniform distribution of oxygen precipitate nucleation centers, the wafer having a front surface and a back surface, the process comprising heating the front surface of the silicon wafer to a temperature of at least about 950.degree. C. while maintaining the back surface of the silicon wafer at a temperature less than 900.degree. C. to create a temperature gradient across the thickness of the wafer.
Dependencies are inferred from the claim text.