Method for heat treatment of silicon wafers

Abstract

A method is provided for the heat treatment of low oxygen concentration silicon wafers obtained from a silicon single crystal produced by the Czochralski process. The method comprises high-temperature oxidation heat treatment for the formation of a high oxygen concentration region under the wafer surface and the subsequent oxygen precipitation heat treatment. The high-temperature oxidation heat treatment can cause inward diffusion of oxygen from the wafer surface to form a region increased in oxygen concentration under the wafer surface, and the subsequent oxygen precipitation heat treatment can form a DZ layer on the wafer surface and stably form oxygen precipitates optimal in size within the wafer at a high density, so that excellent gettering effects can be produced. Further, in case of using as SOI substrates formed by SIMOX, too, the same effects as mentioned above can be produced by carrying out the high-temperature oxidation heat treatment after oxygen ion implantation in the SIMOX process and then carrying out the oxygen precipitation heat treatment.

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