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Abstract

A method of heat-treating a silicon wafer has the steps of: preparing a silicon wafer having an oxygen concentration of 1.2.times.10.sup.18 atoms/cm.sup.3 or less (old ASTM) without generating crystal originated particles(COP'S) and interstitial-type large dislocation(L/D); forming a polysilicon layer of 0.1 .mu.m to 1.6 .mu.m in thickness on a back of the silicon wafer by a chemical-vapor deposition at a temperature of 670.degree. C..+-.30.degree. C.; and heat-treating the silicon wafer having the polysilicon layer in an oxygen atmosphere at 1000.degree. C..+-.30.degree. C. for 2 to 5 hours and subsequently at 1130.degree. C..+-.30.degree. C. for 1 to 16 hours. In this method, the silicon wafer before the formation of the polysilicon layer thereon is the type of a wafer in which oxidation induced stacking faults(OSF's) manifest itself at a center of the wafer when the wafer is subjected to the heat-treatment. Accordingly, the resulting silicon wafer with a polysilicon layer is of OSF fee and COP free, even when the wafer is subjected to the conventional OSF-manifesting heat treatment. The wafer with the polysilicon layer exerts a uniform gettering effect between the peripheral edge and center of the silicon wafer as a result of a uniform oxygen precipitation occurred at the entire surface of the silicon wafer.

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