| 摘要 |
PROBLEM TO BE SOLVED: To produce an epitaxial wafer having a certain level gettering capacity regardless of the position of an ingot. SOLUTION: This production method for the epitaxial wafer comprises subjecting a silicon wafer sliced from a single crystal ingot grown by doping with not less than 1×10<13> atoms/cm<3> of nitrogen to a heat treatment at a temperature of not lower than 700 deg.C but lower than 900 deg.C for 15 min. to 4 hrs. and then to an epitaxial growth treatment on a wafer surface. In this case, it is preferable to regulate an oxygen concentration in the silicon wafer to 11×10<17> atoms/cm<3> or more, and to carry out the above heat treatment in the atmosphere of a mixture of oxygen and inert gas prior to the step of mirror polishing of wafers. Further, in the growth of the single crystal ingot, it is desirable to slow a pulling rate in starting tail formation as compared with that of the body, or to control a cooling rate from 1,050 deg.C to 700 deg.C to 2.5 deg.C/min or lower in the body region to 200 mm above the boundary of the body and tail of the single crystal ingot.
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