Sumco Corporation

Masahiko Mizuta

Shinya Fukushima

Provided is a method of measuring the Fe concentration in a p-type silicon wafer by the SPV method, by which the detection limit for the Fe concentration can be lowered, and the measurement can be performed in a short time. The measurement by the SPV method is performed in a measurement mode in which irradiation with a plurality of lights having mutually different wavelengths is performed during the same period under conditions where (i) Time Between Readings is 35 ms or more and 120 ms or less and Time Constant is 20 ms or more, or Time Between Readings is 10 ms or more and less than 35 ms and Time Constant is 100 ms or more, and (ii) Number of Readings is 12 times or less.

Method of measuring Fe concentration in p-type silicon wafer

A target value of a pull-up speed of the single crystal is set in advance before starting pulling-up of the single crystal for every predetermined pull-up length, the pull-up speed moving average value is calculated from actual values of the pull-up speeds measured from a time point that pulling-up of a predetermined length of the single crystal has been started until the current time point, a corrected value of the pull-up speed target value at a current time point is calculated and the single crystal is pulled up on the basis of this corrected value. When &#x3b1; is a past pull-up length and &#x3b2; is a future pull-up length, a pull-up length (&#x3b1;+&#x3b2;) used for calculating the corrected value of the pull-up speed target value is changed with an actual value of the single crystal diameter.

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Tokyo, Japan

Masahiko Mizuta