Methods for detecting the distribution of COP-free regions in silicon single crystals

Abstract

This invention provides a method for detecting the distribution of COP-free regions in silicon single crystals, relating to the field of silicon single crystal quality testing technology. The method includes: cleaning a silicon wafer to be tested to obtain a first silicon wafer; uniformly coating the surface of the first silicon wafer with a transition metal ion solution to obtain a second silicon wafer; placing the second silicon wafer in a high-temperature environment and performing heat treatment at three temperature gradients to obtain a third silicon wafer; wherein in a first stage, transition metal ions diffuse to the surface of the silicon wafer to activate oxygen precipitates in the Pv region; in a second stage, transition metal ions are promoted to diffuse into the interior of the silicon wafer to develop the low-oxygen Pi region; and in a third stage, high-temperature activation of atomic nuclei aggregation in the B-band region to form differentially spaced rings; cleaning the third silicon wafer with a mixed acid solution to obtain a fourth silicon wafer; placing the fourth silicon wafer in a selective etching solution for selective etching; and detecting the distribution of COP-free regions on the obtained test sample. This method can improve the clarity of the boundaries of each region, thereby improving the accuracy of COP-free region distribution detection.

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