Gettering thresholds for transition metals by oxygen-related defects in silicon

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Abstract
This letter reports a qualitative study of the gettering of technologically important transition metal contaminants by a wide variety of distributions of oxygen precipitates and related defects in silicon. Various metals were diffused into specially prepared silicon wafers containing densities of oxygen precipitates ranging between 105 and 2×1010 cm−3. The precipitates were of a variety of sizes both with and without punched‐out dislocation networks and associated stacking faults. Following previous work and using the Haze Test to monitor gettering activity, a threshold in precipitate density has been determined for the complete gettering of Cu and Ni (about 1×105 and 3×106 cm−3, respectively). No influence of precipitate size (above an as yet to be determined minimum) or of the presence of punched‐out dislocations or stacking faults could be determined for these two metals, the fastest diffusing of the 3d group. Comments on the gettering of Fe are made.