| 摘要 |
PROBLEM TO BE SOLVED: To reduce the size of a void-like defect in a silicon single-crystal rod by doping it with nitrogen and to make the void-like defect in a silicon wafer disappear by subjecting it to hydrogen annealing treatment. SOLUTION: The pulling up speed of a silicon single-crystal rod 14 doped with nitrogen is represented as V (mm/min), and the average temperature- gradient that the silicon single-crystal rod 14 has in a pulling up direction and in a part ranging from the solid-liquid interface of a silicon melt 13 to an 10 mm upper position therefrom is represented as G ( deg.C/mm). The rod 14 is pulled up at such a pulling up speed V that V/G is 0.290-0.340 mm2/min. deg.C. Succeedingly, the silicon single-crystal rod 14 is cooled as it is pulled up. At this time, the rod 14 is cooled from 1,130 deg.C to 1,050 deg.C for 10-30 min. Thereafter, a silicon wafer is made by slicing the silicon single-crystal rod 14 and then the silicon wafer is subjected to hydrogen annealing treatment.
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