FLOW PATTERN DEFECTS IN CZOCHRALSKI-GROWN SILICON-CRYSTALS

The radial distribution of grown-in microdefects in eight Czochralski- grown silicon crystals was measured by counting the how pattern (FP) d efects revealed by preferential etching. At the center of the crystal, the FP-defect density increased from 5.2 to 6.7 x 10(5) l/cm(3), when the pulling speed was increased from 0.8 to 1.1 mm/min. The magnitude of this effect was only about half as large, when the pulling speed w as increased from 1.1 to 1.3 mm/min. Annealing at 1200 degrees C for 2 h in argon ambient was found to decrease the FP-defect densities sign ificantly, but less than that in oxygen ambient.