RADIAL-DISTRIBUTION OF OXYGEN PRECIPITATES IN CZOCHRALSKI SILICON SINGLE-CRYSTALS

The effect of annealing conditions on the radial distribution of oxyge n precipitates in Czochralski (CZ) silicon crystals was examined throu gh two-step annealing. When the preannealing temperature was lower tha n 800-degrees-C, the oxygen precipitation depended on the initial oxyg en concentration, and precipitation near the periphery of the crystal was often suppressed. When the preannealing temperature was higher tha n 900-degrees-C, the oxygen precipitation was enhanced near the periph ery. This result indicates that extremely stable nuclei, whose density is low compared with the total amount of nuclei, exist near the perip hery of the CZ crystals.