CONTROL OF OXYGEN CONCENTRATION IN HEAVILY ANTIMONY-DOPED CZOCHRALSKISI CRYSTALS BY AMBIENT ARGON PRESSURE

In Czochralski-grown (CZ) silicon single crystals, antimony (Sb) dopin g decreases the oxygen concentration by enhancing oxygen evaporation f rom the melt surface. In this study, Ar ambient pressures of around 10 0 Torr over the silicon melt were found to suppress evaporation of oxi de species. To clarify the effect of the growth chamber ambient pressu re on oxygen concentration in grown crystals, heavily Sb-doped CZ sili con crystals were grown under Ar pressures of 30, 60, and 100 Torr. In creasing the Ar pressure increases the oxygen and Sb concentrations at the melt surface. The oxygen concentration under an Ar pressure of 10 0 Torr was 1.2 times higher than that under 30 and 60 Torr when the so lidified fractions are 0.5 or larger. The oxygen evaporation rate is c ontrollable by gas phase transport of Sb2O at high Ar pressures.