Impact of Rapid Thermal Oxidation at Ultrahigh-Temperatures on Oxygen Precipitation Behavior in Czochralski-Silicon Crystals

Abstract

The effect of ultrahigh temperature rapid thermal oxidation (RTO) on the behavior of oxygen precipitates in Czochralski silicon (Cz-Si) wafers was investigated using infrared (IR) tomography. Dense oxygen precipitate nuclei were formed in the bulk of the Cz-Si wafers when the treatment temperature was increased to 1350°C. Furthermore, when ultrahigh-temperature RTO was combined with cooling rates of over 50°C/s, the density of the oxygen precipitate along the radial direction exhibited significant uniformity. It is assumed that the tendency to form oxygen precipitates in Cz-Si wafers during RTO critically depends upon increasing the concentrations of vacancies that form under ultrahigh-temperature conditions and an oxygen atmosphere. Our results clearly indicate that highly dense oxygen precipitate nuclei can uniformly form along the radial direction of the Si wafer during rapid cooling after RTO at temperatures above 1350°C.