Process for growing silicon crystals which allows for variability in the process conditions while suppressing the formation of agglomerated intrinsic point defects

摘要

A process for growing a single crystal silicon ingot having an axially symmetric region substantially free of agglomerated intrinsic point defects. The ingot is grown generally in accordance with the Czochralski method; however, the manner by which the ingot is cooled from the temperature of solidification to a temperature which is in excess of about 900° C. is controlled to allow for the diffusion of intrinsic point defects, such that agglomerated defects do not form in this axially symmetric region. Accordingly, the ratio v/G₀ is allowed to vary axially within this region, due to changes in v or G₀, between a minimum and maximum value by at least 5%.