Influence of back-diffusion of iron impurity on lifetime distribution near the seed-crystal interface in seed cast-grown monocrystalline silicon by numerical modeling

摘要

The distribution of minority carrier lifetime near the seed-crystal interface found in seed cast-grown monocrystalline silicon was clarified in this work. The distribution of lifetime first decreases and then increases from a seed to a crystal. Modeling of the temperature- and time-dependent iron diffusion and segregation during crystal growth showed a concentration distribution of an increase followed by a decrease from a seed to a crystal. The consistency between lifetime and iron distribution near the seed-crystal interface indicates that the back-diffusion of iron impurity from silicon melt into the seed at the duration stage before crystal growth is one of the main reasons for lifetime variation near the seed-crystal interface. Therefore, it is essential to reduce the duration time before crystal growth to obtain good-quality monocrystalline silicon.