The Effect of Temperature on Silicon Nucleation from Melt in Seed-assisted Growth — a Molecular Dynamics Study

Based on the Tersoff potential, we investigated the process of silicon nucleation and crystal growth from melt assisted by silicon carbide seed through molecular dynamics simulations. The results showed that, there is competition relationship between homogeneous and heterogeneous nucleation during silicon solidification growth process. At the low temperature of 0.70 Tm, nucleation mainly takes place in the form of homogeneous nucleation in a divergent nucleation mode, and gradually changes into heterogeneous nucleation as the temperature increases. When the temperature is above 0.78 Tm, the nucleation mode is dominated by heterologous nucleation in a spontaneous nucleation mode. There is a temperature range around 0.74 Tm, which homogeneous nuclei and heterogeneous nuclei exist simultaneously and the nucleation rates are comparable. This temperature range is also slightly affected by the seed of silicon carbide growth planes. We further calculated the variation of the nucleation rate with temperature through the classical nucleation theory in homogeneous and heterogeneous nucleation mode, respectively. The theoretical results are in agreement with the results of molecular dynamics. This work can provide theoretical guidance for the production of high efficiency multicrystalline silicon and cast monocrystalline silicon, which are the mainstream products in the market and two opposite aspects of the nucleation control.