The evolution of the facet-facet groove at grain boundaries in multi-crystalline Si during solidification was investigated by in situ observation of the melt/crystal interface. The grain boundaries changed their propagation direction without any new grain formation or grain boundaries interaction during crystal growth. We monitored the melt/crystal interface over time and carefully estimated the growth velocities on two facets. We found that the facet velocities are different in some of our experimental observations and the development of random grain boundary is strongly dependent on the facet velocities. On the basis of our experimental observations, we discussed the direction of random grain boundary during solidification by considering the growth velocities on two facets.

通过对熔体/晶体界面的原位观察，研究了凝固过程中多晶硅中晶界上小面-小面沟槽的演变。在晶体生长期间，晶界改变了它们的传播方向，而没有任何新的晶粒形成或晶界相互作用。我们随时间监控熔体/晶体界面，并仔细估计了两个方面的生长速度。我们发现，在我们的一些实验观察中，刻面速度是不同的，随机晶界的发展在很大程度上取决于刻面速度。根据我们的实验观察，我们通过考虑两个方面的生长速度，讨论了凝固过程中随机晶界的方向。