The growth of solar silicon ingots by directional solidification using small random (chips) and large oriented (mono-chucks) seeds was carried out, and the defect formations using the ingots grown from the different seeds were compared. To have a similar growth environment, the seeds were placed side by side in the same crucible for the growth. It was observed that the silicon grown from small chips was more vulnerable to carbide precipitation, but the propagation of dislocation clusters was mitigated due to the existence of grain boundaries. On the other hand, the dislocation clusters could easily propagate in the mono-crystalline regime. As a result, as the ingot grew higher, more and larger dislocation clusters were found in the ingot from the large oriented seeds. Images from etched pits, photoluminescence, and minority lifetime were used for the comparison. Similar experiments were also carried in a commercial growth system, and the dislocation clusters in the growth from the small chip seeds were much less than that from the chuck seeds. (C) 2015 Elsevier B.V. All rights reserved.