Porous ceramic substrates that repel Si melt have been developed, and spherical Si crystals have been easily grown using these substrates. Spherical Si crystals grown at cooling rates of less than 100 Kill consist of either single crystals or fewer than three grains. In each of the spherical Si crystals obtained in repeated growth experiments using the same substrate, the carbon and oxygen concentrations were consistently below the specification values for Si in solar cells. Degradation of the porous substrate was also examined to check whether it is possible to reuse the substrate. (C) 2014 Elsevier EN. All rights reserved