Bulk Si production from Si-Fe melts under temperature gradients, part I: Growth and characterization

Silicon growth from Si-Fe melts was investigated in view of producing high-quality Si using induced temperature gradients. Scanning electron microscopy coupled with energy-dispersive spectroscopy and micro-computed tomography analyses were used to characterize the quality of bulk Si, in particular its microstructure and purity. The migration of Si and Fe atoms along a temperature gradient in the mushy zone of the Si-Fe alloy was evidenced, which became the source of Si precipitation on the C substrate, and ultimately forming bulk Si. Furthermore, the content of residual Fe-Si can be decreased in the bulk Si by controlling the temperature gradient, the holding time, and the alloy composition.