IMPROVED PRODUCTION OF MONO-CRYSTALLINE SILICON

摘要

A crystalline silicon ingot is produced using a directional solidification process. In particular, a crucible is loaded with silicon feedstock above a seed layer of uniform crystalline orientation. The silicon feedstock and an upper part of the seed layer are melted forming molten material in the crucible. This molten material is then solidified, during which process a crystalline structure based on that of the seed layer is formed in a silicon ingot. The seed layer is arranged such that a {110} crystallographic plane is normal to the direction of solidification and also so that a peripheral surface of the seed layer predominantly also lies in a {110} crystallographic plane. It is found that this arrangement offers a substantial improvement in the proportion of mono-crystalline silicon formed in the ingot as compared to alternative crystallographic orientations.