Formation mechanism of hollow silicon ingot induced by fountain effect

A hollow silicon ingot was obtained by a solid–liquid separation method inducted by the fountain effect and the formation mechanism of the ingot was also discussed. A layer of solidified shell was formed on the melt surface and the gas dissolved in the melt was separated out. Because of this, the thickness of the shell was gradually increased and expanded due to the sudden change of the chamber pressure leading to the silicon melt being squeezed out from the preset hole of the shell. During this process, the melt left behind contains a high concentration of impurities and can be separated or detached completely from the decontaminated solid. This novel approach has of great potential to inhibit the back diffusion of impurities and to produce a silicon ingot at a high yield rate.