Effect of crucible coating on the grain control of multi-crystalline silicon crystal growth

The effect of crucible coating on the nucleation and grain control of multi-crystalline silicon crystal growth was investigated. Four different firing conditions for silicon nitrite coating were considered. From the solidification of sessile drops of silicon from different cooling rates, it was observed that preferred growth orientation was affected mildly by the coating if the cooling rate was low, but the variations were large. The orientation distributions at the high cooling rate were not affected much by the coating conditions. Crystal growth from different coating conditions at the same directional solidification experiment also indicated that the grain orientations were only slightly affected by coating conditions. Data collected from industrial production further indicated that no significant effect was found on the ingot lifetime and the oxygen content if the firing time was elongated from 4 to 8 h at 1100 °C.

► Different coating firing conditions for sessile drop at different cooling rates.
► Slightly different grain structures at low firing temperature.
► No significant difference in mass production for elongated firing time from 4 to 8 h at 1100 °C.