Continuous melting and directional solidification of silicon ingot with an electromagnetic cold crucible

Abstract

In order to avoid contamination from the crucible and to modify the structures, a new solidification method based on cold crucible technology was used to prepare silicon ingots. A silicon ingot with square cross section was directionally solidified with a cold crucible. The mechanism of the cold crucible directional solidification of silicon ingot was revealed. Due to the induction heat that was released in the surface layer and the incomplete contact between the crucible and the melt, the lateral heat loss was reduced and the silicon ingot was directionally solidified. The structures, dislocation defects and the grain growth orientation of the ingot were determined. The results show that neither intergranular nor intragranular precipitates are found in the ingot, except for the top part that was the last to solidify. The average dislocation density is about 1 to 2 × 106 cm-2. The grains are preferentially orientated.

Keywords

• directional solidification
• silicon ingot
• grain growth
• cold crucible