Numerical And Experimental Investigation Of Octagonal Thermal Field For Improving Multi-Crystalline Silicon Ingot Quality

This paper focused on studying an octagonal thermal field to improve the quality of multi-crystalline silicon ingot. A global numerical model was adopted to investigate the effects of the modified furnace on the temperature distribution and temperature gradients distribution during the directional solidification process. The numerical results indicated that a more uniform temperature distribution and lower temperature gradients were obtained in the modified furnace. Meanwhile, the experimental ingot was obtained by using the modified furnace. Experimental tests of minority carrier lifetime distribution, dislocation clusters, and the average conversion efficiency for the conventional ingot and the modified octagonal ingot were carried out. The results indicated that the modified octagonal silicon ingot could achieve lower defect density, especially near the crucible wall. Therefore, the average conversion efficiency of the modified octagonal ingot was improved by 0.12% compared with the conventional ingot. Furthermore, the mechanism and control of ingot side dislocation multiplication were discussed.