Li B.-W.,Changzhou Trinasolar Co. |
Huang Q.,Changzhou Trinasolar Co. |
Liu Z.-H.,Changzhou Trinasolar Co. |
Huang Z.-F.,Changzhou Trinasolar Co. |
And 2 more authors.
Rengong Jingti Xuebao/Journal of Synthetic Crystals | Year: 2011
On account of the growth process of ingot, the (111) orientation is the major crystal orientation for self-nucleation, Iron impurity shows a certain regular distribution for multicrystalline ingot with a higher content in the top and tail. However a lower content in the middle of the mc-Si ingot. Correspondingly the minority carrier lifetime of wafer have the distribution trend with a lower in the top and tail and a higher in the middle of the ingot. The lifetime in the bottom and top of the ingot can hardly be improved by gettering or passivation due to the considerable impurities. Special gettering process was introduced which could produce the (220) crystal orientation and decrease effectively iron content (top decrease 16.6%, tail decrease 22.0%) and improve the minority carrier lifetime in the top (41.9%) and tail (11.9%) of the ingot.