中文摘要：

通过微合金化获取高性能多晶硅,研究了不同Sn掺入量对定向凝固多晶硅位错及少子寿命的影响。将高纯Sn掺入到精炼冶金级硅（UMG-Si）中,定向凝固多晶硅。研究发现,硅锭位错密度沿轴向分布为中间低,底部和顶部高。在晶体硅中掺入Sn后,不影响硅的电学性能,但明显减少硅锭的位错密度。当掺入Sn含量为20 ppmw、50 ppmw和100 ppmw时,硅锭平均少子寿命由未掺Sn硅锭的0.81μs分别增加至1.22μs、1.47μs和1.31μs。掺Sn可减少位错密度和增加少子寿命,归因于替代位的Sn原子引入晶格应力,Sn易捕获空位V形成Sn-V对,抑制间隙原子形核。

英文摘要：

In order to obtain high performance silicon solar cell by microalloying,researches of the impact of Sn doping on dislocation and minority carrier lifetime（ MCL） of directional solidified mc-Si have been studied. High-purity Sn was added into upgraded metallurgical silicon. The dislocation density of the center of the ingots is low while the dislocation density of the bottom and the top of the ingots are high.The Sn doped ingots show a significantly lower average dislocation density but almost the same resistivity.The MCL increases from 0. 81 μs to 1. 22 μs,1. 47 μs,1. 31 μs when Sn concentration increases from zero to 20 ppmw,50 ppmw,100 ppmw. The dislocation density is reduced and the MCL is improved by nucleation barrier of interstitial atoms and Sn-V（ V： vacancy） pairs due to the induced strain field.