Preparation, microstructure and dislocation of solar-grade multicrystalline silicon by directional solidification from metallurgical-grade silicon
Preparation, microstructure and dislocation of solar-grade multicrystalline silicon by directional solidification from metallurgical-grade silicon
复制标题
冶金级硅定向凝固制备太阳能级多晶硅、微观结构及位错
DOI：
10.1016/s1003-6326(11)61499-4
复制
发表时间：
2012-10-01
影响因子：
4.5
通讯作者：
Fu Heng-zhi
中科院分区：
文献类型：
--
作者：
Su Hai-jun;Zhang Jun;Fu Heng-zhi
采用高温度梯度真空定向凝固技术，以高纯多晶硅为原料，直接制备低成本太阳能级多晶硅。研究了不同生长条件下的显微组织特征、晶粒尺寸、晶界、固液生长界面和位错结构。结果表明，当凝固速率低于60 μ m/s时，可获得高密度、高取向的定向凝固多晶硅棒。随着凝固速度的增加，晶粒尺寸逐渐减小.控制在高温度梯度下获得平坦的固液界面，可有效地沿凝固方向产生排列良好的柱状晶沿着。由于多晶硅的小面生长特性，在微结构中优先形成生长台阶和孪晶界。晶体内位错分布不均匀，位错密度随凝固速度的增加而增加。此外，还对多晶硅的晶体生长行为和位错形成机制进行了讨论。
A vacuum directional solidification with high temperature gradient was performed to prepare low cost solar-grade multicrystalline silicon (mc-Si) directly from metallurgical-grade mc-Si. The microstructure characteristic, grain size, boundary, solid-liquid growth interface, and dislocation structure under different growth conditions were studied. The results show that directionally solidified multicrystalline silicon rods with high density and orientation can be obtained when the solidification rate is below 60 mu m/s. The grain size gradually decreases with increasing the solidification rate. The control of obtaining planar solid-liquid interface at high temperature gradient is effective to produce well-aligned columnar grains along the solidification direction. The growth step and twin boundaries are preferred to form in the microstructure due to the faceted growth characteristic of mc-Si. The dislocation distribution is inhomogeneous within crystals and the dislocation density increases with the increase of solidification rate. Furthermore, the crystal growth behavior and dislocation formation mechanism of mc-Si were discussed.