多晶硅锭中硬质点分析及控制研究

以多晶硅锭中硬质点为研究对象,通过实验研究和数值模拟的方法,对多晶硅锭中硬质点进行形貌和成分分析,并提出改善控制方法。研究结果表明硅锭中部的硬质点较细小,主要由SiC组成;硅锭头部的硬质点较粗大,主要由SiC和Si3N4组成,还有少量O的存在。进一步研究发现多晶硅定向凝固铸锭炉的热场结构对于多晶硅锭硬质点形成有直接影响,通过改进热场结构,优化晶体生长界面,显著减少了铸锭中硬质点的数量。

ANALYSIS AND CONTROL OF HARD SPOTS IN MULTICRYSTALLINE SILICON INGOTS

Hard spots in polycrystalline silicon ingots have been studied through experiment and numerical simulation. Morphology and composition of hard spots in polycrystalline silicon ingots were analyzed,and solution was given. The research results shown that the hard spots in the middle of the silicon ingot are generally small in size and mainly consist of SiC;the hard spots in the top of the silicon ingot are large in size and consist of SiC and Si3N4,and a small amount of oxygen. Further study shown that the thermal structure of polysilicon directionally solidification ingot furnace has a significant effect on the quality of the silicon ingot. An optimized thermal structure can optimize the solid-liquid interface and reduce the formation of the hard spots,thus improving the quality of the ingots.