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研究了多晶硅铸锭过程中,硅锭内部红外探伤测试中显示黑斑位置晶体缺陷的杂质组成,并根据杂质成分推导了此种缺陷的形成机理和条件。采用光致发光(PL)技术、扫描电子显微镜(SEM)和X射线能谱仪(EDS)对杂质进行了表征与分析。结果显示,形成阴影的夹杂在晶界中存在的形态主要为针状或薄片状,其组成成分主要为C,N和Si元素。而Si_3N_4的出现可能有两个原因:一是Si_3N_4涂层脱落而沉积在晶界中;二是溶解在液相中的N局部过饱和。此外,结晶过程中,SiC也随之成核并生长,在晶界上形成夹杂物,同时伴随着微缺陷的增加。据此提出了去除多晶硅锭内部阴影的几点措施。
In the process of polycrystalline ingot ingot ingot ingot ingot, the impurity composition of crystal defect in the spot position was revealed by infrared test, and the formation mechanism and condition of the defect were deduced according to the impurity composition. The impurities were characterized and analyzed by photoluminescence (PL), scanning electron microscopy (SEM) and X-ray energy dispersive spectroscopy (EDS). The results show that the shaded inclusions mainly exist in the grain boundaries as acicular or flaky inclusions, and the main components are C, N and Si. The appearance of Si_3N_4 may be due to two reasons: firstly, the Si_3N_4 coating falls off and deposits in the grain boundary; and second, the partial over-saturation of N dissolved in the liquid phase. In addition, during the crystallization, SiC nucleates and grows as well, forming inclusions in the grain boundaries, accompanied by an increase in microdefects. Based on this, some measures to remove the shadow of polysilicon ingot are put forward.