多晶硅铸锭中碳、氮、氧杂质特性的研究进展

Research Progress of Properties of Carbon,Nitrogen,Oxygen Impurities in Polycrystalline Silicon Ingots

在多晶硅铸锭生产过程中不可避免地会引入碳、氮、氧杂质元素,这些杂质会形成沉淀、复合体等缺陷,成为少数载流子的复合中心,缩短硅的少子寿命,从而降低硅片的太阳能转换效率。因此控制和降低铸锭中这3种杂质元素的含量对提高铸锭的性能和降低生产成本具有重要意义。阐述了碳、氮、氧元素的来源、分布,着重综述了铸锭中3种杂质元素的存在形态及不同形态对铸锭的影响,总结了降低3种杂质元素含量的方法,指出了目前研究的问题,并对铸锭中这3种杂质元素的研究趋势进行了展望。

The impurity elements, such as carbon, nitrogen and oxygen, can be inevitably introduced into silicon ingot to form precipitations, complexes or other defects during casting process. These defects become the recombination centre of the minority carrier to reduce the lifetime and conversion efficiency of the wafers. Therefore, it is of great significance to control and reduce the contents of these impurities in order to improve the performance of the cast ingot and lower the production cost. The introduction and distribution of these impurities are expounded. The existing form of impurities and its impact to the performance of the ingot are described emphatically. The present research problems are pointed out by summarizing the current methods for controlling impurity contents in silicon ingot. On this basis, the future research direction of this field is also proposed.