多场耦合下300mm大直径单晶硅氧的掺杂机理研究

近年来，太阳能电池的大力应用促进了单晶硅的广泛研究。氧作为太阳能级直拉单晶硅中的非金属杂质，在晶体中可形成微缺陷，影响晶体的电阻率，造成后期制备太阳能电池性能不稳定。本项目首先采用2D/3D复合数值模型模拟多场耦合作用下炉内的热场、气体流场和磁场的分布状况；其次，通过研究熔体-坩埚边界薄层内熔体的流动和氧的分布，建立氧的引入机理，并分析工艺参数对大直径坩埚内的熔体对流和氧的传输方式的影响；同时，探讨温度梯度与固液界面和氧分凝扩散的相互影响关系，确定晶体生长速度与氧含量之间的关联性。最后,建立起完善的大直径单晶硅中氧的掺杂机理，并用试验加以验证，为生产高品质大直径单晶硅提供理论指导。

Recently, the extensive application of solar energy accelarate the reserch of the single crystal silicon. Oxygen is one of the main non-metallic impurities in the crystal which can form the micro-defects. It will influnce the resistivity of the crystal, resulting in the decreasing the stability of the solar cells. In this proposal, the distribution of the thermal,flow and magnetic field will be simulated using the 2D/3D composite model under the multi-filed coupling. The introducing mechamism of the oxygen will be discussed by analzing the melt flow and oxygen distribution in the melt-crucible boundary layer.At the same time, the effct of processing parameters on the melt convection and the oxygen transportation will be disccused.It would aslo pay more attention on the influence of the temperature gredient on both the solid-liquid interface and the segregation of the oxygen. Then,the relationship between the growth rate and oxygen concentration will be determined.Finnaly,the doping mechanism of oxygen will be constructed systematically for the CZ single crystal silicon with large diameter, which would be vertified by experiments. This will provide theoretical supporting to the production of large diameter single crystal silicon with high qualities.