微重力下单晶硅生长中热毛细对流的控制研究

在微重力条件下用浮区结晶法生长半导体单晶硅独具优势，但自由界面的温度梯度所诱发的热毛细对流对晶体质量的影响却更为突出。文中提出一种抑制热毛细对流的新方法-表面截割法，即通过适当改变自由表面的状况业抑制热毛细对流；在建立了半浮区（液桥）热毛细对流的数学模型的基础上，利用有限元法对不同截割方式下的流场、温度场做了数值模拟分析。结果表明，表面截割对浮区内的热毛细对流有很好的抑制作用，适当增加截割次数，可使热毛细对流削弱70%以上。

Study on the Reduction of Thermocapillary Convection of the Single-crystal Growth of Silicon under Microgravity

Float-zone method for growth of semi-conductor silicon is considering very promising under microgravity,but the effect of thermocapillary convection induced by surface tension gradient on the crystal quality is quite highlight.In the present work,a nwe method referred to as surface-cut method is suggested to reduce the melt flow.A mathmatical model to describe the thermocapillary convection in a half float-zone with surface-cut is proposed and numerical simulation for the temperature and the flow field under different surface-cut way is conducted using the finite element method.The results show that the effective reduction can be achieved and the flow will be weaked by 70% by proper increase of the surface-cut time.