Removal of phosphorus and boron from molten silicon

为了以较低的能源成本生产太阳能级硅，研究了一种从硅液中脱除磷和硼的工艺。在高真空电子束熔化的硅中注入氧气和水蒸气。反应气体的加入促进了磷的蒸发去除，同时也促进了氧化硼的蒸发。通过研制带有气体进样装置的双Knudsen池质谱仪对反应机理进行了研究。对硅磷合金和硼的挥发物进行了定性和定量评价。

A process to remove phosphorus and boron from molten silicon was studied in order to produce solar-grade silicon at lower energy cost. Oxygen and water vapor were injected into silicon melted with electron beam under high vacuum. Evaporative removal of phosphorus was enhanced by injection of the reactive gases, and evaporation of oxidized boron was also indicated. The mechanism of the reactions was studied by development of a double Knudsen cell mass spectrometer equipped with a gas-injection apparatus. Evaporated species from Si-P alloys and boron were identified and evaluated quantitatively.