Removal of phosphorus and boron from molten silicon

为了以较低的能源成本生产太阳级硅，研究了从熔融硅中去除磷和硼的工艺。在高真空条件下，向用电子束熔化的硅中注入氧气和水蒸气。通过注入活性气体，提高了磷的蒸发去除效果，同时也表明了氧化硼的蒸发效果。研制了配有气体注入装置的双克努森细胞质谱仪，对反应机理进行了研究。对硅磷合金和硼的蒸发物质进行了定量鉴定和评价。

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.