高纯三氯氢硅生产中磷硼杂质的去除

Phosphorus Boron Impurities Removal in the Production of High Purity Trichlorosilane

根据生产实践,总结分析了磷、硼杂质在三氯氢硅中的存在形式以及磷硼元素对多晶硅品质的影响。磷系化合物主要是以高沸物存在,少量以低沸物存在,通过加大各塔塔底的排放可以除去;硼系化合物80%左右是以高沸形式存在,15%左右是以低沸形式存在,还有5%左右的杂质沸点是同一工况下高于三氯氢硅,但低于四氯化硅的沸点。除硼成了三氯氢硅提纯的关键因素,合理控制各塔的排高排低除去硼杂质,降低精馏塔单位产品能耗,提高精馏塔的生产能力。

The effect of phosphorus,boron impurities existing forms and elements in trichlorosilane on the quality of polycrystalline silicon were summarized and analyzed according to the production practice.The phosphorus compounds were mainly high boiling substances,a small amount was low boiling substances,which could be removed through increasing the tower bottom discharge.About 80% of boron compounds were high boiling form,about 15% were low boiling form,and about 5% were impurities whose boiling point higher than trichlorosilane,but less than silicon tetrachloride in the same operating conditions.Boron removal became the key factor in trichlorosilane purification,the reasonable controls of increasing or reducing discharge in the towers to remove boron impurity,reduce the energy consumption per unit product of rectifying tower,and improve the productivity of rectifying tower.