多晶硅还原加压工艺研究

为了降低多晶硅生产成本,对多晶硅生产中的重要环节———三氯氢硅(SiHCl3)还原生成多晶硅工艺进行了改进,将还原炉操作压力由常压提高至0.6 MPa,比较了加压工艺与常压工艺在多晶硅的沉积速度、沉积时间、还原反应耗电量以及多晶硅产品质量等指标上的区别。结果表明,还原炉压力由常压(0.1MPa)提高至0.6 MPa、H2和SiHCl3的量之比降低至3.5～5/1、SiHCl3和H2混合气的最大流量增加至2 000 kg/h、平均供气量约为980 kg/h时,多晶硅的沉积时间由200 h缩短至100 h;沉积速度由7～8 kg/h提高到20 kg/h,提高了150%以上;反应所需的单位耗电量也从135 kWh/kgSi降到75 kWh/kgSi,降幅达44%,从而大幅降低了多晶硅的生产成本;同时,产品质量也得到极大的提升。

Research on Pressurizing Hydrogen Reduction Process of Polysilicon Production

In order to reduce the production cost of polysilicon,the process was improved in increasing the reaction pressure from normal to pressure 0.6 MPa.The differences of deposition rate and time,power consumption,and the quality of polysilicon under the pressuring process and normal process were compared.Result showed that when the furnace pressure was increased from 0.1 MPa to 0.6 MPa at a H2 and SiHCl3 ratio of 3.5-5/1,a maximum SiHCl3 and H2 mixture flow of 2 000 kg/h,an average air flow was about 980 kg/h,the polysilicon deposition time was reduced from 200 h to 100 h and the deposition rate was increased from 7-8 kg/h to 20 kg/h,up by more than 150%.Meanwhile,the unit power consumption was decreased from 135 kWh/kg-Si to 75 kWh/kg-Si with a drop of 44%.Therefore the process dramatically reduced production cost of polysilicon and greatly improved the quality of the product.