感应加热制备太阳能级铸造准单晶硅熔体流动行为研究
|
摘要
用专业晶体生长软件(CG-Sim)对制备太阳能级准单晶硅用真空感应铸锭炉的热场结构以及在熔炼过程中硅熔体的流动行为进行了研究。结果表明,熔体中电磁力是熔体流动的驱动力之一,并且感应线圈与熔体高度的比值(k)对熔体内电磁力的大小和分布具有很大的影响,当k值为1.2时,熔体内形成一个上下贯通的涡流,有利于杂质的挥发。同时,当感应线圈频率在3000~5000 Hz范围时,熔体对流强度较低,可以增加坩埚-熔体边界层的厚度,降低熔体中的氧含量。
The heater configuration and the convective behavior of silicon melt in the vacuum induction melting furnace used for preparing solar-grade casting quasi-single crystal silicon was analyzed by the commercial CG-Sim software.The results show that the electromagnetic force is one of the driving forces to convection.Meanwhile,both strength and distribution of the electromagnetic force are influenced strongly by the ratio of induction coil height to melt depth( defined to k).As k value is 1.2,melt convection develops from two vortexes to one dominating vortex,which is benefit to the impurities evaporation.At the same time,for the inductive frequency within the range from 3000 Hz to 5000 Hz,the flow strength decreases which can increase the thickness of boundary layer between silicon melt and silica crucible,resulting in the deceasing of oxygen concentration in silicon melt.
The heater configuration and the convective behavior of silicon melt in the vacuum induction melting furnace used for preparing solar-grade casting quasi-single crystal silicon was analyzed by the commercial CG-Sim software.The results show that the electromagnetic force is one of the driving forces to convection.Meanwhile,both strength and distribution of the electromagnetic force are influenced strongly by the ratio of induction coil height to melt depth( defined to k).As k value is 1.2,melt convection develops from two vortexes to one dominating vortex,which is benefit to the impurities evaporation.At the same time,for the inductive frequency within the range from 3000 Hz to 5000 Hz,the flow strength decreases which can increase the thickness of boundary layer between silicon melt and silica crucible,resulting in the deceasing of oxygen concentration in silicon melt.
引文
[1]Liu L J,Nakano S,Kakimoto K,et al.Dynamic Simulation of Temperature And Ion Distributions in a Casting Process for Crystalline Silicon Solar Cells with Global Model[J].Journal of Crystal Growth,2006,292:515-518.
[2]Delannoy Y,Barvinschi F,Duffar T.3D Dynamic Mesh Numerical Model for Multi-Crystalline Silicon Furnace[J].Journal of Crystal Growth,2007,303:170-174.
[3]Lou Z S,Zuo R,Su W J,et al.Thermal System Design and Simulation for Growth of Large Grain Multi-Crystal Silicon Ingot[J].Journal of Synthetic Crystals,2011,40(6):1602-1606.
[4]Ma W,Zhong G,Sun L,et al.Influence of an Insulation Partition on a Seeded Directional Solidification Process for Quasi-single Crystalline Silicon Ingot for High-Efficiency Solar Cells[J].Solar Energy Materials&Solar Cell,2012,100:231-238.
[5]Yu Q H,Liu L J,Zhong G X,et al.Control of Solidification Front Shape During Quasi-Single Crystalline Silicon Casting Process[J].Journal of Engineering Thermophysics,2013,34(3):505-508.
[6]Yu Q,Liu L J,Ma W,et al.Local Design of the Hot-zone in an Industrial Seeded Directional Solidification Furnace for Quasi-single Crystalline Silicon Ingots[J].Journal of Crystal Growth,2012,358:5-11.
[7]Black A,Medina J,Pineiro A,et al.Optimizing Seeded Casting of Mono-Like Ssilicon Crystals Through Numerical Simulation[J].Journal of Crystal Growth,2012,353:12-16.
[8]Lv G Q,Ma W H,Yang X,et al.Numerical Simulation on Thermal Process of Metallurgical-Grade Silicon Refining in Vacuum Induction Furnace[J].Transactions of Materials and Heat Treatment,2013,34(8):189-194.
[9]Lv G Q,Ma W H,Wang H,et al.Numerical Simulation on the Flow Behavior of the Melts of Metallurgical-Grade Silicon Refining in a Vacuum Induction Frunace[J].Transactions of Materials and Heat Treatment,2013,34(10):181-186.
[10]Li J,Zhang H Y,Gao M M.et al.Influence of Argon Flow Rate on the Solid/Liquid Interface,Thermal Stress and Oxygen Concentration in the400 mm CZ Silicon with a Magnetic Field[J].Journal of Synthetic Crystals,2014,43(5):1193-1198.
[11]Http://www.str-soft.com/products/CGSim/
[2]Delannoy Y,Barvinschi F,Duffar T.3D Dynamic Mesh Numerical Model for Multi-Crystalline Silicon Furnace[J].Journal of Crystal Growth,2007,303:170-174.
[3]Lou Z S,Zuo R,Su W J,et al.Thermal System Design and Simulation for Growth of Large Grain Multi-Crystal Silicon Ingot[J].Journal of Synthetic Crystals,2011,40(6):1602-1606.
[4]Ma W,Zhong G,Sun L,et al.Influence of an Insulation Partition on a Seeded Directional Solidification Process for Quasi-single Crystalline Silicon Ingot for High-Efficiency Solar Cells[J].Solar Energy Materials&Solar Cell,2012,100:231-238.
[5]Yu Q H,Liu L J,Zhong G X,et al.Control of Solidification Front Shape During Quasi-Single Crystalline Silicon Casting Process[J].Journal of Engineering Thermophysics,2013,34(3):505-508.
[6]Yu Q,Liu L J,Ma W,et al.Local Design of the Hot-zone in an Industrial Seeded Directional Solidification Furnace for Quasi-single Crystalline Silicon Ingots[J].Journal of Crystal Growth,2012,358:5-11.
[7]Black A,Medina J,Pineiro A,et al.Optimizing Seeded Casting of Mono-Like Ssilicon Crystals Through Numerical Simulation[J].Journal of Crystal Growth,2012,353:12-16.
[8]Lv G Q,Ma W H,Yang X,et al.Numerical Simulation on Thermal Process of Metallurgical-Grade Silicon Refining in Vacuum Induction Furnace[J].Transactions of Materials and Heat Treatment,2013,34(8):189-194.
[9]Lv G Q,Ma W H,Wang H,et al.Numerical Simulation on the Flow Behavior of the Melts of Metallurgical-Grade Silicon Refining in a Vacuum Induction Frunace[J].Transactions of Materials and Heat Treatment,2013,34(10):181-186.
[10]Li J,Zhang H Y,Gao M M.et al.Influence of Argon Flow Rate on the Solid/Liquid Interface,Thermal Stress and Oxygen Concentration in the400 mm CZ Silicon with a Magnetic Field[J].Journal of Synthetic Crystals,2014,43(5):1193-1198.
[11]Http://www.str-soft.com/products/CGSim/