准单晶硅铸锭过程中固液相变界面形状的控制

MELT-SOLID INTERFACE SHAPE CONTROL IN THE CASTING PROCESS FOR QUASI-SINGLE CRYSTALLINE SILICON INGOTS

对太阳电池用准单晶硅铸锭过程中的化料、长晶阶段进行数值模拟和实验对比分析,研究不同炉体局部结构下的种晶熔化界面形状和晶体生长界面形状,从传热学的角度揭示优化控制各阶段界面形状的机理。研究结果表明:在准单晶硅铸锭的熔化及长晶阶段,均可通过调整铸锭炉内局部挡板的位置改变热量的传输方向,从而在有效保存种晶的同时提供良好的初始长晶界面形状,减小长晶过程中坩埚壁面附近的界面凹度,抑制此处多晶向铸锭中部生长。

We carried out numerical simulations and experiments to investigate the melting and growing stages in the casting process for quasi-single crystalline silicon （QSC）ingots for solar cells. Different designs of local configuration in the furnace were compared to investigate its effects on the seed-meh interface shape and melt-crystal interface shape. The investigation revealed the mechanism of interface shape control by controlling the heat transfer. The results indicated that adjusting the position of partition block can preserve the seed crystals effectively and provide a good initial interface shape for crystal growth. The improved design can further reduce the interface concavity near the crucible side wall and suppress nucleation and grain growth at the crucible sidewall.