多晶硅铸锭生长过程热应力与位错的数值模拟研究  

Numerical Simulation Study on Thermal Stress and Dislocation in Silicon Multi-crystal Growth

作　　者：王晨东 左然[1] 苏文佳[1] WANG Chen-dong;ZUO Ran;SU Wen-jia(School of Energy and Power Engineering,Jiangsu University,Zhenjiang 212013,China)

机构地区：[1]江苏大学能源与动力工程学院,镇江212013

出　　处：《人工晶体学报》2018年第5期894-898,共5页Journal of Synthetic Crystals

摘　　要：通过对定向凝固多晶硅从凝固过程开始到冷却过程结束进行瞬态数值模拟,研究了多晶硅锭不同生长阶段的温场、热应力及位错密度的关系。模拟结果表明:在长晶及冷却过程中,位错因热应力的存在而发生运动和增殖,晶体内温度梯度是影响晶体位错密度的关键因素。高位错密度区域分布在硅锭顶部、中心部以及周边外缘。硅锭上表面由中心向外缘递减的高位错密度是由于杂质在固液界面前沿富集导致。其中最大位错密度约为2.4×10~4cm^(-2),发生在硅锭中轴顶部;局部最大位错密度约为2.2×10~4cm~(^(-2)),发生在硅锭边缘底角。The temperature,thermal stress and dislocation density of multi-crystalline silicon at different growth stages are studied through transient numerical simulation of the solidification and cooling process.The simulation results show that dislocations move and increase with thermal stress in the growth and cooling process,and the temperature gradient in the crystal is the key factor to the dislocation density. It is found that the high dislocation densities appear at the top,center and outer edge of the silicon ingot.The dislocation density of the ingot surface decreases from the center to the outer edge which is due to the enrichment of impurities at the front of the crystal-melt interface. The maximum dislocation density is about 2. 4 × 104 cm-2,which occurs at the top of the central axis of the silicon ingot. The maximum local dislocation density is about 2. 2 × 104 cm-2,which occurs at the bottom of the ingot.

关 键 词：定向凝固 多晶硅 热应力 位错密度 数值模拟 

分 类 号：O78[理学—晶体学]