Optimization of heat shield for single silicon crystal growth by using numerical simulation

In integrated circuit-grade single silicon Czochralski growth,the position and material of heat shield are main parameters affecting the heat exchange and crystal growth condition.By optimizing the above parameters,we attempted to increase the growth rate and crystal quality.Numerical simulation proved to verify the results before and after optimization.Through analyses of the temperature and microdefect distribution,it is found that the optimized heat shield can further increase the pulling rate and decrease the melt/crystal interface deflection,increase the average velocity of argon flow from ～2 to ～5 m·s-1,which is in favor of the transportation of SiO,and obtain the low defects concentration crystal and that the average temperature along the melt-flee surface is 8 ℃ higher than before avoiding supercooled melt effectively.