高频加热线圈台阶对区熔炉磁场的影响

区熔法是生长单晶硅的重要方法之一，针对区熔法生长单晶硅过程因多晶硅熔化表面热量不均匀而出现“冷针”的问题，利用有限元法对生长区熔硅单晶进行了数值模拟。区熔法生长单晶硅采用高频感应加热，高频加热线圈是区熔炉最为关键的部件之一，线圈的结构、尺寸直接影响到磁场及焦耳热的分布及熔区形状。基于此，建立了有台阶线圈和无台阶线圈下的两种模型，对比了两种模型下熔区附近磁场分布和焦耳热分布，着重分析了高频加热线圈的台阶对磁场及焦耳热分布的影响。研究结果表明，高频加热线圈的结构会直接影响到熔区附近磁场的分布，进而影响熔区生成的焦耳热分布，线圈台阶可使磁场在熔区附近分布得更均匀，从而有效地解决了“冷针”问题。

Effects of high-frequency coil step on distribution of magnetic field in float-zone furnace

Float zone（FZ） method is one of the most important methods of growing monocrystalline silicon. Aiming at the problem of ＂cold needle＂ which is caused by the uneven heat distribution on the melt surface of polycrystalline silicon during the process of growing monocrys- talline silicon by FZ method, a numerical simulation of growing monocrystalline silicon was made by using the finite element method. The coil models with step and without step were built to analyze the magnetic field distribution and joule heat distribution around the melting zone. The results indicate that the structure of high-frequency heating coil directly affects the distribution of the magnetic field around the melting zone, and then affects the distribution of generated joule heat. The step of the high frequency heating coil would result in a more uniform distribu- tion of the magnetic field near the melting zone, and effectively solve the problem of ＂cold needle＂.