用PMCZ法生长的单晶硅中氧和电阻率的均匀性

HOMOGENEITY OF OXYGEN AND RESISTIVITY IN CRYSTAL PREPARED BY PMCZ METHOD

用永磁体环形磁场直拉（ＰＭＣＺ）炉代替普通的ＭＣＺ炉生长了质量较高的单晶硅．在ＰＭＣＺ炉中水平辐射状磁力线均匀分布，可有效地抑制熔体中不规则的对流和固液界面处的温度波动，降低以至消除微观生长速率的起伏．在用ＰＭＣＺ法生长的硅晶体中氧浓度较低，杂质的径向分布均匀性好．简单地讨论了ＰＭＣＺ法控氧优于普通ＭＣＺ法的机理．

Conventional electrical magnetic field has been replaced by ring permanent magnetic field, for CZSi growth, called PMCZ. The line of magnetization field is horizontally radialized distributed. Thermal convection in melt and centrifugal pumping flows due to crystal rotation can be strongly suppressed by the ring permanent field, so that temperature fluctuations and fluctuations of microscopic growth-rate at solid-liquid interface had been suppressed effectively. Under the magnetic field condition, crystal growth is similar to crystal growth in space under reduced gravity conditions, impurity motion is of diffusion-controlled one. Crystal with lower oxygen concentration and more homogeneous dopant at radial direction had been grown under this conditions. The magnetic strength can conveniently be varied by adjustable place each other magnetic device and melt-crystal interface of each other position between 2 or 3 magnetic ring. Thus it can meet the needs of crystal growth process. As compared with electrical magnetic field, electricity and water are out of use of permanent magnetic field, magnetic field strength of PMCZ is more steady, crystal production cost can be reduced.