磁场方向对碱腐蚀构建多晶硅绒面结构的影响

Effect of Magnetic Field Direction on Suede Structure of Alkaline Solution Corroded Polysilicon

在零磁场和2T、4T磁场中用NaOH溶液腐蚀制备多晶硅绒面结构,样品板平面分别平行和垂直于磁场放置。用电子天平称重表征硅片的腐蚀程度、用奥林巴斯LEXT OLS4100共聚焦显微镜观察多晶硅片形貌、用Ocean Optics USB4000光谱仪测量多晶硅片的反射率、用WT-1200硅片测试仪测量样品的少子寿命,研究了磁场方向对碱腐蚀构建多晶硅绒面结构的影响。结果表明:随着磁感应强度的提高多晶硅片的腐蚀程度严重,绒面结构变得均匀和细腻,反射率降低;在磁感应强度相同的条件下碱液中沿着磁场方向运动的OH-离子不受磁场力作用,而运动方向与磁场方向不完全一致的OH-离子受磁场产生的Lorenz力作用。Lorenz力使板平面垂直于磁场方向的硅片样品腐蚀程度更加严重、绒面和断层状结构细腻程度更加显著、少子的寿命更长、反射率更低。磁感应强度为4T时反射率降低到14.5%,在用碱液腐蚀制备多晶硅绒面结构过程中施加强磁场,板平面垂直磁场方向放置硅片减反射效果更加显著。

The surface suede texture of polysilicon wafer was prepared via NaOH solution etching process.The effect of direction(to which the wafer parallel or perpendicular)and intensity(0,2 or 4 T)of the applied magnetic field on the surface texture of polysilicon wafer was investigated by means of weight loss measurement,Olympus LEXT OLS4100 confocal microscope,ocean Optics USB4000 spectrometer and WT-1200 silicon wafer tester.The results show that with the increase of magnetics intensity the corrosion degree of polysilicon wafer increases,and that the suede texture becomes uniform and finer,whereas the reflectivity decreases.With the same applied magnetics intensity,the motion direction of OH-ions along the magnetic field direction in the alkali solution were not affected by the magnetic field force,however,the Lorenz force generated by the magnetic field acts on OH-ions,when who’s motion direction is not exactly in line with the direction of the magnetic field,which then resulted in stronger corrosion for the silicon wafer placed perpendicular to the magnetic field direction,in consequence,the wafer presents much finer in suede texture and stratified structure with longer subatomic lifetime and lower reflectivity,peculiarly the applied magnetics intensity of 4 T could make the reflectivity of the wafer lower to 14.5%.In fact,the surface reflectivity of the polysilicon wafer can be significantly reduced when the polysilicon wafer placed perpendicular to the direction of applied magnetic field during the preparation of surface suede texture with the NaOH solution etching process.