低温酸刻蚀对多晶硅表面织构化的影响

Effects of Low-temperature Etching on Acid Texturization for Multi-crystalline Silicon

采用低温酸刻蚀,通过优化HF-HNO3-H2O腐蚀溶液体系配比及相关工艺参数,在多晶硅材料的表面制备了绒面结构,并进行SEM表面形貌分析和反射谱的测试。结果表明,低温刻蚀比常温刻蚀在生产工艺中更有利于控制反应速度,从而得到效果较好的绒面结构。研究中发现,在不同HF-HNO3-H2O腐蚀溶液体系配比中,温度对反应速率的影响有较大差异,当HNO3含量相对较低时,低温刻蚀工艺有较好的效果。所得最佳绒面制备方案为:酸腐蚀溶液体系配比为VHF∶VHNO3∶VH2O=1∶4∶2,温度为3℃,反应速率控制为2.6μm/min。该方案已在25MW多晶硅太阳电池生产线上实施,不增加工艺难度和生产成本,适合于工业生产。

The textured structure on multi-crystalline silicon was fabricated by low-temperature acid etching method with optimized ratio and technical parameters in HF-HNO3-H2O system,and the surface morphology and reflectivity property of samples were characterized by scanning electron microscope（SEM） and incident-photon-to-electron conversion efficiency（IPCE）.The results show that the low-temperature acid etching is more effective in obtaining favorable textured structure and good controllability of reaction rate,meanwhile,the large difference exists for reaction rate affected by temperature with different ratios of HF-HNO3-H2O solution.Good result can be obtained at low-temperature acid etching under low HNO3 content.The optimum parameters for textured structure on multi-crystalline silicon were concluded as： VHF∶VHNO3∶VH2O=1∶4∶2,temperature as 3 ℃ and etching rate as 2.6 μm/min,which were successfully performed in 25 MW production line of multi-crystalline silicon solar cell.