单晶硅表面微结构对晶体硅光电转换性能有非常重要的影响,晶体硅表面微结构的调节技术一直是半导体、太阳能电池领域研究的热点之一.利用碱液与单晶硅异向腐蚀特性的刻蚀技术,在单晶硅表面可以获得布满金字塔的绒面,但普通碱液刻蚀的绒面,其金字塔大小、形貌和分布随机性大,不利于提高硅太阳电池的转换效率.在普通的碱腐蚀液中加入不同量的特种添加剂,然后在相同的温度、时间下刻蚀单晶硅表面,通过观察样品表面SEM图,发现在普通碱液中加入适量添加剂后刻蚀的单晶硅表面能形成均匀密集分布金字塔,金字塔大小在2—4μm之间,棱边圆滑,表面金字塔覆盖率高;用积分反射仪测量了样品的反射率曲线,发现样品平均反射率下降到12.51%.实验结果表明,在普通碱液中加入特种添加剂,能控制单晶硅表面金字塔的大小和分布.%The controlling technology of micro-structure on the surface of monocrystal silicon is a hot spot issue in semiconductor and solar cell fields because the conversion efficiency of monocrystal solar cell is affected by the structure of pyramid.With the traditional alkaline solution,monocrystal Si surface is easily textured,and becomes the surface full of the pyramid.However,it is difficult to control the sizes,the shapes and the distribution of pyramids in the process.In this paper,we discuss how a new additive influences the sizes,and the shapes of pyramids during the etching process.In experiment,silicon is etched in traditional alkaline solution with addition of the new additive at a fixed temperature and time.Samples are scanned by SEM.The SEM result shows that the samples are uniformly-densely filled with pyramids with smooth edges.The size of pyramid is smaller than that etched in the traditional alkaline solution.The etched surface is covered by pyramids with 2-4μm in size.The reflectance spectrum of the textured surface is measured.The measured reflectance decreases to 12.51%.These experimental results show that the new additive can effectively cantrol the sizes and the distribution of pyramids on the silicon surface during the texturing process,which is very meaningful to control the textured structures of single crystal silicon surface.
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