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本文采用射频等离子体增强化学气相沉积(rf-PECVD)技术在单晶硅衬底上沉积了两个系列的硅薄膜.通过对样品进行固定角度椭圆偏振测试,结果表明第一个系列硅薄膜为非晶硅,形成了突变的a-Si:H/c-Si异质结构,此结构在HIT电池中有利于形成好的界面特性,对于非晶硅薄膜采用通常的Tauc-Lorentz摇摆模型(Genosc)拟合结果很好;第二个系列硅薄膜为外延硅,对于外延硅薄膜,随着膜厚增加晶化率降低,当外延硅薄膜厚度为46 nm时开始非晶硅生长.对于外延硅通常采用EMA模型(即将硅薄膜体层看成由非晶硅和c-Si构成的混合层)拟合结果较好,当硅薄膜中出现非晶硅生长时,将体层分成混合层和非晶硅两层,采用三层模型拟合结果很好.本文证实了椭偏光谱分析采用不同的模型可对单晶硅衬底上不同结构的硅薄膜进行有效表征.
In this paper, two series of silicon thin films were deposited on single crystal silicon substrate by RF plasma enhanced chemical vapor deposition (rf-PECVD) .After fixed angle elliptical polarization test, the results show that the first series of silicon thin films A-Si: H / c-Si heterostructures are formed on the amorphous silicon substrate. This structure facilitates the formation of good interfacial properties in the HIT cell. For the amorphous silicon film, the usual Tauc-Lorentz model (Genosc ), The fitting result is very good. The second series of silicon thin films are epitaxial silicon, and for the epitaxial silicon thin film, the crystallization rate decreases as the film thickness increases, and the amorphous silicon begins to grow when the epitaxial silicon film thickness is 46 nm. Generally, the EMA model (that is, the silicon thin film bulk layer is regarded as a mixed layer composed of amorphous silicon and c-Si) has good fitting results. When amorphous silicon growth occurs in the silicon thin film, the bulk layer is divided into a mixed layer and a non- The results of the three-layer model fitting well are demonstrated in this paper.It is proved that the ellipsometric spectroscopic analysis can effectively characterize the silicon films with different structures on the monocrystalline silicon substrate by using different models.