薄膜硅／晶体硅异质结电池中本征硅薄膜钝化层的性质及光发射谱研究  

Study on the properties and optical emission spectroscopy of the intrinsic silicon thin film in silicon heterojunction solar cells

作　　者：薛源[1] 郜超军[2] 谷锦华[1] 冯亚阳[1] 杨仕娥[1] 卢景霄[1] 黄强[3] 冯志强[3] 

机构地区：[1]郑州大学物理工程学院材料物理教育部重点实验室,郑州450052 [2]郑州大学物理工程学院,郑州450052 [3]光伏科学与技术国家重点实验室,常州天合光能有限公司,常州213031

出　　处：《物理学报》2013年第19期427-433,共7页Acta Physica Sinica

基　　金：国家高技术研究发展计划(批准号:2011AA050501)资助的课题~~

摘　　要：本文采用甚高频等离子体化学气相沉积技术(VHF-PECVD)制备薄膜硅/晶体硅异质结电池中的本征硅薄膜钝化层,光发射谱(OES)测量技术研究了硅薄膜沉积过程中等离子体发光谱随时间的变化.结果表明:在实验优化条件下等离子体发光谱很快达到稳定(大约25 s),并且SiH*/Hα*的比值随时间变化较小,避免了生长过程中硅薄膜结构的不均匀性,这主要是SiH4没有完全耗尽避免了SiH4的反向扩散.进一步研究了沉积参数对稳态发光谱和硅薄膜性质的影响,结果表明:随着硅烷浓度增加,Hα*峰强度减小,SiH*峰强度增加,薄膜从微晶转变成非晶,非晶硅薄膜钝化效果好;随着沉积气压增大,Hα*和SiH*峰强度先增加后减小,高气压下Hα*和SiH*峰强度下降主要是反应前驱物的聚合形成高聚合物,不利于形成高质量的硅薄膜,因此钝化效果下降;随着反应功率密度增加,Hα*和SiH*峰强度增大,当功率密度为150 mW/cm2趋于饱和,硅薄膜的致密度和钝化效果也开始下降,50 mW/cm2的低功率密度下硅薄膜钝化效果差可能是由于原子H浓度低,不能完全钝化单晶硅表面的悬挂键.The intrinsic silicon thin film for passivation of the crystalline silicon wafer surfaces in silicon heterojunction cells was prepared by very high fregucency plasma enhanced CVD （VHF-PECVD）. Plasma emission versus time was recorded by optical emission spectroscopy （OES） during the silicon thin film deposition. Results show that the H＊α and SiH＊ signals stabilize soon （about 25 s after deposition） under the optimized deposition conditions, and the variation of SiH＊/H＊α ratio is little, thus avoiding the structure non-uniformity of silicon film during the growth. The reason is that the SiH4 back diffusion is avoided owing to SiH4 being not fully depleted. The study of the influence of the deposition parameters on steady-state plasma emission spectra and properties of silicon films shows that as the SiH4 concentration increases, the H＊αdecreases and the SiH＊increases, the silicon film will transit from microcrystalline to amorphous, and the good passivation effect can be achieved in the amorphous silicon film. H＊αand SiH＊increase firstly and then decrease with the deposition pressure, the decrease of H＊αand SiH＊ under high pressure can be attributed to a high polymer formation which is not beneficial to the formation of high quality silicon film, and therefore the passivation effect of silicon films decreases under high pressures. H＊α and SiH＊ increase with power density, and are saturated when the power density is 150 mW/cm2;for this the quality and passivation effect of the silicon film begin to decrease, the passivation effect of the silicon film at a power density of 50 mW/cm2 is poor, which may be due to the low concentration of atomic H being unable to fully passivate the dangling bonds at the silicon surface.

关 键 词：薄膜硅 异质结 光发射谱 钝化 

分 类 号：TM912[电气工程—电力电子与电力传动]