Fabrication of silicon thin films with defects below detection limit of electron spin resonance for solar cells by high-speed zone-melting crystallization of amorphous silicon
Fabrication of silicon thin films with defects below detection limit of electron spin resonance for solar cells by high-speed zone-melting crystallization of amorphous silicon
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DOI：
10.1063/1.1421231
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发表时间：
2001-12-03
影响因子：
4
通讯作者：
Komiyama, H
中科院分区：
文献类型：
--
作者：
Ihara, M;Yokoyama, S;Komiyama, H
采用高速（0.7- 4.5mm/s）区熔晶化法（ZMC）制备了缺陷密度低于电子自旋共振（ESR）检测限的非晶硅（a-Si）薄膜。在这封信中，用于区熔再结晶（ZMR）的多晶硅（poly-Si）膜和用于ZMC的a-Si膜各自夹在两个SiO2膜之间。Si膜为0.3-2.0 μ m厚，顶部SiO2膜为0.35-1.5 μ m厚，底部SiO2膜为0.18-1.2 μ m厚。a-Si ZMC薄膜的晶体质量比poly-Si ZMR薄膜的晶体质量高。当扫描速度为0.7- 4.5mm/s时，薄膜中90%以上的晶粒具有（100）择优取向。透射电子显微镜（TEM）显示，在9 μ m直径的观察范围内，a-Si ZMC薄膜中既没有明显的晶界，也没有明显的缺陷。由厚度小于1 μ m的a-Si膜制备的a-Si ZMC膜没有空隙。这种低缺陷密度表明，通过使用这种非常低缺陷密度的硅薄膜，可以制造具有高效率的硅薄膜太阳能电池。(C)2001年美国物理学会。
Silicon (Si) thin films with very-low defect density for solar cells were fabricated by using high-speed (0.7-4.5 mm/s) zone-melting crystallization (ZMC) of amorphous-silicon (a-Si) thin films, resulting in films that had defects below the detection limit of electron spin resonance (ESR). In this letter, poly-crystalline silicon (poly-Si) films for zone-melting recrystallization (ZMR) and a-Si films for ZMC were each sandwiched between two SiO2 films. The Si films were 0.3-2.0 mum thick, the top SiO2 films were 0.35-1.5 mum thick, and the bottom SiO2 films were 0.18-1.2 mum thick. The a-Si ZMC films had higher crystal quality than did the poly-Si ZMR films. Over 90% of the grains in the a-Si ZMC films had preferred (100) orientation when the films were formed at scan speeds 0.7-4.5 mm/s. Transmission electron microscopy (TEM) revealed that neither distinct grain boundaries nor defects were visible in the a-Si ZMC films within the 9-mum-diam observation field. The a-Si ZMC films fabricated from the a-Si films with the thickness smaller than 1 mum had no voids. Such a low defect density indicates that silicon thin-film solar cells with high efficiency can be fabricated by using such very-low defect density silicon thin films. (C) 2001 American Institute of Physics.