Passivation characteristics of SiN_x/a-Si and SiN_x/Si-rich-SiN_x stacked layers on crystalline silicon

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• 作者：Trinh Cham Thi^a ; Koichi Koyama^a ; ^b ; Keisuke Ohdaira^a ; ^{ohdaira@jaist.ac.jp} ; Hideki Matsumura^a ; ^b
• 关键词：Si-rich silicon nitride ; Amorphous silicon ; Solar cell efficiency ; Cat-CVD ; Passivation ; Surface recombination velocity
• 刊名：Solar Energy Materials and Solar Cells
• 出版年：2012
• 期刊代码：81_09270248
• 类别：ce
• 出版时间：May, 2012
• 卷：100
• 期：Complete
• 页码：169-173
• 文件大小：579 K

摘要

High-quality surface passivation is essential for obtaining crystalline silicon (c-Si) solar cells with high energy-conversion efficiency. Silicon-nitride (SiN_x)/amorphous-silicon (a-Si) stacked layers prepared by catalytic chemical vapor deposition (Cat-CVD), also referred to as hot-wire CVD, demonstrate excellent performance as surface passivation layers for c-Si and realize a dramatically low surface recombination velocity (SRV). However, the use of a more transparent material than a-Si is required because the a-Si layer absorbs sunlight. Here, Si-rich SiN_x films, as a more transparent material, with various atomic ratios of silicon/nitrogen (Si/N) are investigated as a replacement for a-Si films. The use of SiN_x/Si-rich-SiN_x stacked layers as passivation films on c-Si wafers results in a SRV as low as 5 cm/s and 30%improvement of the transparency at the wavelength of 400 nm compared to that of the SiN_x/a-Si stacked layers. Moreover, after the annealing process, the passivation characteristics of the stacked layer were significantly improved, with a SRV as low as 3 cm/s.