IBC c-Si(n) Solar Cells Based on Laser Doping Processing for Selective Emitter and Base Contact Formation

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• 作者：Gerard Masmitja ; ^{gerard.masmitja@upc.edu" class="auth_mail" title="E-mail the corresponding author} ; Pablo Ortega ; Isidro Martí ; n ; Gema Ló ; pez ; Cristobal Voz ; Ramó ; n Alcubilla
• 关键词：IBC ; c-Si solar cells ; boron ; laser doping ; surface passivation ; Al2O3 ; silicon carbide
• 刊名：Energy Procedia
• 出版年：2016
• 出版时间：August 2016
• 年：2016
• 卷：92
• 期：Complete
• 页码：956-961
• 全文大小：231 K

文摘

In the last years, there is a clear trend in c-Si solar cell fabrication to place both emitter and base contacts on the back side leading to the so-called Interdigitated Back Contacted (IBC) solar cell structure. This solar cell architecture requires excellent front and rear surface passivation as well as a very low recombination emitter. Moreover, laser doping may be an attractive technique to create both selective emitter and base contacts using appropriate dielectric layers as dopant sources, i.e. Al₂O₃ and a-SiC_x(n) stacks for the p⁺ and n⁺ regions respectively. In this study, we report on a simplified fabrication process for IBC n-type c-Si solar cells combining laser doping and a conventional boron emitter passivated by Al₂O₃ films. Results show very low emitter recombination currents in the ∼10-50 fA/cm² range before laser processing. In addition, selective emitter contacts can be created by laser doping with recombination current densities at each contact point around 4.4 pA/cm² in relatively low and shallow doped boron doped profiles (sheet resistance ∼400 Ω/sq). Finally, IBC solar cells, 3 x 3 cm² device area, were fabricated combining selective laser-doped emitter and base contacts reaching efficiencies up to 20.8%.