Impact of Laser-Induced Oxidation on Silicon Wafer Solar Cells' Performance

• Published in: IEEE journal of photovoltaics Vol. 6; no. 3; pp. 617 - 623
• Main Authors: Du, Zheren, Zhang, Chentao, Li, Fengping, Zhou, Rui, Hong, Minghui
• Format: Journal Article
• Language: English
• Published: Piscataway IEEE 01.05.2016; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Aluminum local back surface field (Al-LBSF); Defects; Dielectrics; Etching; Fabrication; Laser ablation; laser-induced oxidation; Lasers; Nitrogen; Oxidation; Photovoltaic cells; Silicon; silicon wafer solar cells; Silicon wafers; Solar cells; Wafers; laser ablation; silicon wafer solar cells; Aluminum local back surface field (Al-LBSF); laser-induced oxidation
• ISSN: 2156-3381; 2156-3403
• DOI: 10.1109/JPHOTOV.2016.2535243

Lasers are frequently used to locally open dielectric layers for contacting the front or rear side of advanced silicon wafer solar cell architectures. For reasons of cost, laser processes are usually carried out in ambient environment, which inevitably leads to the oxidation of silicon. In order to achieve maximum solar cell efficiency, the laser processing has to be optimized thoroughly. The current research only focuses on minimizing laser-induced defects in silicon. However, our investigation shows another side effect of laser ablation, i.e., laser-induced oxidation, which is often neglected and undesirable for the subsequent metallization process. In this paper, we investigated the impact of laser-induced oxidation, which is caused by laser ablation in air, on the performance of silicon wafer solar cells. We show that by applying a postlaser etching step, laser-induced defects and oxide film can be removed effectively, providing improved conditions for the subsequent metallization process.