Aluminum fire-through with different types of the rear passivation layers in crystalline silicon solar cells

• Published in: Metals and materials international 2012, 18(4), , pp.699-703
• Main Authors: Song, Joo yong, Park, Sungeun, Kim, Young Do, Kang, Min Gu, Tark, Sung Ju, Kwon, Soonwoo, Yoon, Sewang, Kim, Donghwan
• Format: Article
• Language: English
• Subjects: Aluminum; Annealing; Characterization and Evaluation of Materials; Chemistry and Materials Science; Dielectrics; Engineering Thermodynamics; Heat and Mass Transfer; Machines; Magnetic Materials; Magnetism; Manufacturing; Materials Science; Metallic Materials; Passivation; Photovoltaic cells; Processes; Silicon; Silicon dioxide; Solar cells; Solid Mechanics; 재료공학
• ISSN: 1598-9623; 2005-4149
• DOI: 10.1007/s12540-012-4020-0

Aluminum penetration during dielectric layer annealing on silicon was studied for solar cell application. The thickness and uniformity of the aluminum-doped region was examined in variously annealed dielectric layers. Three types of silicon wafers were used with (1) bare Si, (2) SiO 2 layer (80 nm)/Si, and (3) SiN X layer (80 nm)/Si. Local metal contacts were made through laser-drilled holes, and annealing was tested at four different temperatures. Reactions between aluminum and silicon were observed by cross-sectional scanning electron microscopy. Reactions occurred at 660 °C on bare Si and at ca. 690 °C on the SiO 2 layer. However, the SiO 2 did not withstand annealing at higher temperatures. The SiN X layer showed no Al-BSF region in samples annealed at up to 760 °C, making it a suitable material for rear passivation layers in local contact Si solar cells. A Si solar cell fabricated by laser drilling and screen printing showed an efficiency of 12.41% without optimization.