Effects on Metallization of n + -Poly-Si Layer for N-Type Tunnel Oxide Passivated Contact Solar Cells

• Published in: Materials 2024-06, Vol.17 (11), p.2747
• Main Authors: Wang, Qinqin, Gao, Beibei, Wu, Wangping, Guo, Kaiyuan, Huang, Wei, Ding, Jianning
• Format: Article
• Language: English
• Subjects: Chemical vapor deposition; Contact pressure; Efficiency; Heat treating; Lasers; Low pressure; Metallizing; Microscopy; Passivity; Phosphorus; Photovoltaic cells; Polysilicon; Short circuit currents; Silicon; Silicon wafers; Silver; Solar cells; Thickness
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma17112747

Thin polysilicon (poly-Si)-based passivating contacts can reduce parasitic absorption and the cost of n-TOPCon solar cells. Herein, n -poly-Si layers with thicknesses of 30~100 nm were fabricated by low-pressure chemical vapor deposition (LPCVD) to create passivating contacts. We investigated the effect of n -poly-Si layer thickness on the microstructure of the metallization contact formation, passivation, and electronic performance of n-TOPCon solar cells. The thickness of the poly-Si layer significantly affected the passivation of metallization-induced recombination under the metal contact ( ) and the contact resistivity ( ) of the cells. However, it had a minimal impact on the short-circuit current density ( ), which was primarily associated with corroded silver (Ag) at depths of the n -poly-Si layer exceeding 40 nm. We introduced a thin n -poly-Si layer with a thickness of 70 nm and a surface concentration of 5 × 10 atoms/cm . This layer can meet the requirements for low and values, leading to an increase in conversion efficiency of 25.65%. This optimized process of depositing a phosphorus-doped poly-Si layer can be commercially applied in photovoltaics to reduce processing times and lower costs.