Herein, an alternative approach of metallization on tunnel oxide passivated contacts (TOPCon) devices, through the method of localized laser ablation and nickel–copper plating, is presented. The method is demonstrated to be a viable and effective alternative, yielding better performance and results than the conventional screen‐printed contacts. The laser ablation process, with a lower increase in recombination current as compared to screen printing, proves to be a far less damaging process than the latter. TOPCon solar cells, fabricated and compared using the two metallization approaches, show a substantial improvement in an absolute power efficiency of ≈1%. Due to the highly superficial nature of damage with the optimized laser parameters, it enables the reduction of the poly‐Si layer thickness down to 70 nm in the TOPCon stack and also a high cell conversion efficiency of 22%. This allows for a substantial reduction in ownership costs of the final device without compromising on performance, making TOPCon cells with plated contacts an attractive technological upgrade for industrial‐level production following the passivated emitter rear contact cell technology.

Herein, an analysis on the impact of laser contact opening of TOPCon/SiN_xstacks is presented. By etching in tetramethylammonium hydroxide (TMAH), the defect distribution in the interfacial tunnel oxide is accessed and analyzed. The defect density is significantly increased in areas where adjacent laser contact openings (LCO) overlap. Using microscopic photoluminescence (μ‐PL) spectroscopy, it is verified that correlates with an increase in the local recombination rate and thus an increase in theJ_0,Met. Therefore, overlapping LCO of SiN_xin TOPCon/SiN_xstacks should be avoided as much as possible. Furthermore, the investigations indicate that defects in the interfacial oxide are dominantly created along exposed structures like tips and edges of (etched‐back) pyramids. A comparison of TOPCon/SiNx stacks with a variation of TOPCon thicknesses indicate that etch pits, and thus the defect density, related to LCO become more significant at lower thicknesses.

Light-induced plating on laser-structured passivation layer openings is an alternative method to silver screen printing for fabrication of the front-side metal grid on silicon solar cells. Fundamental contact properties, such as adhesion and contact resistance, are determined at the highly inhomogeneous interface of laser-structured silicon and plated nickel. Usage of laser structuring and plating holds the risk that an interfacial oxide layer is incorporated to the contact stack. It is shown within this article that both native and laser-induced oxide formation influence contact properties. Although, a native oxide layer does not impede metal deposition during plating, the dynamics of the layer formation is shown to be changed. It is known that interface oxides harm the contact resistance, and it is reported that postplating annealing decreases the contact resistance. In this article, the microstructural basis of the temperature-induced changes is examined. By transmission electron microscopy and energy dispersive X-ray spectroscopy, no temperature-induced modification of the interface microstructure, such as silicide formation or metal-induced crystallization of the amorphous surface, is observed. Results suggest that the decrease is attributed to a temperature-induced change of the electrical properties of the interface oxide. Considering reports that partially closed interface oxide layers are an inherent feature of laser-structured plated contacts, the results presented motivate reconsidering the objective of postplating annealing. The results indicate that the beneficial impact of silicide formation is overrated for the case of laser-structured plated contacts, whereas the temperature-induced modifications on residual interface oxide layers are neglected in the scientific discussions on the given contact stack.