Laser Ablation and Ni/Cu Plating Approach for Tunnel Oxide Passivated Contacts Solar Cells with Variate Polysilicon Layer Thickness: Gains and Possibilities in Comparison to Screen Printing

摘要

Herein, an alternative approach of metallization on tunnel oxide passivatedcontacts (TOPCon) devices, through the method of localized laser ablation andnickel–copper plating, is presented. The method is demonstrated to be a viable andeffective alternative, yielding better performance and results than the conventionalscreen-printed contacts. The laser ablation process, with a lower increase inrecombination current as compared to screen printing, proves to be a far lessdamaging process than the latter. TOPCon solar cells, fabricated and comparedusing the two metallization approaches, show a substantial improvement in anabsolute power efficiency of 1%. Due to the highly superficial nature of damagewith the optimized laser parameters, it enables the reduction of the poly-Si layerthickness down to 70 nm in the TOPCon stack and also a high cell conversionefficiency of 22%. This allows for a substantial reduction in ownership costs of thefinal device without compromising on performance, making TOPCon cells withplated contacts an attractive technological upgrade for industrial-level productionfollowing the passivated emitter rear contact cell technology.