How to Realize Solar Cells with Laser Structured Plated Ni-Cu-Contacts with Excellent Adhesion and High Fill-Factors without Parasitic Plating
Investigating modifications of the silicon/metal interface during the manufacturing process and the influence on properties of laser-structured Ni-Cu-plated contacts enabled optimizing the metallization process. The micro pattern induced by ultrashort pulsed lasers ensures adhesion even without nickel silicide formation. Minimizing growth of laser-induced and native oxide at the surface of the laser patterned contact openings before plating enables high fill-factors without HF-treatment before metal deposition. Skipping the wet-chemical treatment eliminates parasitic plating on precursors with defective ARC. Compared to the state-of-the-art plating sequence, the approach presented features less process steps and enables improved solar cell aesthetics.