Tunnel oxide passivated contact solar cells completed with ultrashort pulse laser contact opening and electrochemical plating metallization techniques

Tunnel oxide passivated contact (TOPCon) solar cells will likely become the most produced crystalline silicon photovoltaic architecture within the next five years. The technology relies on multiple thin films to improve cell efficiency by further reducing electron-hole recombination at metal-semiconductor interfaces. Lasers are used to remove the anti-reflection thin film layer to prepare regions of the cells for electrical contact formation (“metallization”). This process—laser contact opening or LCO—is challenging in that the underlying thin films must suffer minimal damage. TOPCon is an ideal architecture for implementing electrochemical plating metallization, which has certain advantages over conventional methods. In this work we report on the use of ultraviolet (UV) wavelength ultrashort pulse lasers for TOPCon LCO processing in concert with electrochemical plating metallization. Laser parameters selection is reviewed, and processing results are analyzed with optical and scanning electron microscopy. Complete solar cells are fabricated and performance metrics are discussed.