Easy plating - a simple approach to suppress parasitically metallized areas in front side Ni/Cu plated crystalline Si solar cells
Plated silicon solar cells with nonoptimized antireflective coatings (ARCs) may feature parasitic plating (PP), i.e., unwanted metal depositions in ARC defects/pinholes. The present work introduces the easy plating sequence that takes advantage of native oxide growth to avoid plating in unwanted ARC pinholes or defects due to the electrical insulation of these defects. This prevents PP for plated solar cells. Independent of the ARC pinhole density, an aesthetic immaculate appearance can be achieved using easy plating. It is shown that it is possible to gain up to 0.5 mA/cm2 in short-circuit current density and 6 mV in open-circuit voltage compared to the reference plating sequence at Fraunhofer ISE. The importance to avoid drawbacks in terms of contact resistance and contact adhesion due to laser-induced or native oxide at the Si-Ni interface in the easy plating sequence is discussed in detail and important influencing factors in the process chain are lined out. At this stage of development, low contact resistances are possible in some cases but further research is necessary to fully understand the impact of solar cell design and process-related influencing factors. Easy plating can be an option to avoid PP independent of prior ARC pinhole density.