Different Aspects of Seed Layer-Printed and Light-Induced Plated Front Side Contacts

The properties of fine-line printed contacts on silicon solar cells, in combination with light-induced plating (LIP), are investigated. The seed layers are printed using an aerosol system and a new metallization ink called SISC developed at Fraunhofer ISE. The influence of multiple layer printing on the contact geometry is studied as well as the influence of the contact height on the line resistivity and on the contact resistance. As the line resistivity of fine-line printed fingers needs to be reduced by LIP, three different plating electrolytes are tested on solar cells. The observed differences in line resistivity between ρf = 5×10 -8 Ωm and 2×10 -8 Ωm are explained by taking SEM pictures of the grown LIP silver. Finally, the optimum LIP height for different line resistivities is calculated and experimentally confirmed by processing solar cells with an increasing amount of LIP silver.