8th World Conference on Photovoltaic Energy Conversion; 211-213 Silver (Ag) pastes are widely used in the global market for most solar cell architectures. In particular, lead (Pb) is no longer wanted in productions for environmental reasons. In this work, a model for the contact formation between Pb-free, tellurium (Te) oxide containing screen-printable Ag pastes and silicon is presented. It is shown that Te plays a key role in this model. Te is not only an important part in etching the surface passivation layers with TeO2 dissolving the dielectric layer, but also for a formation of the contacts with Te forming a compound consisting of Ag2Te. Using EDX mapping, precise contact regions can be examined and interpreted for contact formation. The used paste is a novel developed commercial paste which is on a par with other pastes used in industry concerning the resulting contact properties. This is also demonstrated in this work by the very low contact resistances of less than 1 mΩcm2 over a wide range of fire peak temperatures. It is additionally shown that good resistances can be achieved on both nand p-doped regions.
