Influence of Contact Firing Conditions on the Characteristics of bi-facial n-type Silicon Solar Cells Using Ag/Al Pastes☆

In this study we investigate metal spike formation of screen-printed Ag/Al pastes during contact firing in an infrared belt furnace and its influence on the characteristics of n-type bi-facial silicon solar cells. The boron emitters are formed in a co-diffusion step using boron doped PECVD layers. It is demonstrated that the formation of Ag/Al spikes results in strong FF and V-OC losses limiting the solar cell efficiency. This can mainly be attributed to an increased saturation current density of the second diode which is strongly increasing with increasing set peak firing temperature. A detailed scanning electron microscopy analysis reveals that this j(02) increase can be attributed to an increasing area density and depth of the Ag/Al spikes for increasing peak firing temperatures. (C) 2016 The Authors. Published by Elsevier Ltd.