Influence of glass phase in silver paste on metallized contact resistance between rear silver and aluminum electrodes of crystalline silicon PERC cells

Abstract

In the back-side metallization process of the passivated emitter and rear cell (PERC), the contact between the Ag rear electrode and Al rear electrode is an important factor for cell efficiency. In this paper, we report on the effect of Ag paste containing two types of oxide glass frit, V-B-Te and Pb-B-Si, on the Ag/Al contact, owing to their remarkable contrast with regard to the Ag/Al contact resistance. By combining the observation of the Ag/Al interface structure with the investigation on the interaction between glass and Al, glass transition temperature, and the distribution of glass phase in the Ag electrode, the influence of the glass phase on the contact resistance between rear Ag and Al electrodes was clearly elucidated.