Development of High Efficiency Back Passivated Silicon Solar Cells with Screen Printed Contacts

This paper presents a detailed analysis of point-contacted aluminium rear side for silicon solar cells. An industrial feasible process for these solar cells based on screen-printed aluminium layer and thermal oxide/silicon nitride passivation is described. The local removal of the passivation stack by the mean of laser ablation is studied. Laser conditions are found to selectively and locally ablate the layers and reduce the laser-induced damages in the Si and the passivation layer. Results of these studies are applied on large area back passivated solar cells and electrical parameters highlight the importance of parasitic shunting on this type of structure.