Industrial approach for the deposition, through-vias wet opening and firing activation of a backside passivation layer applied on solar cells
The industrial production of bulk silicon solar cells with high efficiency brings advantages as more efficient energy harvesting and better exploitation of materials. The candidate industrial approach conforms to good homogeneity on the whole designated active area as well as reproducible results on the local structuring, hence the scales span 4 order of length magnitude. The approaches used here are based on the improvement of the passivation of the dark side of the cell, employing a so called backside passivation layer (BSPL), this approach is compared to a reference screen printing of Aluminium paste and subsequent firing. The passivation mechanism of the deposited layer is affected by subsequent metallisation steps, some process sequences show with comparison to reference a loss in open circuit voltage and short circuit current, the fill factor can still be comparable. Cells realised with this approach are facing the constraints of the tools, adjustments of the process parameters will deliver the high efficiency that is targeted.