Impact of surface preparation prior to Al2O3 deposition for i-PERC cells

The trend of the photovoltaic industry consisting in decreasing the wafer thickness leads to the strengthening of the requirements related to surface passivation. AlOx is known to be a promising candidate to fulfill these requirements by combining chemical and field effect passivation. However, Al
₂
O
₃
is not implemented in production yet since its integration still faces some issues (aging, thermal stability blisters...). This work focuses on the impact of the surface preparation prior to the AlOx deposition.. We show that HNO
₃
-based cleans are the most suitable for AlOx passivation for a further integration in an industrial solar cell process flow.