CC BY 4.0Sarıgül Duman, ElifElifSarıgül DumanRichter, ArminArminRichterReichel, ChristianChristianReichelFittkau, JensJensFittkauLe Tiec, ChristianeChristianeLe TiecMoldovan, AnamariaAnamariaMoldovanBenick, JanJanBenick2023-05-052023-05-052022Note-ID: 0000656Ahttps://publica.fraunhofer.de/handle/publica/441358https://doi.org/10.24406/publica-131110.1063/5.009063910.24406/publica-1311We present a systematic study on effective passivation of p-type crystalline silicon (c-Si) by Al2O3 and Al2O3/SiNx stacks. Ozone-based atomic layer deposition (ALD) Al2O3 was deposited with varied thickness, ozone concentration and deposition temperature. Thermal stability of fabricated samples was investigated systematically varying post-deposition thermal treatments, such as forming gas annealing (FGA) and fast firing. Blister free Al2O3/SiNx stacks were obtained for Al2O3 thicknesses between 3.5-10 nm yielding effective charge carrier lifetimes (τeff) above 1.5 ms, which correspond to an implied open-circuit voltage (iVoc) above 730 mV. The best performing Al2O3 layers in terms of their passivation quality, deposition uniformity and firing stability after being capped by SiNx were obtained when a low ozone concentration was utilized in the ALD process. As no additional out-gassing process is necessary between ALD Al2O3 and PECVD SiNx deposition, these ozone-based ALD Al2O3 layers have the potential to simplify the rear-side passivation of PERC solar cells in mass production.enconference paper