Novel Passivation and Gettering Strategy for Silicon Wafer by Al₂O₃/n‐poly‐Si/SiOx Stack for High‐Efficiency p‐Type Passivating Tunnel Oxide Contact Solar Cells

This study focuses on the enhanced passivation and gettering of boron‐doped p‐type solar grade silicon wafers by incorporating carrier‐selective and passivating tunnel oxide contact (TOPCon). A symmetrical stack of aluminum oxide (Al 2 O 3 )/p‐doped n‐type polysilicon (n‐poly‐Si)/ ultrathin silicon oxide (SiO x ) in conjunction with long cycles of forming gas annealing is used for enhancing the silicon wafer quality with a novel approach. Multilayer of n‐poly‐Si/SiO x on p‐type crystalline silicon wafer exhibits an implied open‐circuit voltage ( iV oc ) of 726 mV, effective carrier lifetime ( τ eff ) of 857 μs, and a low recombination current density ( J o ) of 1.9 fA cm −2 when subjected to a postdeposition annealing (PDA) of phosphorus‐doped hydrogenated amorphous silicon (n‐a‐Si:H) at 820 °C. To boost passivation and gettering quality, 10 nm‐thick Al 2 O 3 layers on both sides of n‐poly‐Si/SiO x samples are added. This leads to improved τ eff (962 μs), reduced J o (1.1 fA cm −2 ), and higher iV oc (728 mV). Herein, a thinner 50 nm n‐poly‐Si layer for improved properties is applied. The experiments show improved passivation and gettering. A Quokka‐3 simulation examines the potential of high‐efficiency p‐type TOPCon cells. A novel solar‐grade p‐type wafer quality enhancement approach is introduced, amalgamated with Quokka‐3 results, which could be a milestone in high‐efficiency p‐type TOPCon solar cell production.