Dual Function of Antireflectance and Surface Passivation of Atomic-Layer-Deposited $\hbox {Al}_{2}\hbox {O}_{3}$ Films

Surface antireflectance and passivation properties of the Al₂O₃ films deposited on Czochralski Si wafers by atomic layer deposition (ALD) are investigated. Textured Si with 100-nm Al₂O₃ shows a very low average reflectance of ~2.8%. Both p- and n-type Si wafers are well passivated by Al₂O₃ films. The maximal minority carrier lifetimes are improved from ~10 μs before Al₂O₃ passivation to above 3 ms for both p- and n-type Si after Al₂O₃ film deposition and annealing at an appropriate temperature. Hence, an ALD-deposited Al₂O₃ film shows the dual function of antireflectance and surface passivation for solar cell applications.