原子层沉积生长Al2O3薄膜表面钝化机理的研究

In this paper, thin Al2O3 films were grown on different conductivity type of textured crystalline silicon (c-Si) wafers by atomic layer deposition (ALD). The structure property of Al2O3 films were characterized by field emission scanning electron microscopy (FESEM). The effective lifetime (τeff) of the minority carriers for different conductivity type of textured c-Si were measured by quasi-steady-state photoconductance (QSSPC). It is found that τeff of minority carriers of p- and n-type textured c-Si with 23 nm Al2O3 shows the similar value of 9.2 μs and 11.1 μs, respectively. However, after annealing in air, τeff of minority carriers increase to 39.4 μs and 28.2 μs for p- and n-type textured c-Si, respectively, which is demonstrated that Al2O3 films exhibit better surface passivation of p-type textured c-Si. The origin of the more effective surface passivation of p-type textured c-Si is due to the fixed negative charge density and the decrease of defect density at the interface of Si/Al2O3.