Hydrogen passivation effect on P-type poly-Si/SiOx stack for crystalline silicon solar cells

Abstract

Cyclic dehydrogenation-rehydrogenation (D-R) experiments are performed on thin oxide passivated contact (TOPCon) p-type poly-Si/SiOx stack to investigate the role of hydrogen atoms for crystalline silicon solar cell. The dehydrogenation steps are performed by thermal annealing at 450 °C for 1h under vacuum condition, and the rehydrogenation steps by hydrogen plasma treatment (HPT) at 300 °C for 1min. The ultrathin SiOx layer of 0.8±0.1 nm is realized by atomic layer deposition (ALD) technique allowing a precise control at atomic scale. The effective lifetime is enhanced to 1.4 ms by the HPT. The D-R method underlines the contribution of H atoms to the c-Si surface passivation that diffuses into the SiOx/c-Si interface. Besides, the lifetime recovery is well described by a stretched exponential function that indicates the dispersive nature of the p-type poly-Si/SiOx stack.