Research On The Surface Passivation Of Crystalline Silicon Wafer For Solar Cells

As today’s energy crisis and environment pollution become more and more severe, it should extensively contern and research how to highly utilize solar energy which is green and clean. Crystalline solar cell is one of the most efficiency ways to take advantage of solar energy. The passivation technology is particularly important for crystalline solar cells to reduce cost and improve efficiency.We first studied high-pressure water-vapor annealing (HWA) for enhancement of a-Si:H film passivation of silicon surface. All results suggest that after210℃,90min HWA, the passivation of a-Si:H film has a great improvement. During HWA, oxygen atoms enter into the bulk of a-Si:H film, which can make the films’refractive index changes between a-Si:H fims’refractive index and SiO2films’refractive index.The thickness of SiO2film made by heated HNO3liquids is about2nm, but its passivation quality to silicon surface is poor. RTP treatment at20%O2atmosphere is an available way to improve the passivation effect of SiO2film. After20%O2,800℃,45s RTP treatment, the effective carrier lifetime of samples can reach the maximum of80.06μs.RTO treatment is an available way to prepare high quality SiO2film. After100%O2,900℃,180s RTO treatment, the effective carrier lifetime of samples can reach the maximum of146.6μs. Compare with SiNx as the only passivating film, the surface passivation effect of silicon wafer has a huge improvement by SiO2/SiNx stacks.