The effect of SiNx:H stoichiometry on electrical and chemical passivation of Al2O3/SiNx:H stack layer on p-type silicon wafers


Canar H. H., BEKTAŞ G., Keçeci A. E., Asav H., Bütüner S. K., Arlkan B., ...Daha Fazla

12th International Conference on Crystalline Silicon Photovoltaics, SiliconPV 2022, Hybrid, Konstanz, Almanya, 28 - 30 Mart 2022, cilt.2826 identifier identifier

  • Yayın Türü: Bildiri / Tam Metin Bildiri
  • Cilt numarası: 2826
  • Doi Numarası: 10.1063/5.0140213
  • Basıldığı Şehir: Hybrid, Konstanz
  • Basıldığı Ülke: Almanya
  • Orta Doğu Teknik Üniversitesi Adresli: Evet

Özet

In this paper, we report on the influence of SiNx:H stoichiometry on Al2O3/SiNx:H passivation stacks. We analyze the fabricated dielectric layers with four methods: FTIR, C-V, PCD and EQE. SiNx:H with a lower refractive index (SiN1) is poorer in H content than the one with a higher refractive index (SiN2) according to FTIR peaks. The calculated fixed charge density of the non-fired SiN1 layer is larger than SiN2; however, Al2O3 layer has the greatest magnitude but in negative polarity. The charge density of the Al2O3/SiN1 stack increases in magnitude with an increase in peak firing temperature while the Al2O3/SiN2 stack shows a decrease in magnitude. Al2O3/SiN1 stack resists a higher peak temperature during the fast-firing process with a relatively small reduction in iVoc values on symmetrically etched p-Si wafers due to the relatively lower H content of SiN1. Our results suggest that the chemical passivation of Si is more pronounced than the field effect passivation. We also investigate the effect of SiNx:H on the PERC solar cells with Al2O3/SiN1 and Al2O3/SiN2 stacks. The EQE results measured on the fabricated PERC cells demonstrate that the IR response is better for the PERC solar cells with Al2O3/SiN1 rear stack passivation implying enhanced passivation.