On the passivation performance of SiNx, SiOxNy and their stack on c-Si wafers for solar cell applications: Correlation with optical, chemical and interface properties


Canar H. H., Bektaş G., Turan R.

SOLAR ENERGY MATERIALS AND SOLAR CELLS, vol.256, 2023 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 256
  • Publication Date: 2023
  • Doi Number: 10.1016/j.solmat.2023.112356
  • Journal Name: SOLAR ENERGY MATERIALS AND SOLAR CELLS
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, PASCAL, Aerospace Database, Chemical Abstracts Core, Chimica, Communication Abstracts, Compendex, Environment Index, Greenfile, INSPEC, Metadex, Civil Engineering Abstracts
  • Keywords: Fixed charge density, Hydrogen, Interface state density, Silicon nitride, Silicon oxynitride, Surface passivation
  • Middle East Technical University Affiliated: Yes

Abstract

SiNx and SiOxNy layers deposited by the PECVD method are commonly used in silicon solar cells for their excellent thin film properties. In this study, we perform an experimental analysis of the optical, chemical and electrical properties of these films prepared under different process conditions. The C-V measurements for the interface analysis reveal that SiOxNy layers for any refractive index have lower interface state density and fixed charge density than SiNx layers. Additionally, our calculations on the FTIR spectra indicate that SiNx, when compared with SiOxNy, has a significantly higher hydrogen amount which is important in reducing the interface traps. Furthermore, we explain the passivation results obtained from PCD measurement for single SiNx, single SiOxNy and their stack layers on p-type and n-type Si wafers by C-V and FTIR measurements. Our results suggest that depositing a very thin SiOxNy having low Dit beneath SiNx having high Qf and H amount provides superior passivation on p and n-type Si wafers, which is improved further by a subsequent fast-firing process.