Thermal Stability of Copper-Nickel and Copper-Nickel Silicide Contacts for Crystalline Silicon

Abhijit Kale, William Nemeth, Craig Perkins, David Young, Pauls Stradins, Alexander Marshall, Karine Florent, Santosh Kurinec, Sumit Agarwal, Abhijit Kale

Research output: Contribution to journalArticlepeer-review

15 Scopus Citations


Copper is a low-cost, low-damage alternative to Ag paste for front-side metallization of crystalline Si (c-Si) solar cells, but requires conductive diffusion barriers like Ni or NiSi. Thermal stability of these barriers during postmetallization anneal is critical for performance. In this study, we address the structural and chemical stability of Cu contacts with both Ni and NiSi barrier layers, identifying interfacial reactions responsible for their degradation. Superior thermal and chemical stability of single-phase NiSi barrier as compared to Ni is made evident by XRD, Auger, and Raman spectroscopies. Moreover, the commonly used Cu-Ni-Si contact stack does not convert to more stable Cu-NiSi-Si stack upon thermal treatment. Instead, Cu readily alloys with the Ni layer and reacts with the underlying c-Si to form Cu3Si, with no evidence for the formation of NixSi phases. Also, even the superior NiSi barrier slowly dissolves into Cu at elevated temperatures.

Original languageAmerican English
Pages (from-to)2841-2848
Number of pages8
JournalACS Applied Energy Materials
Issue number6
StatePublished - 25 Jun 2018

Bibliographical note

Publisher Copyright:
© 2018 American Chemical Society.

NREL Publication Number

  • NREL/JA-5900-71509


  • copper
  • metallization
  • nickel
  • nickel silicide
  • solar cell


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