Approaches to Metallization for Poly-Si/SiOx Passivated Contacts

Manuel Schnabel, William Nemeth, San Theingi, Abhijit Kale, Marinus Van Hest, David Young, Pauls Stradins, Talysa Klein, Benjamin Lee, Sumit Agarwal

Research output: NRELPresentation


Recent improvements in Si solar cell efficiency beyond 25% have used doped poly-Si/SiOx or a-Si:H passivated contacts, the former culminating in a 25.7% cell with a n-poly-Si/SiOx rear contact 1 that is fundamentally compatible with screen printing and firing. However, metallization of the <100 nm thick stack is challenging and can limit open-circuit voltage (Voc) 2, 3. The goal of the work presented here is to develop metallization routes for poly-Si/SiOx passivated contacts with acceptable contact resistivity and minimized Voc loss. This is approached through incremental as well as disruptive improvements to metal evaporation. We examine all aspects of the poly-Si/SiOx process chain that can contribute to contact performance, including poly-Si/SiOx properties, passivation routes, capping layers, and metal deposition methods and post-treatments. We also discuss how to best quantify the contact resistivity that exists while operating a solar cell at maximum power point. Finally, we present two novel approaches to contacting poly-Si/SiOx - a thermally evaporated ITO interlayer, and a transparent conducting adhesive.
Original languageAmerican English
Number of pages20
StatePublished - 2017

Publication series

NamePresented at the 7th Workshop on Metallization & Interconnection for Crystalline Silicon Solar Cells, 23-24 October 2017, Konstanz, Germany

NREL Publication Number

  • NREL/PR-5900-70266


  • conducting adhesive
  • ITO
  • metallization
  • passivated contact
  • poly-Si


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