Study of screen printed metallization for polysilicon based passivating contacts

Ciftpinar H. E. , Stodolny M. K. , Wu Y., Janssen G. J. M. , Loffler J., Schmitz J., ...More

7th International Conference on Crystalline Silicon Photovoltaics (SiliconPV), Freiburg, Germany, 3 - 05 April 2017, vol.124, pp.851-861 identifier identifier

  • Publication Type: Conference Paper / Full Text
  • Volume: 124
  • Doi Number: 10.1016/j.egypro.2017.09.242
  • City: Freiburg
  • Country: Germany
  • Page Numbers: pp.851-861
  • Keywords: polysilicon, polySi, passivating contact, carrier selective contact, fire through metallization, contact recombination, contact resistance, SOLAR-CELLS


We investigate contacting of n- and p-type polysilicon (polySi) passivating contact layers with industrial screen-printed metal pastes, examining both fire through (FT) and non-fire through (NFT) pastes. The n- and p-type polySi layers, deposited by low pressure chemical vapour deposition and doped by POCl3 diffusion, phosphorus implant, or BBr3 diffusion, result in excellent J(o), even for 50 nm thickness (<2 fA/cm(2) for n-polySi, <10 fA/cm(2) for p-polySi). The contact recombination is investigated by photoluminescence, and by cell test structures to determine V-oc as a function of metallization fraction. The contact resistance is investigated by transfer length method (TLM). The contacts are also extensively studied by high resolution electron microscopy. All-polySi solar cells (i.e., cells with front and back carrier selective layers consisting of polySi) are prepared. Excellent implied V-oc, values of nearly 730 mV and 710 mV are obtained on the un-metallized polished and textured cells, respectively. The contact recombination after applying screen printed metallization can be analyzed well with both methods (PL and V-oc-based) rendering values for the prefactor of the recombination current J(o,c) at the contact areas of about 400 and 350 fA/cm(2) for 200 nm thick n-polySi and p-polySi, respectively. (C) 2017 The Authors. Published by Elsevier Ltd.