Understanding SiOx Layer Breakup in Poly-Si/SiOx Passivating Contacts for Si Solar Cells Using Precisely Engineered Surface Textures

Caroline Lima Salles, Harvey Guthrey, Abhijit Kale, William Nemeth, Matthew Page, David Young, Pauls Stradins, Sumit Agarwal

Research output: Contribution to journalArticlepeer-review

3 Scopus Citations

Abstract

The contact resistivity of polycrystalline silicon on silicon oxide (poly-Si/SiOx) passivating contacts depends on the formation of pinholes in SiOxfor thicknesses ≳1.7 nm. We fabricated these contacts on inverted pyramids and v-grooves in addition to the alkaline-textured random pyramids and planar surface morphologies. The thermal breakup of SiOxwas achieved at peak annealing temperatures of 1050 and 1100 °C. SiOxbreakup at 1050 °C resulted in pinholes created preferentially at vertices in the inverted pyramids, while at 1100 °C, their formation was random. The density of pinholes was greater in textured samples than in polished samples. Both chemical etching and electron beam-induced current (EBIC) were used to visualize the pinholes, the latter being sensitive only to transport pinholes in the p-n junction but not the n+-n junction. We ascribe this difference in EBIC images based on the contact polarity to differences in the collection probability of the minority carriers generated by the electron beam. Our work demonstrates that texture morphology can be exploited to enable the precise engineering of pinholes in poly-Si/SiOxpassivating contacts.

Original languageAmerican English
Pages (from-to)3043-3051
Number of pages9
JournalACS Applied Energy Materials
Volume5
Issue number3
DOIs
StatePublished - 28 Mar 2022

Bibliographical note

Publisher Copyright:
© 2022 American Chemical Society. All rights reserved.

NREL Publication Number

  • NREL/JA-5900-82259

Keywords

  • EBIC
  • inverted pyramids
  • passivating contacts
  • pinholes
  • polysilicon
  • surface morphology
  • v-grooves

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