Excellent Passivation of n‐Type Silicon Surfaces Enabled by Pulsed‐Flow Plasma‐Enhanced Chemical Vapor Deposition of Phosphorus Oxide Capped by Aluminum Oxide

Jimmy Melskens (Corresponding author), R.J. Theeuwes, Lachlan E. Black, Willem-Jan H. Berghuis, Bart Macco, P.C.P. Bronsveld, W.M.M. Kessels

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Phosphorus oxide (POx) capped by aluminum oxide (Al2O3), prepared by atomic layer deposition (ALD), has recently been introduced as a surface passivation scheme for planar n‐type FZ silicon. In this work, a fast pulsed‐flow plasma‐enhanced chemical vapor deposition (PECVD) process for the POx layer is introduced, making it possible to increase the POx deposition rate significantly while maintaining the POx/Al2O3 passivation quality. An excellent surface passivation is realized on n‐type planar FZ and Cz substrates (J0 = 3.0 fA cm−2). Furthermore, it is demonstrated that the POx/Al2O3 stack can passivate textured surfaces and that the application of an additional PECVD SiNx capping layer renders the stack stable to a firing treatment that is typically used in fire‐through contact formation (J0 = 12 fA cm−2). The excellent surface passivation is enabled by a high positive fixed charge density (Qf ≈ 4 × 1012 cm−2) and an ultralow interface defect density (Dit ≈ 5 × 1010 eV−1 cm−2). Finally, outstanding passivation is demonstrated on textured silicon with a heavy n+ surface doping, as is used in solar cells, on par with alnealed SiO2. These findings indicate that POx/Al2O3 is a highly suited passivation scheme for n‐type silicon surfaces in typical industrial solar cells.
Original languageEnglish
Article number2000399
Number of pages6
JournalPhysica Status Solidi : Rapid Research Letters
DOIs
Publication statusAccepted/In press - 7 Oct 2020

Keywords

  • aluminum oxide
  • chemical vapor deposition
  • phosphorus oxide
  • silicon
  • surface passivation

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