Mechanism of Hydrogen Passivation in Passivated Contact Si Solar Cells

Suchismita Mitra, Matthew Hartenstein, Harvey Guthrey, William Nemeth, Steve Harvey, David Young, Sumit Agarwal, Paul Stradins

Research output: NRELPoster


In this abstract, we discuss the mechanism of hydrogen passivation on symmetrical n-Si/ultra-thin SiO2/polySi structures. The hydrogen was introduced from different hydrogen-containing dielectric layers (AlOx:H and SiNx:H and their stacks), as well as by forming gas anneal (FGA). The effusion of hydrogen both from the dielectric layers and in the underlying poly-Si was explored using a quadrupole mass spectrometer (QMS) and FTIR spectroscopy. We show that the strength of hydrogen bonds depend on the deposition technique as well as hydrogenation mechanism. While a PECVD SiNx:H loses hydrogen at a peak temperature of ~450 degrees C, LPCVD SiNx:H, although having less hydrogen compared to PECVD, effuses at a peak temperature of ~850 degrees C. This becomes important to maintain passivation of passivated contacts after firing of metal contacts at high temperatures. On the other hand, it has been observed that SiNx:H provides larger amount of hydrogen to poly-Si after FGA compared to FGA treated AlOx:H, which acts as a capping layer and helps in retaining the hydrogen up to higher temperatures.
Original languageAmerican English
StatePublished - 2023

Publication series

NamePresented at the SiliconPV 2023 Conference, 10-14 April 2023, Delft, The Netherlands

NREL Publication Number

  • NREL/PO-5900-84594


  • hydrogen bonding configuration
  • hydrogen passivation
  • passivation
  • photovoltaic
  • PV
  • Si solar cells


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