An Isotope Study of Hydrogenation of poly-Si/SiOx Passivated Contacts for Si Solar Cells: Preprint

Manuel Schnabel, William Nemeth, Pauls Stradins, David Young, Bas van de Loo, Bart Macco, Wilhelmus Kessels

Research output: Contribution to conferencePaper


For many years, the record Si solar cell efficiency stood at 25.0%. Only recently have several companies and institutes managed to produce more efficient cells, using passivated contacts of made doped poly-Si or a-Si:H and a passivating intrinsic interlayer in all cases. Common to these designs is the need to passivate the layer stack with hydrogen. In this contribution, we perform a systematic study of passivated contact passivation by hydrogen, using poly-Si/SiOx passivated contacts on n-Cz-Si, and ALD Al2O3 followed by a forming gas anneal (FGA) as the hydrogen source. We study p-type and n-type passivated contacts with implied Voc exceeding 690 and 720 mV, respectively, and perform either the ALD step or the FGA with deuterium instead of hydrogen in order to separate the two processes via SIMS. By examining the deuterium concentration at the SiOx in both types of samples, we demonstrate that the FGA supplies negligible hydrogen species to the SiOx, regardless of whether the FGA is hydrogenated or deuterated. Instead, it supplies the thermal energy needed for hydrogen species in the Al2O3 to diffuse there. Furthermore, the concentration of hydrogen species at the SiOx can saturate while implied Voc continues to increase, showing that the energy from the FGA is also required for hydrogen species already at the SiOx to find recombination-active defects to passivate.
Original languageAmerican English
Number of pages5
StatePublished - 2017
Event2017 IEEE 44th Photovoltaic Specialists Conference (PVSC) - Washington, D.C.
Duration: 25 Jun 201730 Jun 2017


Conference2017 IEEE 44th Photovoltaic Specialists Conference (PVSC)
CityWashington, D.C.

NREL Publication Number

  • NREL/CP-5J00-67876


  • deuterium
  • hydrogen
  • passivated contacts
  • SIMS


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