Influence of AlOx Interlayers on LeTID Kinetics in Ga-Doped Cz-Si




Crystalline Silicon, Surface Passivation, Bulk Defects, Degradation, Hydrogen


Light and elevated temperature-induced degradation (LeTID) is causing a reduction in efficiency especially in p-type silicon based solar cells. It is assumed to be strongly influenced by the hydrogen content in the bulk material. The presented work focuses on the impact of differently thick (5-25 nm) atomic layer-deposited aluminum oxide (AlOx) interlayers underneath the hydrogen-rich silicon nitride (SiNy:H) capping layer. The interlayer acts as a diffusion barrier for H during the firing step. It is demonstrated that the AlOx interlayer has a comparable effect on the LeTID kinetics in Ga-doped Cz-Si (Cz-Si:Ga) as it is observed in B-doped Cz-Si (Cz-Si:B). Additionally, it substantially minimizes lifetime degradation in the Cz-Si:Ga sample. With a determined ratio of electron to hole capture cross sections k=26(3), the degradation phenomena are attributed to the LeTID kinetics. Deposition of AlOx barrier layers exceeding 10 nm in thickness does not yield additional positive effects. Resistivity measurements revealed that the change in hole concentration correlates with the defect density for varying AlOx layer thicknesses. The doping concentration seems to influence the change in maximum defect density for varying AlOx layer thicknesses.


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F. Kersten, P. Engelhart, H.C. Ploigt, A. Stekolnikov, T. Lindner, F. Stenzel, M. Bartzsch, A. Szpeth, K. Petter, J. Heitmann, J. W. Müller, “Degradation of multicrystalline silicon solar cells and modules after illumination at elevated temperature”, Solar Energy Materials and Solar Cells, vol.142, pp. 83-86, 2015, doi:

A. Zuschlag, D. Skorka, G. Hahn, “Degradation and regeneration analysis in mc-Si”, in Proc. 43rd IEEE PVSC, 2016, pp. 1051-1054, doi:

N.E. Grant, J.R. Scowcroft, A. I. Pointon, M. Al-Amin, P.P. Altermatt, J.D. Murphy, “Lifetime instabilities in gallium doped monocrystalline PERC silicon solar cells”, Solar Energy Materials and Solar Cells, vol.206, pp. 110299, 2020, doi:

A. Schmid, C. Fischer, D. Skorka, A. Herguth, C. Winter, A. Zuschlag, G. Hahn, “On the role of AlOx thickness in AlOx/SiNy:H layer stacks regarding light- and elevated temperature-induced degradation and hydrogen diffusion in c-Si”, IEEE Journal of Photovoltaics, vol.11, no.4, pp. 967-973, 2021, doi:

L. Helmich, D. C. Walter, D. Bredemeier, J. Schmidt, “Atomic-layer-deposited Al2O3 as effective barrier against the diffusion of hydrogen from SiNx:H layers into crystalline silicon during rapid thermal annealing”, Physica Status Solidi RRL, vol.14, p. 2000367, 2020, doi:

S. Wilking, A. Herguth, G. Hahn, “Influence of hydrogen on the regeneration of boron-oxygen related defects in crystalline silicon”, Journal of Applied Physics, vol.113, p. 194503, 2013, doi:

U. Varshney, B. Hallam, P. Hamer, A. Ciesla, D. Chen, S. Liu, C. Sen, A. Samadi, M. Abbott, C. Chan, B. Hoex, “Controlling light- and elevated-temperature-induced degradation with thin film barrier layers”; IEEE Journal of Photovoltaics, vol.10, no.1, pp. 19-27, 2020, doi:

M. Winter, D.C. Walter, B. Min, R. Peibst, R. Brendel, J. Schmidt, „Light and elevated temperature induced degradation and recovery of gallium-doped Czochralski-silicon solar cells”, scientific reports, vol.12, p. 1-8, 2022, doi:

S. Jafari, Z. Hameiri, “Investigation of light-induced Degradation in Ga- and In-doped Cz silicon”, IEEE 48th Photovoltaic Specialists Conference, pp.814-817, 2021, doi:

A. Herguth, “On the lifetime-equivalent defect density: properties, application, and pitfalls”, IEEE Journal of Photovoltaics, vol.9, no.5, pp. 1182-1194, 2019, doi:

A. Kimmerle, J. Greulich, A. Wolf, “Carrier-diffusion corrected J0-analysis of charge carrier lifetime measurements for increased consistency”, Solar Energy Materials and Solar Cells, vol.142, pp. 116-122, 2015, doi:

A. Herguth, C. Winter, “Methology and error analysis of direct resistance measurements used for the quantification of boron-hydrogen pairs in crystalline silicon”, IEEE Journal of Photovoltaics, vol.11, no.4, pp. 1059-1068, 2021, doi:

J. Simon, A. Herguth, L. Kutschera, G. Hahn, “The dissociation of gallium-hydrogen pairs in crystalline silicon during illuminated annealing”, Physica Status Solidi RRL, vol.16, no.12, p. 2200297, 2022,

D. Lin, Z. Hu, L. Song, D. Yang, X. Yu, “Investigation on the light and elevated temperature induced degradation of gallium-doped Cz-Si”, Solar Energy, vol.225, pp. 407-411, 2021, doi:

A. Herguth, J. Kamphues, “On the impact of bulk lifetime on the quantification of re-combination at the surface of semiconductors”, IEEE Journal of Photovoltaics, vol.13, no.5, pp. 672-681, 2023, doi:




How to Cite

Kamphues, J., Schmid, A., Fischer-Süßlin, R., Hahn, G., & Geml, F. (2024). Influence of AlOx Interlayers on LeTID Kinetics in Ga-Doped Cz-Si. SiliconPV Conference Proceedings, 1.

Conference Proceedings Volume


Silicon Material and Defect Engineering

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