Veröffentlichungen
2017 |
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B. Min, J. Krügener, M. Müller, K. Bothe, and R. Brendel Energy Procedia 124 (Supplement C), 126-130, (2017), ISSN: 1876-6102, (7th International Conference on Silicon Photovoltaics, SiliconPV 2017, 3-5 April 2017, Freiburg, Germany). Abstract | Links | BibTeX | Schlagwörter: emitter, junction formation, passivation, recombination @article{Min2017d,
title = {Fundamental consideration of junction formation strategies for phosphorus-doped emitters with J0e < 10 fA/cm2}, author = {B Min and J Krügener and M Müller and K Bothe and R Brendel}, doi = {10.1016/j.egypro.2017.09.323}, issn = {1876-6102}, year = {2017}, date = {2017-09-21}, journal = {Energy Procedia}, volume = {124}, number = {Supplement C}, pages = {126-130}, abstract = {This work shows the potential of further optimization of phosphorus-doped emitters in p-type silicon solar cells. We investigate the impact of different combinations of phosphorus doping profiles and surface passivation qualities on the saturation current density J0e by considering boundary conditions based on published experimental data. Our simulation study shows that there are two possible ways to achieve J0e values below 10 fA/cm2. One is the reduction of the electrically active phosphorus concentration nsurf at the surface beneath 2×10^19 cm−3 and simultaneously reducing the surface recombination velocity Sp to below 103 cm/s. The other contrarily increases nsurf to values of up to 1×10^21 cm−3 while ensuring full activation of all phosphorus dopants. In the latter case, J0e values below 10 fA/cm2 seem possible, even for Sp = 10^7 cm/s which is equal to the thermal velocity.}, note = {7th International Conference on Silicon Photovoltaics, SiliconPV 2017, 3-5 April 2017, Freiburg, Germany}, keywords = {emitter, junction formation, passivation, recombination}, pubstate = {published}, tppubtype = {article} } This work shows the potential of further optimization of phosphorus-doped emitters in p-type silicon solar cells. We investigate the impact of different combinations of phosphorus doping profiles and surface passivation qualities on the saturation current density J0e by considering boundary conditions based on published experimental data. Our simulation study shows that there are two possible ways to achieve J0e values below 10 fA/cm2. One is the reduction of the electrically active phosphorus concentration nsurf at the surface beneath 2×10^19 cm−3 and simultaneously reducing the surface recombination velocity Sp to below 103 cm/s. The other contrarily increases nsurf to values of up to 1×10^21 cm−3 while ensuring full activation of all phosphorus dopants. In the latter case, J0e values below 10 fA/cm2 seem possible, even for Sp = 10^7 cm/s which is equal to the thermal velocity.
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2016 |
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J. Krügener, Y. Larionova, B. Wolpensinger, D. Tetzlaff, S. Reiter, M. Turcu, R. Peibst, J. -D. Kähler, and T. Wietler Dopant diffusion from p+-poly-Si into c-Si during thermal annealing Inproceedings IEEE (Hrsg.): 2016 IEEE 43rd Photovoltaic Specialists Conference (PVSC), 2451-2454, Portland, OR, USA, (2016), ISBN: 978-1-5090-2725-5. Abstract | Links | BibTeX | Schlagwörter: Annealing, boron, diffusion, junction formation, Junctions, low pressure chemical vapor deposition, passivating contacts, Resistance, Scanning electron microscopy, silicon, Substrates, Temperature measurement @inproceedings{Krügener2016b,
title = {Dopant diffusion from p+-poly-Si into c-Si during thermal annealing}, author = {J Krügener and Y Larionova and B Wolpensinger and D Tetzlaff and S Reiter and M Turcu and R Peibst and J -D Kähler and T Wietler}, editor = {IEEE}, doi = {10.1109/PVSC.2016.7750083}, isbn = {978-1-5090-2725-5}, year = {2016}, date = {2016-06-01}, booktitle = {2016 IEEE 43rd Photovoltaic Specialists Conference (PVSC)}, journal = {Proceedings of the 43rd IEEE Photovoltaic Specialists Conference}, pages = {2451-2454}, address = {Portland, OR, USA}, abstract = {Passivating junctions, like hole-collecting p-polycrystalline silicon/SiOx/crystalline silicon junctions, need a thermal activation to activate their excellent passivation and contact properties. Here, the diffusion of boron from the highly doped poly-Si layer into the Si is often considered to compromise the passivation quality. In contrast we show that at least a slight diffusion of boron into the crystalline silicon is present for optimized annealing conditions. We achieve low emitter saturation current densities of 11 fA/cm2 for in situ p+ doped polysilicon deposited by low pressure chemical vapor deposition. Furthermore, we show that the polysilicon layer and the in-diffused region within the substrate are electrically connected.}, keywords = {Annealing, boron, diffusion, junction formation, Junctions, low pressure chemical vapor deposition, passivating contacts, Resistance, Scanning electron microscopy, silicon, Substrates, Temperature measurement}, pubstate = {published}, tppubtype = {inproceedings} } Passivating junctions, like hole-collecting p-polycrystalline silicon/SiOx/crystalline silicon junctions, need a thermal activation to activate their excellent passivation and contact properties. Here, the diffusion of boron from the highly doped poly-Si layer into the Si is often considered to compromise the passivation quality. In contrast we show that at least a slight diffusion of boron into the crystalline silicon is present for optimized annealing conditions. We achieve low emitter saturation current densities of 11 fA/cm2 for in situ p+ doped polysilicon deposited by low pressure chemical vapor deposition. Furthermore, we show that the polysilicon layer and the in-diffused region within the substrate are electrically connected.
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D. Tetzlaff, J. Krügener, Y. Larionova, S. Reiter, M. Turcu, R. Peibst, U. Höhne, J. -D. Kähler, and T. Wietler Evolution of oxide disruptions: The (w)hole story about passivating contacts Inproceedings IEEE (Hrsg.): 2016 IEEE 43rd Photovoltaic Specialists Conference (PVSC), 0221-0224, Portland, OR, USA, (2016), ISBN: 978-1-5090-2725-5. Abstract | Links | BibTeX | Schlagwörter: Annealing, junction formation, Junctions, Microscopy, passivating contacts, Photovoltaic cells, Photovoltaic systems, pinholes, polysilicon, silicon, silicon oxide @inproceedings{Tetzlaff2016,
title = {Evolution of oxide disruptions: The (w)hole story about passivating contacts}, author = {D Tetzlaff and J Krügener and Y Larionova and S Reiter and M Turcu and R Peibst and U Höhne and J -D Kähler and T Wietler}, editor = {IEEE}, doi = {10.1109/PVSC.2016.7749582}, isbn = {978-1-5090-2725-5}, year = {2016}, date = {2016-06-01}, booktitle = {2016 IEEE 43rd Photovoltaic Specialists Conference (PVSC)}, journal = {Proceedings of the 43rd IEEE Photovoltaic Specialists Conference}, pages = {0221-0224}, address = {Portland, OR, USA}, abstract = {Different models exist describing the current transport in polycrystalline Si/SiOx/crystalline Si junctions. Besides tunneling through thin oxides, transport through pinholes is discussed. We investigate the influence of annealing temperature on the structural properties of polycrystalline Si/SiOx/crystalline Si interfaces and analyze the formation and evolution of holes by high resolution transmission electron microscopy in comparison to electrical results. We prove the existence of pinholes in samples with good electrical properties in agreement with the pinhole model.}, keywords = {Annealing, junction formation, Junctions, Microscopy, passivating contacts, Photovoltaic cells, Photovoltaic systems, pinholes, polysilicon, silicon, silicon oxide}, pubstate = {published}, tppubtype = {inproceedings} } Different models exist describing the current transport in polycrystalline Si/SiOx/crystalline Si junctions. Besides tunneling through thin oxides, transport through pinholes is discussed. We investigate the influence of annealing temperature on the structural properties of polycrystalline Si/SiOx/crystalline Si interfaces and analyze the formation and evolution of holes by high resolution transmission electron microscopy in comparison to electrical results. We prove the existence of pinholes in samples with good electrical properties in agreement with the pinhole model.
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