Veröffentlichungen
2017 |
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C. Gemmel, J. Hensen, S. Kajari-Schröder, and R. Brendel IEEE Journal of Photovoltaics 7 (2), 430-436, (2017), ISSN: 2156-3381. Abstract | Links | BibTeX | Schlagwörter: charge carrier lifetime, Epitaxial growth, Epitaxy, Gettering, minority carrier lifetime, porous silicon (PSI), silicon, Substrates, Surface treatment, Temperature measurement @article{Gemmel2017,
title = {4.5 ms Effective Carrier Lifetime in Kerfless Epitaxial Silicon Wafers From the Porous Silicon Process}, author = {C Gemmel and J Hensen and S Kajari-Schröder and R Brendel}, doi = {10.1109/JPHOTOV.2016.2642640}, issn = {2156-3381}, year = {2017}, date = {2017-03-01}, journal = {IEEE Journal of Photovoltaics}, volume = {7}, number = {2}, pages = {430-436}, abstract = {Kerfless silicon wafers epitaxially grown on porous silicon (PSI) and subsequently detached from the growth substrate are a promising candidate for reducing the cost of the silicon wafer, which is particularly important for silicon photovoltaics. However, the carrier lifetime of these epitaxial wafers has to be at least as high as that of today's standard Czochralski (Cz)-grown wafers in order to become competitive. Here, we compare the measured lifetimes of n-type epitaxial silicon wafers that grow on PSI and epitaxial silicon wafers that grow on nonporous surfaces of epi-ready wafers. The latter are subsequently ground to have free-standing epitaxial wafers. Gettering improves the carrier lifetime of the ground wafers up to 4.2 ms. In contrast, PSI wafers show regions with effective lifetimes of 4.5 ms, even without gettering. This lifetime value is a factor of four larger than lifetimes of Cz wafers which are typically employed in today's PERC solar cells. We model the lifetime measurements with three Shockley-Read-Hall (SRH) defects: two defects that exist in the PSI and in the epi-ready wafer and a third defect that is only present in the epi-ready wafer.}, keywords = {charge carrier lifetime, Epitaxial growth, Epitaxy, Gettering, minority carrier lifetime, porous silicon (PSI), silicon, Substrates, Surface treatment, Temperature measurement}, pubstate = {published}, tppubtype = {article} } Kerfless silicon wafers epitaxially grown on porous silicon (PSI) and subsequently detached from the growth substrate are a promising candidate for reducing the cost of the silicon wafer, which is particularly important for silicon photovoltaics. However, the carrier lifetime of these epitaxial wafers has to be at least as high as that of today's standard Czochralski (Cz)-grown wafers in order to become competitive. Here, we compare the measured lifetimes of n-type epitaxial silicon wafers that grow on PSI and epitaxial silicon wafers that grow on nonporous surfaces of epi-ready wafers. The latter are subsequently ground to have free-standing epitaxial wafers. Gettering improves the carrier lifetime of the ground wafers up to 4.2 ms. In contrast, PSI wafers show regions with effective lifetimes of 4.5 ms, even without gettering. This lifetime value is a factor of four larger than lifetimes of Cz wafers which are typically employed in today's PERC solar cells. We model the lifetime measurements with three Shockley-Read-Hall (SRH) defects: two defects that exist in the PSI and in the epi-ready wafer and a third defect that is only present in the epi-ready wafer.
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2016 |
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V. Steckenreiter, J. Hensen, A. Knorr, S. Kajari-Schröder, and R. Brendel Reuse of substrate wafers for the porous silicon layer transfer Artikel IEEE Journal of Photovoltaics 6 (3), 783-790, (2016). Abstract | Links | BibTeX | Schlagwörter: Carrier lifetime, charge carrier lifetime, Contamination, Epitaxial growth, epitaxial layer, Epitaxial layers, layer transfer, Photovoltaic systems, porous silicon (PSI) process, silicon, substrate reuse, Substrates @article{Steckenreiter2016b,
title = {Reuse of substrate wafers for the porous silicon layer transfer}, author = {V Steckenreiter and J Hensen and A Knorr and S Kajari-Schröder and R Brendel}, doi = {10.1109/JPHOTOV.2016.2545406}, year = {2016}, date = {2016-05-01}, journal = {IEEE Journal of Photovoltaics}, volume = {6}, number = {3}, pages = {783-790}, abstract = {The reuse of the silicon substrate is a key component in the kerfless-porous-silicon-based wafering process. Starting with a boron-doped p+-type substrate, a porous double layer is created, reorganized in a hydrogen bake, and then serves as a substrate for silicon homoepitaxy. After lift-off, the silicon substrate is wet chemically reconditioned and reporosified to serve again as a substrate for epitaxial layer deposition. We reduce the substrate consumption per cycle to 5 ± 0.3 μm/side and demonstrate 14 uses on a 6-in wafer. We investigate the impact of the reuse sequence on the epitaxial layer quality by carrier lifetime measurements. Starting with the third reuse, a pattern becomes visible in lifetime mappings. We observe a degradation of the minority carrier lifetime from 15 to 7 μs after 13 reuses.}, keywords = {Carrier lifetime, charge carrier lifetime, Contamination, Epitaxial growth, epitaxial layer, Epitaxial layers, layer transfer, Photovoltaic systems, porous silicon (PSI) process, silicon, substrate reuse, Substrates}, pubstate = {published}, tppubtype = {article} } The reuse of the silicon substrate is a key component in the kerfless-porous-silicon-based wafering process. Starting with a boron-doped p+-type substrate, a porous double layer is created, reorganized in a hydrogen bake, and then serves as a substrate for silicon homoepitaxy. After lift-off, the silicon substrate is wet chemically reconditioned and reporosified to serve again as a substrate for epitaxial layer deposition. We reduce the substrate consumption per cycle to 5 ± 0.3 μm/side and demonstrate 14 uses on a 6-in wafer. We investigate the impact of the reuse sequence on the epitaxial layer quality by carrier lifetime measurements. Starting with the third reuse, a pattern becomes visible in lifetime mappings. We observe a degradation of the minority carrier lifetime from 15 to 7 μs after 13 reuses.
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2014 |
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R. Brendel, V. Steckenreiter, J. Hensen, J. H. Petermann, and S. Kajari-Schröder Epitaxial Si films carried by thick polycrystalline Si as a drop-in replacement for conventional wafers Inproceedings IEEE (Hrsg.): 2014 IEEE 40th Photovoltaic Specialist Conference (PVSC) , 3515-3520, Denver, CO, USA, (2014), ISBN: 978-1-4799-4398-2. Links | BibTeX | Schlagwörter: Epitaxial growth, Epitaxial layers, Epitaxy, kerfless, Photovoltaic cells, Photovoltaic systems, polycrystalline, porous, Reflectivity, silicon, wafer-equivalent @inproceedings{Brendel2014,
title = {Epitaxial Si films carried by thick polycrystalline Si as a drop-in replacement for conventional wafers}, author = {R Brendel and V Steckenreiter and J Hensen and J H Petermann and S Kajari-Schröder}, editor = {IEEE}, doi = {10.1109/PVSC.2014.6924867}, isbn = {978-1-4799-4398-2}, year = {2014}, date = {2014-06-08}, booktitle = {2014 IEEE 40th Photovoltaic Specialist Conference (PVSC) }, journal = {Proceedings of the 40th IEEE Photovoltaic Specialists Conference}, pages = {3515-3520}, address = {Denver, CO, USA}, keywords = {Epitaxial growth, Epitaxial layers, Epitaxy, kerfless, Photovoltaic cells, Photovoltaic systems, polycrystalline, porous, Reflectivity, silicon, wafer-equivalent}, pubstate = {published}, tppubtype = {inproceedings} } |
2013 |
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M. Ernst, and R. Brendel Macroporous Silicon Solar Cells With an Epitaxial Emitter Artikel IEEE Journal of Photovoltaics 3 (2), 723-729, (2013). Links | BibTeX | Schlagwörter: Epitaxial growth, Epitaxial layers, Epitaxy, Etching, kerf-free, layer transfer, macroporous silicon, Photovoltaic cells, Resistance, silicon, thin films @article{Ernst2013b,
title = {Macroporous Silicon Solar Cells With an Epitaxial Emitter}, author = {M Ernst and R Brendel}, doi = {10.1109/JPHOTOV.2013.2247094}, year = {2013}, date = {2013-04-01}, journal = {IEEE Journal of Photovoltaics}, volume = {3}, number = {2}, pages = {723-729}, keywords = {Epitaxial growth, Epitaxial layers, Epitaxy, Etching, kerf-free, layer transfer, macroporous silicon, Photovoltaic cells, Resistance, silicon, thin films}, pubstate = {published}, tppubtype = {article} } |
2012 |
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M. Ernst, R. Brendel, R. Ferre, N. -P. Harder, and S. Kajari-Schröder Macroporous silicon as an absorber for thin heterojunction solar cells Inproceedings IEEE (Hrsg.): 2012 38th IEEE Photovoltaic Specialists Conference, 001040-001045, Austin, TX, USA, (2012), ISBN: 978-1-4673-0064-3. Links | BibTeX | Schlagwörter: Arrays, Epitaxial growth, free standing, heterojunctions, Indexes, kerf-free, layer transfer, Light emitting diodes, macroporous silicon, monocrystalline, Optical films, Porous Silicon, Radiation detectors, silicon, thin-film silicon @inproceedings{Ernst2012,
title = {Macroporous silicon as an absorber for thin heterojunction solar cells}, author = {M Ernst and R Brendel and R Ferre and N -P Harder and S Kajari-Schröder}, editor = {IEEE}, doi = {10.1109/PVSC.2012.6317781}, isbn = {978-1-4673-0064-3}, year = {2012}, date = {2012-06-01}, booktitle = {2012 38th IEEE Photovoltaic Specialists Conference}, pages = {001040-001045}, address = {Austin, TX, USA}, keywords = {Arrays, Epitaxial growth, free standing, heterojunctions, Indexes, kerf-free, layer transfer, Light emitting diodes, macroporous silicon, monocrystalline, Optical films, Porous Silicon, Radiation detectors, silicon, thin-film silicon}, pubstate = {published}, tppubtype = {inproceedings} } |
2011 |
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R. Brendel, J. H. Petermann, D. Zielke, H. Schulte-Huxel, M. Kessler, S. Gatz, S. Eidelloth, R. Bock, E. Garralaga-Rojas, J. Schmidt, and T. Dullweber IEEE Journal of Photovoltaics 1 (1), 9-15, (2011), ISSN: 2156-3381. Links | BibTeX | Schlagwörter: Aluminum oxide passivation, Bonding, Epitaxial growth, Glass, laser bonding, Lasers, layer transfer, passivation, silicon, thin film/wafer hybrid @article{Brendel2011,
title = {High-Efficiency Cells From Layer Transfer: A First Step Toward Thin-Film/Wafer Hybrid Silicon Technologies}, author = {R Brendel and J H Petermann and D Zielke and H Schulte-Huxel and M Kessler and S Gatz and S Eidelloth and R Bock and E Garralaga-Rojas and J Schmidt and T Dullweber}, doi = {10.1109/JPHOTOV.2011.2165529}, issn = {2156-3381}, year = {2011}, date = {2011-07-01}, journal = {IEEE Journal of Photovoltaics}, volume = {1}, number = {1}, pages = {9-15}, keywords = {Aluminum oxide passivation, Bonding, Epitaxial growth, Glass, laser bonding, Lasers, layer transfer, passivation, silicon, thin film/wafer hybrid}, pubstate = {published}, tppubtype = {article} } |
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R. Brendel, J. Petermann, E. G. Rojas, D. Zielke, J. Schmidt, S. Gatz, and T. Dullweber High-efficiency cells from layer transfer: A first step towards Si thin-film/wafer hybrid technologies Inproceedings IEEE (Hrsg.): 2011 37th IEEE Photovoltaic Specialists Conference, 000046, Seattle, WA, USA, (2011), ISSN: 0160-8371. Links | BibTeX | Schlagwörter: Aluminum oxide, Crystallization, Epitaxial growth, Sawing, silicon @inproceedings{Brendel2011b,
title = {High-efficiency cells from layer transfer: A first step towards Si thin-film/wafer hybrid technologies}, author = {R Brendel and J Petermann and E G Rojas and D Zielke and J Schmidt and S Gatz and T Dullweber}, editor = {IEEE}, doi = {10.1109/PVSC.2011.6185841}, issn = {0160-8371}, year = {2011}, date = {2011-06-01}, booktitle = {2011 37th IEEE Photovoltaic Specialists Conference}, pages = {000046}, address = {Seattle, WA, USA}, keywords = {Aluminum oxide, Crystallization, Epitaxial growth, Sawing, silicon}, pubstate = {published}, tppubtype = {inproceedings} } |
2010 |
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M. Ernst, and R. Brendel Large area macroporous silicon layers for monocrystalline thin-film solar cells Inproceedings IEEE (Hrsg.): 2010 35th IEEE Photovoltaic Specialists Conference, 003122-003124, Honolulu, HI, USA, (2010), ISSN: 0160-8371. Links | BibTeX | Schlagwörter: Epitaxial growth, Microscopy, Optical microscopy @inproceedings{Ernst2010,
title = {Large area macroporous silicon layers for monocrystalline thin-film solar cells}, author = {M Ernst and R Brendel}, editor = {IEEE}, doi = {10.1109/PVSC.2010.5614496}, issn = {0160-8371}, year = {2010}, date = {2010-06-01}, booktitle = {2010 35th IEEE Photovoltaic Specialists Conference}, pages = {003122-003124}, address = {Honolulu, HI, USA}, keywords = {Epitaxial growth, Microscopy, Optical microscopy}, pubstate = {published}, tppubtype = {inproceedings} } |
2009 |
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E. G. Rojas, C. Hampe, H. Plagwitz, and R. Brendel Formation of mesoporous gallium arsenide for lift-off processes by electrochemical etching Inproceedings IEEE (Hrsg.): 2009 34th IEEE Photovoltaic Specialists Conference (PVSC), 001086-001089, Philadelphia, PA, USA, (2009), ISSN: 0160-8371. Links | BibTeX | Schlagwörter: Conductive films, Conductivity, Epitaxial growth, Etching, Gallium arsenide, Glass, Mesoporous materials, Molecular beam epitaxial growth, Substrates, X-ray scattering @inproceedings{Rojas2009b,
title = {Formation of mesoporous gallium arsenide for lift-off processes by electrochemical etching}, author = {E G Rojas and C Hampe and H Plagwitz and R Brendel}, editor = {IEEE}, doi = {10.1109/PVSC.2009.5411208}, issn = {0160-8371}, year = {2009}, date = {2009-06-01}, booktitle = {2009 34th IEEE Photovoltaic Specialists Conference (PVSC)}, pages = {001086-001089}, address = {Philadelphia, PA, USA}, keywords = {Conductive films, Conductivity, Epitaxial growth, Etching, Gallium arsenide, Glass, Mesoporous materials, Molecular beam epitaxial growth, Substrates, X-ray scattering}, pubstate = {published}, tppubtype = {inproceedings} } |