Finite- vs. infinite-source emitters in silicon photovoltaics: Effect on transition metal gettering
Control of detrimental metal impurities is crucial to silicon solar cell performance. Traditional silicon solar cell emitters are diffused in an infinite-source regime and are known to cause strong point defect segregation towards the emitter and thus enhance bulk minority carrier diffusion length....
| Main Authors: | , , , , , , , , , , , , , |
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| Format: | Article |
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Institute of Electrical and Electronics Engineers (IEEE)
2018
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| Online Access: | http://hdl.handle.net/1721.1/119178 https://orcid.org/0000-0001-9352-8741 https://orcid.org/0000-0001-8345-4937 https://orcid.org/0000-0002-4609-9312 |
| Summary: | Control of detrimental metal impurities is crucial to silicon solar cell performance. Traditional silicon solar cell emitters are diffused in an infinite-source regime and are known to cause strong point defect segregation towards the emitter and thus enhance bulk minority carrier diffusion length. With the advent of ion-implantation and chemical vapor deposition (CVD) glasses, finite-source diffused emitters are attracting interest. This contribution aims to increase their adoption by elucidating the dominant gettering mechanisms present in finite-source diffused emitters. Our findings indicate that infinite-source diffusion is critical for effective segregation gettering, but that high enough surface phosphorus concentration can activate segregation gettering via finite-source diffusion as well. In the case of ion-implanted emitters, the traditional segregation gettering may be considerably enhanced by impurity precipitation in the implanted layer. |
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