Details
| Original language | English |
|---|---|
| Title of host publication | SiliconPV 2019 |
| Subtitle of host publication | 9th International Conference on Crystalline Silicon Photovoltaics |
| Editors | Sebastien Dubois, Stefan Glunz, Pierre Verlinden, Rolf Brendel, Arthur Weeber, Giso Hahn, Marco Poortmans, Christophe Ballif |
| Number of pages | 6 |
| ISBN (electronic) | 9780735418929 |
| Publication status | Published - 27 Aug 2019 |
| Event | 9th International Conference on Crystalline Silicon Photovoltaics, SiliconPV 2019 - Leuven, Belgium Duration: 8 Apr 2019 → 10 Apr 2019 |
Publication series
| Name | AIP Conference Proceedings |
|---|---|
| Volume | 2147 |
| ISSN (Print) | 0094-243X |
| ISSN (electronic) | 1551-7616 |
Abstract
We develop processes for advanced phosphorus doping profiles in order to reduce the emitter saturation current density Jo,e of industrial bifacial PERC+ solar cells. With an in-situ oxidation, which takes place in the POCl3 furnace in between the deposition and the drive-in step, the surface concentration was lowered from 3 × 1020 cm-3 to 1.7 × 1020 cm-3. With an additional ex-situ oxidation, which takes place after the phosphorus silicate glass is removed, the phosphorus surface concentration was further reduced to 3 × 1019 cm- 3. The decreased phosphorus surface concentration drastically reduces Jo,e from 106 fA/cm2 down to 22 fA/cm2. The reduced Jo,e increases the implied open circuit voltage up to 712 mV of unmetallized PERC+ test structures and the Voc of PERC+ solar cells up to 678 mV and efficiencies up to 21.8%. However, our solar cell analysis reveals for the first time, that with increasing thermal budget of the applied POCl3 and oxidation recipes the pseudo fill factor (pFF) decreases by up to 1.5%. This corresponds to an efficiency loss of approximately 0.5%abs. We analyse the pFF loss based on different lifetime test structures representing the emitter or the bulk of the PERC+ solar cell. From the lifetime measurements we calculate I-V curves representing the implied fill factor (iFF) of the different parts of the PERC+ solar cell as well as a combined one for the whole cell, which compares well to the measured pFF. The iFF values clearly show that the pFF is mainly limited by wafer bulk material. However, also the iFF values of the emitter slightly decrease with increasing thermal budget.
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SiliconPV 2019: 9th International Conference on Crystalline Silicon Photovoltaics. ed. / Sebastien Dubois; Stefan Glunz; Pierre Verlinden; Rolf Brendel; Arthur Weeber; Giso Hahn; Marco Poortmans; Christophe Ballif. 2019. 140005 (AIP Conference Proceedings; Vol. 2147).
Research output: Chapter in book/report/conference proceeding › Conference contribution › Research › peer review
}
TY - GEN
T1 - Impact of the thermal budget of the emitter formation on the PFF of PERC+ solar cells
AU - Jäger, Philip
AU - Baumann, Ulrike
AU - Dullweber, Thorsten
N1 - Funding information: This work was funded by the German State of Lower Saxony and the German Federal Ministry for Economic Affairs and Energy (BMWi) within the research project “HighPERC” under contract 0325753D as well as “GENESIS” under contract 0324274B and “NextStep” under contract 0324171C. We thank Verena Mertens for her help with the iFF analyzation method and Sonja Bräuning and Till Brendemühl for processing and evaluation.
PY - 2019/8/27
Y1 - 2019/8/27
N2 - We develop processes for advanced phosphorus doping profiles in order to reduce the emitter saturation current density Jo,e of industrial bifacial PERC+ solar cells. With an in-situ oxidation, which takes place in the POCl3 furnace in between the deposition and the drive-in step, the surface concentration was lowered from 3 × 1020 cm-3 to 1.7 × 1020 cm-3. With an additional ex-situ oxidation, which takes place after the phosphorus silicate glass is removed, the phosphorus surface concentration was further reduced to 3 × 1019 cm- 3. The decreased phosphorus surface concentration drastically reduces Jo,e from 106 fA/cm2 down to 22 fA/cm2. The reduced Jo,e increases the implied open circuit voltage up to 712 mV of unmetallized PERC+ test structures and the Voc of PERC+ solar cells up to 678 mV and efficiencies up to 21.8%. However, our solar cell analysis reveals for the first time, that with increasing thermal budget of the applied POCl3 and oxidation recipes the pseudo fill factor (pFF) decreases by up to 1.5%. This corresponds to an efficiency loss of approximately 0.5%abs. We analyse the pFF loss based on different lifetime test structures representing the emitter or the bulk of the PERC+ solar cell. From the lifetime measurements we calculate I-V curves representing the implied fill factor (iFF) of the different parts of the PERC+ solar cell as well as a combined one for the whole cell, which compares well to the measured pFF. The iFF values clearly show that the pFF is mainly limited by wafer bulk material. However, also the iFF values of the emitter slightly decrease with increasing thermal budget.
AB - We develop processes for advanced phosphorus doping profiles in order to reduce the emitter saturation current density Jo,e of industrial bifacial PERC+ solar cells. With an in-situ oxidation, which takes place in the POCl3 furnace in between the deposition and the drive-in step, the surface concentration was lowered from 3 × 1020 cm-3 to 1.7 × 1020 cm-3. With an additional ex-situ oxidation, which takes place after the phosphorus silicate glass is removed, the phosphorus surface concentration was further reduced to 3 × 1019 cm- 3. The decreased phosphorus surface concentration drastically reduces Jo,e from 106 fA/cm2 down to 22 fA/cm2. The reduced Jo,e increases the implied open circuit voltage up to 712 mV of unmetallized PERC+ test structures and the Voc of PERC+ solar cells up to 678 mV and efficiencies up to 21.8%. However, our solar cell analysis reveals for the first time, that with increasing thermal budget of the applied POCl3 and oxidation recipes the pseudo fill factor (pFF) decreases by up to 1.5%. This corresponds to an efficiency loss of approximately 0.5%abs. We analyse the pFF loss based on different lifetime test structures representing the emitter or the bulk of the PERC+ solar cell. From the lifetime measurements we calculate I-V curves representing the implied fill factor (iFF) of the different parts of the PERC+ solar cell as well as a combined one for the whole cell, which compares well to the measured pFF. The iFF values clearly show that the pFF is mainly limited by wafer bulk material. However, also the iFF values of the emitter slightly decrease with increasing thermal budget.
UR - http://www.scopus.com/inward/record.url?scp=85071538713&partnerID=8YFLogxK
U2 - 10.1063/1.5123892
DO - 10.1063/1.5123892
M3 - Conference contribution
AN - SCOPUS:85071538713
T3 - AIP Conference Proceedings
BT - SiliconPV 2019
A2 - Dubois, Sebastien
A2 - Glunz, Stefan
A2 - Verlinden, Pierre
A2 - Brendel, Rolf
A2 - Weeber, Arthur
A2 - Hahn, Giso
A2 - Poortmans, Marco
A2 - Ballif, Christophe
T2 - 9th International Conference on Crystalline Silicon Photovoltaics, SiliconPV 2019
Y2 - 8 April 2019 through 10 April 2019
ER -