Details
| Original language | English |
|---|---|
| Title of host publication | SiliconPV 2019 - 9th International Conference on Crystalline Silicon Photovoltaics |
| Editors | Sebastien Dubois, Stefan Glunz, Pierre Verlinden, Brendel Rolf, Arthur Weeber, Giso Hahn, Marco Poortmans, Christophe Ballif |
| 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
Bulk lifetime studies of crystalline silicon wafers, e.g. with the aim of studying the light-induced degradation and regeneration behavior, require low-temperature surface passivation schemes that do not alter the silicon bulk properties, e.g. through hydrogenation. Aluminum oxide (Al2O3) can provide an excellent and stable surface passivation, however, in order to achieve the best possible surface passivation, an annealing step at ~400°C is typically required, which has been found to alter the bulk properties of some silicon materials. Hence, in this contribution we examine the possibility of passivating the silicon surface using Al2O3 layers that have seen a much lower thermal budget. We demonstrate that we are able to achieve an excellent silicon surface passivation using atomic-layer-deposited Al2O3 with measured effective surface recombination velocities Seff as low as 1.3 cm/s without exceeding a temperature of 250°C. We are able to achieve such excellent low-temperature passivation by applying a post-deposition annealing step at 250°C in combination with the deposition of negative Corona charges on the Al2O3 surface. For samples annealed at only 220°C, we still reach very low Seff values of 2 cm/s after deposition of negative Corona charges. We demonstrate that the Corona-charged low-temperature Al2O3 passivation shows only a slight degradation from an Seff of 1.6 cm/s to an Seff of 5 cm/s after 218 days of storage. Even without any post-deposition anneal and only negative Corona charges deposited, we achieve stable Seff values of 15 cm/s. As an alternative to Corona charging, a short exposure to intense UV light (O = 395 nm) also significantly improves the surface passivation quality of low-temperature-annealed Al2O3-passivated silicon samples. However, the best surface passivation for the latter method is limited to an Seff value of 6.6 cm/s, which is still quite reasonable for bulk lifetime studies.
ASJC Scopus subject areas
- Physics and Astronomy(all)
- General Physics and Astronomy
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SiliconPV 2019 - 9th International Conference on Crystalline Silicon Photovoltaics. ed. / Sebastien Dubois; Stefan Glunz; Pierre Verlinden; Brendel Rolf; Arthur Weeber; Giso Hahn; Marco Poortmans; Christophe Ballif. 2019. 050011 (AIP Conference Proceedings; Vol. 2147).
Research output: Chapter in book/report/conference proceeding › Conference contribution › Research › peer review
}
TY - GEN
T1 - Low-temperature silicon surface passivation for bulk lifetime studies based on corona-charged Al2O3
AU - Veith-Wolf, Boris A.
AU - Schmidt, Jan
N1 - Funding Information: The authors thank Cornelia Marquardt for the preparation of the samples. This work was funded by the German State of Lower Saxony and the German Federal Ministry of Economics and Energy within the research project “LIMES” (contract no. 0324204D).
PY - 2019/8/27
Y1 - 2019/8/27
N2 - Bulk lifetime studies of crystalline silicon wafers, e.g. with the aim of studying the light-induced degradation and regeneration behavior, require low-temperature surface passivation schemes that do not alter the silicon bulk properties, e.g. through hydrogenation. Aluminum oxide (Al2O3) can provide an excellent and stable surface passivation, however, in order to achieve the best possible surface passivation, an annealing step at ~400°C is typically required, which has been found to alter the bulk properties of some silicon materials. Hence, in this contribution we examine the possibility of passivating the silicon surface using Al2O3 layers that have seen a much lower thermal budget. We demonstrate that we are able to achieve an excellent silicon surface passivation using atomic-layer-deposited Al2O3 with measured effective surface recombination velocities Seff as low as 1.3 cm/s without exceeding a temperature of 250°C. We are able to achieve such excellent low-temperature passivation by applying a post-deposition annealing step at 250°C in combination with the deposition of negative Corona charges on the Al2O3 surface. For samples annealed at only 220°C, we still reach very low Seff values of 2 cm/s after deposition of negative Corona charges. We demonstrate that the Corona-charged low-temperature Al2O3 passivation shows only a slight degradation from an Seff of 1.6 cm/s to an Seff of 5 cm/s after 218 days of storage. Even without any post-deposition anneal and only negative Corona charges deposited, we achieve stable Seff values of 15 cm/s. As an alternative to Corona charging, a short exposure to intense UV light (O = 395 nm) also significantly improves the surface passivation quality of low-temperature-annealed Al2O3-passivated silicon samples. However, the best surface passivation for the latter method is limited to an Seff value of 6.6 cm/s, which is still quite reasonable for bulk lifetime studies.
AB - Bulk lifetime studies of crystalline silicon wafers, e.g. with the aim of studying the light-induced degradation and regeneration behavior, require low-temperature surface passivation schemes that do not alter the silicon bulk properties, e.g. through hydrogenation. Aluminum oxide (Al2O3) can provide an excellent and stable surface passivation, however, in order to achieve the best possible surface passivation, an annealing step at ~400°C is typically required, which has been found to alter the bulk properties of some silicon materials. Hence, in this contribution we examine the possibility of passivating the silicon surface using Al2O3 layers that have seen a much lower thermal budget. We demonstrate that we are able to achieve an excellent silicon surface passivation using atomic-layer-deposited Al2O3 with measured effective surface recombination velocities Seff as low as 1.3 cm/s without exceeding a temperature of 250°C. We are able to achieve such excellent low-temperature passivation by applying a post-deposition annealing step at 250°C in combination with the deposition of negative Corona charges on the Al2O3 surface. For samples annealed at only 220°C, we still reach very low Seff values of 2 cm/s after deposition of negative Corona charges. We demonstrate that the Corona-charged low-temperature Al2O3 passivation shows only a slight degradation from an Seff of 1.6 cm/s to an Seff of 5 cm/s after 218 days of storage. Even without any post-deposition anneal and only negative Corona charges deposited, we achieve stable Seff values of 15 cm/s. As an alternative to Corona charging, a short exposure to intense UV light (O = 395 nm) also significantly improves the surface passivation quality of low-temperature-annealed Al2O3-passivated silicon samples. However, the best surface passivation for the latter method is limited to an Seff value of 6.6 cm/s, which is still quite reasonable for bulk lifetime studies.
UR - http://www.scopus.com/inward/record.url?scp=85071527311&partnerID=8YFLogxK
U2 - 10.1063/1.5123860
DO - 10.1063/1.5123860
M3 - Conference contribution
AN - SCOPUS:85071527311
T3 - AIP Conference Proceedings
BT - SiliconPV 2019 - 9th International Conference on Crystalline Silicon Photovoltaics
A2 - Dubois, Sebastien
A2 - Glunz, Stefan
A2 - Verlinden, Pierre
A2 - Rolf, Brendel
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 -