Details
| Original language | English |
|---|---|
| Title of host publication | 2020 47th IEEE Photovoltaic Specialists Conference, PVSC 2020 |
| Publisher | Institute of Electrical and Electronics Engineers Inc. |
| Pages | 1274-1278 |
| Number of pages | 5 |
| ISBN (electronic) | 9781728161150 |
| ISBN (print) | 978-1-7281-6116-7 |
| Publication status | Published - 2020 |
| Event | 47th IEEE Photovoltaic Specialists Conference, PVSC 2020 - Calgary, Canada Duration: 15 Jun 2020 → 21 Aug 2020 |
Publication series
| Name | Conference Record of the IEEE Photovoltaic Specialists Conference |
|---|---|
| Volume | 2020-June |
| ISSN (Print) | 0160-8371 |
Abstract
Passivating contacts formed by poly-Si on oxide (POLO) junctions yield high passivation qualities after an appropriate annealing process at temperatures between 800°C and 1050°C. In today's typical cell process, firing is applied in the end of cell production mainly to form screen printed contacts. Thus, a high stability of the passivation quality against this firing process is required - and also expected since a previous high-temperature process for POLO junction formation implies a much higher thermal budget. However, in this work we found a significant decrease in effective lifetimes of up to 75% for n-type POLO samples with 1.5 nm interfacial oxide at firing temperatures of 620°C to 900°C. This holds without a supply of hydrogen (no capping layers). Experiments with hydrogen-rich dielectric capping layers show, however, that a coating with AlOx:H as opposed to SiNy:H (n = 2.05), can significantly increase the stability of the passivation upon firing. Capacitance-voltage measurements show that the saturation current density correlates to the density of defect states at the SiOx/c-Si interface when varying the firing temperature. Although firing with hydrogen supplying layers such as AlOx:H seems to be viable, our results may indicate that the chemical configuration of the SiOx/Si interface changes from Si-O to Si-H bonds upon firing. If this hypothesis holds true, possible implications on the long-term stability of the passivation quality should be evaluated.
Keywords
- firing, passivating contacts, passivation, POLO
ASJC Scopus subject areas
- Engineering(all)
- Control and Systems Engineering
- Engineering(all)
- Industrial and Manufacturing Engineering
- Engineering(all)
- Electrical and Electronic Engineering
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2020 47th IEEE Photovoltaic Specialists Conference, PVSC 2020. Institute of Electrical and Electronics Engineers Inc., 2020. p. 1274-1278 9300849 (Conference Record of the IEEE Photovoltaic Specialists Conference; Vol. 2020-June).
Research output: Chapter in book/report/conference proceeding › Conference contribution › Research › peer review
}
TY - GEN
T1 - Firing stability of n-type poly-Si on oxide junctions formed by quartz tube annealing
AU - Hollemann, Christina
AU - Haase, Felix
AU - Krugener, Jan
AU - Brendel, Rolf
AU - Peibst, Robby
N1 - Funding Information: This work is funded by the German Federal Ministry of Economic Affairs (BMWi) and the state of lower Saxony Funding Information: ACKNOWLEDGMENT The authors thank the Federal Ministry of Economic Affairs (BMWi) and the state of lower Saxony for funding this work, Miriam Berger, Anja Christ und Annika Raugewitz (all from ISFH) as well as Raymond Zieseniss and Guido Glowatzki (both from Institute of Electronic Materials and Devices) for sample processing. We furthermore would like to thank Longi for the supply of these special wafers.
PY - 2020
Y1 - 2020
N2 - Passivating contacts formed by poly-Si on oxide (POLO) junctions yield high passivation qualities after an appropriate annealing process at temperatures between 800°C and 1050°C. In today's typical cell process, firing is applied in the end of cell production mainly to form screen printed contacts. Thus, a high stability of the passivation quality against this firing process is required - and also expected since a previous high-temperature process for POLO junction formation implies a much higher thermal budget. However, in this work we found a significant decrease in effective lifetimes of up to 75% for n-type POLO samples with 1.5 nm interfacial oxide at firing temperatures of 620°C to 900°C. This holds without a supply of hydrogen (no capping layers). Experiments with hydrogen-rich dielectric capping layers show, however, that a coating with AlOx:H as opposed to SiNy:H (n = 2.05), can significantly increase the stability of the passivation upon firing. Capacitance-voltage measurements show that the saturation current density correlates to the density of defect states at the SiOx/c-Si interface when varying the firing temperature. Although firing with hydrogen supplying layers such as AlOx:H seems to be viable, our results may indicate that the chemical configuration of the SiOx/Si interface changes from Si-O to Si-H bonds upon firing. If this hypothesis holds true, possible implications on the long-term stability of the passivation quality should be evaluated.
AB - Passivating contacts formed by poly-Si on oxide (POLO) junctions yield high passivation qualities after an appropriate annealing process at temperatures between 800°C and 1050°C. In today's typical cell process, firing is applied in the end of cell production mainly to form screen printed contacts. Thus, a high stability of the passivation quality against this firing process is required - and also expected since a previous high-temperature process for POLO junction formation implies a much higher thermal budget. However, in this work we found a significant decrease in effective lifetimes of up to 75% for n-type POLO samples with 1.5 nm interfacial oxide at firing temperatures of 620°C to 900°C. This holds without a supply of hydrogen (no capping layers). Experiments with hydrogen-rich dielectric capping layers show, however, that a coating with AlOx:H as opposed to SiNy:H (n = 2.05), can significantly increase the stability of the passivation upon firing. Capacitance-voltage measurements show that the saturation current density correlates to the density of defect states at the SiOx/c-Si interface when varying the firing temperature. Although firing with hydrogen supplying layers such as AlOx:H seems to be viable, our results may indicate that the chemical configuration of the SiOx/Si interface changes from Si-O to Si-H bonds upon firing. If this hypothesis holds true, possible implications on the long-term stability of the passivation quality should be evaluated.
KW - firing
KW - passivating contacts
KW - passivation
KW - POLO
UR - http://www.scopus.com/inward/record.url?scp=85099533467&partnerID=8YFLogxK
U2 - 10.1109/PVSC45281.2020.9300849
DO - 10.1109/PVSC45281.2020.9300849
M3 - Conference contribution
AN - SCOPUS:85099533467
SN - 978-1-7281-6116-7
T3 - Conference Record of the IEEE Photovoltaic Specialists Conference
SP - 1274
EP - 1278
BT - 2020 47th IEEE Photovoltaic Specialists Conference, PVSC 2020
PB - Institute of Electrical and Electronics Engineers Inc.
T2 - 47th IEEE Photovoltaic Specialists Conference, PVSC 2020
Y2 - 15 June 2020 through 21 August 2020
ER -