Details
| Original language | English |
|---|---|
| Pages (from-to) | 849-857 |
| Number of pages | 9 |
| Journal | IEEE journal of photovoltaics |
| Volume | 13 |
| Issue number | 6 |
| Publication status | Published - 30 Aug 2023 |
Abstract
The fast-firing step commonly applied at the end of solar cell production lines triggers 'Light- and elevated-Temperature-Induced Degradation' (LeTID) effects of the carrier lifetime in Ga-doped Cz-Si wafers and solar cells made thereof. As far as the defect formation within the silicon bulk is concerned, the key parameters of the fast-firing step are the peak firing temperature (FT) and the band velocity vband of the conveyor belt, where the latter mainly defines the cooling ramp after the firing peak. In this contribution, we show that the extent of LeTID and the dependence on the applied temperature during degradation increase strongly with increasing measured FT (from 680 °C to 800 °C), vband (from 2.8 to 7.2 m/min), and the refractive index n of the hydrogen-rich silicon nitride layer deposited on the wafer surfaces (from 2.07 to 2.37). Through temperature-dependent degradation experiments, we determine an activation energy of EA = (0.55 ± 0.10) eV of the LeTID mechanism in Ga-doped Cz-Si, which is independent of FT and vband. From this observation we conclude that a single defect activation mechanism is most likely responsible for the examined LeTID effect, independent of the firing conditions. However, the concentration of recombination-active defect centers after LeTID depends critically on FT, vband, and n, which we attribute to variations of the in-diffused hydrogen concentrations from the silicon nitride layers during firing. Our experiments hence point towards an involvement of hydrogen in the LeTID mechanism observed in Ga-doped Cz-Si.
Keywords
- Carrier lifetime, degradation, gallium, LID, light- and elevated-temperature-induced degradation (LeTID), silicon
ASJC Scopus subject areas
- Materials Science(all)
- Electronic, Optical and Magnetic Materials
- Physics and Astronomy(all)
- Condensed Matter Physics
- Engineering(all)
- Electrical and Electronic Engineering
Cite this
- Standard
- Harvard
- Apa
- Vancouver
- BibTeX
- RIS
In: IEEE journal of photovoltaics, Vol. 13, No. 6, 30.08.2023, p. 849-857.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Impact of Fast-Firing Conditions on Light- and Elevated-Temperature-Induced Degradation (LeTID) in Ga-Doped Cz-Si
AU - Winter, Michael
AU - Walter, Dominic C.
AU - Schmidt, Jan
PY - 2023/8/30
Y1 - 2023/8/30
N2 - The fast-firing step commonly applied at the end of solar cell production lines triggers 'Light- and elevated-Temperature-Induced Degradation' (LeTID) effects of the carrier lifetime in Ga-doped Cz-Si wafers and solar cells made thereof. As far as the defect formation within the silicon bulk is concerned, the key parameters of the fast-firing step are the peak firing temperature (FT) and the band velocity vband of the conveyor belt, where the latter mainly defines the cooling ramp after the firing peak. In this contribution, we show that the extent of LeTID and the dependence on the applied temperature during degradation increase strongly with increasing measured FT (from 680 °C to 800 °C), vband (from 2.8 to 7.2 m/min), and the refractive index n of the hydrogen-rich silicon nitride layer deposited on the wafer surfaces (from 2.07 to 2.37). Through temperature-dependent degradation experiments, we determine an activation energy of EA = (0.55 ± 0.10) eV of the LeTID mechanism in Ga-doped Cz-Si, which is independent of FT and vband. From this observation we conclude that a single defect activation mechanism is most likely responsible for the examined LeTID effect, independent of the firing conditions. However, the concentration of recombination-active defect centers after LeTID depends critically on FT, vband, and n, which we attribute to variations of the in-diffused hydrogen concentrations from the silicon nitride layers during firing. Our experiments hence point towards an involvement of hydrogen in the LeTID mechanism observed in Ga-doped Cz-Si.
AB - The fast-firing step commonly applied at the end of solar cell production lines triggers 'Light- and elevated-Temperature-Induced Degradation' (LeTID) effects of the carrier lifetime in Ga-doped Cz-Si wafers and solar cells made thereof. As far as the defect formation within the silicon bulk is concerned, the key parameters of the fast-firing step are the peak firing temperature (FT) and the band velocity vband of the conveyor belt, where the latter mainly defines the cooling ramp after the firing peak. In this contribution, we show that the extent of LeTID and the dependence on the applied temperature during degradation increase strongly with increasing measured FT (from 680 °C to 800 °C), vband (from 2.8 to 7.2 m/min), and the refractive index n of the hydrogen-rich silicon nitride layer deposited on the wafer surfaces (from 2.07 to 2.37). Through temperature-dependent degradation experiments, we determine an activation energy of EA = (0.55 ± 0.10) eV of the LeTID mechanism in Ga-doped Cz-Si, which is independent of FT and vband. From this observation we conclude that a single defect activation mechanism is most likely responsible for the examined LeTID effect, independent of the firing conditions. However, the concentration of recombination-active defect centers after LeTID depends critically on FT, vband, and n, which we attribute to variations of the in-diffused hydrogen concentrations from the silicon nitride layers during firing. Our experiments hence point towards an involvement of hydrogen in the LeTID mechanism observed in Ga-doped Cz-Si.
KW - Carrier lifetime
KW - degradation
KW - gallium
KW - LID
KW - light- and elevated-temperature-induced degradation (LeTID)
KW - silicon
UR - http://www.scopus.com/inward/record.url?scp=85169707023&partnerID=8YFLogxK
U2 - 10.1109/JPHOTOV.2023.3304118
DO - 10.1109/JPHOTOV.2023.3304118
M3 - Article
AN - SCOPUS:85169707023
VL - 13
SP - 849
EP - 857
JO - IEEE journal of photovoltaics
JF - IEEE journal of photovoltaics
SN - 2156-3381
IS - 6
ER -