Details
| Original language | English |
|---|---|
| Pages (from-to) | 50-54 |
| Number of pages | 5 |
| Journal | Solar Energy Materials and Solar Cells |
| Volume | 158 |
| Issue number | 1 |
| Early online date | 18 Jun 2016 |
| Publication status | Published - Dec 2016 |
Abstract
The manufacturing process of Passivated Emitter and Rear Totally diffused (PERT) solar cells on n-type crystalline silicon is significantly simplified by applying multifunctional layer stacks acting as diffusion source, etching and diffusion barrier. We apply boron silicate glasses (BSG) capped with silicon nitride (SiN z) layers that are deposited by means of plasma enhanced chemical vapor deposition (PECVD). Optimum PECVD deposition parameters for the BSG layer such as the gas flow ratio of the precursor gases silane and diborane SiH 4/B 2H 6=8% and the layer thickness of 40 nm result in a boron diffusion with saturation current density J 0,B below 10 fA/cm 2 applying an AlO x/SiN y passivation and firing. The PECVD BSG diffusion source is integrated into the n-type PERT back junction (BJ) solar cell process with screen-printed front and rear contacts. The only high temperature step is a POCl 3 co-diffusion for the formation of the boron emitter from the PECVD BSG layer and for the formation of the phosphorus-doped front surface field (FSF). An independently confirmed energy conversion efficiency of 21.0% is achieved for a 156×156 mm 2 large n-PERT BJ cell with this simplified process flow. This is the highest efficiency reported for a large-area co-diffused n-type PERT BJ solar cell using a PECVD BSG as diffusion source. For comparison, reference n-type PERT BJ cells with separate POCl 3 and BBr 3 diffusions reach an efficiency of 21.2% in our lab. A synergistic efficiency gain analysis (SEGA) for the co-diffused n-PERT BJ cell shows that the main possible efficiency gain of 1.1% abs. originates from recombination in the phosphorus-diffused front surface field while the PECVD BSG boron-doped emitter accounts for only 0.1% abs. efficiency gain. We evaluate the use of the PECVD BSG/SiN z stack as a rear side passivation as a replacement of the AlO x/SiN y stack in order to further simplify the process flow. We obtain J 0,B values of 40 fA/cm 2, an implied open-circuit voltage of 682 mV and a simulated n-PERT BJ cell efficiency of 21.1%.
Keywords
- Co-diffusion, Device simulation, Efficiency gain analysis, PECVD boron silicate glass, Silicon solar cells, n-PERT back junction
ASJC Scopus subject areas
- Materials Science(all)
- Electronic, Optical and Magnetic Materials
- Energy(all)
- Renewable Energy, Sustainability and the Environment
- Materials Science(all)
- Surfaces, Coatings and Films
Sustainable Development Goals
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In: Solar Energy Materials and Solar Cells, Vol. 158, No. 1, 12.2016, p. 50-54.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - 21.0%-efficient screen-printed n-PERT back-junction silicon solar cell with plasma-deposited boron diffusion source
AU - Wehmeier, Nadine
AU - Nowack, Anja
AU - Lim, Bianca
AU - Brendemuhl, Till
AU - Kajari-Schröder, Sarah
AU - Schmidt, Jan
AU - Brendel, Rolf
AU - Dullweber, Thorsten
N1 - Funding Information: We thank Miriam Berger for n-PERT cell processing, Sarah Spätlich for diffusion optimization and David Sylla for laser processes. This work was funded by the German Federal Ministry for Economic Affairs and Energy under Grant 0325880A (PERC 2.0) and by the State of Lower Saxony .
PY - 2016/12
Y1 - 2016/12
N2 - The manufacturing process of Passivated Emitter and Rear Totally diffused (PERT) solar cells on n-type crystalline silicon is significantly simplified by applying multifunctional layer stacks acting as diffusion source, etching and diffusion barrier. We apply boron silicate glasses (BSG) capped with silicon nitride (SiN z) layers that are deposited by means of plasma enhanced chemical vapor deposition (PECVD). Optimum PECVD deposition parameters for the BSG layer such as the gas flow ratio of the precursor gases silane and diborane SiH 4/B 2H 6=8% and the layer thickness of 40 nm result in a boron diffusion with saturation current density J 0,B below 10 fA/cm 2 applying an AlO x/SiN y passivation and firing. The PECVD BSG diffusion source is integrated into the n-type PERT back junction (BJ) solar cell process with screen-printed front and rear contacts. The only high temperature step is a POCl 3 co-diffusion for the formation of the boron emitter from the PECVD BSG layer and for the formation of the phosphorus-doped front surface field (FSF). An independently confirmed energy conversion efficiency of 21.0% is achieved for a 156×156 mm 2 large n-PERT BJ cell with this simplified process flow. This is the highest efficiency reported for a large-area co-diffused n-type PERT BJ solar cell using a PECVD BSG as diffusion source. For comparison, reference n-type PERT BJ cells with separate POCl 3 and BBr 3 diffusions reach an efficiency of 21.2% in our lab. A synergistic efficiency gain analysis (SEGA) for the co-diffused n-PERT BJ cell shows that the main possible efficiency gain of 1.1% abs. originates from recombination in the phosphorus-diffused front surface field while the PECVD BSG boron-doped emitter accounts for only 0.1% abs. efficiency gain. We evaluate the use of the PECVD BSG/SiN z stack as a rear side passivation as a replacement of the AlO x/SiN y stack in order to further simplify the process flow. We obtain J 0,B values of 40 fA/cm 2, an implied open-circuit voltage of 682 mV and a simulated n-PERT BJ cell efficiency of 21.1%.
AB - The manufacturing process of Passivated Emitter and Rear Totally diffused (PERT) solar cells on n-type crystalline silicon is significantly simplified by applying multifunctional layer stacks acting as diffusion source, etching and diffusion barrier. We apply boron silicate glasses (BSG) capped with silicon nitride (SiN z) layers that are deposited by means of plasma enhanced chemical vapor deposition (PECVD). Optimum PECVD deposition parameters for the BSG layer such as the gas flow ratio of the precursor gases silane and diborane SiH 4/B 2H 6=8% and the layer thickness of 40 nm result in a boron diffusion with saturation current density J 0,B below 10 fA/cm 2 applying an AlO x/SiN y passivation and firing. The PECVD BSG diffusion source is integrated into the n-type PERT back junction (BJ) solar cell process with screen-printed front and rear contacts. The only high temperature step is a POCl 3 co-diffusion for the formation of the boron emitter from the PECVD BSG layer and for the formation of the phosphorus-doped front surface field (FSF). An independently confirmed energy conversion efficiency of 21.0% is achieved for a 156×156 mm 2 large n-PERT BJ cell with this simplified process flow. This is the highest efficiency reported for a large-area co-diffused n-type PERT BJ solar cell using a PECVD BSG as diffusion source. For comparison, reference n-type PERT BJ cells with separate POCl 3 and BBr 3 diffusions reach an efficiency of 21.2% in our lab. A synergistic efficiency gain analysis (SEGA) for the co-diffused n-PERT BJ cell shows that the main possible efficiency gain of 1.1% abs. originates from recombination in the phosphorus-diffused front surface field while the PECVD BSG boron-doped emitter accounts for only 0.1% abs. efficiency gain. We evaluate the use of the PECVD BSG/SiN z stack as a rear side passivation as a replacement of the AlO x/SiN y stack in order to further simplify the process flow. We obtain J 0,B values of 40 fA/cm 2, an implied open-circuit voltage of 682 mV and a simulated n-PERT BJ cell efficiency of 21.1%.
KW - Co-diffusion
KW - Device simulation
KW - Efficiency gain analysis
KW - PECVD boron silicate glass
KW - Silicon solar cells
KW - n-PERT back junction
UR - http://www.scopus.com/inward/record.url?scp=84977568003&partnerID=8YFLogxK
U2 - 10.1016/j.solmat.2016.05.054
DO - 10.1016/j.solmat.2016.05.054
M3 - Article
VL - 158
SP - 50
EP - 54
JO - Solar Energy Materials and Solar Cells
JF - Solar Energy Materials and Solar Cells
SN - 0927-0248
IS - 1
ER -