Boron-emitter development for TOPCon c-Si solar cells based on plasma-deposited boron diffusion source and poly-Si(n) passivating contact
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Author
Schaller, Thibault
Genç, Ezgi
Hurni, Julien
Lunghi, Ludovica
Ballif, Christophe
Morisset, Audrey
Haug, Franz Josef
DOI
10.1016/j.solmat.2025.113808
Abstract
The n-type TOPCon technology is currently the leading approach in the industry. Generally, it involves two high-temperature steps that can result in long cycle times and expensive processes. In this context, we propose a lean manufacturing process based on the successive PECVD-deposition of the front and rear doped layers, followed by a co-annealing step in which front emitter formation and rear passivating contact activation are performed simultaneously. We first investigated the influence of the PECVD process parameters and the thermal budget of the co-annealing step on the active boron concentration profile, the passivation quality, and contact resistivity. Then, we investigated the effect of a drive-in step under O<inf>2</inf> environment to reduce the surface concentration and increase the depth of the emitter. Finally, we investigated the compatibility of the rear passivating contact with the drive-in step. The introduction of the drive-in step made it possible to obtain active boron concentration profiles with the desired surface concentration and depth. However, even though we obtained promising results regarding the compatibility of the rear passivating contact with the drive-in step, we observed that further optimization is necessary to avoid blistering of the n-type poly-Si layer and improve the uniformity of the rear passivation.
Publication Reference
Solar Energy Materials and Solar Cells, 293, art. no. 113808
Year
2025