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Process optimization for the front side of P-type silicon solar cells

 
: Werner, S.; Lohmüller, E.; Maier, S.; Kimmerle, A.; Spribille, A.; Wasmer, S.; Clement, F.; Wolf, A.

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Fulltext urn:nbn:de:0011-n-3112921 (297 KByte PDF)
MD5 Fingerprint: f7cbd6eba4e51913c1cfa0987f5bdf44
Created on: 7.11.2014


Bokhoven, T.P. ; European Commission:
29th European Photovoltaic Solar Energy Conference and Exhibition, EU PVSEC 2014 : Proceedings of the international conference held in Amsterdam, The Netherlands, 22 - 26 September 2014, DVD
München: WIP, 2014
ISBN: 3-936338-34-5
pp.1342-1347
European Photovoltaic Solar Energy Conference and Exhibition (EU PVSEC) <29, 2014, Amsterdam>
English
Conference Paper, Electronic Publication
Fraunhofer ISE ()
PV Produktionstechnologie und Qualitätssicherung; Silicium-Photovoltaik; Pilotherstellung von industrienahen Solarzellen; passivation; doping; diffusion; metallization; solar cell

Abstract
In this work, we optimize the front side of p-type Czochralski-grown silicon (Cz-Si) solar cells by investigating industrial-type phosphorus diffusion processes, and by adapting the front-side metallization. The utilization of a metallization grid with less coverage, combined with double printing, results in an increase in conversion efficiency of 0.5 %abs for p-type Cz-Si H-pattern cells with aluminium back surface field. By incorporating in-situ oxidation into the diffusion process, we realize a surface doping concentration of ≈ 2·1020 cm-3 for our improved emitter. With this diffusion process, a low emitter dark saturation current density of 85 fA/cm2 is achieved while maintaining low specific contact resistance ≤ 4 mΩcm2. The application of this emitter results in a gain in of 0.4 %abs for p-type Cz-Si high-performance metal wrap trough (HIP-MWT) solar cells in comparison to a diffusion process without in-situ oxidation. For the best performing HIP-MWT cell, reaches 20.5 %. Furthermore, we test the stability and reproducibility of our improved diffusion process in ten runs with 200 wafers each. The mean sheet resistance is found to be (85 ± 2) Ω/sq, revealing high homogeneity over full-load runs.

: http://publica.fraunhofer.de/documents/N-311292.html