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High Throughput Low Energy Industrial Emitter Diffusion and Oxidation

 
: Meßmer, M.; Lohmüller, S.; Weber, J.; Piechulla, A.; Nold, S.; Horzel, J.; Wolf, A.

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Fulltext urn:nbn:de:0011-n-6061857 (537 KByte PDF)
MD5 Fingerprint: 3a9c55408e7894af87e601c9ac2eff19
Created on: 12.11.2020

Poster urn:nbn:de:0011-n-606185-12 (523 KByte PDF)
MD5 Fingerprint: e2ab52211ecfcd33d8cdb367be4e998d
Created on: 13.11.2020


Pearsall, Nicola (ed.):
37th European Photovoltaic Solar Energy Conference and Exhibition, EU PVSEC 2020 : 07-11 September 2020, Online Conference
München: WIP, 2020
ISBN: 3-936338-73-6
pp.370-377
European Photovoltaic Solar Energy Conference and Exhibition (EU PVSEC) <37, 2020, Online>
English
Conference Paper, Electronic Publication
Fraunhofer ISE ()
Photovoltaik; Silicium-Photovoltaik

Abstract
In this work, we investigate an approach of shortened low pressure (LP) POCl3 diffusion and a high throughput thermal oxidation with stacked wafers to form the emitter for passivated emitter and rear cells (PERC). As the high temperature processes such as LP-POCl3 diffusion and thermal oxidation account for a significant share of the manufacturing costs of PERC solar cells, our high throughput approach is very promising in terms of reducing both, production costs and energy consumption. Compared to state-of-the-art POCl3 diffusion and low temperature oxidation, a 40% reduction of the specific costs and a 50% reduction of the energy consumption of the high temperature processes is feasible. We examine this approach by using four different adapted LP-POCl3 diffusion processes using only the deposition phase (omitting further drive-in and in-situ oxidation) in combination with a “stack oxidation” process. Detailed characterization of the properties of the emitter and oxide layers after diffusion and after oxidation confirm a high quality emitter formation resulting in emitter dark saturation current density j0e ≈ 32 fA/cm2 at Rsh ≈ 183 Ω/sq. Although the wafers are oxidized in a stack of horizontally oriented wafers touching each neighboring wafer, a very homogeneous oxide grows resulting in high passivation quality. Further, we find that this adapted emitter diffusion process allows for effective laser doping, which is promising for selective emitter formation.

: http://publica.fraunhofer.de/documents/N-606185.html