Going to finite source emitter: improved emitter technology by reduction of the dead P-layer for high-efficiency crystalline silicon solar cells
conference paper
Standard in industrial in-line emitter processing is to apply an excess phosphorus source on the wafer prior to diffusion. Subsequently, a constant and high phosphorus concentration is present on the surface during the diffusion process. This paper shows that a reduction in the concentration, and thus in the emitter, can give a significant gain in Voc and Jsc as the dead P-layer is reduced. Homogeneous reduction over the complete wafer is important to obtain a maximum gain in Jsc and Voc. Different application methods are tested on homogeneity and the effect on Jsc and Voc. To optimize the contacting of these emitters, different pastes are tested on their contacting ability. It is shown that an efficiency increase of 0.1% absolute can be obtained with these emitters for industrial in-line applications, which can be easily and directly implemented in new and existing lines. No additional costs are required and no yield loss is expected, while at the same time the HF usage decreases as the glass is thinner and contains less phosphorus.
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TNO Identifier
821556
Publisher
ECN
Source title
23rd European Photovoltaic Solar Energy Conference and Exhibition, Valencia, Spain, 1-5 september 2008.
Collation
5 p.
Place of publication
Petten
Pages
5 p.
Files