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Local Laser Crystallization of a-Si on Tunneling SiOx for Passivated Contacts of Solar Cells
G. Jia, A. Gawlik, J. Dellith, A. Dellith, G. Andrä, R. Glatthaar, B. Terheiden, J. Plentz
Silicon Materials and Cells
Subtopic: Low Temperature Route for Si Cells
Event: 37th European Photovoltaic Solar Energy Conference and Exhibition
Session: 2DV.3.46
ISBN: 3-936338-73-6
0,00 EUR
Document(s): poster


A well passivated emitter has proven to have efficiency over 25%1,2, and industrial mass production has already demonstrated an average efficiency of over 23% and module output power over 345 W3. To further drive the conversion efficiency of crystalline silicon (c-Si) solar cells, it is critical to reduce further the surface recombination losses, and the parasitic absorption by the ITO. We propose in this contribution a concept based on a selective emitter approach with locally prepared crystalline silicon thin layer instead of on whole area, which is deposited on a passivating tunneling SiOx oxide, and screen printing metal contacts on top of the pc-Si. The main processing steps are sketched in Fig. 1 with an example of n-type Si substrate. A 75 nm highly doped (using B or P sources for p- or n-type, respectively) a-Si film will be deposited by a high rate e-beam evaporation system on top of the passivating tunneling SiOx (~2 nm) layer, and it will be locally crystallized by laser scanning using diode (808 nm), Nd-YAG (532 nm) and Excimer lasers. The excess a-Si layer will be removed by a selective wet chemical etching, and the metal contact will be prepared on top of the crystallized-Si by screen printing. The preliminary results will be presented.