Plasma chemical etching for c-Si photovoltaics
    Structuring of TCO layers for TF-Photovoltaics
    Infection control – Process and materials studies
    Application demonstrator for infection control
    Energy storage – Process and materials R&D
    Application demonstrator for energy storage
    Interface technologies for durable adhesion
    Application demonstrator for interface technologies
    Cross-cutting equipment development

Plasma chemical etching for c-Si photovoltaics

Adjusting of top pyramid angle of c-Si by variation of gas composition: Increase of internal reflectivity of cell structure from 65-70 % for standard screen-printed Al to > 90 %
© Academy of Sciences of the Czech Republic, Institute of Physics (ASCR)

Principle of atmospheric pressure plasma source based on dc-arc
© Fraunhofer IWS

View into reactor for continuous microwave plasma-chemical etching at atmospheric pressure
© Fraunhofer IWS

R&D of novel atmospheric pressure plasma chemical etching (AP-PCE) for application in silicon solar wafer processing

• target: increased photovoltaic cell performance by introducing tailored micro- and nano-structured morphology of both front and rear surface
• adjusting of top pyramid angle of c-Si by variation of gas composition
• increase of internal reflectivity of cell structure from 65-70% for standard screen-printed Al to > 90%

Atmospheric pressure plasma chemical etching of silicon

• test of alternative etching gases with low global warming potential (GWP)
• in-situ process characterization by OES and FTIR spectroscopy investigation of atmospheric pressure microwave plasma for silicon etching
• optical modelling of solar cell and application oriented tests

Conclusion

• atmospheric pressure plasma chemical etching: very useful technique to modify the rear surface morphology of Si solar cells
• combined nano-micro structure substantially increases light harvesting: efficiencies up to 17.2 % achieved for PV cell structures with conventional Al BSF

c-Si photovoltaic demonstrator

• design and construction of equipment demonstrator to explore industrial feasibility of technologies being developed for plasma chemical etching of silicon
• introducing advanced 3D surface structuring techniques and control of nano-roughness, pinches, and radius of curvatures
• cost reduction for crystalline silicon solar cell manufacturing by combining process steps, substantial decrease of wafer break rate for thinner silicon wafers (<150 µm), and increased wafer throughput rate