Presented at MRS Spring Meeting 2011.
“A key issue for the production of thin films in photovoltaics, optical coatings, or corrosion protection is cost reduction. In this context, vacuum based processes are often limited especially when large substrates are to be processed. Atmospheric pressure (AP) processes instead allow to process large substrates with mobile coater head technology where the substrate is fixed, but are also ideally suited for in-line processing. At Fraunhofer IWS, CVD processes and equipment for atmospheric pressure processing is developed with and without plasma. Plasma processes focus on silicon etching using fluorine containing precursors and deposition of silicon nitride thin films, both for crystalline photovoltaics. High etching rates allow for rapid texturing, edge isolation but also the texturing of TCO materials. As a key technology a linear extended arc is used with precursor injection into the remote plasma. Due to the good scalability of this plasma source, substrates up to 600 mm wide can be processed. Further application examples include the deposition of corrosion protective coatings and polymer activation for adhesion intensification. A high degree of crystallinity in TiO2 and SnO2:F coatings is obtained using plasma-free AP technology. Highly active photocatalytic coatings are obtained and TCO coatings can be deposited in a homogeneous way with low resistance. A further application of AP-CVD is the deposition of carbon nanotube forests using catalytic nanoparticles (Fe) as seed and methane at 700-800°C. The latter is a high rate deposition method for the production of CNT forests up to 70 mu m for the generation of electrode materials.”