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High-Productive Aluminum Deposition of Back Contacts for Hetero-Junction Solar Cells by Electron Beam Evaporation
J.-P. Heinß, H. Schlemm, F. Wünsch
Back Contact, Cost Reduction, High Deposition Rate, Metallization, Metallisation
Wafer-Based Silicon Solar Cells and Materials Technology
Subtopic: Manufacturing and Processing
Event: 32nd European Photovoltaic Solar Energy Conference and Exhibition
Session: 2BV.7.49
961 - 965
ISBN: 3-936338-41-8
Paper DOI: 10.4229/EUPVSEC20162016-2BV.7.49
0,00 EUR
Document(s): paper, poster


Currently back contacts of Silicon HJT (Hetero Junction Technology) cells are sputtered or screen printed Ag-layers or structures. The present work aims to replace these cost-intensive manufacturing steps by electron beam evaporation of aluminum using axial beam guns. Al-layers of the necessary thickness have been evaporated with a dynamic deposition rate of up to 3000 nm.m/min while keeping the solar cell below 200°C to avoid any thermal damage of underlying layers and junctions. The deposited aluminum layers exhibit specific electrical resistance of 2.8.10-6 Ω.cm, specific electrical contact resistance of 10-3 Ω.cm2 and more than 92 % averaged reflection in the NIR. By exchanging only the metallization step in a standard HJT cell processing without further process-optimization lead to cell efficiencies of 20.6 %. It can be stated that the electron beam evaporation can meet the technical and economical demands of the HJT production process. The high deposition rate can ensure the rear-side metallization of a 100 MW production line in one single deposition equipment.