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Sputtered Aluminum Oxide for Rear Side Passivation of p-Type Silicon Solar Cells
G. Krugel, W. Wolke, F. Wagner, J. Rentsch, R. Preu
Passivation, Sputtering, Optical Properties, Aluminum Oxide, Solar Cell Efficiency
Wafer-Based Silicon Solar Cells and Materials Technology
Subtopic: Silicon Solar Cell Improvements
Event: 27th European Photovoltaic Solar Energy Conference and Exhibition
Session: 2CV.6.57
1958 - 1962
ISBN: 3-936338-28-0
Paper DOI: 10.4229/27thEUPVSEC2012-2CV.6.57
0,00 EUR
Document(s): paper


Aluminum oxide is an excellent candidate for the surface passivation of silicon wafers. Due the incorporation of a high density of negative charges near the interface surface and a low defect density a very good passivation can be achieved. Today, aluminum oxide layers are predominantly deposited by atomic layer deposition and plasma-enhanced chemical vapor deposition. Reactive sputtering is an alternative not requiring trimethylaluminum. Nevertheless, there are doubts concerning the passivation quality of sputtered aluminum oxide. In this contribution we analyse the influence of deposition parameters on the properties of the sputtered layers. Measurements of interface defects density and the density of fixed charges at the interface can explain a good passivation quality after firing. Additionally, results for LFC-PERC solar cells are presented showing a statistically significant improve in efficiency compared to standard BSF solar cells. This can be explained by a lower recombination rate and a higher reflectivity at the rear side of the solar cell.