|Adhesion Analysis of Evaporated Aluminum on Passivation Layers for Rear Metallization of PERC Silicon Solar Cells|
|Julia Kumm, Dirk Eberlein, Philip Hartmann, Winfried Wolke, Andreas Wolf, Ralf Preu
Fraunhofer Institute for Solar Energy Systems, Freiburg, Germany
To investigate the adhesion quality of Aluminum (Al) rear metallization deposited by means of physical vapour deposition (PVD) on PERC silicon solar cells, test samples with different PVD Al metallization layers on common rear passivation stacks are fabricated. Since the standard cannot be applied for the adhesion measurement of this sample type, a peel-test and a direct-pull method are introduced, criteria for adhesion evaluation are developed and applicability and comparability of the methods are discussed. The adhesion results show a great variety of adhesion quality depending on the sample setup, but a sufficiently good adhesion quality can be achieved for all investigated passivation layers by choosing appropriate PVD parameters.