On the choice of the test structure for the electrical characterization of dielectrics for silicon solar cells

Surface passivation of Si solar cells is typically achieved by deposition of a dielectric layer. Via the investigation of Al2O3 passivation layers, we show that care must be taken when performing capacitance–voltage (C –V) measurements in order to obtain results that are meaningful at solar cell level. The passivation properties of a dielectric are not only affected by post-deposition treatments but also by the presence and the nature of a metal covering the dielectric. Consequently, this Letter emphasizes how important it is to perform C –V measurements on a device structure that resembles as closely as possible that of the finished solar cell, using the same metal, deposition technique and thermal budget. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)