Deactivation of the boron-oxygen recombination center in silicon by illumination at elevated temperature

The boron-oxygen-related recombination center responsible for the light-induced degradation of solar cells made on boron-doped oxygen-contaminated silicon is deactivated by simultaneously annealing the silicon wafer in the temperature range 135-210 degrees C and illuminating it with white light. The recombination lifetime after deactivation is found to be stable under illumination at room temperature. The deactivation process is shown to be thermally activated with an activation energy of 0.7 eV. Based on the experimental findings, a defect reaction model is proposed explaining the deactivation of the boron-oxygen center. (C) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.