Investigation of laser-fired rear-side recombination properties using an analytical model

This paper presents the application of the analytical model for locally contacted rear sides recently published by Fischer to the determination of recombination losses of solar cells with fixed metallization fraction, but varying contact pitch. After the successful experimental validation of the model on oxide-passivated solar cells with ohmic contacts, the model was used for a detailed investigation of rear sides prepared by the laser-fired contacts (LFC) method. In this way the surface recombination velocity (SR V) at the very contact areas was extracted for a broad base doping range. The determined parameterization allows the calculation of the SRV of any LFC rear side concerning base doping and contact pitch. The excellent passivation quality of the alnealed oxide with LFC contacts is shown: on 1 (100) Omega cm FZ an effective SRV of only 35 (4.3) cm/s could be measured with 1000 mu m contact pitch.