Fast LBIC in-line characterization for process quality control in the photovoltaic industry

The photovoltaic industry asks for fast, non-destructive techniques for in-line characterization tools in solar cells production. We shall show in this paper that the use of the light beam induced current technique (LBIC) is capable to get in a few seconds time photocurrent maps of large area solar cells and to correlate these data with the cell efficiency. The samples analysed in this study are industrial 10×10 cm2 multicrystalline silicon solar cells. The LBIC setup works with three laser sources at 633, 780 and 830 nm, taking the laser beam power below 1 mW. The laser beams are moved on the wafer surfaces using a galvanometer x–y scanner system and the beam size on the focus has a diameter of about 65 μm. We demonstrated the possibility to obtain quantitative information about the cell quality in <3 s from the photocurrent maps with a pretty good correlation with the efficiency data.