Spatially resolved trapping detection and correlation with material quality in multicrystalline silicon
We present images of the total trap density in standard industrial material which are extracted from Carrier Density Imaging (CDI/ILM) measurements. We demonstrate the influence of high temperature on the trap distribution as well as the spatial correlation of traps and crystal defect density. From these observations we deduce that the trapping effect may originate from impurities located at crystal defects. Fast trapping measurements on ascut wafers are presented that may be used to predict the diffusion length distribution of the processed solar cell for a given cell process. This prediction may be very useful for inline characterisation of starting material.