Iron imaging in multicrystalline silicon wafers via photoluminescence

We have extended the development of a recent interstitial iron imaging technique based on photoluminescence (PL) imaging and iron-boron pair dissociation. The method is best applied below the lifetime crossover point, in order to avoid FeB pair breaking during the PL measurements. We have applied this high resolution iron imaging technique to a range of multicrystalline silicon wafers from different parts of an ingot, both before and after phosphorus gettering. The high spatial resolution mega-pixel images of the dissolved iron concentration generated in this way help to better understand the behavior of iron in this material, and it´s response to cell processing steps.