The lateral distribution of Fe in CIGS/steel foil is often observed to be non-uniform. Regular SIMS profile analysis may therefore not provide representative sampling.
The use of a large collection area is shown to reduce the location to location variation significantly, providing a more representative sampling of the average Fe concentration in the sample.
Large area SIMS image depth profiles not only provides a large data collection area, but also ion images that show lateral distribution of impurities. Depth profiles can be re-constructed after analysis to provide variation of impurities at different locations.