Through close interactions with our clients, Eurofins EAG (EAG) scientists came to know that low concentrations of unwanted contaminant species were just as important. These impurities can be detrimental to device performance or lifetime, even at very low (≤ppm) concentrations. This led EAG scientists to develop special instrumentation and analytical protocols to achieve record level detection limits to be able to do reliable contamination evaluation. The most common impurities are hydrogen, oxygen, sulfur, and copper, which may be present as contamination spikes at interfaces or crystal defect regions. When trying to isolate and eliminate the source of contamination, knowing the exact location of these impurity spikes in the layer growth sequence is also important. Therefore, appropriate selection of matrix markers, acquired in accurate synchronization with impurity elements, during SIMS data collection is crucial.