Spectra of the sample were obtained at different acceleration voltages to realize different penetration depths and k ratios for the elements, which are required for layer thickness calculation. In this case 12, 15, 20, 25 and 30 kV were used. The K ratios were determined by the ESPRIT software and input to STRATAGem. Results are obtained through fit procedures, involving K ratios, layer thickness, layer composition and substrate composition.
This procedure generates reliable results for many different types of layers with different compositions and thicknesses ranging from nm to several µm, including multi-layer structures. In this example it could be determined that the layer is approximately 185 nm thick and consists of 50.3% Fe and 49.7% Ni, which is in good agreement with the given values.