Abstract: | A simple analytical function is derived to describe the interface shapes measured in sputter depth profiling by using X‐ray photoelectron spectroscopy or secondary ion mass spectrometry. This function involves the convolution of a central Gaussian function, often taken to describe the roughness, together with an exponential tail to describe mixing and an exponential approach often taken to describe an information depth. This model is consistent with Hofmann's mixing‐roughness‐information model that does the same by numerical analysis, but we present a direct analytical function that is more transparent to the user. The differential of the function gives Dowsett's function for delta layers. Depending on which of the 3 base parameters are identified as sample related, the analyst can obtain the centroid of the underlying composition. These functions are used to show the extent that the common measure of depth resolution for step edges and delta functions diverge as the profile becomes less Gaussian. |