Determination of the interface region in multilayer Si/Mo by Auger depth profile and factor analysis

Target factor analysis was applied to an Auger depth profile to determine the interface region of a thin multilayer Si/Mo sample whose cross-section was observed by TEM. Optimized sputter conditions were used for the Auger depth profile and the result clearly shows the structure in the Si/Mo multilayer with very high depth resolution. Principal component analysis (PCA) was applied to the Si LMM spectra and suggested that three components exist in the Si profile. Target transformation with three components revealed two spectra with different shapes and one unknown spectrum. The first of two spectra were identified as Si metal and silicide by their shapes. The concentration profile of these components corresponded very closely to the structure observed by TEM and this profile showed that the unknown spectrum originated from Mo.