3D XPS Imaging of Surface Nano-structures; A New Technique

XPS energy spectra vary characteristically with the depth distribution of electron emitting atoms on the nano-scale. This is the basis for the by now well known and widely used method [1] to non-destructively determine atomic depth distributions with nano-meter resolution by analysis of the inelastically scattered electrons associated with the XPS peak.A new algorithm which is suitable for automation was suggested recently [2]. For each XPS signal, this algorithm determines the total amount of the corresponding atoms within the outermost ~ 10 nm and it also determines their depth distribution. The validity of the algorithm for large area (~5×5mm2) XPS was demonstrated experimentally by comparison to more elaborate quantification methods [3]. Software that can automatically analyze several thousand spectra corresponding to the situation in XPS imaging is developed. The software produces nondestructively an image of the surface with nanometer depth resolution. The practical applicability for XPS imaging was recently demonstrated [4-6]. Here, we will summarize the technique and discuss its capabilities for 3D XPS-imaging of Surface Nano-structures