Anomalous X-ray Scattering for Structural and Chemical Analysis of Thin Films

Anomalous x-ray scattering (AXS) is a relatively new technique that can directly provide chemical and structural information simultaneously. Atomic scattering factor varies anomalously both in magnitude and phase as the probing x-ray energy approaches binding energies of core electrons of a specific element. Consequently, the change of the scattering intensity is directly related to the chemical content of the element incorporated in the structure. In this paper, we have applied the AXS to study two distinct classes of thin films; InGaN/GaN multiple quantum wells and a passive oxide film on stainless steel surface. AXS method is proven to be an effective method determining absolute chemical composition of InGaN independent of the lattice strain, which is especially valuable for the InGaN multiple quantum wells. We also found that the passive film on stainless steel consists of a Cr oxide inner layer and a Fe/Cr oxide outer layer.