Soft X-ray absorption study of sputtered tin oxide films

The bonding structure of tin oxide (SnOx) films grown by reactive DC magnetron sputtering has been studied by the combination of X-ray diffraction (XRD) and soft X-ray absorption near-edge structure (XANES). The oxygen incorporation in the films has been controlled by the O2 partial pressure (PO2) in the O2/Ar discharge mixture. In addition, the impact of substrate heating and post-deposition flash lamp annealing (FLA) on crystal growth has been studied. In general, it has been stablished a transition from SnO to SnO2 arrangements by increasing PO2, where XRD and XANES provide complementary results about the formation of single- and mixed-phase films. In samples produced at room temperature, XANES gives unique information about such structural evolution, as well as related to defects like the incorporation of O2 molecules at high PO2. FLA on samples grown at room temperature promotes crystal growth and the phase evolution follows the initial structural selectivity. Finally, the optical properties and surface morphology of the films have been correlated with the structural identification.