Structural Characterization of Thin Films by X-Ray Diffraction and Reflectivity

Abstract

X-ray polycrystalline diffraction was used to track progress toward improving the structural properties of SrS:(Eu,Sm) thin films. These thin films are used as the active layer of the ETOM (Electron Trapping Optical Memory) media. In this study conventional x-ray diffraction and x-ray reflectivity were used to evaluate the effect of two deposition parameters on film structures. Line broadening analysis performed using the Warren-Averbach technique showed the beneficial effects of a hydrogen sulfide reactive atmosphere and the RF magnetron sputtering technique on crystallite size and microstrain. A factor of five improvement in crystallite size and a factor of two reduction in microstrain was observed. Film thickness, density, and interfacial and surface roughnesses were determined for two SrS thin films. The sin2Ψ technique was used to determine the in-plane biaxial stress for two films prepared by different deposition techniques. These films exhibit inhomogeneous stress states with an average stress of less than IMPa.