Recently, various thin film and multilayer materials are being developed and produced for use as functional devices. The characteristics of such a device are often influenced by layer parameters such as film thickness, film density and surface/interface roughness. X-ray reflectivity (XRR) is one of the techniques widely used to evaluate these parameters quantitatively.
XRR has various advantages over other characterization techniques: there is no need to treat the sample before measurement or measure reference samples, it is non-destructive, and it can be used with multi-layer systems and opaque materials.
XRR analysis is preceded by a pattern fitting process between the measured and the calculated XRR pattern. During pattern fitting, layer structure parameters are refined, commonly by using the least square method. However, it is very hard to find the best-fit model using only this method when the initial values of the structural parameter are quite different from the real ones. Therefore, practitioners of XRR analysis were often required to have a specialist’s understanding of material science as well as enough experience to construct appropriate structure models.
GlobalFit (Reflectivity Analysis), the newly released XRR analysis software from Rigaku Corp., overcomes these difficulties with the use of two powerful tools for data analysis and automatic profile fitting.