Profiling of fibre texture gradients in thin films by anomalous X-ray diffraction

摘要

Anomalous X-ray diffraction is applied to the quantitative determination of fiber texture gradients. Use is made of a theoretical model, in which crystallographic texture is described by an order parameter n and the depth dependent n(z) is assumed to follow a linear behavior (M. Birkholz, 2007, J. Appl. Cryst., 40, 735). The presented method is based on the extension of kinematic diffraction under inclusion of an inhomogeneous texture and relies on the profiling of different layer depths by tuning the wavelength in the neighborhood of an elemental absorption edge. As an example, thin ZnO:Al layers are investigated and large fiber texture gradients dn/dz between 0.03 and 0.3 m.r.d. nm~(-1) (multiples of a random distribution per nanometer) are revealed to occur in these samples. The approach is concluded to be well suited for the study of microstructure evolution as often observed during the growth of thin films.