Recent Novel X-ray Reflectivity Techniques: Moving Towards Quicker Measurement to Observe Changes at Surface and Buried Interfaces

Abstract

The present paper reviews recent extensions of the X-ray reflectivity technique, which is a powerful tool for the non-destructive exploration of layered films and which can provide data on density, layer thickness, interface roughness, interdiffusion etc. With conventional X-ray reflectivity measurement, samples need to be sufficiently stable, and analysis is basically concerned with the static structure. In view of the growing need to observe changes to the buried interfaces of a variety of thin films and multilayers, it is crucial to develop novel methods and instruments that enable reflectivity measurements to be carried out much more quickly, preferably without any motion of the sample, the detector or the optics, i.e., without a θ/2θ scan. One can observe structural variations by noting changes in the position of critical angles, the frequency of interference fringes, or the degree of decay of the curve. This paper introduces recent developments in such rapid X-ray reflectivity techniques, as well as some interesting applications.