Grazing Incidence X-Ray Methods for Near-Surface Strutural Studies

X-ray diffraction represents the classical method for determining the crystalline structure of solid materials. The basic principle of X-ray diffraction, Bragg¿s Law, was expounded early last century, and subsequently supplemented by theories regarding the detailed interpretation of X-ray diffraction patterns. Over the past several decades instrumentation has evolved continuously, with more powerful and collimated X-ray beams and different diffraction geometries opening up possibilities for structural analysis in many different applications. Sophisticated software packages now aid researchers in determining the structure of very complex crystallographic systems. As research into surface modification has led to more and more applications in industry, especially of thin films, ¿grazing incidence¿ or ¿glancing angle¿ geometries have been developed in order to render X-ray diffraction more surface sensitive. Many XRD equipment manufacturers now offer systems, or system attachments for ¿Glancing Angle¿ or ¿Grazing Incidence¿ X-Ray Diffraction (GAXRD, GIXRD, GIXD or GXRD). The main purpose of this chapter is to provide a broad outline of the two major grazing incidence X-ray diffraction geometries and the differences between these and the standard ¿¿2¿ diffraction method. The technique of Grazing Incidence X-Ray Reflectivity (GXRR, GIXR, GXR or XRR) is also described since the related theory is of central relevance here and it is often applied on the same systems used for GAXRD. In order to complete the picture concerning grazing incidence X-ray structural analysis, a particular variant of X-ray Absorption Spectroscopy is briefly mentioned in this section. However this technique can only be effectively applied at synchrotron radiation sources, and a full description of it and the enormous range of applications where it can be utilised would require a lengthy article in itself. GXRR and one of the two principle glancing angle diffraction techniques are described in a little more detail, these being normally applied on laboratory X-ray systems. The chapter will not deal in detail with theory, and the reader is referred to the appropriate bibliography for details concerning the theoretical basis of the techniques described.

GIBSON Peter; 

2011-05-30

WILEY-VCH

JRC52794

978-3-527-32047-9,