Synchrotron White Beam Topographic Imaging in Grazing Bragg-Laue Geometries

The technique of synchrotron white beam topographic imaging in grazing Bragg-Laue geometries has been developed at the Stony Brook synchrotron topography station (beamline X-19C) at the National Synchrotron Light Source. This technique enables both general quality characterization and imaging of defects in subsurface regions of thickness which can range from hundreds of angstroms to hundreds of micrometers as determined by the effective penetration depth of the x rays. This penetration depth, which is shown in most cases to be determined by the kinematical theory of x-ray diffraction, can be conveniently varied in a controlled manner by simple manipulation of the diffraction geometry, thereby enabling a depth profiling of the defect content. The fundamentals of the technique are described, and its advantages and disadvantages compared to existing techniques are discussed. Brief examples of the application of the technique in the characterization of defects in both single crystals and heteroepitaxial systems are given, and the general applicability of the technique is discussed.