After a short history of X-ray diffraction topography, from the early stage of laboratory X-ray topography to recent synchrotron-radiation applications, is described, the development of science and technology for the synchrotron X-ray topography and its industrial applications are reviewed in more detail. In addition, the recent trend of synchrotron topography research is clarified on the basis of several data obtained from 256 papers which have been published since 2000.
The lattice defects in bulky crystals have three-dimensional distribution. The evaluation technique should provide three-dimensional information of these defects. X-ray topography is the only way to nondestructively characterize the defects in the single crystals with high sensitivity to strain. However, a laboratory X-ray source is too weak to get three-dimensional information by X-ray topography. Synchrotron light source showed the possibility of three-dimensional X-ray topography with its performance. In this report, we describe the techniques of three-dimensional X-ray topography and its applications at SPring-8.
Dislocations in silicon carbide (SiC) have been analyzed by means of double-crystal X-ray topography. Strain caused by a dislocation is sensitively observed by using the X-rays with small angular divergence. In this article, the authors describe the principle and method of the double-crystal X-ray topography, introduce SiC as a material developing for power electronics devices, and show practical observations of dislocations with high resolution.
X-ray topographic studies on characterization of semiconductor thin layer were reviewed. Reflection topographs of thin layer were taken by synchrotron radiation X-ray from a storage ring. In these papers, relaxation mechanisms of mismatch in lattice constant between thin layer and substrate were clarified and critical thickness for formation of misfit dislocations was determined for various hetero-epitaxial grown semiconductor thin film. Investigations using grazing incident X-ray topography on semiconductor thin film were also surveyed.
X-ray topography, especially synchrotron X-ray topography, provides a useful tool for the characterization of protein crystals in order to characterize the defects. We observed clear images of dislocations in hen-egg white lysozyme crystals. In this article we overviewed the research on crystal defects, especially dislocations of protein crystals by synchrotron X-ray topography.
When the dispersion angle of X-rays in a perfect crystal is large, interference fringes are observed between the beams in the Bragg-Laue mode and Bragg-Bragg-Laue mode in the emitted beams from the lateral surface. If the crystal is weakly bent, X-rays propagate along a path of hyperbolic form and are diffracted from the incident surface, which is called mirage diffraction. Under the condition, mirage interference fringes between two mirage diffraction beams are observed not only from the incident surface but also from the lateral surface. Two approaches are proposed to determine strain parameters in the bent crystal by using the mirage interference fringes from the incident surface or the lateral surface. In one approach, the third peak of the mirage interference fringes is used. In the other, the region is used where no direct beam reaches to the lateral surface. The resultant strain parameters determined by the two approaches show excellent agreement. Some characteristics and advantages of using mirage interference fringes are discussed.
We investigated the crystalline quality of 72 nm-thick strained Si layers of 12-inch supercritical thickness strained Si-on-insulator (SC-sSOI) wafers by synchrotron X-ray topography. In the large-area X-ray topographs obtained at the glancing incident condition several kinds of contrast showing crystalline imperfections were observed all over the wafers, such as macule and crosshatch patterns. From the analysis of a series of X-ray topographs obtained by changing the incident angle to the sample surface, we obtained 2-dimensional distributions of lattice inclination and strain, indicating that the cross-hatch patterns observed in X-ray topographs were due to the fluctuation of lattice inclination.
Semiconductor epitaxial CVD single crystal diamond is considered a potential material for power devices because of its unique characteristics. In the discussion on the relationship between crystal quality and device performance, the atomic purity and defect concentration have been considered. In this paper, the dislocation analysis is shown for the suggestion of the established standard dislocation analysis method. The aggregation of edge dislocation and mixed dislocation are observed by the analysis by using X-ray topography.