A series of nano-indents was introduced both into 20 x 20mm (100) wafer pieces and into whole wafers as a means of introducing controlled strain. Visualization of the three-dimensional structure of crystal defects was demonstrated. The silicon samples were then treated by using various thermal anneal processes to initiate the formation of dislocation loops around the indents. A series of X-ray section topographs of both the indents and the dislocation loops were taken. The topographs were recorded on a CCD system combined with a high-resolution scintillator crystal and were measured by repeated cycles of exposure and sample translation along a direction perpendicular to the beam. The resulting images were then rendered into three dimensions using three-dimensional medical tomography algorithms that showed the dislocation loops formed. Furthermore this technique allowed for the production of a video showing the rotation of the rendered topographs around any defined axis. The software also had the capability of splitting the image along a segmentation line and viewing the internal structure of the strain fields.

Three-Dimensional X-Ray Diffraction Imaging of Process-Induced Dislocation Loops in Silicon. D.Allen, J.Wittge, J.Stopford, A.Danilewsky, P.McNally: Journal of Applied Crystallography, 2011, 44[3], 526-31