X-ray Topography maps crystal defects in a silicon carbide wafer (Copyright QinetiQ

X-ray topography (XRT) is a non-destructive characterisation technique for imaging, by means of X-ray diffraction, the micrometer to centimetre defect microstructure of crystals. The crystal sample is illuminated by a parallel X-ray beam and an image of a selected diffracted beam recorded. Contrast features are seen where there are imperfections in the crystal which cause variations in the long-range atomic order.

XRT is a powerful technique for characterising the growth of crystal substrates and thin (e.g. epitaxial) films. CEMMNT offers standard (single crystal) XRT for analysis of defective or deformed single crystals, and high resolution (double crystal) XRT for analysis of high quality single crystals. Common materials measured include silicon, silicon carbide, diamond, sapphire, gallium arsenide and cadmium mercury telluride. Imaging through patterned surface layers is possible, to investigate device defects.

• Imaging defects and distortions in crystals
• Sensitivity to individual defects
• Sub-surface imaging
• Analysis Area: up to 100 x 100 mm
• Spatial resolution: ~ 1 micron achievable

• Inspection of crystal substrates, and epitaxial layer quality
• Defect density measurement (high sensitivity)
• Inspection of device defects
• Mapping crystal distortion and strain
• Mapping residual sub-surface damage

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