Defect Structure Analysis in Single Crystal Substrates using XRTmicron

Highlights

• Three-dimensional section X-ray topography enables non-destructive visualization and reconstruction of defect networks inside single-crystal substrates with high spatial resolution.
• Combining diffraction contrast with g·b analysis allows identification of dislocation Burgers vectors, providing information that many other defect characterization techniques cannot obtain.
• Dual-wavelength operation, automated switching between transmission and reflection geometries, and digital image acquisition make it possible to rapidly characterize a wide range of functional crystals, including SiC, sapphire, ScAlMgO₄  (SAM), and MgO.

Summary

X-ray topography is a powerful non-destructive technique for evaluating crystalline defects in single-crystal substrates used in advanced electronic and optoelectronic devices. Modern implementations combine high-brilliance microfocus X-ray sources, multilayer optics, digital detectors, and automated data acquisition to dramatically improve imaging speed while enabling three-dimensional reconstruction of defect structures inside crystals.

Three-dimensional section topography is particularly valuable because it acquires sequential section images throughout a crystal volume and reconstructs them into a 3D dataset. This allows researchers to inspect internal dislocation networks, stacking faults, and other extended defects from arbitrary cross-sections without physically sectioning the sample. Such capability is especially useful for semiconductor materials where buried defects influence device performance.

A major advantage of X-ray topography is its ability to perform diffraction-based g·b analysis, in which the visibility of a dislocation depends on the relationship between the diffraction vector and the Burgers vector. By recording images under different diffraction conditions, dislocation types and crystallographic slip systems can be identified, providing structural information that complements other defect characterization techniques.

Applications demonstrate the versatility of the approach across several technologically important materials. In sapphire substrates used for GaN epitaxy, X-ray topography reveals dislocation configurations beneath epitaxial layers and distinguishes major slip systems while showing that many defects remain confined within the substrate rather than propagating to the growth interface. Studies of ScAlMgO₄  (SAM) substrates show exceptionally high crystal quality, with very few dislocations and only subtle striation patterns visible in three-dimensional reconstructions. Analysis of MgO substrates highlights grain boundaries, slight crystal misorientations, and processing-induced surface damage while demonstrating the value of selecting Cu or Mo radiation depending on the desired penetration depth.

For wide-bandgap semiconductor materials such as 4H-SiC, detailed defect characterization plays an important role in improving device performance and reliability. Automated digital analysis and integration with complementary inspection methods support faster identification and classification of dislocations, enabling more comprehensive evaluation of crystal quality for advanced semiconductor manufacturing.