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arXiv · 2606.27744

Three-dimensional visualization of threading dislocation in GaN by polarized-light microscopy

Yukari Ishikawa·Kisara Matsumoto·Kazuki Ohnishi·Yongzhao Yao
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Abstract

We demonstrate high-throughput three-dimensional imaging of threading dislocations in ammonothermal GaN wafers using polarized-light microscopy with collimated LED illumination. Threading dislocations exhibited focal-depth-dependent in-plane shifts, enabling visualization of their three-dimensional inclination behavior over large areas. Synchrotron radiation X-ray topography indicated that dislocations with identical in-plane Burgers vector components tended to exhibit similar trace geometries and inclination directions. The threading dislocations were found to be tilted by approximately 3.3{\deg} from the c-axis in directions perpendicular to their Burgers vectors, indicating climb-mediated motion associated with strain relaxation during crystal growth. These results demonstrate a simple nondestructive approach for large-area three-dimensional characterization of dislocations in GaN wafers.

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Yukari Ishikawa, Kisara Matsumoto, Kazuki Ohnishi, Yongzhao Yao. 2026-06-26. Three-dimensional visualization of threading dislocation in GaN by polarized-light microscopy. https://arxiv.org/abs/2606.27744

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