High-speed, High-Resolution, Three-Dimensional Imaging of Threading Dislocations in beta-$Ga_{2}O_{3}$ via Phase-Contrast Microscopy

TL;DR

This paper introduces a nondestructive phase-contrast microscopy method for high-resolution 3D imaging of threading dislocations in beta-Ga2O3, offering advantages over synchrotron X-ray topography.

Contribution

The study demonstrates PCM as a practical, high-resolution, 3D imaging technique for dislocations in wide-bandgap semiconductors, with improved spatial resolution and depth visualization.

Findings

PCM provides enhanced spatial resolution over SR-XRT.

PCM enables 3D visualization of dislocation paths along depth.

PCM allows in-plane tracing of dislocation lines for slip system analysis.

Abstract

This study presents a nondestructive, high-resolution method for three-dimensional imaging of threading dislocations in beta-$Ga_{2}O_{3}$ (010) using phase-contrast microscopy (PCM). A one-to-one correspondence between dislocation contrasts in PCM images and synchrotron X-ray topography (SR-XRT) images confirms the detection capability of PCM. Compared to SR-XRT, PCM provides enhanced spatial resolution, enabling the distinction of closely spaced dislocations with sub-10-micrometer separation. PCM facilitates direct visualization of dislocation propagation paths along the depth (z) direction by systematically shifting the focal plane into the crystal. In addition, the projection of stacked PCM images enables in-plane (XY) tracing of dislocation lines, providing insight into the preferred slip systems in beta-$Ga_{2}O_{3}$. This work establishes PCM as a versatile and laboratory-accessible technique for three-dimensional, nondestructive characterization of dislocations across entire wide-bandgap semiconductor wafers within a practically acceptable time frame.