High-Resolution Dislocation Imaging and Micro-Structural Analysis of Hvpe-BetaGa2O3 Films Using Monochromatic Synchrotron Topography
Journal Article - Open Access
NAVAL RESEARCH LAB WASHINGTON DC WASHINGTON United States
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Threading and basal dislocations were observed and their Burgers vectors b over right arrow were analyzed in 20 mu m thick halide vapor phase homoepitaxially grown beta-gallium oxide beta-Ga2O3 films using 15 keV monochromatic synchrotron X-ray topography with symmetric reflection 004 and two asymmetric reflections 205 and 115 in back-reflection and grazing incidence angle geometries, respectively. In a 1 x 1.5 cm2 sample, threading screw dislocations with b over right arrow 001 were observed with a density of 30 cm-2, whereas a single threading edge dislocation with b over right arrow 100 was observed. Basal dislocations with b over right arrow 12 112 were observed with a density of similar to 20 cm-2, and a single basal dislocation with b over right arrow 010 was observed. Rocking curve mapping of the three reflections was also performed on the entire sample with the same setup and a high resolution x-ray camera to obtain the full width at half maximum FWHM, strain, and curvature maps in two almost orthogonal directions. The epilayer demonstrated excellent crystalline quality with a median FWHM of 8.2 arc sec in the 004 reflection and a very low median strain of similar to vertical bar 8 x 10-5vertical bar obtained from both sample directions. The median radius of curvature was similar to-100 m along the 100 direction and similar to 280 m along the 010 sample axis, indicating very low lattice plane curvature that enables high manufacturability and reliability of devices. C 2018 Authors.