High-resolution dislocation imaging and micro-structural analysis of HVPE-βGa2O3 films using monochromatic synchrotron topography

Abstract

Threading and basal dislocations were observed and their Burgers vectors (b→) were analyzed in 20 µm thick halide vapor phase homoepitaxially grown beta-gallium oxide (β−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 × 1.5 cm2 sample, threading screw dislocations with b→=001 were observed with a density of 30 cm−2, whereas a single threading edge dislocation with b→=100 was observed. Basal dislocations with b→=12112 were observed with a density of ∼20 cm−2, and a single basal dislocation with b→=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 ∼|8 × 10−5| obtained from both sample directions. The median radius of curvature was ∼−100 m along the [100] direction and ∼280 m along the [010] sample axis, indicating very low lattice plane curvature that enables high manufacturability and reliability of devices.