Synchrotron-radiation x-ray topography and reticulography of bulk β-Ga2O3 crystals grown by the cold crucible method

The structural properties of a β-Ga2O3 single crystal grown by the oxide crystal growth from cold crucible (OCCC) method were investigated using synchrotron radiation x-ray topography and x-ray reticulography. The region grown beneath the seed exhibits high crystalline quality with a rocking curve full width at half maximum of about 26 arc sec. During diameter enlargement, a twist-type lattice misorientation develops between the central and laterally expanded regions, originating near the shoulder and propagating along boundaries parallel to the 〈010〉 growth direction. Dislocation analysis reveals that 〈010〉-oriented screw dislocations dominate the defect structure with densities of ∼105 cm−2, while higher densities (∼106 cm−2) appear in the wing region (i.e., the laterally expanded region formed during diameter enlargement). These results clarify defect formation in OCCC-grown β-Ga2O3 and provide insights into optimizing growth conditions.