Synchrotron-radiation X-ray topography and reticulography of bulk $\beta$-Ga${}_2$O${}_3$ crystals grown by the cold crucible method

Abstract

The structural properties of a $\beta$-Ga${}_2$O${}_3$ 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 arcsec. 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 ~$10^5$cm${}^{-2}$, while higher densities (~$10^6$cm${}^{-2}$) appear in the wing region. These results clarify defect formation in OCCC-grown $\beta$-Ga${}_2$O${}_3$ and provide insights for optimizing growth conditions.

35 pages, 9 figures