Study of Phase Transition in MOCVD Grown Ga2O3 from κ to β Phase by Ex Situ and In Situ Annealing

We report the post-growth thermal annealing and subsequent phase transition of Ga2O3 grown on c-plane sapphire substrates by metal organic chemical vapor deposition (MOCVD). demonstrated at temperatures higher than 900 °C under N2 ambience, either in situ or ex annealing, can induce from nominally metastable κ- to thermodynamically stable β-phase. This was analyzed structural characterizations such as high-resolution scanning transmission electron microscopy x-ray diffraction. The highly resistive as-grown epitaxial layer becomes conductive after 1000 °C. Furthermore, we demonstrate that lead a crack-free β-Ga2O3.