Heteroepitaxial β-Ga2O3 thick films on sapphire substrate by carbothermal reduction rapid growth method

Abstract The heteroepitaxial β -Ga 2 O 3 thick films were rapidly grown on various oriented sapphire substrates using carbothermal reduction method. The β -Ga 2 O 3 films were prepared in our home-made vertical dual temperature zone furnace. The growth direction as well as surface morphology showed the strong dependence on the orientation of the sapphire substrate. The fastest growth rate was obtained reaching approximate 15 μ m h −1 on c -plane sapphire substrate according to the average 30 μ m thickness of β -Ga 2 O 3 films grown for 2 h measured by cross-section scanning electron microscope. The Raman spectra indicated the pure-phase β -Ga 2 O 3 films without obvious strain. The bandgap for grown films were in range of 4.6–4.7 eV confirmed by x-ray photoelectron spectra and Tauc plot from absorption spectra. Secondary ion mass spectrometry was used to check the impurities indicating a limited amount of residual carbon inside the films even though graphite as the reducing agent. The results in this work give promising alternative method of rapid epitaxial β -Ga 2 O 3 thick films for the application on high-power electronic devices.