Growth of α- and β-Ga ₂ O ₃ epitaxial layers on sapphire substrates using liquid-injection MOCVD

Abstract

Abstract Ga 2 O 3 , a wide-bandgap semiconductor material, offers a great potential for power and high-voltage electronic devices. We report on the growth of undoped α - and β -phase Ga 2 O 3 using liquid-injection metal-organic chemical vapor deposition (LI-MOCVD) on sapphire substrates. Using the same precursor (gallium acetylacetonate) and deposition temperature of 700 °C, the phase selection was controlled by the sapphire substrate orientation, where the growth of α - and β -phase Ga 2 O 3 was achieved on m - and c -plane surface, respectively. As deduced from x-ray diffraction, α -Ga 2 O 3 films show epitaxial character, while β - Ga 2 O 3 films exhibit highly textured structure. Oxygen flow was also found to have a strong impact on the phase purity of α -Ga 2 O 3 for the flow rates examined. Optical and electrical properties of the layers grown at different oxygen flow rates were also studied systematically. LI-MOCVD growth of α -phase Ga 2 O 3 layers at relatively high deposition temperature widens the high-temperature processing of the Ga 2 O 3 -based electronic and optoelectronic devices.