High-quality (001) β-Ga2O3 homoepitaxial growth by metalorganic chemical vapor deposition enabled by in situ indium surfactant

Abstract

(001) β-Ga2O3 homoepitaxy on commercially available large-size (001) β-Ga2O3 substrates remains a significant challenge for the wide bandgap semiconductor community. In this Letter, high-quality homoepitaxial (001) β-Ga2O3 films were grown via metalorganic chemical vapor deposition (MOCVD) with the assistance of an in situ indium surfactant, where the growth modes and mechanisms were also elucidated. During the growth of β-Ga2O3, an etching process occurred by the desorption of the suboxide Ga2O, resulting in rough surface morphology with streaky grooves oriented along the [010] direction. It is postulated that the parallel grooves were associated with the surface desorption and anisotropic diffusion characteristics of β-Ga2O3. To suppress the desorption, indium surfactant was introduced into the growth environment. A 2D-like growth feature was prompted subsequently by the coadsorption of In and Ga atoms, accompanied by relatively smooth surface morphology. The crystal quality had no degradation despite the incorporation of indium in the epitaxial film. The O II peak of the β-Ga2O3 film shifted ∼0.5 eV toward higher binding energy due to an increasing number of oxygen vacancies originating from the indium incorporation. This work provides a systemic investigation on the growth of high-quality (001) β-Ga2O3 homoepitaxial films by MOCVD, which is critical for the development of β-Ga2O3 electronic devices for future power switching and RF applications.