Metal organic chemical vapor deposition 2: Heteroepitaxial mocvd growth of α-, β-, and ε-Ga2O3 Thin Films on Sapphire Substrates

Abstract

This chapter reviews the heteroepitaxial growth of α-, (Figure presented.) β-, and ε-gallium oxide (Ga2O3) films, with a focus on those grown using the metalorganic chemical vapor deposition (MOCVD) technique. Variations in growth conditions and substrates result in the growth of different polymorphs of Ga2O3 or combinations of them. β-Ga2O3 is consistently reported as the dominant phase to grow at high substrate temperatures >700 °C. At lower substrate temperatures, α- and ε- metastable phases have been observed. Other growth conditions and substrates that have yielded α- and (Figure presented.) ε-Ga2O3 epitaxial films are also discussed. Doping of MOCVD-grown β-Ga2O3 is also briefly reviewed, where Si and Sn are the most commonly used dopants. Doping concentrations between 1 ✕ 1017 and 8 ✕ 1019 cm-3 have been achieved, with corresponding electron mobility values between ~130 and 50 cm2/Vs.