Quantum chemical calculation and growth process of Ga2O3 grown via TEGa under different oxygen sources in MOCVD

Abstract

Ga₂O₃, a fourth-generation ultrawide-bandgap semiconductor material, offers a broad range of potential applications in automotive electronics, electrical devices, and other high-power electronic domains. Metal–organic chemical vapor deposition (MOCVD) is an important technique for growing semiconductor thin films. To obtain high-quality Ga₂O₃, it is vital to comprehend the chemical vapor deposition process. In this study, the thermal decomposition and adduct formation pathways of triethylgallium (TEGa) with H₂O, O₂, and N₂O molecules were studied using density functional theory. Potential energy scanning was performed and the reaction energy barrier was obtained. Further, the kinetic parameters were calculated, and the entire reaction mechanism, including the gas-phase and surface reactions, was presented. To investigate and compare the growth rates under various oxygen sources with experimental results, the chemical mechanisms were also employed in conjunction with the computational fluid dynamics method. In addition, the growth process, reaction source distribution, and intermediate product dispersion in MOCVD are discussed. The results indicate that the adduct formation pathway is the main route for the growth of Ga₂O₃ in MOCVD. The Ga(OH)₃ polymer is the source of nanoparticles in the gas-phase reaction, which is ultimately hydrolyzed to Ga₂O₃ nanoparticles. Ga(OH)₃ can be produced using TEGa and H₂O/O₂/N₂O. The reaction temperature of TEGa with H₂O was the lowest, followed by those of TEGa with N₂O and O₂. This study could facilitate the understanding of the MOCVD process for growing Ga₂O₃ films.