Room-Temperature Fabrication of High Breakdown Field Ga2O3 Films via Aerosol Deposition Method

Gallium oxide (Ga2O3) is emerging as a promising next-generation material for power semiconductor devices due to a theoretical electric field of 8 MV/cm. Ga2O3 films for power semiconductors have been developed using various processing techniques such as metal organic chemical vapor deposition, hydride vapor phase epitaxy, molecular beam epitaxy, and the sol-gel method. However, existing methods are complex, require high-temperature heat treatment, involve the use of toxic solvents, and demand extended film growth times. In this study, Ga2O3 films with a high breakdown field were developed at room temperature using an eco-friendly and simplified aerosol deposition (AD) method. The microstructure, dielectric constant, leakage current, and breakdown field of Ga2O3 films fabricated using four carrier gases (air, He, N2, and O2) were systematically investigated. The root-mean-square (RMS) roughness of all Ga2O3 films was approximately 200 nm, with comparable internal density. However, the Ga2O3 film fabricated using O2 gas exhibited an appropriate dielectric constant (10.6 at 10 kHz), low leakage currents (3.0 × 10−10 A/cm2 at 10 kV/cm), and a breakdown field of 1.2 MV/cm attributed to the reduced influence of oxygen vacancies. Furthermore, the RMS roughness of the Ga2O3 film was reduced to 96.8 nm by employing a nozzle-tilting method, which enabled the fabrication of a Ga2O3 film with a high breakdown field of 4.2 MV/cm. These findings highlight the excellent potential of Ga2O3 films fabricated using a simple AD process at room temperature for application in power semiconductor devices.