Enhancement of the properties of a Beta-GA2O3-based diode using fluorine-doped Ga2O3 films deposited by a liquid-phase method

Abstract

The purpose of this research is to investigate a low-cost liquid-phase deposition (LPD) method for preparing gallium oxide ([Formula: see text]-Ga2O[Formula: see text] films. This approach has the advantages of being easy and not requiring a vacuum, and it is suitable for large-area manufacturing. First, the LPD method was used to precipitate GaOOH particles below a pH of 8 and at 80[Formula: see text]C; these were used as the precursor for the gallium oxide ([Formula: see text]-Ga2O[Formula: see text] films. Ammonium fluoride (NH4F) with concentrations of 0.1, 0.3, and 0.5 M was added to the solution to form fluorine-doped (F-doped) GaOOH. The precipitated F-doped GaOOH powders were analyzed using an energy-dispersive X-ray spectroscopy (EDS) on a field emission scanning electron microscope to identify elemental F, Ga, and O. We found that the concentration of F ions increased with the NH4F concentration. The deposited films were then annealed at 900[Formula: see text]C for 4 h to transform the F-doped GaOOH into F-doped [Formula: see text]-Ga2O3. EDS was used to analyze the F-doped [Formula: see text]-Ga2O3 films, and we found that their F[Formula: see text] ion concentration also increased with the NH4F concentration. XPS analysis was used to confirm the existence of F[Formula: see text] ions in the F-doped [Formula: see text]-Ga2O3 films. The analyzed results also showed that as the NH4F concentration increased, the electrical performance of F-doped gallium oxide improved. Finally, the F-doped [Formula: see text]-Ga2O3 films were used to fabricate F-doped [Formula: see text]-Ga2O3/p[Formula: see text]-Si junction diodes, and their J–V properties were thoroughly investigated. We found that the rectification characteristics of the F-doped [Formula: see text]-Ga2O3/p[Formula: see text]-Si diodes could be significantly improved.