Ga2O3/4H-SiC n-n isotype heterojunction diodes were fabricated by depositing Ga2O3 thin films by RF magnetron sputtering. The influence of annealing atmosphere on the film quality and electrical properties of Ga2O3 layers was investigated. X-ray diffraction (XRD) analysis showed a significant increase in the peak intensities of different faces of β-Ga2O3 {(-201), (-401) and (002)}. X-ray photoelectron spectroscopy (XPS) measurement showed that the atomic ratio of oxygen increases under high-temperature annealing. Moreover, an N2-annealed diode exhibited a greater rectifying ratio and a lower thermal activation energy owing to the decrease in oxygen-related traps and vacancies on the Ga2O3 film and Ga2O3-metal interface.
Keywords: gallium oxide; heterojunction diodes; silicon carbide; thermal activation energy.