Growth and Performance Enhancement of Sputtered ZnGa₂O₄ MOSFETs on Sapphire Substrates

Metal-oxide-semiconductor field-effect transistors (MOSFETs) based on wide-band-gap semiconductors have garnered significant attention for their potential in high-performance and energy-efficient electronic devices. In this study, we explore the low-temperature growth, characterization, and performance of ZnGa 2 O 4 film based MOSFETs on sapphire substrates through the utilization of radio frequency (RF) magnetron sputtering. The characteristics of ZnGa 2 O 4 films were meticulously investigated at various annealing temperatures, specifically 400, 600, and 900 °C. Our findings revealed that the crystallinity of ZnGa 2 O 4 films was notably superior at a low annealing temperature of 400 °C. Subsequently, we fabricated MOSFET devices by patterning the ZnGa 2 O 4 films to create gate, source, and drain regions using a conventional photolithography process. The electrical characteristics of the ZnGa 2 O 4 MOSFETs were thoroughly examined, unveiling their operation in the depletion mode. These devices exhibited a threshold voltage of −5 V, a maximum drain current of 110 mA/mm, a remarkable high drain current on–off current ratio of 10 7, and an excellent breakdown voltage of 575 V, underlining their suitability for high-power applications. This research demonstrates the successful fabrication of ZnGa 2 O 4 based depletion-mode MOSFETs using a sputtering technique, offering a pathway toward the development of next-generation electronic devices with enhanced performance.