Depletion-Mode β -Ga₂O₃ MOSFETs Grown by Nonvacuum, Cost-Effective Mist-CVD Method on Fe-Doped GaN Substrates

In this work, β -Ga₂O₃ MOSFETs grown by nonvacuum, cost-effective mist chemical vapor deposition (mist-CVD) method on Fe-doped GaN substrates were demonstrated for the first time. X-ray diffraction (XRD) and transmission electron microscopy (TEM) measurements identify the pure β -Ga₂O₃ phase and the heteroepitaxial relationship with (201) β -Ga₂O₃ || (0002) GaN. MOSFETs based on β -Ga₂O₃ thin films with source-drain spacings ( $L_{gd})$ of 14 and 25 μm were fabricated and characterized. The destructive breakdown voltages ( $V_{BR})$ were measured to be 836 and 1420 V, respectively. The on-off ratio of the corresponding MOSFETs was about five orders of magnitude. These results suggest the great application potential of the nonvacuum and cost-effective mist-CVD epitaxial growth method in β -Ga₂O₃ MOSFETs, which will greatly decrease the device cost.