Source-field-plated Ga2O3 MOSFET with a breakdown voltage of 550 V

Ga2O3 metal-oxide-semiconductor field-effect transistors (MOSFETs) with high-breakdown characteristics were fabricated on a homoepitaxial n-typed beta-Ga2O3 film, which was grown by metal organic chemical vapor deposition (MOCVD) on an Fe-doped semi-insulating (010) Ga2O3 substrate. The structure consisted of a 400 nm unintentionally doped (UID) Ga2O3 buffer layer and an 80 nm Si-doped channel layer. A high k HfO2 gate dielectric film formed by atomic layer deposition was employed to reduce the gate leakage. Moreover, a source-connected field plate was introduced to enhance the breakdown characteristics. The drain saturation current density of the fabricated device reached 101 mA/mm at V-gs of 3 V. The off-state current was as low as 7.1 x 10(-11) A/mm, and the drain current I-ON/I-OFF ratio reached 10(9). The transistors exhibited three-terminal off-state breakdown voltages of 450 and 550 V, corresponding to gate-to-drain spacing of 4 and 8 mu m, respectively.