Source-field-plated Ga 2 O 3 MOSFET with a breakdown voltage of 550 V

Ga 2 O 3 metal–oxide–semiconductor field-effect transistors (MOSFETs) with high-breakdown characteristics were fabricated on a homoepitaxial n-typed β -Ga 2 O 3 film, which was grown by metal organic chemical vapor deposition (MOCVD) on an Fe-doped semi-insulating (010) Ga 2 O 3 substrate. The structure consisted of a 400 nm unintentionally doped (UID) Ga 2 O 3 buffer layer and an 80 nm Si-doped channel layer. A high k HfO 2 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 × 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 μ m, respectively.