Source-Field-Plated β-Ga2O3 MOSFET with Record Power Figure of Merit of 50.4 MW/cm2

In this letter, source-field-plated β-Ga ₂ O ₃ MOSFETs are fabricated on Si-doped homoepitaxial film on (010) Fe-doped semi-insulating β-Ga ₂ O ₃ substrate. Ohmic contact resistance (R _c ) between metal- and ion-implanted source/drain layer of 1.0 Ω · mm is obtained by employing the Si-ion implantation. The fabricated source-field-plated β-Ga ₂ O ₃ MOSFETs with source-to-drain distance (L _sd ) of 11 and 18 μm present high-saturation drain current (I _ds,sat ) of 267 and 222 mA/mm with low R _on,sp of 4.57 and 11.7 mΩ · cm ² , respectively. The drain extension in the source-field plate effectively suppresses the peak electric field and improves the breakdown voltage greatly. The destructive breakdown voltages (V _br ) are measured to be 480 and 680 V for the devices with L _sd of 11 and 18 μm, respectively. Most of all, the power figure of merit (V _br ² /R _on,sp ) is as high as 50.4 MW/cm ² , which is the highest value among any β-Ga ₂ O ₃ MOSFETs ever reported.