Source-Field-Plated $\beta$ -Ga 2 O 3 MOSFET With Record Power Figure of Merit of 50.4 MW/cm 2

In this letter, source-field-plated $\beta $ -Ga 2 O 3 MOSFETs are fabricated on Si-doped homoepitaxial film on (010) Fe-doped semi-insulating $\beta $ -Ga 2 O 3 substrate. Ohmic contact resistance ( ${R}_{\textsf {c}}$ ) between metal- and ion-implanted source/drain layer of $1.0~\Omega ~\cdot $ mm is obtained by employing the Si-ion implantation. The fabricated source-field-plated $\beta $ -Ga 2 O 3 MOSFETs with source-to-drain distance ( ${L}_{\textsf {sd}}$ ) of 11 and $18~\mu \text{m}$ present high-saturation drain current ( ${I}_{\textsf {ds,sat}}$ ) of 267 and 222 mA/mm with low ${R}_{\textsf {on,sp}}$ of 4.57 and 11.7 $\text{m}\Omega ~\cdot $ 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 ( ${V}_{\textsf {br}}$ ) are measured to be 480 and 680 V for the devices with ${L}_{\textsf {sd}}$ of 11 and 18 $\mu \text{m}$ , respectively. Most of all, the power figure of merit ( ${V}_{\textsf {br}}^{\textsf {2}}/{R}_{\textsf {on,sp}})$ is as high as 50.4 MW/cm 2 , which is the highest value among any $\beta $ -Ga 2 O 3 MOSFETs ever reported.