Multi-kV class $β$-Ga$_2$O$_3$ MESFETs with a Lateral Figure of Merit up to 355 MW/cm$^2$

Abstract: We demonstrate over 3 kV gate-pad-connected field plated (GPFP) $\beta$-Ga$2$O$_3$ lateral MESFETs with high lateral figure of merit (LFOM) using metalorganic vapor phase epitaxy (MOVPE) grown channel layers and regrown ohmic contact layers. Using an improved low-temperature MOVPE selective area epitaxy process, we show that a total contact resistance to the channel as low as 1.4 $\Omega$.mm can be achieved.The GPFP design adopted here using PECVD (plasma-enhanced chemical vapor deposition) deposited SiN$_x$ dielectric and SiN$_x$/SiO$_2$ wrap-around passivation exhibits up to ~14% improved R${ON}$, up to ~70% improved breakdown voltage (V${BR}$ = V${DS}$ - V${GS}$) resulting in up to $\sim$3$\times$ higher LFOM compared to non-FP $\beta$-Ga$_2$O$_3$ lateral MESFETs. The V${BR}$ (~2.5 kV) and LFOM (355 MW/cm$^2$) measured simultaneously in our GPFP $\beta$-Ga$2$O$_3$ lateral MESFET (with L${GD}$ = 10 $\mu$m) is the highest value achieved in any depletion-mode $\beta$-Ga$_2$O$_3$ lateral device.