Scaled beta-Ga2O3 thin channel MOSFET with 5.4 MV/cm average breakdown field and near 50 GHz f(MAX)

xThis Letter reports a high performance beta-Ga2O3 thin channel MOSFET with T gate and degenerately doped (n++) source/drain contacts regrown by metal organic chemical vapor deposition. Highly scaled T-gate with a gate length of 160-200nm was fabricated to achieve enhanced RF performance and passivated with 200nm silicon nitride. Peak drain current (I-D,I-MAX) of 285mA/mm and peak transconductance (gm) of 52 mS/mm were measured at 10V drain bias with 23.5 Omega mm on resistance (R-ON). Metal/n++ contact resistance of 0.078 Omega mm was extracted from transfer length measurements. RON is possibly dominated by interface resistance between channel and highly doped n++ regrown layer. A gate-to-drain breakdown voltage of 192V is measured for LGD = 355nm resulting in average breakdown field (E-AVG) of 5.4 MV/cm. This EAVG is the highest reported among all sub-micron gate length lateral FETs. Current gain cut off frequency (fT) of 11 GHz and record power gain cut off frequency (f(MAX)) of approximately 48 GHz were extracted from small signal measurements. fT is limited by DC-RF dispersion due to interface traps which needs further investigation. The f(T)V(BR) product is 2.112 THz V for 192V breakdown voltage. Device surpasses the switching figure of merit of Silicon and competitive with mature wide bandgap devices.