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β-Ga2O3 metal-semiconductor field-effect transistors are realized with superior reverse breakdown voltages (VBR) and ON currents (IDMAX). A sandwiched SiNx dielectric field-plate design is utilized that prevents etching-related damage in the active region and a deep mesa-etching was used to reduce reverse leakage. The device with LGD=34.5μm exhibits an IDMAX of 56 mA/mm, a high ION/IOFF ratio >108 and a very low reverse leakage until catastrophic breakdown at ∼4.4kV. A power figure of merit (PFOM) of 132 MW/cm2 was calculated for a VBR of ∼4.4kV. The reported results are the first >4kV-class Ga2O3 transistors to surpass the theoretical FOM of Silicon.

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This Letter reports a high performance β-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 160–200 nm was fabricated to achieve enhanced RF performance and passivated with 200 nm silicon nitride. Peak drain current (ID,MAX) of 285 mA/mm and peak transconductance (gm) of 52 mS/mm were measured at 10 V drain bias with 23.5 Ω mm on resistance (RON). Metal/n++ contact resistance of 0.078 Ω 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 192 V is measured for LGD = 355 nm resulting in average breakdown field (EAVG) 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 (fMAX) 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 fT·VBR product is 2.112 THz V for 192 V breakdown voltage. Device surpasses the switching figure of merit of Silicon and competitive with mature wide bandgap devices.

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