3000-V 4.3- $\hbox {m}\Omega \cdot \hbox {cm}^{2}$ InAlN/GaN MOSHEMTs With AlGaN Back Barrier

This letter reports the fabrication of InAlN/GaN high-electron mobility transistors (HEMTs) with a three-terminal off-state breakdown voltage (BV) of 3000 V and a low specific on-resistance of 4.25 mΩ·cm². To reduce the drain-to-source leakage current in these devices, an AlGaN back barrier has been used. The gate leakage current in these devices is in the ~10^-10 A/mm range owing to the use of a SiO₂ gate dielectric. This current level is more than six orders of magnitude lower than in Schottky-barrier HEMTs. The combination of an AlGaN back barrier, the high charge sheet density of InAlN/GaN HEMTs, and the low leakage due to the gate-dielectric layer allows for a figure-of-merit BV²/R_ON,SP of ~2.1 × 10⁹ V²·Ω^-1·cm^-2.