Integration of high permittivity BaTiO3 with AlGaN/GaN for near-theoretical breakdown field kV-class transistors

In this Letter, we discuss AlGaN/GaN HEMTs integrated with high permittivity BaTiO3 dielectric to enable enhanced breakdown characteristics. We show that using high permittivity BaTiO3 dielectric layers in the gate and drain access regions prevents premature gate breakdown, leading to average breakdown fields exceeding 3 MV/cm at a gate-to-drain spacing of 4 μm. The higher breakdown fields enable a high power figure of merit above 2.4 GW/cm2 in devices with a gate-to-drain spacing of 6 μm. This work demonstrates that electrostatic engineering using high-permittivity dielectrics can enable AlGaN/GaN HEMTs in approaching the material breakdown field limits.