Electrostatic Engineering Using Extreme Permittivity Materials for Ultra-Wide Bandgap Semiconductor Transistors

The performance of ultra-wide bandgap semiconductors like β-Ga ₂ O ₃ is critically dependent on achieving high average electric fields within the active region of the device. In this article, we show that dielectrics like BaTiO ₃ with extremely high dielectric constant can provide an efficient field management strategy by improving the uniformity of electric field profile within the gate-drain region of lateral field-effect transistors. Using this strategy, we achieved high average breakdown field of 1.5 and 4 MV/cm at gate-drain spacing (L _gd ) of 6 and 0.5 μm, respectively in β-Ga ₂ O ₃ , at a high channel sheet charge density of 1.6 × 10 ¹³ cm ^-2 . The high channel charge density along with the high breakdown field enabled a record power figure of merit (V _br ² /R _ON ) of 376 MW/cm ² at a gate-drain spacing of 3 μm.