Electrical and Thermal Performance of Ga₂O₃–Al₂O₃–Diamond Super-Junction Schottky Barrier Diodes

The design space of Ga₂O₃-based devices is severely constrained due to its low thermal conductivity and absence of viable p-type dopants. In this work, we discuss the limits of operation of a novel Ga₂O₃–Al₂O₃–diamond-based super-junction device concept, which can alleviate the constraints associated with Ga₂O₃-based devices. The improvements achieved using the proposed device concept are demonstrated through electrical and thermal simulations of Ga₂O₃–Al₂O₃–diamond-based super-junction Schottky barrier diodes (SJ-SBDs) and non-punch-through or conventional Schottky barrier diodes (NP-SBDs). The SJ-SBD enables operation below the RON -breakdown voltage limit of Ga₂O₃ NP-SBD, enabling >4 kV blocking voltage at RON of 1–3 mΩ cm2. The maximum switching frequency of SJ-SBD may be only a few kHz, as it is limited by the activation energy of acceptors (0.39 eV) in the diamond. Crucially, compared with NP-SBD, the use of diamond also results in ~60% reduction in temperature rise during static power dissipation. Polycrystalline diamond (PCD) properties depend on detailed microstructure and benefits compared to ideal Ga₂O₃ NP-SBD arise for diamond critical fields ≥6 MV/cm and thermal conductivities as low as 50–150 W/(m ⋅ K).