Fabrication and characterisation of optical float-zone (100) β-Ga₂O₃ Schottky diodes

We conducted a rapid fabrication of Ga₂O₃ vertical Schottky barrier diodes using Ti/Au for ohmic contacts and Ni/Au for Schottky contacts on a (100) Sn-doped β-Ga₂O₃ grown by optical float-zone and analysed the device characteristics and performance. Approximately 190 diodes were fabricated with varying contact sizes-50 µm and 100 µm-and different contact shapes, including circular, square, and squiricle configurations. Of these, eighteen devices were tested for their current-voltage and capacitance-voltage characteristics. The best-performing device achieved a breakdown voltage of 52 V. Our studies show that, besides the intrinsic defects within the material, electric field-induced defects may also contribute to the increased leakage current, catastrophic damage, and surface cracks mainly along the [010] and also on [001] directions beneath the Schottky contacts, as confirmed by scanning electron microscopy. Optimising the device design and fabrication process, lowering doping concentrations and reducing intrinsic defects in the drift layers could significantly enhance the performance and reliability of Ga₂O₃-based Schottky diodes for the next-generation power electronics components.