High performance lateral Schottky diodes based on quasi-degenerated Ga₂O₃

Ni/β-Ga₂O₃ lateral Schottky barrier diodes (SBDs) were fabricated on a Sn-doped quasi-degenerate n⁺-Ga₂O₃ (201) bulk substrate. The resultant diodes with an area of 7.85×10^-5 cm² exhibited excellent rectifying characteristics with an ideality factor of 1.21, a forward current density (J) of 127.4 A/cm² at 1.4 V, a specific on-state resistance (R_{on, sp}) of 1.54 mΩ·cm², and an ultra-high on/off ratio of 2.1×10¹¹ at ±1 V. Due to a small depletion region in the highly-doped substrate, a breakdown feature was observed at -23 V, which corresponded to a breakdown field of 2.1 MV/cm and a power figure-of-merit (V_B²/Ron) of 3.4×105 W/cm². Forward current–voltage characteristics were described well by the thermionic emission theory while thermionic field emission and trap-assisted tunneling were the dominant transport mechanisms at low and high reverse biases, respectively, which was a result of the contribution of deep-level traps at the metal–semiconductor interface. The presence of interfacial traps also caused the difference in Schottky barrier heights of 1.31 eV and 1.64 eV respectively determined by current–voltage and capacitance–voltage characteristics. With reduced trapping effect and incorporation of drift layers, the β-Ga₂O₃ SBDs could further provide promising materials for delivering both high current output and high breakdown voltage.