High performance lateral Schottky diodes based on quasi-degenerated Ga2O3

摘要

Ni/β-Ga2O3 lateral Schottky barrier diodes (SBDs) were fabricated on a Sn-doped quasi-degenerate n+-Ga2O3 ((-2)01)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 (Ron,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 (V2B/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.