High performance lateral Schottky diodes based on quasi-degenerated Ga2O3**Project supported by the National Key R&D Program of China (Grant No. 2017YFB0403003), the National Natural Science Foundation of China (Grant Nos. 61774081, 61322403, and 91850112), the State Key R&D Project of Jiangsu, China (Grant No. BE2018115), Shenzhen Fundamental Research Project, China (Grant Nos. 201773239 and 201888588), State Key Laboratory ofWide-Bandgap Semiconductor

Abstract

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