High Breakdown Voltage (−201) -Ga2O3 Schottky Rectifiers

β-Ga 2 O 3 Schottky barrier diodes were fabricated in a vertical geometry structure consisting of Ni/Au rectifying contacts without edge termination on Si-doped epitaxial layers (10 μm, n~4×10 15 cm -3 ) on Sn-doped bulk Ga 2 O 3 substrates with full-area Ti/Au back Ohmic contacts. The reverse breakdown voltage, VBR, was a function of rectifying contact area, ranging from 1600 Vat 3.1×10 -6 cm 2 (20-μm diameter) to ~250 Vat 2.2×10 -3 cm -2 (0.53-mm diameter). The current density near breakdown was not strongly dependent on contact circumference but did scale with contact area, indicating that the bulk current contribution was dominant. The lowest ON-state resistance, Ron, was 1.6 mQ· cm 2 for the largest diode and 25 mQ·cm 2 for the 1600-V rectifier, leading to a Baliga figure-of-merit (V2BR/Ron) for the latter of approximately 102.4 MW·cm -2 . The ON-OFF ratio was measured at a forward voltage of 1.3 V and ranged from 3×10 7 to 2.5×10 6 for reverse biases from -5 to -40 V and showed only a small dependence on temperature in the range from 25 °C to 100 °C.