High reverse breakdown voltage Schottky rectifiers without edge termination on Ga₂O₃

Vertical geometry Ni/Au-β-Ga₂O₃ Schottky rectifiers were fabricated on Hydride Vapor Phase Epitaxy layers on conducting bulk substrates, and the rectifying forward and reverse current-voltage characteristics were measured at temperatures in the range of 25-100 °C. The reverse breakdown voltage (V_BR) of these β-Ga₂O₃ rectifiers without edge termination was a function of the diode diameter, being in the range of 920-1016 V (average value from 25 diodes was 975 ± 40 V, with 10 of the diodes over 1 kV) for diameters of 105 μm and consistently 810 V (810 ± 3 V for 22 diodes) for a diameter of 210 μm. The Schottky barrier height decreased from 1.1 at 25 °C to 0.94 at 100 °C, while the ideality factor increased from 1.08 to 1.28 over the same range. The figure-of-merit (V_BR²/R_on), where R_on is the on-state resistance (∼6.7 mΩ cm²), was approximately 154.07 MW·cm⁻² for the 105 μm diameter diodes. The reverse recovery time was 26 ns for switching from +5 V to −5 V. These results represent another impressive advance in the quality of bulk and epitaxial β-Ga₂O₃.