High reverse breakdown voltage Schottky rectifiers without edge termination on Ga_2O_3

摘要

Vertical geometry Ni/Au-β-Ga_2O_3 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 ℃. The reverse breakdown voltage (V_(BR)) of these β-Ga_2O_3 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℃ to 0.94 at 100 ℃, while the ideality factor increased from 1.08 to 1.28 over the same range. The figure-of-merit (V_(BR)~2/R_(on)), where R_(on) is the on-state resistance (~6.7 mΩ cm~2), 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~Ga_2O_3.