7.5 kV, 6.2 GW cm-2 NiO/β-Ga2O3 vertical rectifiers with on-off ratio greater than 1013

Vertical geometry NiO/beta n-Ga2O/n(+) Ga2O3 heterojunction rectifiers with contact sizes from 50 to 200 mu m diameter showed breakdown voltages (V-B) up to 7.5 kV for drift region carrier concentration of 8 x 10(15) cm(-3). This exceeds the unipolar 1D limit for SiC and was achieved without substrate thinning or annealing of the epi layer structure. The power figure-of-merit, V-B(2)/R-ON, was 6.2 GW cm(-2), where R-ON is the on-state resistance (9.3-14.7 m Omega cm(2)). The average electric field strength was 7.56 MV/cm, approaching the maximum for beta-Ga2O3. The on-off ratio switching from 5 to 0 V was 2 x 10(13), while it was 3 x 10(10)-2 x 10(11) switching to 100 V. The turn-on voltage was in the range 1.9-2.1 V for the different contact diameters, while the reverse current density was in the range 2 x 10(-8)-2 x 10(-9) A cm(-2) at -100 V. The reverse recovery time was 21 ns, while the forward current density was >100 A/cm(2) at 5 V.

Automated summary

Vertical geometry NiO/beta n-Ga2O/n(+) Ga2O3 heterojunction rectifiers with different contact sizes demonstrated high breakdown voltages up to 7.5 kV. The devices exceeded the unipolar 1D limit for SiC without requiring substrate thinning or annealing. The power figure-of-merit, V-B(2)/R-ON, was 6.2 GW cm(-2), and the average electric field strength approached the maximum for beta-Ga2O3. The rectifiers exhibited high on-off ratios and low reverse current densities, with fast reverse recovery time and high forward current density.