Vertical <i>β</i> -Ga <sub>2</sub> O <sub>3</sub> Schottky rectifiers with 750 V reverse breakdown voltage at 600 K
Xinyi Xia, Minghan Xian, Patrick H. Carey, Chaker Fares, F. Ren, Marko J. Tadjer, S. J. Pearton, Thieu Quang Tu, Ken Goto, Akito Kuramata
Abstract
Abstract Field-plated vertical Ga 2 O 3 rectifiers were operated up to 600 K with reverse breakdown voltage ( V B ) of 750 V, 950 V at 500 K and 1460 V at 400 K. The barrier height was 1.3 eV at 300 K and reduced to 0.7 eV at 600 K, with ideality factors of 1.05 ± 0.05 and 2 ± 0.1, respectively at these temperatures. On-state resistance, R ON , was 13 mΩ cm 2 at 300 K and 41 mΩ cm 2 at 600 K, leading to respective Baliga figures of merit of 151 MW cm −2 (300 K) and 13.9 MW cm −2 (600 K). The on–off ratio was >10 4 for all temperatures measured. The leakage current showed a good fit to the thermionic field emission model when the reverse voltage was less than 80 V, and it was dominated by the tunneling effect at higher voltage. The transition voltage from thermionic emission to tunneling effect decreased as the temperature increased. At high reverse voltage, a large number of electrons are injected into the drift region, and the current shows an I ∝ V n relationship with voltage, indicating a trap-assisted space-charge-limited conduction (SCLC) mechanism. We observed this SCLC relation when the reverse voltage was larger than 400 V for 500 and 600 K. The associated trap energies for these two regions were extracted as 0.2 and 0.4 eV, consistent with levels in the gap.