DC and dynamic switching characteristics of field-plated vertical geometry beta-Ga2O3 rectifiers

Abstract

Reverse breakdown voltages larger than 1 kV have been reported for both unterminated Ga2O3 vertical rectifiers (1000-1600 V) and field-plated Schottky diodes (1076-2300 V) with an epi thickness of 8-20 mu m. If the doping is in the 10(16) cm range, the breakdown is usually in the 500-800V regime. Furthermore, the switching characteristics of discrete Ga2O3 vertical Schottky rectifiers exhibited reverse recovery times in the range of 20 to 30 ns. Large area (up to 0.2 cm(2)) Ga2O3 rectifiers were fabricated on a Si-doped n-Ga2O3 drift layer grown by halide vapor phase epitaxy on a Sn-doped n(+) Ga2O3 (001) substrate. A forward current of 2.2 A was achieved in single-sweep voltage mode, a record for Ga2O3 rectifiers. The on-state resistance was 0.26 Omega.cm(2) for these largest diodes, decreasing to 5.9 x 10 Omega.cm(2) for 40x40 mu m devices. We detail the design and fabrication of these devices. In addition, an inductive load test circuit was used to measure the switching performance of field-plated, edge-terminated Schottky rectifiers with a reverse breakdown voltage of 760 V (0.1 cm diameter, 7.85 x10(-3) cm(2) area) and an absolute forward current of 1 A on 8 mu m thick epitaxial beta-Ga2O3 drift layers. These devices were switched from 0.225 A to -700 V with t of 82 ns, and from 1 A to -300 V with t of 64 ns and no significant temperature dependence up to 125 degrees C. There was no significant temperature dependence of t(rr)up to 150 degrees C.