Vertical Geometry, 2-A Forward Current Ga2O3 Schottky Rectifiers on Bulk Ga2O3 Substrates

Large area (up to 0.2 cm(2)) Ga2O3 rectifiers without edge termination 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(-4) Omega . cm(2) for 40 x 40 mu m(2) devices. The temperature dependence (25 degrees C-125 degrees C) of forward current density was used to extract the barrier height of 1.08 eV for Ni and a Richardson's constant of 48 A . cm(-2) . K-2. Ideality factors were in the range 1.01-1.05, with the barrier height decreasing with temperature. The reverse breakdown was a strong function of diode area, decreasing from 466 V (1.6 x 10(-5) cm(2)) to 15 V for 0.2 cm(2). This led to power figure-of-merits (V-B(2)/RON) in the range 3.68 x 10(8)-865 W . cm(-2) over this area range. The reverse breakdown voltage scaled approximately as the contact perimeter, indicating it was dominated by the surface and decreased with temperature with a negative temperature coefficient of 0.45 V . K-1. The reverse recovery time when switching from +1 V to reverse bias was 34 ns.