High Voltage GaN Schottky Rectifiers

Mesa and planar GaN Schottky diode rectifiers with reverse breakdown voltages (V(sub RB)) up to 550V and gt;2000V, respectively, have been fabricated. The on-state resistance, R(sub ON), was 6m(Omega)(centerdot) cm(sup 2) and 0.8(Omega)cm(sup 2), respectively, producing figure-of-merit values for (V(sub RB))(sup 2)/R(sub ON) in the range 5-48 MW(centerdot)cm(sup -2). At low biases the reverse leakage current was proportional to the size of the rectifying contact perimeter, while at high biases the current was proportional to the area of this contact. These results suggest that at low reverse biases, the leakage is dominated by the surface component, while at higher biases the bulk component dominates. On-state voltages were 3.5V for the 550V diodes and(ge)15 for the 2kV diodes. Reverse recovery times were and lt;0.2(micro)sec for devices switched from a forward current density of(approx)500A(centerdot)cm(sup -2) to a reverse bias of 100V