High Breakdown Voltage (-201) β-Ga2O3 Schottky Rectifiers

beta-Ga2O3 Schottky barrier diodes were fabricated in a vertical geometry structure consisting of Ni/Au rectifying contacts without edge termination on Si-doped epitaxial layers (10 mu m, n similar to 4x10(15) cm(-3)) on Sn-doped bulk Ga2O3 substrates with full-area Ti/Au back Ohmic contacts. The reverse breakdown voltage, V-BR, was a function of rectifying contact area, ranging from 1600 V at 3.1x10(-6) cm(2) (20-mu mdiameter) to similar to 250V at 2.2x10(-3) cm(-2) (0.53-mm diameter). The current density near breakdown was not strongly dependent on contact circumference but did scale with contact area, indicating that the bulk current contributionwas dominant. The lowest ON-state resistance, R-on, was 1.6 m Omega.cm(2) for the largest diode and 25 m Omega.cm(2) for the 1600-V rectifier, leading to a Baliga figure-of-merit (V-BR(2)/R-on) for the latter of approximately 102.4 MW.cm(-2). The ON-OFF ratio was measured at a forward voltage of 1.3 V and ranged from 3x10(7) to 2.5x10(6) for reverse biases from -5 to -40 V and showed only a small dependence on temperature in the range from 25 degrees C to 100 degrees C.