High-Voltage Regrown Nonpolar m -Plane Vertical p-n Diodes: A Step Toward Future Selective-Area-Doped Power Switches

We report high-voltage regrown nonpolar m-plane p-n diodes on freestanding GaN substrates. A high blocking voltage of 540 V at ~1 mA/cm2(corresponding to an electric field of E ~ 3.35 MV/cm), turn-ON voltages between 2.9 and 3.1 V, specific on-resistance of 1.7 mΩ·cm2at 300 A/cm2, and a minimum ideality factor of 1.7 were obtained for the regrown diodes. Our results suggest that Si, O, and C interfacial impurity levels up to 2×1017cm-3, 8×1017cm-3, and 1×1019cm-3, respectively, at the metallurgical junction of m-plane, p-n diodes do not result in very early breakdown in the reverse bias although the off-state leakage current in the forward bias is affected. The impact of the growth interruption/regrowth on diode performance is also investigated.