High-Breakdown-Voltage and Low-Specific-on-Resistance GaN p-n Junction Diodes on Free-Standing GaN Substrates Fabricated Through Low-Damage Field-Plate Process

In this letter, we describe the characteristics of Gallium Nitride (GaN) p-n junction diodes fabricated on free-standing GaN substrates with low specific on-resistance R-on and high breakdown voltage V-B. The breakdown voltage of the diodes with the field-plate (FP) structure was over 3 kV, and the leakage current was low, i.e., in the range of 10(-4) A/cm(2). The specific on-resistance of the diodes of 60 mu m diameter with the FP structure was 0.9 m Omega.cm(2). Baliga's figure of merit (V-B(2)/R-on) of 10 GW/cm(2) is obtained. Although a certain number of dislocations were included in the device, these excellent results indicated a definite availability of this material system for power-device applications. (C) 2013 The Japan Society of Applied Physics