Over 1.0 kV GaN p-n junction diodes on free-standing GaN substrates

This report describes the fabrication and characteristics of GaN p-n junction diodes on free,standing GaN substrates with low dislocation density. We have demonstrated GaN p-n junction diodes with a unique field-plate (FP) structure. The breakdown voltage V(B) is further imporved due to the FP structure and the low dislocation density. The breakdown voltage of a diode of 60mm in diameter with the FP structure is over - 1000 V, and the leakage current is below 10(-9) A until reaching the breakdown voltage. Even in larger diodes (100 and 200 um in diameter) with FP, the breakdown voltage is over -800V. However, the specific on resistance R(on) is high due to damage by the plasma process of sputtering. The specific on resistance is further imporved due to using a low damage passivation film. As a result, a specific on resistance of 1.2 Omega m.cm(2) is obtained. (C) 2011 WILEY-VCH Verlag Gmbh & Co. KGaA, Weinheim