Electrical characterization of GaN p-n junctions with and without threading dislocations

The effect of dislocations on the electrical characteristics of GaN p-n junctions has been examined through current-voltage measurements. Lateral epitaxial overgrowth (LEO) was used to produce areas of low dislocation density in close proximity to areas with the high dislocation density typical for growth on sapphire. A comparison of p-n diodes fabricated in each region reveals that reverse-bias leakage current is reduced by three orders of magnitude on LEO GaN. Temperature-dependent measurements on the LEO diodes indicate that the remaining leakage current in these devices is associated with a deep trap level. (C) 1998 American Institute of Physics.