  InGaN/GaN tunnel junction contacts were grown on top of an InGaN/GaN blue
(450 nm) light emitting diode wafer using plasma assisted molecular beam
epitaxy. The tunnel junction contacts enable low spreading resistance n-GaN top
contact layer thereby requiring less top metal contact coverage on the surface.
A voltage drop of 5.3 V at 100 mA, forward resistance of 2 x 10-2 ohm cm2 and a
higher light output power are measured in tunnel junction LED. A low resistance
of 5 x 10-4 ohm cm2 was measured in a MBE grown tunnel junction on GaN PN
junction device, indicating that the tunnel junction LED device resistance is
limited by the regrowth interface and not by the intrinsic tunneling
resistance.
