Effect of an oxidized Ni/Au p contact on the performance of GaN/InGaN multiple quantum well light-emitting diodes

Feasibility of an oxidized Ni/Au p contact on some aspects of device applications for a GaN/InGaN multiple quantum well light-emitting diode (LED) was investigated. For the oxidation of Ni/Au p contact, furnace annealing of a completely fabricated LED was performed at 600°C for 5 min in an O₂ ambient. For the case of LED with an oxidized Ni/Au system, the I - V measurements showed a reduction in series resistance of the diode by 17.2%. In addition, the optical output power of the oxidized LED was increased by a factor of 2. However, a significant degradation in reliability characteristics was observed, which might detract from the direct application of the Ni/Au oxidation process. We also conclude that the improvement of oxidized Ni/Au contact properties is mainly due to the formation of an intermediate NiO layer, rather than an enhancement in p-type activation.