Effect of Reflective P-Type Ohmic Contact on Thermal Reliability of Vertical InGaN/GaN LEDs

Abstract

We report on the enhanced thermal reliability of vertical-LEDs (V-LEDs) using novel reflective p-type ohmic contacts with good thermal stability. The reflective p-type ohmic contacts with Ni/Ag-Cu alloy multi-layer structure shows low contact resistivity, as low as 9.3 x 10(-6) Omega cm(2), and high reflectance of 86% after annealing at 450 degrees C. The V-LEDs with Ni/Ag-Cu alloy multi-layer structure show good thermal reliability with stress time at 300 degrees C in air ambient. The improved thermal stability of the reflective ohmic contacts to p-type GaN is believed to play a critical role in the thermal reliability of V-LEDs.