Improved long-term thermal stability of InGaN∕GaN multiple quantum well light-emitting diodes using TiB2- and Ir-based p-Ohmic contacts

In Ga N ∕ Ga N multiple quantum well light-emitting diodes (MQW-LEDs) were fabricated with either Ni∕Au∕TiB2∕Ti∕Au or Ni∕Au∕Ir∕Au p-Ohmic contacts and annealed at 200 and 350°C for 45days. By comparison with companion devices with conventional Ni∕Au Ohmic contacts fabricated on the same wafer, MQW-LEDs with TiB2- and Ir-based Ohmic metallization schemes showed superior long-term thermal stability as judged by the change in turn-on voltage, leakage current, and output power, a promising result for applications where reliable operation at high temperature is required.