The illuminance and temperature distribution degradation of high power GaN LED caused by detachment of multilayer electrode

摘要

In this work, the high power GaN-based unpackaged chip was drive with high current of 600 mA and high temperature of 130 degrees C till failure. A large stain area was found in the main light area of die after degradation and the leakage current increased by tiny range. And the illuminance degraded greatly as shown in distribution map. In the meantime, the temperature rose dramatically. FIB, SEM and TEM characterization demonstrated that the detachment between multilayer metal electrodes was the main cause of the stain area and the degradation of illuminance and temperature, and also the higher junction temperature played a key role in this detachment phenomenon.