Failure Mechanism for GaN-Based High-Voltage Light-Emitting Diodes

We report a detailed reliability test study on GaN-based high-voltage light-emitting diodes. Under high temperature (i.e., 80°C) and high current injection (i.e., 100 mA) conditions, it was found that Al metal whiskers were formed from the sidewall of the Cr/Al/Ti/Pt/Au p-finger metal after 120-h burn-in test. It was also found that the whiskers became longer as we increased the burn-in time. Furthermore, it was found that the formation of Al whiskers is directly related to Al migration.