Reliability test and failure analysis of high-brightness LEDs from Cree under the various injection currents

In this paper, the reliability and degradation mechanisms of high-brightness LEDs were studied, which were prepared by Cree and currently available on the market. Results revealed that operating currents had an important effect on the service performance of treated LEDs. Only at 350mA the tested LEDs had a good performance; at 750mA and 1000mA, they had the significant degradation; at 2000mA, they had the serious failure of death light within 24 hours. Encapsulant carbonization, delamination and interfacial defects were found to contribute to the degradation of high power LEDs. This study would provide some guidance for the end users as well as some basic data for the current package technique.