发光二极管
材料科学
结温
光电子学
压力(语言学)
二极管
降级(电信)
亮度
加速老化
热的
复合材料
光学
电子工程
气象学
哲学
工程类
物理
语言学
作者
Lorenzo Roberto Trevisanello,Matteo Meneghini,G. Mura,M. Vanzi,M. Pavesi,Gaudenzio Meneghesso,Enrico Zanoni
出处
期刊:IEEE Transactions on Device and Materials Reliability
[Institute of Electrical and Electronics Engineers]
日期:2008-06-01
卷期号:8 (2): 304-311
被引量:155
标识
DOI:10.1109/tdmr.2008.919596
摘要
Short-term accelerated life test activity on high brightness light emitting diodes is reported. Two families of 1-W light-emitting diodes (LEDs) from different manufacturers were submitted to distinct stress conditions: high temperature storage without bias and high dc current test. During aging, degradation mechanisms like light output decay and electrical property worsening were detected. In particular, the degradation in light efficiency induced by thermal storage was found to follow an exponential law, and the activation energy of the process was extrapolated. Aged devices exhibited a modification of the package epoxy color from white to brown. The instability of the package contributes to the overall degradation in terms of optical and spectral properties. In addition, an increase in thermal resistance was detected on one family of LEDs. This increase induces higher junction temperature levels during operative conditions. In order to correlate the degradation mechanisms and kinetics found during thermal stress, a high dc current stress was performed. Results from this comparative analysis showed similar behavior, implying that the degradation process of dc current aged devices is thermal activated due to high temperatures reached by the junction during stress. Finally, the different effects of the stress on two families of LEDs were taken into account in order to identify the impact of aging on device structure.
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