大功率发光二极管的寿命试验及其失效分析

以GaN基蓝光LED芯片为基础光源制备了大功率蓝光LED,并通过荧光粉转换的方法制备了白光LED.对大功率蓝光和白光LED进行了寿命试验,并对其失效机理进行了分析.结果表明,大功率LED的光输出随时间的衰减呈指数规律,缺陷的生长和无辐射复合中心的形成,荧光粉量子效率的降低,静电的冲击,电极性能不稳定,以及封装体中各成分之间热膨胀系数失配引起的机械应力都可能导致大功率LED的失效.

Life Test and Failure Mechanism Analyses for High-power LED

High-power blue light -e mitting diodes were fabricated with the blue LED chips as primary light source,a nd high-power white LEDs were fabricated by phosphor conversion.Life of high-p ower blue and white LEDs was measured,and the failure mechanism was investigated . Results show that the light output of LEDs degrades exponentially with the tim e,the growth of defects and formation of nonradiative recombination centers, qua ntum efficiency reduction of phosphor, the destroy of static electricity, breaka ge of metallization layer and solder instability for flip-chip, and mechanical stress within the LED package caused by the variations in ambient temperature an d self-heating,and so on,will result in the failure for high-power LEDs.