大功率GaN基白光LED荧光层失效机理研究  

Failure Mechanism of Phosphor Layer for High-Power GaN-Based White-LED

作　　者：吴艳艳[1] 冯士维[1] 周舟[1] 魏光华[1] 

机构地区：[1]北京工业大学电子信息与控制工程学院,北京100124

出　　处：《激光与光电子学进展》2012年第10期168-173,共6页Laser & Optoelectronics Progress

基　　金：国家863计划(2009AA032704);北京市自然科学基金(4092005)资助课题

摘　　要：在某些情况下长期服役,发现部分白光发光二极管(LED)器件表面出现黑色物质,影响了光的转换和取出。采用切割剖面、扫描电镜(SEM)和能量弥散光谱仪(EDS)等微区分析手段,辅以电流和温度加速应力实验,对部分老化后表面出现变黑现象的芯片进行分析,发现变黑样品的C与Si的原子数比是13.21,高于未变黑样品(8.45)。而有机材料在温度和光照条件下会发生降解碳化,这是LED封装失效的主要原因,与芯片本身无关,验证了高温是最主要的失效因素,光照影响也不可忽略。芯片和封装材料膨胀系数不匹配造成的界面应力、长时间蓝光照射引起的光降解和光热耦合作用造成了器件灾变性失效。The appearance of black zone on the surface of white light-emitting diode （LED） with phosphor layer has greatly affected light conversion and extraction. Using micro-area analytical tools such as cutting section, scanning electron microscope （SEM） and energy dispersive spectrometer （EDS）, the acceleration stress test for current and temperature is carried out and the blacking phenomenon for part of the chip aging surfaces is analyzed. The experimental results show atomic number ratio of C to Si in blackened LED is 13. 21, higher than that of the unchanged （8.45）. There is a main cause about LED encapsulation failure that organic materials can degrade and carbonize in high temperature and lighting conditions, which is verified. And therefore, lighting effect cannot be ignored. But the chip has nothing to do with the failure. Interface stress induced by the mismatch of the expansion coefficient of the chip and packaging materials, photo-degradation and optic-thermal coupling resulted from long time blue-light illumination make the devices disastrously invalid.

关 键 词：光学器件 失效机理 微区分析 发光二极管 芯片变黑 

分 类 号：TN383.1[电子电信—物理电子学]