Failure analysis techniques for high power light emitting diodes

As the most promising candidate for the realization of high-efficiency light sources for general lighting, the high power lighting emitting diodes(HP-LEDs) still have reliability issues that hinder the large scale application of LED devices. Nowadays, the reliability is becoming an essential barrier for LED devices to substitute the traditional light sources. Failure analysis is one of the key approaches to improving the reliability of LED products. In this paper, three techniques, namely fluorescent penetrant inspection (FPI), chemical decapsulation and Nano-CT scanning, which are usually applied in other fields, are proposed as major failure analysis tools. Both of their advantages and disadvantages are also recommended, and then combining fluorescent penetrant inspection (FPI) and chemical decapsulation with field scanning electron microscope (FSEM) to analyze the failure modes of one LED sample undergoing 200 thermal shock cycles, and find the fracture of gold wire is attributed to excessive tensile stress of shrink of silicone encapsulations.