Accelerated Life Testing and Fault Analysis of High-Power LED

The quality assessment and reliability improvement of high-power light-emitting diodes (LEDs), which are used in lighting applications, are important. Conventional lifetime testing for LEDs lasts approximately 6000 h. Accelerated life testing (ALT) to quickly assess LED quality and faults is essential for the mass production of LEDs. This paper conducted a systematic nondestructive fault analysis for the ALT of LEDs to effectively detect defect growth. A nondestructive z-scan analysis revealed the defects across the LED cross section (top-bottom); these defects were consistent with the results of destructive focused ion beam analysis. The results showed that parasitic series resistance degrades LED performance and that it ranges from 1.5 to 10.7 Ω under an aging current of 1 A applied for less than 50 h.