Study of high brightness LED samples aged under stress temperature conditions: Electrical characterizations and signature evolution analysis

LED devices used in lighting or backlighting applications are expected to be stable with a long life time. Manufacturers are thus interested in early detection of well-know degradation mechanisms and relationship between electrical signature evolutions and aging in order to predict the end of life of LED devices. This report presents electrical analysis results of four kind of high power LEDs through accelerated aging under temperature stress conditions. The first part of this paper describes the device, the aging protocol used, and the thermal measurements performed to improve and/or quantify the homogeneity. In the second part, I-V and C-V electric characterizations are described using methods to avoid capacitance or temperature warm-ups artifacts. Aging signature of Nichia and thermal influence on I-V measurements of Bridgelux BXRA-W3500 are presented.