Acceleration factor analysis of aging test on gallium nitride (GaN)-based high power light-emitting diode (LED)

Abstract

Global warming highlights the effect of light-emitting diodes (LEDs), the advantages of which include lo w pollution and power consumption, as well as a long operation lifetime. However, LED research and development is limited by Illuminating Engineering Society of North America (IES) LM-80-08. This standard reliability test, which is utilized by most LED companies, is time-consuming and prolongs time-to-market. LEDs are degraded by various types of stresses, including temperature, current, and optical stresses. Thus, this study proposes an accelerated aging test for high-power LEDs under different high-temperature stresses without input current. 1-W LEDs based on gallium nitride (GaN) from the same series were obtained as test samples. At the beginning of the accelerated aging test, the device structure is presumably known. This test aims to (i) extrapolate the degradation model to accurately estimate lifetime; and (ii) propose a method to shorten IES LM-80-08 and TM-21-11, which last for a minimum of 6000 h. The results of the accelerated aging test show that sufficiently high-temperature stress effectively shortens the unstable period of the LED chip. During aging, light output degraded as well, and the activation energy of the degradation process was 0.65 eV. This value was obtained by applying the Arrhenius model as the prediction model for the lumen maintenance and temperature of the LED. The LED lifetime estimated by the prediction model varied from that projected by the experimental method by only 10%.