Reliability evaluation of GaN based light-emitting diodes under high-temperature stressing

The reliability evaluation of Light Emitting Diodes (LED) is analyzed by lifetime test, which is usually derived from the accelerated test. In order to find the problem why the LED cannot reach the claimed lifetime, the reliability issue of the LED is investigated by the accelerated temperature tests. One of the accelerated test environment temperature is 55 °C and the environment is an oven, while the other is the room temperature of 23 °C. All the HP-LED samples are driven by the same current 450 mA. Some of the samples in the oven showed the phenomenon of current leakage since 200 hours aging, but the samples in the room temperature did not. In addition, luminous flux of the samples in the oven decreased faster after the same aging period. The HP-LED with current leakage shows faster luminous flux descending. In a word, the degradation behaviors of GaN based light-emitting diodes under high-temperature stressing is investigated.