关键词: 大功率LED, 死灯, 暗亮, 失效分析, SiO2保护层

Abstract: The causes of two types of failures in high-power LED project-light lamp, namely, dead and dim lights, are confirmed through failure reproduction. Through testing the semiconductor characteristics of abnormal LED beads, it is determined that these two failure modes are open circuits and leakage circuits. Inspection of the appearance of the open-circuit and leakage LED beads reveals blackening on the same side of the chip position, suggesting a possible burnout on the chip surface. After chemical decapsulation, there are abnormal electrode breakdown, burning and pull off at the cathode position on the die surface of the open-circuit LED beads, and the same abnormal electrode breakdown and burning are found at the finger position on the die surface of the leakage LED beads. The focused ion beam (FIB) and CP-SEM analysis of the die surface of the normal LED beads on the failure board shows that the disconnection of the open bead cathode and the breakdown and burning of the leakage bead finger position are mainly caused by interface void defects at the cathode position and the lack of SiO₂ protective layer around the finger and cathode position.

Key words: high-power LED, dead light, dim light, failure analysis, SiO2 protective layer