Variation of Electrostatic Discharge Robustness Induced by the Surface Morphology of High Power Light-Emitting Diodes

The capability of high-power nitride-based light-emitting diodes (HPLED) to withstand electrostatic discharge (ESD) is very important key index due to the horizontal structure of the insulating property of the sapphire substrate. Accordingly, the investigation of ESD failure mechanisms is a beneficial topic. However, it is difficult to real-time monitor the damage caused by the ESD stress because it occurred in a very short period. Before the series ESD stress, atomic force microcopy (AFM) and conductive AFM (C-AFM) were applied to explore the correlation between surface morphology and electrical properties of LED chips. Furthermore, after the series ESD stress, transmission electron microscopy (TEM) was used to investigate the failure modes and compare to the distribution of the surface current observed by C-AFM. These findings suggest that the V-shaped defect and surface morphology are strong correlate to the endurance of ESD stress.