Optical and electrical characterization of reverse bias luminescence in InGaN light emitting diodes

Abstract

This study investigates the reliability physics of the reverse bias luminescence (RBL) of InGaN/GaN light emitting diodes. Optical and electrical characterization techniques including surface temperature measurements, 2D X-ray fluorescent element analysis, and 2D electroluminescence (EL) measurements reveal the leakage current distribution and the origin of the reverse bias leakage current. Using these techniques, this study examines the electroluminescence behavior and surface temperature distribution in forward bias and reverse bias conditions. Results show that the reverse bias EL originates from hot electron-induced emission, which in turn is due to the leakage current in the high electric field region caused by metal contact abnormalities. The optical and electrical characterization techniques adopted in this study are a promising screening tool for correlating device failures with fabrication processes.