Characterization of nitride-based LED materials and devices using TOF-SIMS

Nitride‐based light‐emitting diodes (LEDs) have been developed significantly in terms of both fundamental understanding as well as application, but there are still many new challenges, such as the droop effects and reliability issues, which hinder further progress. SIMS is an important technique and has been widely used to monitor the doping concentrations in the LED multilayers and characterize the layer interface qualities. However, most of them are performed by magnetic sector‐based instruments. In this study, we measured layer structures for nitride‐based LED epilayers using time‐of‐flight SIMS. By changing different surface qualities, the primary ion raster sizes, the oxygen partial pressures, and the optimized conditions to achieve better LED depth profiles were obtained, under which the super lattice structures of AlGaN/GaN and the modulation of Mg atom concentrations can also be clearly distinguished. Copyright © 2014 John Wiley & Sons, Ltd.