Study of Mg diffusion during metalorganic chemical vapor deposition of GaN and AlGaN

The diffusion behaviors of Mg in GaN and AlGaN layers are investigated using otherwise undoped GaN test structures containing three Mg-dopant spikes. These simplified structures enable accurate dopant profiling by avoiding the formation of nonplanar V-shaped defects, as confirmed by atomic force microscopy measurements. We also study the Mg distribution in GaN:Mg/AlGaN heterostructures. In all cases, no significant diffusion/segregation behaviors were observed for Mg in nitride material systems at 1060 °C over a 1.25 h time.