Enhanced p-type conduction in GaN and AlGaN by Mg-δ-doping

Mg-δ-doping in GaN and AlGaN epilayers has been investigated by metalorganic chemical vapor deposition. It was demonstrated through electrical, optical, and structural studies that Mg-δ-doping improves not only p-type conduction, but also the overall quality of p-type GaN and AlGaN epilayers. A twofold (fivefold) enhancement in lateral (vertical) p-type conduction have been achieved for GaN and AlGaN epilayers. It is argued that the observed dislocation density reduction (of about one order of magnitude) is due to the growth interruption in the Mg-δ-doping duration that partially terminates the dislocation propagation in the growth direction. Furthermore, Mg-δ-doping also reduces Mg impurity self-compensation and enhances hole concentrations in Mg-δ-doped GaN or AlGaN.