Enhanced performance of p-GaN by Mg δ doping

The electrical and structural properties of Mg δ-doped GaN epilayers grown by MOCVD were investigated. Compared to uniform Mg-doping GaN layers, it has been shown that the delta-doping (δ-doping) process could suppress the dislocation density and enhance the p-type performance. The influence of pre-purge step on the structural properties of GaN was also investigated. The hole concentration of p-GaN decreases when using a pre-purge step. These results can be explained convincingly using a simple model of impurity incorporation under Ga-free growth condition.