N-type group III nitride semiconductor stacked layer structure

An n-type Group III nitride semiconductor stacked layer structure comprising a first n-type layer which includes layers containing n-type impurity atoms at a high concentration and layers containing n-type impurity atoms at a low concentration, and a second n-type layer containing n-type impurity atoms at an average concentration smaller than that of the first n-type layer, wherein the layers containing n-type impurity atoms at a high concentration and the layers containing n-type impurities at a low concentration alternately and periodically exist in the first n-type layer and the second n-type layer neighbors the layer containing n-type impurity atoms at a low concentration in the first n-type layer.