Characteristics of Mg-Doped GaN and AlGaN Grown by H2-Ambient and N2-Ambient Metalorganic Chemical Vapor Deposition

Abstract

The characteristics of Mg-doped GaN and AlGaN grown by H2-ambient and N2-ambient metalorganic chemical vapor deposition are compared and discussed. While as-grown Mg-doped GaN and AlGaN grown under H2-ambient show high resistivity, p-type GaN and AlGaN with high acceptor concentration were obtained by N2-ambient growth without any post-treatment. The hydrogenation process of the Mg acceptor and the dissociation process of hydrogen atoms from Mg–H complexes might occur simultaneously in the case of N2-ambient growth. The films grown under N2-ambient were clearly shown to have superior characteristics in uniformity and reproducibility to those grown under H2-ambient, since the characteristics of the films grown under N2-ambient are steady over the wide range of growth temperature. Our results indicate that the N2-ambient growth is suitable for the mass production of GaN-based light-emitting devices in the respects that the device fabrication process can be simplified and that the uniformity and the reproducibility of the layer properties are greatly improved.