Mg in GaN: Incorporation of a volatile species at high temperatures during molecular beam epitaxy

We examine the epitaxial incorporation behavior of the volatile p-type dopant Mg at high growth temperatures during the molecular beam epitaxy of GaN on the [0001] surface, and report interesting doping behavior. The net Mg incorporation is independent of the arriving Mg flux over a flux variation of two decades, and dependent strongly on the growth temperature of the epilayer, limiting the net hole concentrations obtainable to the low 1017 cm-3 range. These results are explained in terms of incorporation either through a surface Mg phase, or via the availability of specific sites on the surface for Mg incorporation. © 1997 American Institute of Physics.