Radical-beam gettering epitaxy of GaN layers on nitrogen-ion-implanted GaAs substrates

Thin GaN films have been grown on N super(+)-ion-implanted single-crystal GaAs(111) substrates by radical-beam gettering epitaxy, and their structural perfection has been assessed by high-resolution x-ray diffraction. At growth temperatures from 770 to 970 K, the layers consist of hexagonal GaN and have mirror-smooth surfaces. Nitrogen-ion implantation into the substrate favors the formation of a sharp film/substrate interface owing to radiation-enhanced gallium diffusion. Analysis of the GaN/GaAs structures by Auger electron and x-ray photoelectron spectroscopies in combination with depth profiling indicates that the GaN layer is enriched in gallium. The N: Ga atomic ratio in the films is 0.98: 1, which is attributable to radiation-enhanced gallium diffusion.