Formation of diluted III–V nitride thin films by N ion implantation

Diluted ${\mathrm{III–N}}_x–{\mathrm{V}}_{\text{1−x}}$ alloys were successfully synthesized by nitrogen implantation into GaAs, InP, and ${\mathrm{Al}}_y{\mathrm{Ga}}_{\text{1−y}}\mathrm{As}.$ In all three cases the fundamental band-gap energy for the ion beam synthesized ${\mathrm{III–N}}_x–{\mathrm{V}}_{\text{1−x}}$ alloys was found to decrease with increasing N implantation dose in a manner similar to that observed in epitaxially grown ${\mathrm{GaN}}_x{\mathrm{As}}_{\text{1−x}}$ and ${\mathrm{InN}}_x{\mathrm{P}}_{\text{1−x}}$ alloys. In ${\mathrm{GaN}}_x{\mathrm{As}}_{\text{1−x}}$ the highest value of x (fraction of “active” substitutional N on As sublattice) achieved was 0.006. It was observed that ${\mathrm{N}}_{\mathrm{As}}$ is thermally unstable at temperatures higher than $\text{850\hspace{0.05em}°}\mathrm{C}.$ The highest value of x achieved in ${\mathrm{InN}}_x{\mathrm{P}}_{\text{1−x}}$ was higher, 0.012, and the ${\mathrm{N}}_{\mathrm{P}}$ was found to be stable to at least $\text{850\hspace{0.05em}°}\mathrm{C}.$ In addition, the N activation efficiency in implanted ${\mathrm{InN}}_x{\mathrm{P}}_{\text{1−x}}$ was at least a factor of 2 higher than that in ${\mathrm{GaN}}_x{\mathrm{As}}_{\text{1−x}}$ under similar processing conditions. ${\mathrm{Al}}_y{\mathrm{Ga}}_{\text{1−y}}{\mathrm{N}}_x{\mathrm{As}}_{\text{1−x}}$ had not been made previously by epitaxial techniques. N implantation was successful in producing ${\mathrm{Al}}_y{\mathrm{Ga}}_{\text{1−y}}{\mathrm{N}}_x{\mathrm{As}}_{\text{1−x}}$ alloys. Notably, the band gap of these alloys remains direct, even above the value of y $\text{(y>0.44)}$ where the band gap of the host material is indirect.