Ion-beam synthesis of amorphous gallium nitride

Amorphous gallium nitride (a-GaN) has been synthesized for the first time by implanting gallium into amorphous silicon nitride (a-SiNx) films. The a-GaN is only formed when gallium is implanted into hydrogenated amorphous silicon nitride (a-SiNx:H-y,) films with x > 1.5. The nitrogen concentration,x of the substrate is varied by changing the feed-gas ratio during plasma-enhanced chemical vapour deposition of the nitride film. Using a pre-determined composition and implant condition, the implanted gallium is made to bond with the nitrogen to form a surface layer of a-GaN. Low-temperature annealing, compatible with large-area glass substrates, is then used to increase the thickness of the a-GaN and to transform more of the a-SiNx. X-ray photoelectron spectroscopy and Rutherford back-scattering spectroscopy have been used to examine the bond structure, composition and the depth profile of the synthesized material.