High crystalline aluminum nitride via highly enhanced adatom diffusion driven by point defect complex

Abstract While aluminum nitride (AlN) holds the great promise for futuristic optoelectronic applications, the efficient growth of single-crystalline AlN with high crystallinity remains the challenge. We visualize that VAl-3ON point defect complex in aluminum nitride films encourages high crystalline AlN growth by improving adatom diffusivity. Oxygen dopant atoms in nitrogen sites (ON) had the tendency to repel impinging Al adatoms, and the oxygen incorporation was followed by formation of a point-defect complex with Al vacancies (VAl–3ON). This repulsive interaction between ON and Al increased the diffusion length of Al adatoms, thus suppressing the nucleation and encouraging a coherent ripening of AlN. Raman spectroscopy and density functional theory (DFT) calculations jointly revealed that the internal stress in the AlN film and its negative impact on crystallinity have been released by the oxygen incorporation. We expect that this study will be applicable to the fabrication of group III nitride materials with excellent structural properties.