Density functional theory study on surface adsorptions in AlN metalorganic vapor phase epitaxy process

By the density functional theory (DFT) study, the adsorptions of the main surface precursors, MMAl and DMAlNH2, on the ideal and NH2-covered AlN(0001)-Al surfaces were investigated for AlN MOVPE process. By comparing the adsorption energies, the Mulliken Populations and the partial density of states (PDOS) for adsorbed atoms at different surface sites, it is found that on the ideal AlN surface, MMAl can be stably adsorbed at T4, H3 or Br sites with similar probabilities; DMAlNH2 can be stably adsorbed at Top-Top or 3Top sites, with dissociative adsorption occurring at the latter site. On the NH2-covered surface, MMAl can be stably adsorbed at T4 and H3 sites with similar probabilities; while DMAlNH2 can be stably adsorbed at only Top site. On the Al-terminated ideal AlN surface, the adsorption of DMAlNH2 is more stable than that of MMAl; while on the N-terminated (NH2-covered) AlN surface, the adsorption of MMAl is much more stable than that of DMAlNH2.

Automated summary

The study found that there are differences in the adsorption positions and stability of MMAl and DMAlNH2 under different surface conditions, with the adsorption on NH2-covered surfaces being more affected.