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

• Published in: Applied surface science Vol. 544; p. 148773
• Main Authors: Lin, Peng, Niu, Nannan, Zuo, Ran, Fang, Yulong, Feng, Zhihong
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.04.2021
• Subjects: AlN; Density functional theory; MOCVD; Surface reaction; Density functional theory; AlN; Surface reaction; MOCVD
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2020.148773

Fig. 6 Adsorption structures of MMAl and DMAlNH2 on the NH2-covered AlN surface: (a) and (b) MMAl adsorbed at T4 and H3 sites with three Alads-Ns bonds formed; (c) DMAlNH2 adsorbed at Top site, with one Alads- Ns bond formed. [Display omitted] •Adsorptions of MMAl and DMAlNH2 on ideal and NH2-covered AlN surfaces are studied.•MMAl can be stably adsorbed at T4, H3 or Br site of ideal surface.•DMAlNH2 can be stably adsorbed at 3Top sites with dissociative adsorption.•MMAl can be adsorbed at T4 or H3 site and DMAlNH2 at Top site on NH2-ended surface.•Adsorption stability of DMAlNH2 is opposite to MMAl on ideal and NH2-ended surfaces. 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.