【摘要】 利用量子化学的密度泛函理论（DFT）,对AlN的MOCVD生长中表面反应前体MMAl、DMAlNH₂分别在理想、NH₂覆盖AlN（0001）-Al面的吸附进行研究。通过分析表面吸附位、吸附能、分波态密度图等,确定可能的稳定吸附结构和吸附倾向。研究发现:在理想和NH₂覆盖的AlN（0001）-Al面,MMAl吸附在T4位和H₃位,吸附概率相近,MMAl与表面形成3个Al-Als键（理想AlN表面）或3个Al-Ns键（NH₂覆盖的AlN表面）。在理想AlN表面,DMAlNH₂吸附在Top-Top位,与表面形成N-Als键和Al-Als键;在NH₂覆盖的AlN表面,DMAlNH₂吸附在Top位,与表面形成Al-Ns键。对比两种粒子在理想和NH₂覆盖表面的吸附能,发现在理想表面DMAlNH₂的吸附能大于MMAl,即DMAlNH₂优先吸附;在NH₂覆盖表面,MMAl的吸附能明显大于DMAlNH₂,即MMAl优先吸附。更多还原

【Abstract】 Quantum chemistry study with DFT method on surface adsorption of precursors MMAl and DMAlNH₂ on the ideal and NH₂-covered AlN（ 0001）-Al surface in AlN-MOCVD were conducted. By comparing the surface adsorption sites,adsorption energies and partial density of states（ PDOS）,the possible adsorption structure and adsorption tendency were determined. It is found that MMAl is adsorbed at T4 and H₃ sites on both ideal and NH₂-covered AlN（ 0001）-Al surfaces.The adsorption energies are similar,with three Al-Alsbonds（ ideal surface） or Al-Nsbonds（ NH₂-covered surface）.DMAlNH₂ is adsorbed at the Top-Top site（ ideal surface） with both N-Alsbond and Al-Alsbond formed,and at the Top site（ NH₂-covered surface） with an Al-Nsbond. Comparing the adsorption energies of two precursors,on the ideal surface,the adsorption energy of DMAlNH₂ is greater than that of MMAl,and thus DMAlNH₂ is preferentially adsorbed; on NH₂-covered surface,the adsorption energy of MMAl is much greater than that of DMAlNH₂,and thus MMAl adsorption is preferred.更多还原